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  • 2000-2004
  • 1990-1994  (11,145)
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  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructural study on human lung in alveolitis versus pulmonary fibrosis (1993)
    Springer
    Journal of molecular medicine 71 (1993), S. 452-460 
    Details
    ISSN: 1432-1440
    Keywords: Electron microscopy ; Alveolitis ; Pulmonary fibrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Lung specimens of 21 patients with diffuse interstitial lung disease were examined. The present ultrastructural study outlines the topography and distribution of inflammatory changes in the interstitium, endothelium, and in pneumocytes and phagocytes. Alveolitis is characterized by marked regenerative activity of type II pneumocytes (cuboid metaplasia), intraluminal macrophage accumulation, endothelial swelling, multilamination of the endothelial basement membrane, pericapillary edema, and primarily by cellular infiltrates in the interstitial space. The most prominent feature of the interstitium in pulmonary fibrosis is the lack of immunoinflammatory cells. In some areas there is a marked absence of alveolar lumen while only a small number of macrophages are present in the remaining alveolar lumen. Most of the capillaries in the fibrous septum have been destroyed. Ultrastructural studies of lung biopsies in patients with diffuse interstitial lung disease allow the differentiation between alveolitis and pulmonary fibrosis and thus contribute to a therapeutic decision.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180059
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  • 2
    Electronic Resource
    Electronic Resource
    Intracranial solitary-type infantile myofibromatosis (1993)
    Springer
    Child's nervous system 9 (1993), S. 246-249 
    Details
    ISSN: 1433-0350
    Keywords: Infantile myofibromatosis, solitary type ; Intracranial myofibromatosis ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An unusual case of infantile myofibromatosis of the solitary type occurring in an intracranial location in a 48-day-old female infant is presented. To our knowledge, there are no other descriptions in the literature of infantile myofibromatosis with exclusively intracranial involvement. The immunohistochemical and electron microscopic findings confirm the myofibroblastic origin of the proliferation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00303579
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  • 3
    Electronic Resource
    Electronic Resource
    Carbohydrate distribution and cellular injuries in acid rain and cold-treated spruce needles (1993)
    Springer
    Trees 8 (1993), S. 75-84 
    Details
    ISSN: 1432-2285
    Keywords: Picea abies (L.) Karst ; Freezing injury ; Acid rain ; Carbohydrate histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The cellular structures of acid rain-irrigated needles of several provenances of Norway spruce (Picea abies L. Karst) seedlings were studied after winter experimental freezing. Frost injuries and recovery were characterized by visual damage scoring and classification of mesophyll cell alterations, also using histochemical methods for carbohydrate fluorescent staining. The treatment with-30° C during the late dormancy period was sufficient to cause significant injuries and intracellular degradation in the tissues of the green needles. The most affected seedlings in terms of visual injury scoring were found among those treated with clean water or at pH 3, while freezing injury, defined as an occlusion of phenolic substances in the central vacuole of the mesophyll cells, was most abundant in the needles from spruces irrigated either with clean water or at pH 4 or pH 3. Electron microscopy revealed the details of the injury, e. g. thinning out of the cytoplasm and chloroplast stroma, darkening of the chloroplasts and eventually swelling of the chloroplasts and protoplast. PAS and ConA reactions in the needle tissue revealed intense starch accumulation in the mesophyll and transfusion tissues as early as in March, with a tendency to increase, especially in the untreated needles during the recovery period. Plasma membrane disturbances were indicated by histochemical identification of callose deposits in the mesophyll cell walls, these being most abundant in the acid rain-treated needles. All these findings suggest that freezing at −30° C was more deleterious to the seedlings pretreated with acid or clean water than to those not given additional irrigation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197684
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  • 4
    Electronic Resource
    Electronic Resource
    Response of xylem parenchyma by suberization in some hardwoods after mechanical injury (1993)
    Springer
    Trees 8 (1993), S. 23-30 
    Details
    ISSN: 1432-2285
    Keywords: Wound responses ; Hardwoods ; Xylem parenchyma ; Suberization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Wound responses of xylem parenchyma by suberization were investigated in some hardwoods by light and electron microscopy. Suberized ray and axial parenchyma cells form a distinct boundary around the wound in all investigated species. Vessels and fibres within and close behind the suberized area appeared more or less occluded; vessels in Fagus, Quercus, and Populus contained suberized tyloses, those in Betula and Tilia contained amorphous and fibrillar deposits. A common mechanism for suberin deposition in the parenchyma cells became evident. Cisternae of the endoplasmic reticulum were apparently involved in suberization. Suberin compounds are extruded by cytoplasmic vesicles, which fused with the plasma membrane, in order to release their content. The suberin layer exhibited the typical lamellated structure; cytoplasmic continuity between suberized cells by plasmodesmata was maintained through the suberin layer. Fagus revealed the most intense suberized area as compared with the other species. Within the reaction zone of Fagus and Quercus, some individual ray and axial parenchyma cells exhibited a subdivision into 2 or 3 compartments prior to suberization. Subdivision was achieved by the formation of a primary wall-like layer. Subsequently, the compartments became individually suberized. Wounding during winter did not induce suberization. Also, samples wounded and kept under water during the vegetation period showed no response. The role of suberization in the effectivity of wound-associated compartmentalization is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240978
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  • 5
    Electronic Resource
    Electronic Resource
    Granulomatous reaction and tissue remodelling in the cutaneous lesion of chromomycosis (1993)
    Springer
    Virchows Archiv 422 (1993), S. 285-291 
    Details
    ISSN: 1432-2307
    Keywords: Chromomycosis ; Skin ; Granuloma ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The cell-mediated immune reaction was studied in the cutaneous lesion of chromomycosis, using monoclonal antibodies against polymorphonuclear neutrophils, macrophage and lymphocyte subsets, endothelial and fibroblast cells. In addition, immunostaining of the main degradative enzymes (neutrophil elastase and interstitial collagenase) and certain important cytokines (transforming growth factor-β, tumour necrosis factor-α and interferon-γ) suggested an explanation for the granulomatous reaction and the associated tissue remodelling. The distribution pattern of neutrophils and macrophage subsets, observed by computer-aided image analysis, suggests that the in situ persistence of fungi is the main pathological factor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01608337
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  • 6
    Electronic Resource
    Electronic Resource
    Solitary fibrous tumour of the thyroid: Clinicopathological, immunohistochemical and ultrastructural study of three cases (1993)
    Springer
    Virchows Archiv 422 (1993), S. 491-497 
    Details
    ISSN: 1432-2307
    Keywords: Solitary fibrous tumour ; Mesenchymal tumour ; Thyroid ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We describe three cases of solitary fibrous tumour (SFT) arising from thyroid stroma. Grossly, the tumours were clearly delimited but only partly encapsulated. The following histomorphological growth patterns were observed: bundles of cells in storiform configuration; non-structured bundles; prevalence of fibrous matrix; highly cellular, non-structured; prevalence of loose, non-structured extracellular substance; cellular proliferation and vascular spaces in a haemangiopericytic configuration and a lipomatous component. Immunohistochemical investigation demonstrated intense, diffuse vimentin positivity and focal, less intense actin positivity in all three cases. At electron microscopy we observed a primitive cell of mesenchymal type, with cytoplasm poor in organelles and rich in filaments; this cell sometimes presented differentiation characteristics. SFT is at present the most correct term for the lesions presented here despite some morphological characteristics which differ from cases reported in the literature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606459
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  • 7
    Electronic Resource
    Electronic Resource
    Multiple papillary adenomas of type II pneumocytes found in a 13-year-old boy with von Recklinghausen's disease (1993)
    Springer
    Virchows Archiv 423 (1993), S. 319-322 
    Details
    ISSN: 1432-2307
    Keywords: Multiple papillary adenomas ; Type II pneumocyte ; Von Recklinghausen's disease ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of multiple papillary adenomas of type II pneumocytes is reported. A 13-year-old boy with von Recklinghausen's disease had small nodular lesions in both lungs without symptoms. The biopsied lung contained greyish-white nodules ranging in size from 0.5 to 2 mm. Light microscopic examination revealed cuboidal to low columnar cells arranged in a papillary pattern. Elastic fibres were present in the tumour stroma. Electron microscopically, the cells had osmiophilic lamellar bodies in the cytoplasm and short microvilli along the free border. The tumour cells expressed immunoreactivity for epithelial membrane antigen and surfactant apoprotein antibodies. More than 6 years after open lung biopsy, the patient is well but small nodular shadows can still be identified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606898
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  • 8
    Electronic Resource
    Electronic Resource
    The morphological substrate of autonomic regulation of the bronchial epithelium (1993)
    Springer
    Virchows Archiv 423 (1993), S. 469-476 
    Details
    ISSN: 1432-2307
    Keywords: Ciliary regulation ; Cytoskeleton ; Bronchial epithelium ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Observations of explanted bronchial mucosa show that ciliary function is maintained for 7 days subsequent to explantation. This finding demonstrates that non-neural mechanisms exist which regulate ciliary function. Ultrastructural and immunohistochemical studies both for light and electron microscopy were performed on human bronchial biopsy material and lung resection specimens in order to recognize the morphological substrate of this regulatory mechanism. A complex system of cytokeratin filaments and microtubules radiate through the whole cytoplasm of ciliated cells with direct contact to the nucleus, cilia, microvilli, desmosomes and to the apical terminal adhesive complex. Between the basal bodies and the apical terminal adhesive complex microfilaments can be found. In the apical cytoplasm a dense filamentary network is seen in association with the adhesive complex. These morphological findings indicate that the cytoskeleton of the bronchial epithelium plays a key role in the co-ordination of ciliary function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606537
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  • 9
    Electronic Resource
    Electronic Resource
    Muscle regeneration after exercise-induced myoglobinuria: An electron microscopic study (1993)
    Springer
    Virchows Archiv 423 (1993), S. 91-95 
    Details
    ISSN: 1432-2307
    Keywords: Muscle regeneration ; Myonuclei ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Muscle regeneration was studied by light and electron microscopy in a case of exercise-induced acute myoglobinuria in a young patient with carnitinepalmityl-transferase deficiency. Various stages of regeneration existed in the foci of necrosis scattered throughout apparently normal muscle. Activated satellite cells, myoblasts and myotubes were found, some of them containing myofibrils. Among the cells accumulating in the necrotic fibres, some apparently contained surviving myonuclei. In some fibres of normal size, developing myofibrils were abundant. Surviving myonuclei may be of significance in the reaction of muscle cells after injury.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606582
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  • 10
    Electronic Resource
    Electronic Resource
    In vitro study of the bronchial mucosa duringPseudomonas aeruginosa infection (1993)
    Springer
    Virchows Archiv 423 (1993), S. 39-43 
    Details
    ISSN: 1432-2307
    Keywords: Pseudomonas aeruginosa ; Bacterial adherence ; Bronchial mucosa ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The route of bacterial infection of the lower respiratory tract is generally one of descent subsequent to colonisation of the oral and oropharyngeal mucosa. The interaction betweenPseudomonas aeruginosa (wild type) and the bronchial epithelium was studied in bronchial mucosal probes cultured in tissue culture medium. It was possible to demonstrate that, even after loss of the mucus layer, adherence between the bacteria and the bronchial epithelium does not take place if ciliary function remains intact. Only after mechanical destruction of the bronchial epithelium, in proximity to squamous metaplasia or after loss or malfunction of the cilia of the bronchial epithelial cells was adhesion between bacteria and bronchial epithelial cells or basement membrane demonstrated by electron microscopy. After loss of the cilia following adenovirus-infection, adhesion betweenP. aeruginosa and the bronchial epithelial cells was visible. These results indicate that ciliary function must be of crucial significance in bacterial epithelial colonisation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606430
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  • 11
    Electronic Resource
    Electronic Resource
    Parachordoma: An ultrastructural and immunohistochemical study (1993)
    Springer
    Virchows Archiv 422 (1993), S. 239-245 
    Details
    ISSN: 1432-2307
    Keywords: Parachordoma ; Extraskeletal myxoid chondrosarcoma ; Chordoma ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of parachordoma of the left calf in a 19-year-old Chinese female is reported. The tumour showed multinodular growth pattern and consisted of round or oval tumour cells with abundant eosinophilic cytoplasm and myxoid matrix. Tumour cells formed small nests and sometimes showed concentric arrangement. Physaliferous-like cells and undifferentiated spindle cells were occasionally observed among the cell nests. The myxoid matrix was positive for high-iron diamine stain, indicating the presence of chondroitin 4- and 6- sulphates and keratan sulphate. Ultrastructurally, well-developed rough endoplasmic reticulum, abundant intermediate filaments, microvillous cytoplasmic processes, pinocytic vesicles, and desmosome-like junctional structures were found. Tumour cells were positive for S-100 protein and vimentin, but negative for cytokeratin, epithelial membrane antigen, carcinoembryonic antigen, and desmin. These results are consistent with the definition of parachordoma as a soft tissue neoplasm consisting of cells with histology and ultrastructure similar to those of chordoma cells but with immunohistochemistry similar to that of chondroid tumour cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01621808
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  • 12
    Electronic Resource
    Electronic Resource
    Post-irradiation bladder dysfunction: development of a rat model (1993)
    Springer
    Urological research 21 (1993), S. 383-388 
    Details
    ISSN: 1434-0879
    Keywords: Bladder dysfunction ; Electron microscopy ; Histology ; X-irradiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this research was to establish a small animal model for the functional and morphological study of post-irradiation bladder dysfunction. Young adult female Wistar rats were X-irradiated with single doses of 10, 15, 20 or 25 Gy. Filling cystometry was performed to assess changes in reservoir function: the volume infused to produce a rise in intravesical pressure of 5 cmH2O was calculated as an index of compliance. A biphasic reduction in this index was noted in animals receiving 15–25 Gy; the first reduction developed at about 4 weeks, and the second started at 3–4 months and persisted at 6 months. Bladder tissue was taken at this time (6 months post-irradiation) for morphological study. Histological examination demonstrated an increased mast cell density in the irradiated bladders, but was otherwise non-specific; fibrosis was discernible in only half of the 18 animals studied. Electron microscopy showed focal degeneration of smooth muscle cells, and in some areas there was selective degeneration of unmyelinated axon profiles. The biphasic reduction in the compliance index is consistent with the timing of the symptoms of the acute and late irradiation reactions reported by radiotherapy patients. Changes in axon profiles and mast cell density may be of functional significance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300073
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  • 13
    Electronic Resource
    Electronic Resource
    Two bacteria causing farmer's lung: Fine structure ofThermoactinomyces vulgaris andSaccharopolyspora rectivirgula (1993)
    Springer
    Mycopathologia 121 (1993), S. 143-147 
    Details
    ISSN: 1573-0832
    Keywords: Electron microscopy ; Farmer's lung ; Saccharopolyspora rectivirgula ; Thermoactinomyces vulgaris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The fine structure ofThermoactinomyces vulgaris andSaccharopolyspora rectivirgula is described by transmission electron microscopy. These two bacteria are the most common microbes causing farmer's lung. The fine structure of hyphae, germination of endospores and the details of conidial wall layers ofT. vulgaris, as well as the fine structure of septate hypha and globose, polygonal conidia ofS. rectivirgula are described. The conidial wall ofT. vulgaris consisted of an inner multilayered spore coat, intermediate spore coat and outer spore coat. The findings are important for the investigations to find fragments of these bacteria in the lungs of exposed patients and experimental animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01104069
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  • 14
    Electronic Resource
    Electronic Resource
    Sensory nerve endings in the beak skin of Japanese quail (1993)
    Springer
    Anatomy and embryology 187 (1993), S. 131-138 
    Details
    ISSN: 1432-0568
    Keywords: Beak skin ; Quail ; Free nerve ending ; Merkel nerve ending ; Grandry corpuscle ; Herbst corpuscle ; Ruffini corpuscle ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study is concerned with the distribution and ultrastructure of sensory nerve endings in the beak skin of adult Japanese quail (Coturnix coturnix japonica). The following nerve endings were found: free nerve endings, clusters of dermal Merkel nerve endings, Herbst corpuscles and Ruffmi corpuscles. The latter were found only in the dermis of the tip of the upper beak. The remaining endings were present in the skin of all areas of upper and lower beak. Free nerve endings were supplied by either thin myelinated axons or unmyelinated C-fibers and were localized in the dermis close to the basal layer of the epidermis. Merkel cells formed clusters (up to 50) localized below and between the epidermal cones of the beak skin. Disc-shaped thickenings of nerve endings were squeezed between individual Merkel cells. Small Herbst corpuscles were found in the dermis close to the epidermal cones of the beak skin. Large Herbst corpuscles occurred in deep layers of the dermis. The Ruffmi corpuscles were cylindrical in shape (80 μm × 400 μm) and arranged in groups of up to ten corpuscles. Each corpuscle was surrounded by an incomplete fibrous capsule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00171744
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  • 15
    Electronic Resource
    Electronic Resource
    Giant collagen plaques in Creutzfeld-Jakob disease (1993)
    Springer
    Acta neuropathologica 85 (1993), S. 323-326 
    Details
    ISSN: 1432-0533
    Keywords: Creutzfeld-Jakob disease ; Electron microscopy ; Giant collagen plaques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report two cases of Creutzfeld-Jakob disease with clusters of giant collagen fibers. To our knowledge, these abnormally large collagen fibers have never been described in patients with degenerative diseases of the central nervous system. The significance of the formation of such plaque-like large collagen fibers has as yet not been elucidated. It is felt that these represent a product of the degenerative process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227729
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  • 16
    Electronic Resource
    Electronic Resource
    Giant axonopathy in streptozotocin diabetes of rats (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 42-48 
    Details
    ISSN: 1432-0533
    Keywords: Streptozotocin diabetes ; Electron microscopy ; Giant axonopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of peripheral sensory nerves was investigated in adult Wistar rats suffering from experimental diabetes mellitus 6 and 10 weeks after the injection of streptozotocin. Giant axons were seen in sections from the nerves of streptozotocintreated rats; some contained masses of neurofilaments, others were predominantly filled with ill-defined vesicles. At the swollen axons, the myelin sheath was thinned or absent. In other regions, large intramyelinic vacuoles were observed. A number of nerve fibers broke down completely and underwent Wallerian degeneration. This was accompanied by Schwann cell proliferation and formation of Büngner bands. Concomitantly with axonal degeneration, nerve regeneration started from intact internodes. The pathomorphology of streptozotocin diabetic neuropathy closely resembles that of some toxic distal axonopathies. This points to a common metabolic basis of giant axonopathies of different etiology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454897
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  • 17
    Electronic Resource
    Electronic Resource
    Pathological and experimental investigations in a case of gigantism (1993)
    Springer
    Acta neuropathologica 85 (1993), S. 167-174 
    Details
    ISSN: 1432-0533
    Keywords: Pituitary adenoma ; Gigantism ; Electron microscopy ; Immunocytochemistry ; Cell culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A pituitary adenoma was transsphenoidally removed from a 4.5-year-old girl suffering from gigantism. Prior to the operation both the growth hormone (GH) and the prolactin (PRL) levels in the serum were elevated. By light microscopy the tumor appeared to be an acidophilic adenoma. Two distinct cell types, the densely granulated and the sparsely granulated cells, could be distinguished by electron microscopy. Double immunolabeling revealed the presence of GH alone in some densely granulated cells and PRL alone in some sparsely granulated cells, as well as GH and PRL co-localized in both of the morphologically distinguished cell types. Both cell types were identified in the monolayer and the suspension cultures by electron microscopy. GH and PRL concentrations in the culture media were measured by radioimmunoassay. The basal secretion of growth hormone was almost uniform during the 3-week cell culture period. GH and PRL release was significantly inhibited by bromocriptine. Our studies revealed a bimorphous and bihormonal mixed adenoma in childhood.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227764
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  • 18
    Electronic Resource
    Electronic Resource
    Dialysis-associated encephalopathy: light and electron microscopic morphology and topography with evidence of aluminum by laser microprobe mass analysis (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 249-258 
    Details
    ISSN: 1432-0533
    Keywords: Dialysis encephalopathy ; Aluminium ; Silver staining ; Laser microprobe ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Recently we described silver-staining variants for the demonstration of β/A4 amyloid and neurofibrillary tangles in senile dementia of Alzheimer type (SDAT). The same methods allowed, for the first time, the visualization of characteristical patterns and distinct morphological changes in human dialysis-associated encephalopathy. Light and electron microscopy demonstrated typical silver-stained inclusions in the cytoplasm of choroidal epithelium, glia and neurons. Performing laser microprobe mass analysis on en-bloc silver-stained semithin sections, evidence for significant amounts of aluminum was obtained within the lesions. Prominent aluminum-signals were obtained additionally in adjacent structures and nuclei of sections which were stained with toluidin-blue exclusively. Silver-stained paraffin sections of ten patients with a history of long-term hemodialysis were evaluated. The choroidal epithelium-obviously the most sensitive structure-showed black inclusions ranging from a few dots to a complete black staining of cells. Glial cells presented massive silver-stained deposits, which were restricted to the gray matter. Finally, neurons revealed numerous fine-granular black inclusions, scattered throughout the cytoplasm. Brain stem nuclei were primarily affected, but neurons within cortex, subcortical gray matter and spinal cord were also involved to various degrees; inclusions were not evident in the nucleus dentatus and the oliva inferior. Vessel-related deposits were found frequently. By electron microscopy the cytoplasm of neurons was filled either with large amounts of small electron-dense granules, or with lipofuscin granules, containing numerous irregular, non-membrane-bound inclusions. Massive electron-dense depositions were seen in the cytoplasm of choroidal epithelia and in proximity to nuclei of cortical astro- and oligodendroglia. The described neuronal changes and, in particular, alterations of choroidal epithelium and glia are completely different from characteristic plaques and tangles in SDAT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00304139
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  • 19
    Electronic Resource
    Electronic Resource
    Detection of human papillomavirus type 2a DNA in verrucae vulgares by electron microscopic in situ hybridization (1993)
    Springer
    Archives of dermatological research 285 (1993), S. 255-260 
    Details
    ISSN: 1432-069X
    Keywords: Human papillomavirus ; In situ hybridization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Electron microscopic in situ hybridization (EMISH) of common warts (verrucae vulgares) of the hands was performed using a biotinylated human papillomavirus type 2a (HPV-2a) DNA probe and immunogold labelling of ultrathin sections of 2% glutaraldehyde-fixed, Lowicryl K4M-embedded tissues. It was first established that the warts contained HPV-2a DNA by light microscopic in situ hybridization. The HPV-2a probe chiefly labelled cells in the horny, granular and upper spinous layers of the epidermis, and labelling decreased towards the basal cell layer. The gold particles were located precisely on the viral particles in the nuclei of granular cells. The lower limit of detection by EMISH was found to be the keratinocytes of the third cellular layer above the basal cells. These keratinocytes showed evidence of a viral cytopathic effect, suggesting that vegetative DNA replication in infected keratinocytes occurs at least as early as this level of the epidermis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371593
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  • 20
    Electronic Resource
    Electronic Resource
    Electron microscopy of calcification during high-density suspension culture of chondrocytes (1993)
    Springer
    Calcified tissue international 53 (1993), S. 127-134 
    Details
    ISSN: 1432-0827
    Keywords: Chondrocytes ; High-density suspension culture ; Electron microscopy ; Matrix vesicle ; Apatite formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Chondrocyte cultures grown in centrifuge tubes with intermittent centrifugation differentiate into hypertrophic chondrocytes and form calcification. We examined chondrocytes cultured in this system electron microscopically. Rat growth-plate chondrocytes were seeded in a plastic centrifuge tube and cultured in the presence of Eagle's minimum essential medium supplemented with 10% fetal bovine serum and 50 μg of ascorbic acid per ml. Specimens were examined by using electron microscopy and selected-area electron-diffraction techniques. In the early stage of culture, a few chondrocytes were scattered and extracellular matrices were not observed. In the middle stage of the cultures, the chondrocytes resembled proliferative cells. Matrix vesicles appeared to be budding from the cell surfaces of chondrocytes and were observed sparsely in the extracellular matrices, which were well formed around the chondrocytes. Matrix vesicles increased substantially during the following cultures. In the mature stage of the cultures, crystal formation related to matrix vesicles was observed. In the 33-day cultures, several masses of calcified matrix were formed and it was confirmed to be apatite by selected-area electron diffraction analysis. The chondrocytes appeared hypertrophic during this same stage. The 56-day culture was similar to the 33-day culture. It was concluded that this culture system provides an extracellular-matrix mineralization which is produced by chondrocytes per se.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01321891
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  • 21
    Electronic Resource
    Electronic Resource
    Cellular location, activity states, and macromolecular organization of glucoamylase in Clostridium thermosaccharolyticum (1993)
    Springer
    Archives of microbiology 160 (1993), S. 284-287 
    Details
    ISSN: 1432-072X
    Keywords: Bacterial glucoamylase ; Clostridium thermosacharolyticum ; Cellular location ; Activity states ; Macromolecular organization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By application of immunocytochemical techniques at the electron microscope level, glucoamylase was localized to the cell periphery in Clostridium thermosaccharolyticum during and following growth on starch, sucrose or glucose. Levels of immunolabelling were found to be relatively independent of growth substrate and of phase of growth, whereas previous studies had demonstrated strong dependence of glucoamylase activity on growth conditions; previously high levels of glucoamylase activity had been detected after growth on starch (i.e. during the stationary phase after growth) and only very low activities detected during exponential growth and following growth on glucose. The results presented demonstrate that levels of the glucoamylase protein are independent of measurable enzyme activity, and imply that the protein is constitutive. This indicates that the protein can exist in active and inactive states in the cell. By analogy with similar systems, we consider it likely that “maturation” or “activation” of newly synthesized glucoamylase occurs during (or following) transport through the cytoplasmic membrane. Electron microscopy of individual protein molecules which had been subjected to negative staining revealed that the enzyme consists of two domains of approximately equal size which are linked by a “hinge” region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292078
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  • 22
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of cellular compartments involved in secretion of the low molecular weight, alkaline xylanase by Trichoderma reesei (1993)
    Springer
    Archives of microbiology 159 (1993), S. 417-422 
    Details
    ISSN: 1432-072X
    Keywords: Trichoderma reesei ; Xylanase ; Ultrastructural localization ; Immunogold labelling ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The intracellular location of the “low-molecular weight, alkaline” xylanase (XYN II) of Trichoderma reesei RUT C-30 was investigated during growth on xylan, using immunoelectron microscopy. A monoclonal antibody, produced against XYN II, was used for this purpose. The enzyme was found at the endoplasmic reticulum and in electron dense 0.2 to 0.8 μm vesicles, as well as in the vacuole, at the plasma membrane and in the fungal cell-wall. No staining occured in the cytoplasm, the mitochondria and the nucleus. No Golgi-like structures could be seen. Addition of the carboxylic ionophore monensin blocked xylanase as well as total protein secretion. The results are discussed with respect to XYN II being secreted by T. reesei via a pathway involving the endoplasmic reticulum and secretory vesicles and/or the vacuole.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00288587
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  • 23
    Electronic Resource
    Electronic Resource
    The malonate decarboxylase enzyme system of Malonomonas rubra: evidence for the cytoplasmic location of the biotin-containing component (1993)
    Springer
    Archives of microbiology 160 (1993), S. 126-131 
    Details
    ISSN: 1432-072X
    Keywords: Malonomonas rubra ; Propionigenium modestum ; Malonate decarboxylase ; Methylmalonyl-CoA decarboxylase ; Biotin ; Avidin ; Electron microscopy ; High pressure freezing ; Immunolabeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Malonate decarboxylase of Malonomonas rubra is a complex enzyme system involving cytoplasmic and membrane-bound components. One of these is a biotin-containing protein of Mr 120'000, the location of which in the cytoplasm was deduced from the following criteria: (i) If the cytoplasm was incubated with avidin and the malonate decarboxylase subsequently completed with the membrane fraction the decarboxylase activity was abolished. The corresponding incubation of the membrane with avidin, however, was without effect. (ii) Western blot analysis identified the single biotin-containing polypeptide of Mr 120'000 within the cytoplasm. (iii) Transmission electron micrographs of immuno-gold labeled M. rubra cells clearly showed the location of the biotinyl protein within the cytoplasm, whereas the same procedure with Propionigenium modestum cells indicated the location of the biotin enzyme methylmalonyl-CoA decarboxylase in the cell membrane. The biotin-containing protein of the M. rubra malonate decarboxylase enzyme system was not retained by monomeric avidin-Sepharose columns but could be isolated with this column in a catalytically inactive form in the presence of detergents. If the high binding affinity of tetrameric avidin towards biotin was reduced by destructing part of the tryptophan residues by irradiation or oxidation with periodate, the inhibition of malonate decarboxylase by the modified avidin was partially reversed with an excess of biotin. Attempts to purify the biotin protein in its catalytically active state using modified avidin columns were without success.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00288714
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  • 24
    Electronic Resource
    Electronic Resource
    Ultrastructure of Bacillus pulvifaciens (1993)
    Springer
    Archives of microbiology 159 (1993), S. 114-118 
    Details
    ISSN: 1432-072X
    Keywords: Bacillus pulvifaciens ; Vegetative cells ; Spotes ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ultrastructure of vegetative cells and spores of Bacillus pulvifaciens was studied by CTEM and SEM methods. The vegetative cells are rods, 1.6–4.5 μm long and 0.4–0.6 μm wide, exhibiting typical ultrastructural features of Gram-positive bacteria. The spores are of ellipsoidal shape, 0.6×1.2 μm in size, with six longitudinal ribs reaching up to 130 nm in height. There are satelite ribs on both sides of the longitudinal ribs, reaching up to 20 nm in height. Between the longitudinal ribs, additional transversal ribs were observed in SEM. A special tubular layer, separating the outer and inner coat of the spores, was revealed in ultrathin sections. This layer seems to be a typical ultrastructural feature of Bacillus pulvifaciens spores.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00250269
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  • 25
    Electronic Resource
    Electronic Resource
    Effect of medium composition on the ultrastructure of Lactobacillus strains (1993)
    Springer
    Archives of microbiology 160 (1993), S. 132-136 
    Details
    ISSN: 1432-072X
    Keywords: Lactobacillus ; Medium composition ; Metal cations ; Electron microscopy ; Protoplast-like forms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The growth of some locally isolated Lactobacillus strains forming D(-) or L(+) lactic acid, Lactobacillus helveticus ATCC 15009 and Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 was examined in different media. L. helveticus and Lactobacillus LBL strains formed atypical protoplast-like cells in LAPT medium, sensitive to SDS and proteinase. Specific morphological changes in the cell wall structure of these variants were revealed by transmission and scanning electron microscopy. The effect of glucose and various salts on their appearance was investigated. The prevalent role of metal cations, especially of Mg2+, was established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00288715
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  • 26
    Electronic Resource
    Electronic Resource
    Development of quasi-multicellular bodies of Treponema denticola (1993)
    Springer
    Archives of microbiology 160 (1993), S. 206-213 
    Details
    ISSN: 1432-072X
    Keywords: Treponema denticola ; Spirochetes ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The formation of quasi-multicellular bodies of Treponema denticola was analysed using different electron microscopical methods. These bacteria could develop four different conformations: (i) normal helical forms; (ii) twisted spirochetes, forming plaits; (iii) twisted spirochetes, forming club-like structures; (iv) spherical bodies in different size. Treponemes within spherical bodies, plaits, and clubs proved to be enclosed in a common outer sheath in which the normal arrangement of their axial flagella was lost. The development of the quasi-multicellular bodies starting from the monoforme spirochetes was elucidated and this morphogenetic process is illustrated by a schematic drawing. Factors which might be involved in the induction of the structures are discussed and their possible pathogenetic importance is considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249126
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  • 27
    Electronic Resource
    Electronic Resource
    Ultrastructure of the taste disc in the red-bellied toad Bombina orientalis (Discoglossidae, Salientia) (1993)
    Springer
    Cell & tissue research 272 (1993), S. 59-70 
    Details
    ISSN: 1432-0878
    Keywords: Sensory cells ; Taste organ ; Electron microscopy ; Bombina orientalis, Rana pipiens (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The taste disc of the red-bellied toad Bombina orientalis (Discoglossidae) has been investigated by light and electron microscopy and compared with that of Rana pipiens (Ranidae). Unlike the frog, B. orientalis possesses a disc-shaped tongue that cannot be ejected for capture of prey. The taste discs are located on the top of fungiform papillae. They are smaller than those in Ranidae, and are not surrounded by a ring of ciliated cells. Ultrastructurally, five types of cells can be identified (mucus cells, wing cells, sensory cells, and both Merkel cell-like basal cells and undifferentiated basal cells). Mucus cells are the main secretory cells of the taste disc and occupy most of the surface area. Their basal processes do not synapse on nerve fibers. Wing cells have sheet-like apical processes and envelop the mucus cells. They contain lysosomes and multivesicular bodies. Two types of sensory cells reach the surface of the taste disc; apically, they are distinguished by either a brush-like arrangement of microvilli or a rod-like protrusion. They are invaginated into lateral folds of mucus cells and wing cells. In contrast to the situation in R. pipiens, sensory cells of B. orientalis do not contain dark secretory granules in the perinuclear region. Synaptic connections occur between sensory cells (presynaptic sites) and nerve fibers. Merkel cell-like basal cells do not synapse onto sensory cells, but synapse-like connections exist between Merkel cell-like basal cells (presynaptic site) and nerve fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323571
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  • 28
    Electronic Resource
    Electronic Resource
    Neural structures in the receptive field of pleural ganglion mechanosensory neurons of Aplysia californica (1993)
    Springer
    Cell & tissue research 273 (1993), S. 487-497 
    Details
    ISSN: 1432-0878
    Keywords: Neurons ; Immunofluorescence ; Tubulin ; Electron microscopy ; Chemoreceptors ; Mechanoreceptors ; Aplysia californica (Mollusca)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The peripheral processes of the mechanoafferents that, when stimulated, initiate the much-studied tail withdrawal reflex of Aplysia californica have not been characterized. We show that immunofluorescence staining for class III β-tubulin highlights neurons and reveals nerve tracts and fine neuronal processes in Aplysia tissue. Coupled with transmission and scanning electron microscopy, class III β-tubulin immunofluorescence is consistent with the possibility that mechanoafferents in the receptive field of pleural ganglion mechanosensory neurons penetrate the tail epidermis and terminate as ciliated endings. This view is reinforced by comparisons among neuronal processes in several mechanosensory epidermal regions and in a chemosensory epidermis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333703
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  • 29
    Electronic Resource
    Electronic Resource
    Isolated brush cells of the rat stomach retain their structural polarity (1993)
    Springer
    Cell & tissue research 271 (1993), S. 47-57 
    Details
    ISSN: 1432-0878
    Keywords: Brush cells ; Cell isolation ; Stomach ; Polarity ; Light microscopy ; Electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The brush cells (BC) are highly polarized elements occurring in epithelia of endodermal origin. They have a preferential topographical distribution in the organs in which they reside. In the stomach of the rat, BC prevail near the transitional zone separating the forestomach from the glandular stomach. Thus, a method was developed to isolate and recover BC from this organ with the aim of investigating the changes they may undergo after dissociation. Strips of the rat stomach were severed from the very proximal border of the glandular region and incubated in Hanks' balanced salt solution containing pronase. After sedimentation of the dissociated cells (crude sediment containing all stomach epithelial cell types) two successive cell fractions were prepared on preformed Percoll gradient in an attempt to enrich BC in a defined layer. BC were recovered in a fraction at a density close to 1.03 g/ml where they represented about 2% of all cells. The isolated BC changed their form from columnar to pear-shaped; however, they maintained their structural polarity over 2 h as demonstrated by light microscopy, transmission-and scanning-electron microscopy. The fine structure of BC was always satisfactorily preserved. Maintenance of the structural polarity of isolated BC is contrary to the general rule according to which all conventional epithelial cells examined to date lose their polarity after isolation. This result is discussed in relation to morphological findings in isolated sensory cells (hair cells, photoreceptor cells) leading to the suggestion that BC are more similar to these than to conventional epithelial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297540
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  • 30
    Electronic Resource
    Electronic Resource
    Cathodoluminescence-emitting lipid droplets in rat testis: a study by analytical color fluorescence electron microscopy (1993)
    Springer
    Cell & tissue research 271 (1993), S. 217-225 
    Details
    ISSN: 1432-0878
    Keywords: Testis ; Electron microscopy ; Cathodoluminescence ; Lipid droplets ; Cholesterol esters ; Vitamin A esters ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Cathodoluminescence (CL) from lipid droplets (LDs) in the rat testis was examined by analytical color fluorescence electron microscopy. The results show that (1) the Cl at wavelengths of 320 nm (CL320) and 450 nm (CL450) is derived from cholesterol esters and a mixture of lipids including vitamin A esters, respectively; (2) CL320 in the LDs of Leydig cells sharply decreases on postnatal day 21, while CL320 and CL450 in the LDs of Sertoli cells begin to be detectable; (3) the CL450-emitting LDs in seminiferous tubules, whose distributional patterns display cyclic changes during the spermatogenic cycle, are involved in spermatogenesis; and (4) the intensity of CL as well as the distributional patterns of CL-emitting LDs in testicular cells change after hypophysectomy, vitamin-A deficiency, and treatment with ethylene dimethane sulfonate and testosterone propionate. This study demonstrates that analytical color fluorescence electron microscopy is a useful tool for in-vivo observation of some specific compounds which cannot be visualized by other methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318608
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  • 31
    Electronic Resource
    Electronic Resource
    Modulation of galanin and neuromedin U-like immunoreactivity in rat corticotropes after alteration of endocrine status (1993)
    Springer
    Cell & tissue research 272 (1993), S. 137-146 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary ; Galanin ; Neuromedin-U ; Corticotropes ; Immunocytochemistry ; Electron microscopy ; Plasticity ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The localization of galanin in rat lactotropes and human corticotropes is well established. Neuromedin U immunoreactivity is present in rat corticotropes but radioimmunoassay of thyroid-manipulated rat pituitaries has also linked it to the thyroid axis. We found galanin immunoreactivity in some rat corticotropes, so we have re-examined rat anterior pituitary galanin- and neuromedin U-like immunoreactivity by use of immunocytochemistry and electron microscopy in rats in the normal state and after estrogen administration or adrenalectomy. In normal rats galanin immunoreactivity was present in a few corticotropes and lactotropes, females showing more than males; neuromedin U-like immunoreactivity was present in some thyrotropes and most corticotropes, in both sexes. Where galanin, neuromedin U and ACTH immunoreactivities were colocalized in corticotropes they were present in the same granules. Estrogen administration caused an increase in number of galanin immunoreactive lactotropes, as previously shown. The proportion of neuromedin U-positive corticotropes was not affected. After adrenalectomy, only females showed a significant increase in the proportion of galanin-positive corticotropes. Neuromedin U immunoreactivity was significantly increased in both sexes, as previously shown. Thus, in rat, as in man, galanin can be present in corticotropes and its expression appears to be sexrelated. This finding, and the demonstration of thyrotrope neuromedin U (only examined in normal females), provide correlation with previous experiments. The influence of endocrine status on the expression of these novel peptides underlines the inherent plasticity of pituitary endocrine cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323579
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  • 32
    Electronic Resource
    Electronic Resource
    Endothelial cell connecting filaments anchor endothelial cells to the subjacent elastic lamina in the developing aortic intima of the mouse (1993)
    Springer
    Cell & tissue research 272 (1993), S. 211-219 
    Details
    ISSN: 1432-0878
    Keywords: Aorta ; Endothelium ; Anchoring filaments ; Microfibrils ; Elastin ; Electron microscopy ; Mouse (C57/BL)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The ultrastructural association of endothelial cells with the subjacent elastic lamina was investigated in the developing mouse aorta by electron microscopy. In the 5-day postnatal aorta, extensive filament bundles extend along the subendothelial matrix connecting the endothelial cells to the underlying elastic lamina. The connecting filaments form lateral associations with the abluminal surface of the endothelial cells in regions of membrane occupied by membrane-associated dense plaques. On the intracellular face of each plaque, the termini of stress fibers penetrate and anchor to the cell membrane in alignment with the extracellular connecting filaments. Both the stress fibers and the connecting filaments are oriented parallel to the longitudinal axis of the vessel. High magnification electron micrographs of individual endothelial cell connecting filaments reveal features similar to those of elastin-associated microfibrils. Each connecting filament consists of a 9–10 nm linear core with an electron-lucent center and peripheral spike-like projections. From the filaments, small thread-like extensions span laterally, linking the filaments into a loose bundle and anchoring them to the endothelial cell membrane and the surface of the elastic lamina. The filaments also appear heavily coated with electron-dense material; often with some degree of periodicity along the filament length. During development, the number of endothelial cell connecting filaments decreases as the elastic lamina expands and the subendothelial matrix is reduced. In the aortic intima of mature mice, the elastic lamina is closely apposed to the abluminal surface of the endothelial cell and no connecting filaments are seen. These observations suggest that endothelial cell connecting filaments are developmental features of the aortic intima which, together with the intracellular stress fibers, aid to maintain the structural integrity of the endothelial cell layer during development by providing the cells with protection from intraluminal shear forces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302726
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  • 33
    Electronic Resource
    Electronic Resource
    Structure-activity relationships in corpora allata of the cockroach Diploptera punctata: roles of mating and the ovary (1993)
    Springer
    Cell & tissue research 274 (1993), S. 279-293 
    Details
    ISSN: 1432-0878
    Keywords: Corpora allata ; Electron microscopy ; Morphometry ; Ovariectomy ; Juvenile hormone ; Cockroach, Diploptera punctata (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Morphometric studies were made on corpora allata of the cockroach Diploptera punctata from animals in which increasing gland size is not coupled to hormone synthesis (ovariectomized mated females; last-instar larvae) and in which gland size is coupled to hormone synthesis (normal mated and virgin females; penultimate-instar larvae). Cell number, gland volume, and juvenile hormone synthesis were measured. From electron micrographs, nuclear, cytoplasmic, and extracellular volumes; and cell membrane area were calculated; and fine structure described. Low-activity glands of ovariectomized mated females resembled high-activity glands from mated females in high cell number, large overall and cytoplasmic volume, and low nuclear-cytoplasmic ratio; they differed in having organelles typical of low-activity glands, mitochondria with dense matrices and large whorls of smooth endoplasmic reticulum. Inactive lastinstar larval glands resembled mated ovariectomized, female glands in increased cell number and organelles characteristic of inactive glands; however, their nuclearcytoplasmic volume ratio was much higher. Penultimate cytoplasmic volume ratio was much higher. Penultimate larval glands with high activity per cell resembled active glands of normal mated females. Ovariectomy did not change morphometric parameters of virgin female glands; thus mating results in increase in size of adult female glands whereas the growing ovary is needed for changes in mitochondria and endoplasmic reticulum associated with high juvenile hormone synthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318747
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  • 34
    Electronic Resource
    Electronic Resource
    Scanning and transmission electron-microscopic study of peripolar cells in the newborn lamb kidney (1993)
    Springer
    Cell & tissue research 274 (1993), S. 597-604 
    Details
    ISSN: 1432-0878
    Keywords: Peripolar cells ; Juxtaglomerular apparatus ; Cytoplasmic granules ; Exocytosis ; Electron microscopy ; Sheep, newborn
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Scanning and transmission electron microscopy were used to study the ultrastructural characteristics and positions of granulated peripolar cells in newborn lamb kidney. Following tissue fixation by vascular perfusion in situ, the vascular pole region of the glomerulus was exposed for examination by scanning electron micoscopy following removal of the glomerular tuft. Peripolar cells were recognized by their surface morphology enabling their quantification and an assessment of the relationship of their position in the renal cortex. The prominent expression of peripolar cells in this species was confirmed. Almost every vascular pole examined revealed peripolar cells (405 out of 407; 99.5%) and thus, throughout the cortex, the distribution of peripolar cells was the same as the distribution of renal corpuscles. Larger, more protruding peripolar cells were observed in the outer cortical renal corpuscles. The numbers of peripolar cells encircling each vascular pole ranged from 1 to 10. There was no correlation between number of granulated peripolar cells at the vascular pole and the position of the renal corpuscle within the renal cortex. As viewed by transmission electron microscopy, organelles of protein synthesis were abundant in the cytoplasm of peripolar cells. Exocytosis of cytoplasmic granules was observed by both scanning and transmission electron microscopy implying that a process of regulative secretion occurs from these cells. The use of ultrastrural techniques has provided evidence supporting the concept that peripolar cells are prominent in the cuff region of each renal corpuscle of the newborn lamb and further-more that peripolar cells in this species most likely have a secretory function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314558
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  • 35
    Electronic Resource
    Electronic Resource
    Collagen fibrillogenesis in a three-dimensional fibroblast cell culture system (1993)
    Springer
    Cell & tissue research 273 (1993), S. 571-575 
    Details
    ISSN: 1432-0878
    Keywords: Collagen fibril ; Three dimensional cell culture ; Ascorbate ; Aminopropeptide, type I ; Aminopropeptide, type III ; Electron microscopy ; Immunoelectron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The purpose of this study was to follow collagen fibril formation in a newly developed three dimensional cell culture system. Human neonatal foreskin fibroblasts were grown on a nylon mesh in Dulbecco's Modified Eagles Medium (DMEM) supplemented with 10% fetal calf serum and antibiotics. Fibrillogenesis was initiated by the addition of 50 micrograms/ml ascorbate to confluent cultures. Sample meshes were processed for electron microscopy or immuno-electron microscopy. Fibrils ≈20–30 nm in diameter, with 67 nm periodicity, were first detected five days after the addition of ascorbate. As cultures progressed, cells organized into parallel layers between which collagen fibers continued to form and increase in diameter. By day 50, fiber diameter ranged from 30 to 80 nm and large bundles were seen. No collagen fibril formation occurred in control cultures to which no ascorbate was added. However, large amounts of microfibrils were observed. Antibodies against the aminopropeptide of type I procollagen were found to bind to fibrils with diameters less than 34 nm while antibodies against the aminopropeptide of type III collagen bound primarily to fibers which ranged from 35–54 nm in diameter. We believe that this system, which morphologically resembles a normal dermis, will werve as an excellent model for the study of collagen fibrillogenesis.
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    URL: http://dx.doi.org/10.1007/BF00333710
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  • 36
    Electronic Resource
    Electronic Resource
    Some horizontal cells of the bovine retina receive input synapses in the inner plexiform layer (1993)
    Springer
    Cell & tissue research 272 (1993), S. 447-457 
    Details
    ISSN: 1432-0878
    Keywords: Horizontal cells ; Calcium-binding protein ; Synaptie input ; Inner plexiform layer ; Immunoreactivity ; Electron microscopy ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Bovine retinae were stained immunocytochemically with antibodies against the calcium-binding protein, calbindin. Horizontal cells in the outer plexiform layer were heavily labelled. The processes of most horizontal cells were confined to the level of the outer plexiform layer, and the tips of their dendrites were positioned as the lateral elements of the cone triads, viz. the usual mammalian arrangement. However, some of the horizontal cells had additional thick processes descending to branch within the inner plexiform layer, where they were postsynaptic at bipolar cell dyads and where they also received input from amacrine cells. No output synapses of horizontal cells were observed in the inner plexiform layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318551
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  • 37
    Electronic Resource
    Electronic Resource
    Basic fibroblast growth factor-like immunoreactivity in the rat trigeminal sensory system and peri-oral skin with vibrissae (1993)
    Springer
    Cell & tissue research 272 (1993), S. 417-427 
    Details
    ISSN: 1432-0878
    Keywords: Basic fibroblast growth factor ; Trigeminal ganglion ; Immunohistochemistry ; Electron microscopy ; In situ hybridization histochemistry ; Vibrissae ; Hair ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have characterized an antiserum against basic fibroblast growth factor (bFGF) by immunoblot, investigated the location of bFGF-like immunoreactivity (bFGF-IR) in the trigeminal sensory system and perioral skin endowed with vibrissae, and demonstrated the site of bFGF mRNA expression in the vibrissae by in situ hybridization histochemistry. Light-microscopic immunohistochemistry has demonstrated that bFGF-IR is present not only in trigeminal ganglion neurons and their central and peripheral processes, but also in cells of the matrix, external root sheath and papillae of vibrissae and the stratum basale of the stratified squamous epithelium of the skin. Electron microscopy has revealed intense bFGF-IR mainly in cytoplasmic regions, other than the lumen of rough endoplasmic reticulum and the Golgi apparatus, in trigeminal ganglion neurons, in fibroblast-like cells in the papillae, and in capsules of vibrissae. In contrast, actively proliferating and/or differentiating cells in the matrix of vibrissae have intensely stained euchromatin and weakly labeled cytoplasm that, unlike that of the aforementioned cells, contain immunoreaction products in discrete spots less than 100 nm in diameter, implying the generation of different molecular forms of bFGF in cells of the matrix and papillae. Moreover, the accumulation of bFGF in the euchromatin appears to take place in cells at non-mitotic stages (possibly interphases), characterized by a conspicuous nucleolus and well-developed nuclear envelope. A digoxigenin-labeled cRNA probe for the demonstration of bFGF mRNA gives conspicuous hybridization signals mainly in the matrix of vibrissae. These findings suggest that bFGF is involved in the growth and differentiation of matrix cells during certain periods of the cell cycle and that it acts as a non-mitogenic mediator in the adult trigeminal sensory system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318548
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  • 38
    Electronic Resource
    Electronic Resource
    Evidence that an extrahypothalamic pituitary corticotropin-releasing hormone (CRH)/adrenocorticotropin (ACTH) system controls adrenal growth and secretion in rats (1993)
    Springer
    Cell & tissue research 272 (1993), S. 439-445 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal growth ; CRH ; ACTH ; Hypophysectomy ; Electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Within two weeks, hypophysectomy induced in rats a striking decrease in the level of circulating ACTH (the concentration of which was at the limit of sensitivity of our assay system), coupled with a net reduction in the plasma corticosterone concentration and an evident adrenal atrophy. Zona fasciculata, the main producer of glucocorticoids, was decreased in volume, due to a lowering in both the number and average volume of its parenchymal cells. Subcutaneous ACTH infusion (0.1 pmol·min-1), administered during the last week following hypophysectomy, restored the normal blood level of ACTH and completely reversed all effects of hypophysectomy on the adrenals. Subcutaneous infusion for one week with α-helical-CRH or corticotropin-inhibiting peptide (1 nmol·min-1), which are competitive inhibitors of CRH and ACTH, evoked a further significant lowering of plasma corticosterone concentration and markedly enhanced adrenal atrophy in hypophysectomized rats. These findings strongly suggest that an extrahypothalamic pituitary CRH/ACTH system may be involved in the maintenance of the growth and steroidogenic secretory activity of the rat adrenal cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318550
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  • 39
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    Serotoninergic innervation of the alimentary canal of the Colorado potato beetle, Leptinotarsa decemlineata: structural and functional aspects (1993)
    Springer
    Cell & tissue research 273 (1993), S. 475-485 
    Details
    ISSN: 1432-0878
    Keywords: Serotonin ; Alimentary canal, insect ; Stomatogastric neryous system ; Immunohistochemistry ; Bioassay ; Electron microscopy ; Leptinotarsa decemlineata (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Immunohistochemical studies showed that the alimentary canal of Leptinotarsa decemlineata receives serotoninergic innervation from different neurons in the central and stomatogastric nervous system. The foregut is innervated by the frontal ganglion. Four of the 6–8 large neurons present in this ganglion have axons which run to the musculature of the oesophagus, crop, sphincter, and frontal area of the midgut. They are accompanied by axons from neurons in the suboesophageal ganglion, and by axons from as yet unidentified non-immunoreactive neurons in thebrain and/or the ventral nerve cord. The posterior part of the midgut is essentially devoid of serotoninergic innervation. The hindgut is innervated by two large neurons in the caudal tip of the last abdominal ganglion. The axons always run to the circular and longitudinal muscles of the crop, the circular muscles of the sphincter, and the longitudinal muscles of the hindgut. Immunohistochemical electron microscopy suggests that exocytosis of the immuno-labelled vesicles may occur at some distance from the muscle fibres, implying a neurohormonal release of this neurochemical. A bioassay used to demonstrate the type of effect of serotonin on isolated hindguts in vitro, indicated a clear inhibitory effect on spontaneous contractions at concentrations of 10-8–10-5 M. This effect was dose-dependent. Axons found in association with the cryptonephridial system on the hindgut might be involved in the control of diuresis although we have not tested this possibility experimentally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333702
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  • 40
    Electronic Resource
    Electronic Resource
    Diffuse serotoninergic neurohemal systems associated with cerebral and suboesophageal nerves in the head of the Colorado potato beetle Leptinotarsa decemlineata (1993)
    Springer
    Cell & tissue research 273 (1993), S. 327-333 
    Details
    ISSN: 1432-0878
    Keywords: Serotonin (5-HT) ; Neurohemal systems ; Immunohistochemistry ; Electron microscopy ; Targeted release ; Leptinotarsa decemlineata (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We analyzed the anatomy of two diffuse neurohemal systems for serotonin in the head of the Colorado potato beetle Leptinotarsa decemlineata by means of immunohistochemistry. One system is formed by axons from two bilateral pairs of neurons in the frontal margin of the suboesophageal ganglion that enter the ipsilateral mandibular nerve, emerge from this nerve at some distance from the suboesophageal ganglion, and cover all branches of the mandibular nerve with a dense plexus of immunoreactive axon swellings. The other system is formed by axons from two large neurons in the frontal ganglion that enter the ipsilateral frontal connectives, emerge from these connectives, and form a network of axon swellings on the labroforntal, pharyngeal, and antennal nerves and on the surface of the frontal ganglion. Immunohistochemical electron microscopy demonstrated that the axon swellings are located outside the neural sheaths of the nerves and hence in close contact with the hemolymph. We therefore suggest that these plexuses represent extensive neurohemal systems for serotonin. Most immunoreactive terminals are in direct contact with the hemolymph, and other terminals are closely associated with the muscles of the mandibles, labrum, and anterior pharynx, as well as with the salivary glands, indicating that these organs are under serotoninergic control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312835
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  • 41
    Electronic Resource
    Electronic Resource
    Association of two barley yellow mosaic virus (RNA 2) encoded proteins with cytoplasmic inclusion bodies revealed by immunogold localisation (1993)
    Springer
    Protoplasma 173 (1993), S. 113-122 
    Details
    ISSN: 1615-6102
    Keywords: Barley yellow mosaic virus ; Cytoplasmic inclusion bodies ; Electron microscopy ; Hordeum vulgare ; Immunogold labeling ; RNA 2-encoded proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Antisera were raised against the RNA 2-encoded proteins of 28 kDa and 70 kDa of barley yellow mosaic virus (BaYMV) by using the corresponding cDNA sequences of a German isolate for protein overexpression inEscherichia coli BL 21 and subsequent purification. The proposed processing of a 98 kDa precursor polyprotein encoded by the long open reading frame of RNA 2 to two proteins of 28 kDa and 70 kDa could be confirmed by immunoprecipitation of the in vitro transcribed and translated cDNA-clone of RNA 2 and Western blot analysis of fragmentated protein extracts of BaYMV-infected winter barley plants. In situ localisation studies of infected leaf tissue using immunogold labeling techniques for electron microscopy revealed that both viral proteins of BaYMV (RNA 2) were associated with the crystal-like cytoplasmic inclusion bodies. No other parts of the cells and no other inclusions (pinwheelstructures or aggregated virus particles) showed any gold labeling when the 28 kDa and 70 kDa antisera were used. We suppose that both RNA 2-encoded proteins take part in the formation of the crystal-like cytoplasmic inclusion bodies which are the most dominant structures in the cytoplasm of BaYMV-infected tissue. Possible functions of the 28 kDa and 70 kDa protein of BaYMV (RNA 2) are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01379000
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  • 42
    Electronic Resource
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    Ultrastructural studies of the termite (Odontotermes obesus) gut microflora and its cellulolytic properties (1993)
    Springer
    World journal of microbiology and biotechnology 9 (1993), S. 108-112 
    Details
    ISSN: 1573-0972
    Keywords: Electron microscopy ; celluloytic microorganisms ; termite gut
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The major gut microflora colonizing the hind gut of a higher termite,Odontotermes obesus, included morphologically diverse bacteria, both coccoid and rod-shaped, along with spirochaetes, pseudomonads and actinomycetes. Flagellated protozoa were totally absent. When the gut extract was inoculated on plates containing carboxymethyl cellulose or cellobiose, higher numbers of bacteria grew than on plates without cellulosic sources. The gut homogenate exhibited strong hydrolytic activity when carboxymethyl cellulose,p-nitrophenyl-β-d-glucoside or xylan were used as substrate, indicating the role of gut microbiota in the process of cellulose and hemicellulose digestion. Activities were highest in the hind gut, and the paunch was probably the major site of polysaccharide digestion in this higher termite.In vitro cultivation of some of the isolates revealed both cellulase and xylanase activities. To our knowledge, this is the first report on ultrastructural studies of the higher termiteOdontotermes obesus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656529
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  • 43
    Electronic Resource
    Electronic Resource
    Morphological appearances of human lens epithelial cells in culture (1993)
    Springer
    Documenta ophthalmologica 84 (1993), S. 351-363 
    Details
    ISSN: 1573-2622
    Keywords: Cell culture ; Electron microscopy ; Human lens epithelium ; Morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A system for culturing human lens epithelial cells in the laboratory was developed. The morphological appearances of the cells was studied using phase contrast, scanning and transmission electron microscopy. Cell marker studies using monoclonal antibodies to cyto-keratin, vimentin and epithelial membrane antigen were also performed. There was a marked increase in cell size as a function of time in culture. After 3 to 4 weeks cells showed early signs of ageing. By 6 to 8 weeks the majority of the cells had become very irregular in shape and demonstrated irregularities of the plasma membrane and intra-cytoplasmic vacuole formation. The cells stained strongly for vimentin and epithelial membrane antigen. Staining with cytokeratin was somewhat weaker. This culture technique provides us with a suitable model for studying the growth behavior of these cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01215449
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  • 44
    Electronic Resource
    Electronic Resource
    Synovial sarcoma of the hypopharynx in an 11-year-old boy: treatment by partial snpraglottic laryngopharyngectomy (1993)
    Springer
    European archives of oto-rhino-laryngology and head & neck 249 (1993), S. 499-502 
    Details
    ISSN: 1434-4726
    Keywords: Hypopharynx-Synovial sarcoma ; Supraglottic laryngopharyngectomy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Synovial sarcoma in an extra-articular location is a very rare tumor, particularly in relation to childhood tumors. We report our experiences with an 11-year-old boy who suffered from swallowing difficulties caused by a polypoid tumor of the hypopharynx. Biopsy demonstrated a fusocellular carcinoma, while the epithelial components showed cytokeratin and neuron-specific enolase positivity. A correct final diagnosis could only be established by the histology of the surgical preparation following partial laryngopharyngectomy. The presence of spindle cells associated with glandular-like ones proved the synovial character of the tumor. The spindle cells were negative for epithelial marker but were positive for vimentin. S-100 protein positivity could only be demonstrated in the nerve elements encapsulated in the tumor. Ultrastructural examinations confirmed the presence of the different cell types. The spindle cells were rich in intermediate fibers, as demonstrated by electron microscopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00168865
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  • 45
    Electronic Resource
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    The cochlear glomeruli in the modiolus of the guinea pig (1993)
    Springer
    European archives of oto-rhino-laryngology and head & neck 250 (1993), S. 44-50 
    Details
    ISSN: 1434-4726
    Keywords: Cochlear glomeruli ; Guinea pig ; Corrosion casting ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cochlear glomeruli were studied in guinea pigs using scanning electron microscopy of vascular corrosion casts and transmission electron microscopy of tissue sections. Two types of coiled vessels forming the cochlear glomeruli were found in the bony wall of the modiolus. First, upper glomeruli were seen situated in the bony wall next to the scala vestibuli; second, lower glomeruli were located in the osseous spiral lamina just above the spiral ganglion. Upper glomeruli gave rise to radiating arterioles which supplied capillaries of the stria vascularis, while lower glomeruli fed the capillaries of the spiral lamina and limbus. Unlike the main supplying arteries, smooth muscle cells were not present in the walls of the arterioles forming the glomeruli and a peculiar layer of lamellar pericytes was found. The arterioles were strikingly longer than their parent vessels and no autonomic nerves were found in close spatial relationship. Hence, these findings indicate that the cochlear glomeruli serve as efficient devices for reducing cochlear blood pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00176948
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  • 46
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    Electron and fluorescence microscopic investigations on composition and structure of the epithelial basement membrane of the human inferior nasal concha (1993)
    Springer
    European archives of oto-rhino-laryngology and head & neck 250 (1993), S. 401-407 
    Details
    ISSN: 1434-4726
    Keywords: Basement membrane ; Nasal concha ; Nasal mucosa ; Electron microscopy ; Immunofluorescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light and electron microscopic as well as immunohistochemical investigations were performed on the basement membrane (BM) of the nasal mucosa from the inferior nasal conchae of 20 patients, aged 15–50 years. Two of the patients served as controls. Clinical disorders requiring the turbinectomies were hyperplastic nasal inferior conchae (17 patients) and immobile cilia syndrome (1 patient). In all cases light microscopy demonstrated a 10–15 μm thick homogeneous BM underneath an intact epithelium. Electron microscopic findings revealed a typical subepithelial basal lamina (BL). The remaining parts of the BM consisted of single, isolated 25-mm-thick collagenous fibrils. Only a few cells and small unmyelinated nerves occurred in this layer. Immunohistochemical investigations showed BL components (collagen type IV, laminin, nidogen and heparan sulfate proteoglycan) directly underneath the epithelium. Collagen types I, III, V, and VI could also be demonstrated immunohistochemically in the remaining parts of the BM. Collagen type VII was allocated to the anchor filaments beneath the BL. This special BM is presumed to contribute to mechanical stabilization of the epithelium. The significance of the BL and the subepithelial connective tissue for the behavior of the epithelium — e.g. direction of differentiation - are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180386
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  • 47
    Electronic Resource
    Electronic Resource
    Sugar-binding sites with specificity for glucosamine in the guinea pig middle ear mucosa (1993)
    Springer
    European archives of oto-rhino-laryngology and head & neck 250 (1993), S. 412-417 
    Details
    ISSN: 1434-4726
    Keywords: Sugar-binding site ; Guinea pig ; Middle ear ; Lipopolysaccharide ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Glucosamine-binding sites were detected in Lowicryl K4M-embedded guinea pig middle ear mucosa by electron microscopy, using glucosaminyl bovine serum albumin. Incubation of ultrathin tissue sections with gold-labeled glucosaminyl bovine serum albumin (GlcN/BSA/gold) resulted in binding mainly on cilia, microvilli, rough endoplasmic reticulum and nuclei. The sugar binding was not inhibited after ultrathin sections had been digested with trypsin or neuraminidase. Various carbohydrates and glycoconjugates were tested as competitive inhibitors of G1cN/BSA/gold labeling on the tissue sections. The sugar specificity range detected by the glucosamine-binding sites included glucosamine, N-acetylglucosamine, mannose and fucose, whereas N-acetylgalactosamine, galactose and glucose were not detectable. A series of endotoxic substances such as Salmonella minnesota Re595 lipid A complex with BSA and lipopolysaccharides (LPS) derived from Escherichia coli 055: B5 or S. minnesota Re595 also competed with GlcN/BSA/gold binding. This indicates that the lipid A backbone glucosamine or other carbohydrate portions of LPS is a part of the structure recognized by glucosamine binding sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180388
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  • 48
    Electronic Resource
    Electronic Resource
    Frequency dependence of the complex dielectric constant of sodium carboxymethyl cellulose (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 51-61 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Dielektrizitätskonstante (ε′) nd dielektrischer Verlust (ε″) von drei Carboxymethylcellulose-Proben mit verschiedenem Substitutions- und Polymerisationsgrad wurden im Frequenzbereich 0,1 - 10000kHz bei Temperaturen zwischen 10 und 60oC gemessen. Im Gegensatz zu nativer Baumwollecellulose, die zwei Relaxztionsprozesse (β und γ) zeigt, wurde nur jeweils ein Relaxationsprozeß zwischen 0,1 und 1kHz gefundern. Die dielektrischen Eigenschaften hängen dabei nicht nur vo Substritutionsgrad, sondern auch vom gewichtsmittleren Polymerisationsgrad und der Homogenität der Substitution ab.
    Notes: The dielectric constant, ε′, and dielectric loss, ε″, were determined for three solid carboxymethyl cellulose samples having different levels of substitution and different degrees of polymerization over a frequency range of 0.1 - 10 000 kHz at temperatures from 10-60°C. In contrast to the two relaxation processes, γ and β, previously observed in native cotton cellulose, only one relaxation process within a frequency range of 0.1 - 1 kHz was identified. It was found that the dielectric properties do not only depend on the degree of substitution, but also on the weight-average degree of polymerization and uniformity of distribution.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040104
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    An automated high pressure capillary rheometer with hydraulic driveDedicated to Prof. Dr. Otto Vogl on the occasion of his 65th birthday (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 63-71 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wird ein neues Kapillar-Rheometer beschrieben, bei dem der Druck, mit dem die Meßflüssigkeit durch die Kapillaren gepreßt wird, durch eine hydraulische Vorrichtung erzeugt wird. Das Gerät ist voll zautomatisiert und wird durch einen PC gesteuert. Verschiedene Meß-Moden können vorgewählt und dann automatisch ausgeführt werden. Einige vorläufige Ergebnisse an Newtonschen Flüssigkeiten und an Polymerlösungen zeigen das Funktionieren des neuen Rheometers.
    Notes: A new capillary rheometer design is described, in which a hydraulic device is used to produce the pressure driving the sample fluid through capillaries. The device is fully automated and controlled by a PC unit. Various measuring modes can be preselected and are automatically executed. Some preliminary results with New tonian fluids and with polymer solutions show the functioning of the new rheometer.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040105
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  • 50
    Electronic Resource
    Electronic Resource
    A redox reaction mediated by polymeric membranes containing electron carriers (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 73-83 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Naphthochinonderivate wurden als Elektronen- und Protonenüberträger in Polymermembranen für Redoxreaktionen eingesetzt. Eine solche, Vitamin K1 enthaltende Membran, läßt den Oxidations-Reduktions-Prozeß zwischen zwei wäßrigen Lösungen von Eisen(III) cyanid bzw. Natriumdithionit nur ziemlich langsam ablaufen. Ein effektiverer Überträger war Vitamin K3; die Reaktion verlief zunächst rasch, jedoch beiweideerholten Anwendungen immer langsamer, da ein Teil dieses, in senier reduzierten Form wasserlöslichen Überträgers während der Reaktion aus der Membran herausgelöst wurde. 2-Alkyloxy-1,4-naphthochinone wie z.B. das Hexyloxyderivat erwiesen sich als wirksame, die Reaktion unterstützende Elektronen- und Protonenüberträger, und in diesen Fällen führten wiederholte Anwendungen nicht zu Verzögerungen.
    Notes: A redox reaction was mediated by polymeric membranes which contain naphthoquinone derivatives as electron and proton carriers. When such a membrane containing vitamin K1 was placed between two aqueous solutions of potassium ferricyanide and sodium dithionite, the oxidation-reduction of them took place, but the reaction was rather slow. Although vitamin K3 was a more effective carrier and the reaction proceeded fast, the reaction rate decreased in the repeated runs. Since the reduced form of this carrier is slightly soluble in water, a part of the carrier got dissolved in the aqueous phase from the membrane during the reaction. 2-Alkyloxy-1,4-naphthoquinones such as 2-hexyloxy-1,4-naphthoquinone effectively transported electrons and protons through the polymeric membranes, promoting the membrane-mediated reaction; in these cases no retardation was observed in the repeated runs.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040106
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    Zinkacrylat und andere feste Monomere als Vernetzungsmittel für ungesättigte PolyesterNach einem Beitrag zur Tagung der Arbeitsgemeinschaft „Verstärkte Kunststoffe“, Berlin, September 1991. (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 85-89 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The peroxide-initiated copolymerisation of an unsaturated polyester with zinc acrylate, diallyl phthalate prepolymer and a solid vinyl ester resin was investigated. The curing was followed by means of gelation curves and differential scanning calorimetry. The studies showed that zinc acrylate has the highest reactivity.
    Notes: Die Peroxid-initiierte Copolymerisation eines ungesättigten Polyesters mnit Zinkacrylat, Diallylphthalat-Prepolymer und einem Vinylesterharz wurde untersucht. Der Härtungsverlauf wurde anhand der Gelierungskurven und mitels Differentialkalorimetrie verfolgt. Die Prüfungen zeigten, daß Zinkacrylat die größte Reaktivität hat.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040107
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  • 52
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    Copolymers of anionic polymerization of octanelactam with laurolactam. II. Kinetics of isothermal crystallizationPart I cf.1. (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 91-100 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Kinetik der isothermen Kristallisation des anionisch hergestellten Copolyamids PA 8/12 aus ω-Octanlactam (OL) und ω-Laurinlactam (12-Dodecanlactam) (LL) wurde nach der Avrami-Gleichung über den gesamten Zusammensetzungsbereich mittels DSC untersucht. Die Kristallisationsparameter Halbwertszeit (t1/2), Avrami-Index (n), Geschwindigkeitskonstante (k) und Kristallinitätsgrad wurden für verschiedene Kristallisationstemperaturen bestimmt. Eine Beziehung dieser Parameter zur Copolyamidzusammensetzung sowie zu Kristallisations- und Unterkühlungstemperaturen wurde untersucht und die Ergebnisse diskutiert. Desweiteren wurden die Werte de hier behandelten mit denen der in der Literaturgeschriebenen Homopolymeren verglichen.
    Notes: The isothermal crystallization kinetics of the anionic copolyamides of ω-octanelactam (OL) with ω-laurolactam (LL) (nylon-8/nylon-12), covering a wide composition range (0/100 - 100/0 OL/LL, mol/mol), was established according to the Avrami equation by the use of differential scanning calorimetry. The crystallization parameters half-time crystallization (t1/2), Avrami index (n), rate constant (k), and reduced crystallinity were determined for various crystallization temperatures. These parameter values are correlated to the composition of the copolyamides, the crystallization and supercooling temperature, and the results are discussed.Differences in kinetic parameter values between the homopolymers of this paper and those for the hydrolytic nylon-8 and nylon-12 reported in literature were observed and discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040108
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    Possibilities for the formation and characterization of solid-state-structures in aromatic polyoxadiazoles (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 111-118 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Abhängig von den Fällbedingungen tritt Poly(p-phenylen-1,3,4-oxadiazole) in zwei Modifikationen auf. Dies kann sowohl durch FTIR-Spektroskopie als auch mit Röntgenweitwinkelstreuung nachgewiesen werden. In beiden Fällen zeigt jede Modifikation charakteristische Peaks. Bei der Verarbeitung zu Fäden oder Filmen aus Lösungen in konzentrierter Schwefeläure durch Fällen in Wasser wird die im thermodynamischen Ungleichgweicht stehende β-Modifikation erhalten. Unter speziellen Bedingungen ist es möglich, die dreidimensional geordnete Gleichgewichtsstruktur direkt herzustellen. Verarbeitungsprodukte aus dieser α-Modifikation weisen merklich höhere Festigkeiten auf.
    Notes: Depending on the coagulation conditions, poly(p-phenylene-1,3,4-oxadiazole) in the solid state forms two modifications, as can be evidenced by FTIR spectroscopy and by wide-angle X-ray scattering curves (WAXS). In both cases each modification is detectable by characteristic peaks. Processing of fibers or films from solutions in concentrated sulfuric acid by coagulation in water results in the formation of a thermodynamically non-equilibrium form, defined as β-modification. Under special conditions it is possible to obtain the three-dimensionally ordered equilibrium α-structure that leads to processing products with markedly higher tenacities.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040110
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    Zur Optimierung der Synthese von Poly(p-phenylen-1,3,4-oxadiazol) in Oleum (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 101-110 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: By a new technique for the addition of monomers it is possible to increase the reproducibility of the synthesis of poly(1,4-phenylene-1,3,4-oxadiazoles) by one order of magnitude in relation to the known method, measured by the standard deviation of the relative viscosity of polymer solutions in concentrated sulfuric acid. This method leads to polymers with very high molecular weights under markedly milder reaction conditions and in shorter reaction times than by the classic method.The influence of the most important reaction parameters on the reaction rate and equilibrium of the polycondensation was investigated. An [η]/Mw-relation was established based on light-scattering and viscometric investigations of polymer solutions in concentrated sulfuric acid.
    Notes: Die Reproduzierbarkeit der Synthese von Poly(p-phenylen-1,3,4-oxadiazolen) in Oleum Kann durch eine veränderte Monomerzugabetechnik, gemessen an der Standardabweichung der relativen Lösungsviskosität, um eine Größenordunung verbessert werden. Die Polykondensation verläft unter deutlich milderen Bedingungen in kürzeren Reaktionszeiten zu Polymeren mit höheren Molmassen als nach der bekannten Methode.Der Einfluß verschiedener Parameter auf die Reaktionsgeschwindigkeit und das Polykondensationsgleichgewicht wurde eingehend untersucht. Auf der Basis streulicht photometrischer und viskosimetrischer Messungen an Polymerlösungen in konzentrierter Schwefelsäure wurde eine [η]/Mw-Bezeihung ermittelt.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040109
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    Electronic Resource
    Ölfettsäremodifizierte wäßrige Polymethacrylatdispersionen (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 127-137 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Water-borne paints have received greater attention. Existing concepts related to suitable binders are polymethacrylate dispersions crosslinkable by autoxidation. Essential synthesis steps of such dispersions and characteristic properties also of adequate coatings are described.Oil fatty acid structure units are enriched in the shell-region of the dispersed particles and the rest of nearly 30% is localized in the water phase as substituent of a water-soluble copolymer.
    Notes: Wäßrige Anstrichsysteme setzen sich in zunehmendem Maße durch. Als eine Entwicklungsvariante für diesbezüglich geeignete Bindemittel kommen autoxidativ vernet zende Polymethacfrylatdispersionen in Betracht. Es werden wesentliche Schritte der Synthese derartiger Dispersionen un dcharakteristische Eigenschaften auchvon Beschichtungen vorgestellt.Die Ölfettsäurestruktureinheiten sind im Schalenbereich der disperigierten Teilchen angereichert, und sie befinden sich außerden zu etwa 30% in der wäßrigen Phase als Substituenten eines löslichen Copolymeren.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040112
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    Electronic Resource
    Electronic Resource
    A new supertough epoxy formulation with high crosslinking density (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 153-159 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ein hochvernetztes duroplastisches Epoxidharz wurde durch “reactive blending” in Gegenwart von Bisphenol A-Polycarbonat (PC) modifiziert. FTIR-Untersuchungen zeigten, daß der Umsatz nach dem Härtungs- und Nachhärtungsprozeß durch den PC-Anteil im Blend erniedrigt wird. Darüber hinaus wurde beobachtet, daß Bruch festigkeit des Blendsystems mit wachsendem PC-Gehalt merklich steigt. Für die Phasentrennung der Unterschußkomponente während der Vernetzung wurden keine Beweise gefunden.
    Notes: A highly crosslinked thermosetting epoxy resin was modified by a reactive blending process carried out in the presence of bisphenol-A polycarbonate (PC). FTIR spectroscopy investigations demonstrated that the presence of PC in the blend decreases the reactants conversion after the curing and postcuring processes. Moreover, it was found that the fracture toughness of this blend system increases markedly by increasing the PC content in the blend. No evidence of phase separation of the minor component during the crosslinking reaction steps was observed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040114
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  • 57
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    Antibacterial activity of copolymers of trialkyl(4-vinylbenzyl)ammonium chlorides with acrylonitrile (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 119-125 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die antibakterielle Wirkung von Homopolymeren von Cetyldimethyl(4-vinylbenzyl)ammoniumchlorid (VB16), Lauryldimethyl(4-vinylbenzyl) ammoniumchlorid (VB12) und TRimethyl(4-vinylbenzyl)ammoniumchlorid (VB1) und deren Copolymeren mit Acrylnitril wurde untersucht. Alle Homo- und Copolymeren wirkten bei den getesteten Bakterienarten-B. subtilis, S. aureus, E. coli und P. aeruginosa - keimtötend. Besondrs stake Effekte zeigten sich bei gram-positiven B.-subtilis- und S.-aureus-Kulturen. Die keimtötende Wirkung nahim in der Reihe VB16 〉 VB12 ≫ VB1 ab.
    Notes: Homopolymers of cetyldimethyl(4-vinylbenzyl)ammonium chloride (VB16), lauryl-dimethyl(4-vinylbenzyl)ammonium chloride (VB12), and trimethyl (4-vinylbenzyl)ammonium chloride (VB1), and copolymers of these compounds with acrylonitrile were examined for antibacterial activity using B. subtilis, S. aureus, E. coli, and P. aeruginosa. All homopolymers and copolymers showed germicidal action to the bacterias, especially strong action to gram-positive B. subtilis and S. aureus. The strength of the germicidal action of the quaternary ammonium branches was in the order: VB16 〉 VB12 ≫ VB1.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040111
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  • 58
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    Electronic Resource
    Permeation von Gasen in Polymermembranen aus thermoplastischer Stärke (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 161-175 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The permeability of gases in films and membranes of thermoplastic starch (TPS) was investigated. The permeability- and diffusion coefficients were measured with the time-lag method on films on TPS with different plasticizer contents and at different temperatures. The experimentally determined low permeabilities were comparable to those of synthetic polymers available on the market. TPS shows at low water activities permeabilities similar to good gasbarrier materials. With increasing water content - as it is already shown for other hydrophilic polymers - the gasbarrier property of TPS gets lost. Together with earlier works on the structure and the thermodynamical behaviour of the starch, the molecular parameters and their influence on the permeability were discussed.
    Notes: Als Alternative zu den heutigen Massenkunststoffen wurde die Möglichkeit eines Einsatzes von thermoplastischer Stärke (TPS) als Barrierewerkstoff in Filmen und Membranen untersucht. Die Permeations- und Diffusionskoeffizienten wurden mitels der Induktionszeit-Methode an Filmen aus TPS in Abhängigkeit von Temperatur und Weichmachergehalt ermitelt. Die expermentell gefundence gute Gasbarriereeigen schaft der Stärke gegenüber Sauerstoff und Stickstoff wurde durch vergleichende Messungen an Handelsprodukten ergänzt. Die TPS zeigt bei nieedrigen Wassergehalten denhandelsüblichen Barrierepolymeren vergleichbare Gaspermeationsraten. Mit steigen dem Wassergehalt verliert sie- wie die meisten hydrophilen Polymere - ihre Gasbarrierewirkung.Gemeinsam mit früheren Arbeiten über die Struktur und die Eigenschaften von thermoplastischer Stärke wurden die molekularen Parameter und ihr Einfluß auf die Gasdurchlässigkeit diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040115
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    Linear polythioesters, XX. Products of interfacial polycondensation of 4,4′-bis(mercaptomethyl)-biphenyl with some aliphatic and isophthaloyl dichlorides (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 139-152 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch Phasengrenzflächenpolykondensation von 4,4'-Bis(mercaptomethyl)biphenyl mit ausgewählten aliphatischen und isomeren Phthalsäuredichloriden wurden neue Polythioester erhalten.Um die optimalen Bedingungen der Phasengrenzflächenploykondensation zu bestimmen, wurde der Einfluß folgender Faktoren auf die reduzierte Viskosität and die Ausbeute der Polythioester ermittelt: Art der organischen Phase, Konzentration der Reagenzien. Verhältnis der wässeigen zur organischen Phase, Art und Konzentration des HCI-Akzeptors, Reaktionstemperatur und -zeit. Die Polykondensation von Dithiol mit Adipinisäuredichlorid und Isophthalsäuredichlorid wurde als Modellsystem genauer untersucht. Die Polythioesterstrukturen wurden mittels Elementaranalyse, IR-Spektroskopie und Röntgenstrukturanalyse bestätigt. Aus der thermogravimetrischen Analyse wurde die Zersetzungstemperatur, der Gewichtsverlust bei dieser Temperatur und das Maximum der Zersetzungsgeschwindigkeit erhalten. Es wurden weiterhin einige physikalisch-chemische, mechanische und dielektrische Eigenschaften ermittelt. Aufgrund der schlechten Löslichkeit der Polythioester konnten die mittleren Molekulargewichte nicht bestimmt werden.
    Notes: New polythioesters were synthesized by interfacial polycondensation of 4,4'-bis(mercaptomethyl)biphenyl with selected aliphatic and isomeric phthaloyl dichlorides.To determine optimum polycondensation conditions, the influence of the following factors on reduced viscosity and yield were studied: type of organic phase, concentration of reagents, aqueous/organic phase ratio, type and concentration of hydrogen chloride acceptor, rate of acid chloride addition, reaction temperature and reaction time.A thorough examination was carried out only for the polycondensation of dithiol with adipoyl and isophthaloyl dichlorides chosen as a model system. The structures of polythioesters were confirmed by elemental analysis, X-ray analysis and infrared spectroscopy. The temperature of initial decomposition, the percentage of its mass loss, and temperature of the fastest decomposition process from curves of differential and thermogravimetric analysis were determined. Some physicochemical, mechanical and electrical properties were determined. The molecular weights were not measured because of the low solubility of the obtained polythioesters.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040113
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    Chemische Kopplung von Polystyrol und Polybutadien in Schmelzemischungen durch Verwendung eines organischen Sulfonylazids (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 177-189 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Investigations on chemical coupling of heterogeneous polystyrene-polybutadiene blends were carried out using an organic sulfonylazide. The coupling process was realized in the melt mixing process on a laboratory melt kneader. The efficiency of the coupling agent was evaluated by IR-spectroscopical, microscopical, and dynamic-mechanical analysis and by mechanical properties of the blends. The graft copolymers forming in the melt cause an increase of the stress-strain properties and the impact strength of the blends.
    Notes: Es wurden Untersuchungen zur chemischen Kopplung heterogener Polystyrol-Polybutadien-Blends bei Einsatz eines organischen Sulfonylazids während des Schmelzemischens im Laborinnenmischer angestellt. Die Wirksamkeit des Kopplungsagens wurde anhand infrarotspektroskopischer, mikroskopischer und dynamisch-mechanischer Analysen sowie anhand des merchanischen Eigenschaftsbildes der Belends beurteilt. Die sich in der Schmelze bildenden Pfropfcopolymeren führen zu einer Erhöhung der Phasenwechselwirkungen un dami zu einer Verbesserung der Festigkeits- und Zähigkeits-eigenschaften der Blends.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040116
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    Interpenetrierende Polymernetzwerke aus ungesättigten Polyesterharzen und Dian-Dicyanat (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 205 (1993), S. 19-30 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Interpenetrating polymer networks (IPN) were obtained by the simultaneous crosslinking of unsaturated polyester resins and Bisphenol A dicyanate. The copolymerization of the unsaturated polyester with styrene occurred according to the radical mechanism, whereas Bisphenol A dicyanate underwent a cyclotrimerization, thus forming a polytriazine (polycyanurate) network. The IPNs are characterized by elevated glass transition temperature and increased mechanical strength in comparison with corresponding unsaturated polyester resin without Bisphenol A dicyanate.
    Notes: Interpenetrierende Polymernetzwerke (IPN) wurden durch die gleichzeitige Vernetzung ungesättigter Polyesterharze und Dian-Dicyanat erhalten. Die Copolymerisation von ungesättigtem Polyester mit Styrol erfolgte nach dem radikalischen Mechanismus, während das Dian-Dicyanat cyclotrimerisierte, wodurch sich ein Polytriazin(Polycyanurant)- Netzwerk bildete. Die IPN zeichnen sich durch erhöhte Glastemperatur und mechanische Festigkeit im Vergleich zum entsprechenden ungesättigten Polyesterharz ohne Dian-Dicyanat-Zusatz aus.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052050102
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    Zur Bestimmung des Modifikatorgehaltes von Stearinsäure- und Titanat-modifizierten CaCO3-Füllstoffen (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 205 (1993), S. 1-17 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Simultaneous TG/DTA analysis has been used for determination of surface coating of CaCO3-filler with stearic acid (STS) or isopropyl triisostearoyl titanate (titanate). The method has been used for several model samples as well as for commercial fillers with surface coating concentrations of 0-2.7% for stearic acid and 0-4.0% for titanate. A reliable agreement of surface coating concentration of STS determined by simultaneous TG/DTA analysis and C-analysis was achieved if the temperature range of decomposition of the surface-modifying agent was taken into account. This was found for stearic acid between 180 and 450°C (〉1% STS at 500°C) and for titanate between 120 and 450°C (〉 1% titanate at 500°C) from the slopes of the TG- and DTA curves. The mass loss in the range of decomposition is equal to the concentration of surface coating in the case of STS. For titanate-modified fillers an amount of 10% of the mass loss must be added. For determination of surface coating of CaCO3-fillers having higher contents of humidity (〉 0.2%) it is necessary to know this amount, otherwise the STS determination has to be performed by oxidation heat.
    Notes: Zur Bestimmung des Modifikatorgehaltes von Stearinsäure(STS)-bzw. Isopropyltriisostearyltitanat(Titanat)-modifizierten CaCO3-Füllstoffen wurde die simultane TG/DTA-Analyse genutzt. die Methode wurde für Modellproben sowie für verschiedene kommerzielle Füllstoffe mit einem Konzentrationsbereich von 0 - 2,7% STS bzw. 0 - 4% Titanat angewendet. Eine ausreichende Übereinstimmung der Modifikatorkonzentrationen für STS, bestimmt durch simultane TG/DTA-Analyse sowie eine C-Analyse, wird erreicht, wenn der Zersetzungsbereich des Modifikators berücksichtigt wird. Dieser liegt für Stearinsäurezwischen180°C und 450°C (bei STS 〉 1% bei 500°C) und für Isopropyltriisostearyltitanat zwischen 120 und 450°C (Titanat 〉 1% bei 500°C) und wird aus dem Anstieg der TG-bzw. DTA-Kurve erhalten. Der diesem Zersetzungsbereich zuzuordnende Masseverlust entspricht bei STS-modifizierten Füllstoffen dem Stearinsäuregehalt. Bei Titanat-modifizierten CaCo3-Füllstoffen ist ein Betrag von 10% des Masseverlustes hinzuzufügen. Für die Modifikatorgehaltsbestimmung von CaCo3-Füllstoffen, die einen höheren Feuchtigkeitsgehalt (〈 0,2%) aufweisen, ist die Kenntnis dieser Größe notwendig, anderenfalls ist die STS-Bestimmung über die Oxidationswärme zu realisieren.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052050101
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    Announcements (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 204 (1993), S. 191-191 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052040117
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    Removal of methyl orange by systems of insoluble poly(glycidyl methacrylate)-g-tetraethylene-pentamine and -g-polyethyleneimines (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 205 (1993), S. 31-45 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Entfernung von Methylorgane (MO) aus Wasser oder einer Pufferlösung (pH7) durch Adsorption and Reaktionsprodukten von Poly(gylcidylmethacrylat) (PGMA) mit Tetraethylenpentamin oder mit einem Polyethylenimin mit einem Molekulargewicht von 600 (PE1600) wurde untersucht. Das Adsorptionsverhalten läßt sich besser mit der Freundlich-Gleichung als mit der Klotz-Gleichung beschreiben. Adsorptionsgeschwindigkeit und adsorbierte Menge waren in Wasser größer als in der Pufferlösung, in der durch Salzbildung die Adsorption vermindert wird. Die adsorbierte Menge hängt nicht immer von der Menge der an PGMA gebundenen PE1600-Gruppen ab.
    Notes: A study was made of the removal of methyl orange (MO) solutes in water and in a pH 7 buffer solution by the reaction products of insoluble poly(glycidyl methacrylate) (PGMA) with tetraethylenepentamine (TEP) or polyethylenimine (PEI) having molecular weight of about 600 (PEI600). An examination was made of the adaptability of the Freundlich adsorption formula and the Klotz equation to removal behaviour of these polymers, which was noted to conform better to the Klotz equation than to the Freundlich adsorption formula. The removal rate and the amount removed were greater in water than in a pH 7 buffer solution, and decreased due to coexisting salts. The amount removed does not always depend on the amount of PEI600 groups bound to PGMA.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052050103
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    Effect of strain rate and temperature on stress-strain properties of EVA-LDPE blends and the mechanism of strain hardening (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 205 (1993), S. 59-74 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Das Zug-Dehnungs-Verhalten von verschiedenen Blends aus Poly(ethylen-co-vinylacetat) (EVA, 28 wt.-% VA-Anteil) und Polyethylen (LDPE) wurde bei unterschiedlichen Dehnungsgeschwindigkeiten und Temperaturen untersucht. Die Zug-Dehungs-Kurven solcher semikristalliner Polymerblends bestehen aus drei Teilen - elastischer oder Hookescher Bereich, Bereich des Aneinanderabgleitens der Ketten sowie Dehnungshärtungsbereich. Eine Verminderung der Dehnungsgeschwindigkeit bewirkt eine Vergrößerung des Dehnungshärtungsbereiches. Die Erhöhung der Meßtemperatur beeinflußt der Dehnungshärtung bei erhöhten Temperaturen vom Kristallschmelzpunkt der Hauptkomponente des Blends abhängt. Röntgen- und DSC-Untersuchun-gen zeigen, daß die Dehnungshärtung von einer Veränderung der Kristallistruktur in LDPE und LDPE-reichen Blends ausgeht, während sie in EVA und EVA-reichen Blends auf eine induzierte Kristallisation in der amorphen Phase zurückzuführen ist.
    Notes: Stress-strain behaviour of different blends of poly(ethylene-co-vinyl acetate) (EVA) (28 wt.-% VA content) and low density polyethylene (LDPE) is studied under various strain rates and temperatures. It is found that stress-strain plots of such semicrystalline polymer blends consist of three parts, namely, elastic or Hookeian region, region of chain slippage and region of strain hardening. Decrease in strain rate has an increasing effect on the strain hardening region. Increase in measurement temperature adversely affects the whole stress-strain plot. It is apparent from the study that at an elevated temperature the process of strain hardening is dependent on the crystalline melting point of the major component in the blend. The X-ray and DSC studies reveal that the process of strain hardening is mainly due to a change in internal order of crystallites in LDPE and LDPE-rich blends, whereas in EVA and EVA-rich blends it is due to induced crystallization in the amorphous phase.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052050105
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    Effect of structure and composition on physico-mechanical properties of methyl methacrylate/alkyl (meth)acrylate copolymers (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 205 (1993), S. 47-58 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Methylmethacrylat (MMA) mit einem Prepolymergehalt von 6-8% wurde mit unterschiedlichen Anteilen (1-20%) 2-Ethylhexylmethacrylat (EMMA), n-Hexylmethacrylat (HMA), 2-Ethylhexylacrylat (EHA) oder n-Hexylacrylat (HA) copolymerisiert. Aus den erhaltenen Copolymeren wurden Folien hergestellt, an denen der Einfluß der Copolymerstruktur auf Lichtdurchlässigkeit, Dichte und mechanische Eigenschaften ermittelt wurde. zugsfestigkeit and Speichermodul nahmen mit zunehmendem Comonomergehalt ab. Die Dehnung stieg im Fall von MMA/EHA- und MMA/HA-Copolymerfolien mit 15 und 20 Gew.-% Comonomeranteil merklich an. Mittels DMTA wurde die Erweichungstemperatur der Copolymeren bestimmt. Die HDT und die Erweichungstemperatur nahmen unter Biegebelastung mit steigendem Comonomergehalt de Copolymeren ab.
    Notes: The paper describes the fabrication of cast acrylic sheets by copolymerizing a prepolymer syrup of methyl methacrylate (MMA) with varying amounts (1-20 wt.-%) of 2-ethylhexyl methacrylate (EHMA), n-hexyl methacrylate (HMA), 2-ethylhexyl acrylate (EHA) and n-hexyl acrylate (HA). The effect of structure of copolymer on light transmittance, density and mechanical properties was evaluated. Tensile strength and storage modulus decreased with increasing comonomer content. Strain increased significantly in the case of MMA/EHA and MMA/HA copolymer sheets having 15 and 20 wt.-% of comonomer. Softening temperature of copolymer samples was determined using dynamic mechanical thermal analysis. Heat deflection temperature under flexural load and softening temperature decreased with increasing comonomer content in copolymer.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052050104
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    Preparation and properties of silicon-containing copolymers for near-UV resists, IIPart I, cf.12.. Poly[(N-(4-hydroxyphenyl)maleimide)-alt-(p-trimethylsilyl-α-methylstyrene)] (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 205 (1993), S. 75-90 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Poly[(N-(4-hydroxyphenyl)maleimid)-alt-(p-trimethylsilyl-a-methylstryol)] (a-PHTMMS) und einige N-(4-hydroxyphenyl)maleimid-alt-p-trimethylisilyl-a-methylstyrol-enthaltende Copolymere wurden synthetisiert, um mit Diazonaphtochinonsulfonat neue Resists für den nahen UV-Bereich (DNS) zu entwickeln.Durch die kettenversteifende Wirkung der Maleimid-Gruppe wurde eine hohe thermische Stabilität mit einer Glasübergangstemperatur von 240°C und einer Zersetzungstemperatur von 425°C erreicht. Daraus hergestellte lithographische Biler widerstanden noch bei 250°C thermischer Verformung. Die hergestellten siliciumhaltigen Resists wurden auch als oberste Schicht in zweischichtigen Materialien für die Anwendung in der Mikrolithographie untersucht.
    Notes: Poly[(N-(4-hydroxyphenyl)maleimide)-alt-(p-trimethylsilyl-α-methylstyrene)] (α-PHTMMS) and several N-(4-hydroxyphenyl)maleimide -alt-p-α-methylstyrene related copolymers were synthesized for novel positive near-UV resists containing diazonaphthoquinone sulfonate (DNS). The chain-stiffening effect of the maleimide group was responsible for high thermal resistance. Thus, a high glass transition temperature of 240°C and thermal decomposition temperature of 425°C were obtained. Lithographic positive images were obtained which resisted thermal deformation at 250°C. The prepared silicon-containing resists were also used as the top imaging layer of a bilayer resist for microlithographic application.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/apmc.1993.052050106
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    On the polymerization of styrene in the presence of some benzanthrone dyes (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 205 (1993), S. 91-95 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Polymerisation von Styrol in Anwesenheit von Fluoreszenzfarbstoffen, Derivaten des Benzanthrons, wurde untersucht. Die Abhängigkeit der Polymerisationsgeschwindigkeit des Styrols vom Charakter des Farbstoffs wurde ermittelt. Spektrophotometrisch wurde festgestellt, daß 70-80% des Farbstoffs in das Polymere eingebaut werden, ohne daß dies zu einer bedeutenden Veränderung des Molekulargewichts und der Molekulargewichtsverteilung führt.
    Notes: The polymerization of styrene in the presence of some fluorescent dyes, benzanthrone derivatives, has been investigated. The dependence of the polymerization rate of styrene on the character of the dye was determined. It was found spectrophotometrically that 70 - 80% of the dye reacted in the polymerization, thus the coloured fluorescent polymers were obtained. They are resistant to wet treatment and decolouration by solvent. The incorporation of the dye into the polymer chain does not significantly affect the molecular weight and polydispersity of the coloured polymers.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052050107
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    The influence of sepiolite on the dynamic moduli and thermal transition of compatible and incompatible blends based on poly(vinylidene fluoride) (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 205 (1993), S. 97-106 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Im vorliegenden Beitrag wird über die Veränderungen der dynamischen Moduli und der thermiscen Übergänge von Polyvinylidenfluorid in kompatiblen Blends mit Polymethylmethacrylat und in nicht kompatiblen Blends mit Polystyrol berichtet. Die Wirkung des Sepioliths auf die Kompatibilität dieser Blends wurde untersucht.
    Notes: This paper reports on a study of dynamic moduli and thermal transitions of poly(vinylidene fluoride) in compatible blends with poly(methylmethacrylate) and in non-compatible blends with polystyrene. The effects of sepiolite on the compatibility of these blends have been studied.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052050108
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  • 70
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    Improvement of ageing properties of rubber films prepared from radiation-vulcanized natural rubber latex (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 205 (1993), S. 107-115 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Strahlungsvulkanisation von Naturgummilatex (NRL) mit n-Butylacrylat führt bei daraus hergestellten Filmen zu höheren Zugfestigkeiten. Die Alterungseigenschaften von strahlungsvulkanisiertem Naturgummi (RVNRL) wurden in Gegenwart unterschiedlicher Antioxidantien untersucht. Um für die Filme aus RVNRL geeignete Antioxidantien zu finden, wurde die Gelfraktion mit Xylol in Gegenwart von 1-Gew.-% Antioxidans unter einem Luftstrom extrahiert. Antioxidantien, die während der Extraktion einer durch oxidativen Abbau bedingten Verringerung des Gelanteils entgegenwirken, sind für die Alterungssuntersuchungen mit RVNRL geeignet. Es zeigte sich, daß Tris(nonylphenyl)phosphit (Nonflex TNP) und 2,5-Di-tert-amylhydrochinon (Antage DAH) unter 12 getesteten Antioxidantien am effektivsten waren.
    Notes: Radiation-vulcanization of natural rubber latex (NRL) with n-butyl acrylate gives a higher tensile strength for films obtained after casting. The ageing properties of radiation-vulcanized natural rubber in the presence of various antioxidants have been investigated. In order to find out suitable antioxidants for radiation-vulcanized natural rubber latex (RVNRL) films, extraction of the gel fraction was carried out in xylene with 1 wt.-% antioxidant and air bubbling. Antioxidants which give less reduction in gel fraction due to oxidative degradation during extraction are effective for ageing tests of RVNRL films. It was found that tris(nonylated phenyl) phosphite (Nonflex TNP) and 2,5-di-tert-amylhydroquinone (Antage DAH), among 12 different antioxidants tested, were the most effective antioxidants for RVNRL films.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/apmc.1993.052050109
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    Porous ion-exchange membranes, 2Part 1 cf.1.. Effect of adhesion promoters (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 205 (1993), S. 131-139 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Stearinsäure bzw. Dibutylphthalat wurden als Adhäsionsverbesserer zu mit Calciumcarbonat gefüllten ternären Blends, bestehend aus einem Polyethylen/Poly(strol-co-divinylbenzol)-Interpolymeren und Polypropylen, zugegeben. Daraus wurden nach einem bereits beschriebenen Verfahren poröse Ionenaustauschermembranen (PIEM) hergestelt. Die Adhäsionsverbesserer führen dabei zu einer beträchtlichen Erhöhung des Porendurchmessers, da die Diffusion von Chlorsulfonsäure zu den Calciumcarbonatkörnern und damit die Bildung großer Mengen Kohlendioxid erleichtert wird. Andere PIEM-Eigenschaften werden nicht sigifikant beeinflußt.
    Notes: The previously described preparation of porous ion-exchange membranes (PIEM's) from the ternary blends of polyethylene interpolymer with poly(styrene-co-divinylbenzene) and polypropylene and calcium carbonate filler has been supplemented with the use of stearic acid and dibutyl phthalate as adhesion promoters. It was noted that both promoters govern the huge increase of pore diameter without any significant disturbances in the other PIEM's properties. The facilitating effect of chlorosulfonic acid diffusion toward calcium carbonate grains and large amounts of carbon dioxide volatilization was concluded. This is the basic point of pore creation to be discussed in this paper.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/apmc.1993.052050111
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    Macroporous membranes, IV. Synthesis and properties of poly[(2,3-epoxypropyl methacrylate)-co-(N-vinyl-2-pyrrolidone)-co-(ethylene dimethacrylate)] membranesPart III see1. (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 205 (1993), S. 141-149 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Makroporöse Membranen aus Terpolymeren von 2,3-Epoxypropylmethacrylat, N-Vinyl-2-pyrrolidon und Ethylendimethacrylat, wurden durch radikalische Suspensionscopolymerisation hergestellt und danach mit Ammoniak modifiziert. Charakteristische Eigenschaften der Membranen wei Porosität, spezifische Oberfläche, Porengröße, Wasserdurchlässigkeit und mechanische Eigenschaften wurden bestimmt. Ein niedriger Gehalt an N-Vinyl-2-pyrrolidon verbessert die mechanischen Eigenschaften der Membranen. Der Mechanismus der Bildung der makroporösen Struktur und der Heterogenitäten wird diskutiert.
    Notes: Macroporous membranes based on terpolymers of 2,3-epoxypropylmethacrylate, N-vinyl-2-pyrrolidone, and ethylenedimethacrylate were prepared by radical suspension copolymerization and subsequently modified with ammonia. The membranes were characterized by their porosity, specific surface area, pore size, water permeability and mechanical properties. The low content of N-vinyl-2-pyrrolidone improves the mechanical properties of the membranes. The mechanism of formation of the macroporous structure and heterogeneities is discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052050112
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    Photomodifizierung von Ultrafiltrationsmembranen, 2. Ultrafiltrationseigenschaften von mit Arylaziden photochemisch modifizierten Polyacrylnitril-membranenTeile dieser Arbeit wurden präsentiert auf der 23. Hauptversammlung der Gesellschaft Deutscher Chemiker, München, 9.-13.9.1991. Teil 1 cf. Angew. Makromol. Chem. 210 (1993) 69. (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 210 (1993), S. 97-117 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The aim of the studies was to characterize the ultrafiltration properties of a variety of photochemically modified membranes, made by a new approach starting with two types of PAN-UF membranes and using nine aromatic azides bearing different more or less hydrophilic or hydrophobic substituents. The influence of the surface functionalization (hydrophilization, introduction of charges/hydrophobization) realized by this means onto the water permeability, the dextrane selectivity, and the permeabilities during and after UF, resp., after simple contact with solutions of ovalbumine and lysozyme was the major subject. Modified membranes made using the aryl azides with hydrophilic groups, 4-azidobenzoic acid, Ib, (4-azidophenyl)trimethylammonium iodide, If, sodium (4-azido)-benzene sulfonate, Id, showed enhanced water fluxes and reduced dextrane retention. All the other azides caused reduced water permeability, enhanced dextrane selectivity, and significant flux reductions as a consequence of contact with ovalbumin solutions (pH = 5.0). The strongest effects were achieved with the two expecially hydrophobic compounds, 2-naphthyl azide, Ih, and 2-naphthoyl azide, IX. On the other hand, a pronounced positive effect of photo-modification on the protein fouling behaviour became evident in the UF of lysozyme (0.05%, pH = 10.5). Using the membranes modified with Id a much higher filtrate flux (Jv = 48.1 l/m2h) was observed as compared with the original PAN membrane (Jv = 13.1 I/m2h). The perspectives and the limitations of the developed modification strategy are discussed.
    Notes: Nach einem neuartigen Verfahren mit Hilfe von neun, mit verschieden hydrophilen bzw. hydrophoben Substituenten synthetisierten aromatischen Aziden unterschiedlich photochemisch modifizierten Polyacrylnitril-Ultrafiltrations-Membranen wurden in UF-Versuchen charakterisiert. Dabei sollte der Einfluß der so erzielten Oberflächenfunktionalisierungen (Hydrophilierung, Einführung von Ladungen oder Hydrophobierung) auf das Trennverhalten (Wasserdurchläassigkeit und Selektivitäat für Dextrane, Permeabilität während und nach der UF bzw. nach einfachem Kontakt mit Ovalbuminund mit Lysozym-Lösungen) studiert werden. Die Modifizierung mit den Arylaziden, die hydrophile Gruppen enthalten (4-Azidobenzoäure, Ib, (4-Azidophenyl)-tri-methylammoniumiodid, If, Natrium-4-azidobenzolsuflfonat, Id), führt zu einer erhöhten Durchlässigkeit der Membranen für Wasser und Dextrane. Alle anderen Azide, darunter besonders stark die deutlich hydrophoben 2-Naphthoylazid, Ih, und 2-Naphthoylazid, IX, verringern die Wasserpermeabilität, erhöhen das Rückhaltevermögen für Dextrane und verstärken die Effekte der Wechselwirkungen mit Ovalbumin (pH = 5,0). Das wird in Flußreduzierungen verglichen mit der unmodifizierten PAN-UF-Membran sichtbar. Ein positiver Effekt der Photomodifizierung wird besonders deutlich bei der UF von Lyasozym (0,05%, pH = 10,5) mit der mit Id modifizierten Membran (Jv = 48,1 l/m2h) im Vergleich zur Ausgangs-Membran (Jv = 13,1 1/m2h). Die Perspektiven und die Grenzen des Modifizierungsverfahrens werden abschließend diskutiert.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052100108
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    Membranen aus poly(p-phenylen-1,3,4-oxadiazol) (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 210 (1993), S. 197-205 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: For solving specific problems of separation, high demands on membrane materials will be made in relation to thermal stability and resistance in a wide pH-range and against organic solvents. Membranes from poly(p-phenylen-1,3,4-oxadiazole) are prepared by different methods and their separation properties in ultrafiltration are investigated.
    Notes: Poly(p-phenylen-1,3,4-oxadiazol) (POD) ist aufgrund seiner thermischen Stabilität, pH- und Lösungsmittelbeständigkeit ein interessanter Werkstoff zur Herstellung von Membranen. Die Herstellung von POD-Membranen und deren Trenneigenschaften im Prozeß der Ultrafiltration werden untersucht.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052100115
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    Poly(sulfide sulfone) by activated nucleophilic displacement polymerization (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 211 (1993), S. 79-87 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ein Poly(sulfidsulfon) wurde durch aktivierte nucleophile Substitution der Nitrogruppen von Bis(4-nitrophenyl)sulfon mit wasserfreiem Natriumsulfid bei 200 C in N-Methyl-2-pyrrolidon (NMP) hergestellt. Das Polymere löst sich in NMP, Dimethylformamid (DMF), Dimethylsulfoxid und anderen hochpolaren Lösungsmitteln. Das Molekulargewicht des Polymeren mit einer inhärenten Viskosität von 15 ml/g bei 30°C in DMF wurde mittels 1H-NMR-Spektroskopie zu Mn = 2500 bestimmt. Die Glastemperatur liegt bei ca. 73°C; der Veraschungsrückstand bei 600°C in Luft beträgt 36%, der Sauerstoffindex (LOI) ca. 37.
    Notes: A poly(sulfide sulfone) was synthesized by activated nucleophilic displacement reaction between bis(4-nitrophenyl)sulfone and anhydrous sodium sulfide at 200°C in N-methyl-2-pyrrolidone (NMP). The polymer is soluble in NMP, dimethylformamide, dimethylsulfoxide and other highly polar solvents. The molecular weight of the polymer (M̄n = 2.500) having an inherent viscosity of 15 mL/g at 30°C in DMF was determined by 1H-NMR spectroscopy. The polymer has a glass transition at approx. 73°C and char residue of 36% at 600°C in air. The limiting oxygen index of the polymer is ∼37.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052110107
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    Agitation scale-up model for the suspension polymerization of vinyl chloride (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 211 (1993), S. 35-51 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurden Untersuchungen durchgeführt, um ein auf experimentellen Ergebnissen basierendes mathematisches Modell zu entwickeln, welches die Durchmischung und andere Polymerisationsparameter mit der Partikelgröße von PVC korreliert und die Grenzen der Rührgeschwindigkeit in einem definierten Rührersystem festlegt.Dazu wurde eine Computer-Regressionsanalyse von etwa 30 in Reaktoren von 10L bis 27 m3 Volomen durchgeführten Vinylchlorid-Polymerisationen berechnet. Die Partikelgröße (d50) hängt dabei ab von den Polymerisationsparametern Rührerdurchmesser (D), Rührergeschwindigkeit (N), Durchmesser des Reaktorbehälters (T), Flüssigkeitsstand (H1) und Volumen des Reaktorbehälters (V) (NWe = Weber-Zahl): d50 = 4346.8 (N)-0.905 (D)-0.901 (T)-0.514 (H1)-0.131d50/D = 273292.1 NWe-0.51 undNmin = 3049.1 D-1.1 (T/D)-0.113In diesen Gleichungen sind nur die Werte 3049, 1, -0,113, 4346, 8 und 273 292, 1 abhängig von der Zusammensetzung des Polymerisationsgemisches. Wird dieses geändert, müssen diese Variablen anhand von einer oder zweier Polymerisationen im Pilotmaßstab ermittelt werden, um die Beziehungen an die neue Zusammensetzung anzupassen und so eine Übertragung auf einen größeren Reaktor zu ermöglichen.
    Notes: Studies were carried out to develop a mathematical model based on experimental results to correlate agitation and other polymerization parameters with the particle size of PVC and to specify the limits of agitation speed within the defined agitation system. Computer regression analysis of about 30 vinyl chloride polymerizations in reactors with 10 L to 27 m3 tank volume are carried out. The particle size of PVC (d50) is correlated to various polymerization parameters such as impeller diameter (D), impeller speed (N), reactor tank diameter (T), liquid height (H1) and tank volume (V) (NWe = Weber number): d50 = 4346.8 (N)-0.905 (D)-0.901 (T)-0.514 (H1)-0.131d50/D = 273292.1 NWe-0.51Nmin = 3049.1 D-1.1 (T/D)-0.113In these equations only the values 3049.1, -0.113, 4346.8 and 273 292.1 depend on the recipe. When the recipe is changed these variables must be determined by one or two bench-scale polymerizations to adjust the correlations to the new recipe conditions so that they can be also used for scale-up purposes with the new recipe.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/apmc.1993.052110104
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    Modelluntersuchungen zur topologie der härtung geordneter epoxidnetzwerke (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 211 (1993), S. 61-77 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: 4-Phenyl-4-(2,3-expoxypropyl)benzoate (I) can be cured to thermoset networks with a different degree of order by using isomeric aminophenyl aminobenzoates II to V as curing agents. The formation of intermediates during the curing reaction was studied by means of model compounds. From the reaction of the monoamino-substituted phenylbenzoates VI to IX the reactivities for the primary and the secondary aminoprotons towards epoxide was determined. The kinetic data were used for a stepwise simulation of the curing reaction. Arguments were found that in case of diamines with 4-aminobenzoate structure well ordered intermediates are formed, which crosslink in an early stage of the reaction.
    Notes: Die Härtung von 4-Phenyl-4-(2,3-epoxypropoxy)benzoat (I) mit den isomeren Aminophenylaminobenzoaten II bis V führt zu unterschiedlich geordneten Epoxidnetzwerken. Die Bildung verschiedener Intemediate während der Härtungsreaktion wurde anhand von Modellverbindungen studiert. Aus der Reaktion der monoamino-substituierten Phenylbenzoate VI bis IX mit Epoxid wurden die Reaktionskostanten für die Addition an das primäre und das sekundäre Wasserstoffatom der Aminogruppen bestimmt. Die kinetischen Daten lassen sich für eine schrittweise Simulation des Härtungsverlaufs verwenden. Es wurden Argumente dafür gefunden, daß sich bei Verwendung der Amine mit 4-Aminobenzoat-Strukturen gut geordnete, schnell vernetzende Intermediate bilden.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/apmc.1993.052110106
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    Modelling the polymerization of 1,3-butadiene in solution with a neodymium catalyst (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 211 (1993), S. 89-101 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die diskontinuierliche Polymerisation von Butadien in Hexan bei 45°C mit einem in-situ-aktivierten Ziegler-Katalysator aus Neodymversatat, Ethylaluminiumsesquichlorid und Triisobutylauminium wurde untersucht. Die Polymerisationsgeschwindigkeit wurde durch Dichtemessungen verfolgt. Zur Beschreibung der Polymerisationskinetik bei verschiedenen Katalysatorzusammensetzungen wurde ein mathematisches Modell entwickelt. Bei einem molaren Aluminium/Neodym-Verhältnis über 40 kann mittels Gelpermeationschromatographie eine bimodale Molmassenverteilung beobachtet werden, was zu der Annahme führt, daß im Polymerisationssystem mehr als eine aktive Spezies anwesend ist.
    Notes: The batch polymerization of butadiene in hexane with an in-situ-activated Ziegler-Catalyst containing neodymium versatate, ethylaluminium sesquichloride and triisobutylaluminium was studied at 45°C. The rate of polymerization was determined by online density measurements. A mathematical model has been developed which is able to describe the kinetics of polymerization at different catalyst ratios. At molar ratios of aluminium/neodymium above 40 a bimodal molar mass distribution can be observed by gel permeation chromatography which leads to the assumption of more than one active species being present in the polymerization system.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/apmc.1993.052110108
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    Removal of escherichia coli from water by systems based on insoluble poly(glycidyl methacrylate)-G-tetraethylenepentamine and -G-polyethylenimine (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 206 (1993), S. 1-9 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Fähigkeit von zwei Polymeren zur Adsorption von Escherichia coli (E. coli) in sterilisierter physiologischer Kochsalzlösung wurde untersucht. Als Polymere wurden die Reaktionsprodukte von unlöslichen Poly(glycidylmethacrylat)-Kügelchen (PGMA) mit Tetraethylenpentamin (TEP) bzw. Polyethylenimin mit einem Molekulargewicht von 60 (PEI600) verwendet. Die Zahl der vermehrungsfähigen Zellen nahm in Gegenwart dieser Polymeren ab. Elektronenmikroskopisch konnte nachgewiesen werden, daß diese Abnahme durch Adsorption der Bakterien auf der Polymeroberfläche verursacht wird. Die Koeffizienten (D) der Abnahme der vermehrungsfähigen Zellen (E. coli) betragen 53 und 62 ml g-1 h-1 für PGMA-TEP bzw. PGMA-PEI600. Sie werden mit den Koeffizienten bereits untersuchter Polymerer verglichen.
    Notes: A study was made of the removal of Escherichia coli (E. coli) from water by systems based on insoluble poly(glycidyl methacrylate)-g-tetraethylenepentamine and -g-polyethylenimine, i.e., the reaction products of insoluble poly(glycidyl methacrylate) (PGMA) beads with tetraethylenepentamine (TEP) or polyethylenimine having molecular weights of about 600 (PEI600). The polymers (PGMA-TEP and PGMA-PEI600) were brought into contact with E. coli in sterilized physiological saline. These polymers made the viable cell numbers decrease in this medium. It was confirmed by observation of polymer surfaces with a scanning electron microscope that this decrease was caused by adsorption of the bacterial cells onto these polymers. The decrease coefficients of viable cell numbers (D) for E. coli by these polymers were 53 ml g-1 h-1 for PGMA-TEP and 62 ml g-1h-1 for PGMA-PEI600, being compared with D by other polymers studied previously.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052060101
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    Thermal dehydrochlorination of PVC in the presence of rubber seed oil (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 206 (1993), S. 11-20 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Dehydrochlorierungsgeschwindigkeit von PVC in Gegenwart von Gummisamenöl (RSO), epoxydiertem Gummisamenöl (ERSO) sowie Metallseifen der daraus hergestellten Fettsäuren wurde unter Stickstoff gemessen. Die Anfangsgeschwindigkeiten der Dehydrochlorierung und die Zeit bis zu einem Abbauumsatz von 1% zeigen einen stabilisierenden Effekt der RSO-Derivate mit der Reihenfolge ERSO-Metalseifen 〈 RSO-Metalliseifen 〈 ERSO 〈 RSO.
    Notes: Dehydrochlorination rates of PVC in nitrogen atmosphere were determined in the presence of rubber seed oil (RSO), epoxidized rubber seed oil (ERSO), barium soap of rubber seed oil fatty acids and barium soap of epoxidized fatty acid of rubber seed oil. The initial rates of dehydrochlorination and the time required for the degradation to attain 1% conversion showed that the rubber seed oil derivatives exert a stabilizing effect on the degradation of PVC. The order of the stabilizing effect was found to be metal soaps of ERSO 〈 metal soaps of RSO 〈 ERSO 〈 RSO.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052060102
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  • 81
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    Wirkung von Diisocyanat als reaktiver Koppler in TPU/PA6-Blends (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 206 (1993), S. 21-38 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: To improve materials performance like the temperature of deformation under flexural load of thermoplastic polyurethanes (TPU) blending with thermoplastics is sensible. A good compatibilization and phase adhesion of thermodynamical incompatible blend-components can be achieved by the use of the right coupling agents. In the case of blends with TPU and PA6 diisocyanate is given into the melt during the extrusion. Through the chemical reactions effects of compatibilization are achieved in the cases of blends with polyesterpolyurethanes and PA6 produced by extrusion and injection moulding and by reactions in solution, too. These could be perceived as consequence of MDI-initiated reactions within the phase boundary layer. The possible reactions with the PA6-phase will be discussed by the use of a model-system made in solution. No effects of compatibilization by MDI could be proved in the polyetherpolyurethan/PA6-system. The chemical characterization of the blends was realized by GPC and FTIR whereas the properties of the morphology are proved with the help of DSC, DMA and transmission electron microscopy (TEM).
    Notes: Zur Verbesserung der Werkstoffeigenschaften von thermoplastischen Polyurethanen (TPU), wie etwa der Wärmeformbeständigkeit, ist es sinnvoll, ein Blending mit Thermoplasten vorzunehmen. Eine gute Phasenverträglichkeit und Phasenhaftung bei thermodynamisch unverträglichen Blendkomponenten kann durch geeignete reaktive Koppler erreicht werden. Bei den Blends aus TPU and PA6 wird Diisocyanat während der Extrusion in der Schmelze eingebracht. Durch die ablaufenden chemischen Reaktionen werden bei extrudierten und verspritzten Blends und bei aus der Lösung erzeugten Systemen aus Polyesterpolyurethan und PA6 verträglichkeitsverbessernde Wirkungen erreicht. Diese wurden als Folge von mit 4,4′-Diphenylmethandiisocyanat (MDI) initiierten Reaktionen in der Grenzschicht erkannt, wobei die möglichen Reaktionen mit der PA6-Phase anhand eines Modellsystems aus der Lösung diskutiert werden. Bei Blends aus Polyetherpolyurethan und PA6 wurde keine Verträglichkeitsvermittlung durch MDI nachgewiesen. Die chemische Charakterisierung der Blends erfolgte durch GPC und FTIR, während die morphologischen Eigenschaften mittels DSC, DMA und Elektronenmikroskopie dokumentiert wurden.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052060103
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  • 82
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    Kinetics analysis of the curing of a diepoxy-diamine system (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 206 (1993), S. 39-52 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Reaktion von 4,9-Dioxa-1,12-dodecandiamin (DDDD) mit dem Diglycidylether von Bisphenol A (DGEBA) wurde mittels isothermer und dynamischer Differentialkalorimetrie untersucht. Die Enthalpie der Reaktion einer Epoxygruppe mit einem Amin-Wasserstoff wurde zu 112 ± 5 kJ/mol bestimmt.Die Gültigkeit eines kinetischen Modells wurde bestätigt. Es beinhaltet zwei konkurrierende Mechanismen: zum einen die Katalyse durch Hydroxy-Gruppen, die entweder an die Epoxykette gebunden sind oder während der Reaktion gebildet werden (Aktivierungsenergie 77 ± 5 kJ/mol), zum anderen eine nicht katalysierte Reaktion mit einer höheren Aktivierungsenergie (103 ± 3 kJ/mol).Eine Gelierung beeinflußt die Kinetik der isothermen Härtung nicht. Aus den Gelzeiten wurde die Bruttoaktivierungsenergie ermittelt (62 ± 2 kJ/mol).
    Notes: The reaction between the diglycidylether of bisphenol A (DGEBA) and 4,9-dioxa-1,12-dodecanediamine (DDDD) has been studied by means of isothermal and dynamic differential scanning calorimetry. The enthalpy of the reaction of an epoxy group with an amino-hydrogen has been determined to be 112 ± 5 kJ/mol. A kinetic model has been validated. It involves two competitive mechanisms: one is catalysed by the hydroxy groups initially present on the epoxy chain or generated during the reaction (activation energy 77 ± 5 kJ/mol), the other is not catalysed with a higher activation energy (103 ± 3 kJ/mol).For each isothermal curing, the kinetics are not modified by gelation. Evaluated from the gel times, the overall activation energy of the reaction is equal to 62 ± 2 kJ/mol.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/apmc.1993.052060104
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  • 83
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    New flame-retardant poly(pyromellitic imide aryl phosphoramide-ester)s (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 206 (1993), S. 63-68 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch Grenzflächen-Polykondensation von N,N′-bis(4-hydroxyphenyl)pyromellitsäurediimid mit Dichloriden verschiedener Phosphoramide wurden flammhemmende Polymere erhalten. Diese wurden mittels IR- und 1H-NMR-Spektroskopie und Elementaranalyse charakterisiert. Thermische Stabilität und Entflammbarkeit wurden thermogravimetrisch bzw. durch Bestimmung des Sauerstoff-Indexes untersucht.
    Notes: Flame-retardant poly(pyromellitic imide aryl phosphoramide-ester)s were synthesized by interfacial polycondensation of N,N′-bis(p-hydroxyphenyl)pyromellitic diimide with aryl phosphoramidic dichlorides. The polymers were characterized by IR and 1H-NMR spectroscopy. The molecular composition was confirmed by elemental analysis. The thermal stability and flammability of the polymers were studied by thermogravimetry and limiting oxygen index, respectively.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/apmc.1993.052060106
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  • 84
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    Studies on simultaneous curing of nadimides and allyl nadic-imidesNadic imide: Bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide. and thermal behaviour of cured resinsPaper presented at VIIIth National Symposium and Workshop on Thermal Analysis held at Bhubaneshwar on December 19-21, 1991. (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 206 (1993), S. 53-62 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Einfluß von Zusammensetzung und chemischer Struktur auf die thermischen Eigenschaften von Polyimiden aus handelsüblichen Allyl-„Nadimid“-Harzen und Phosphor enthaltenden “Nadimid”-Harzen wurde untersucht. Thermogravimetrische Messungen unter Stickstoff an Harzen, die 1 h bei 300 gehärtet wurden, ergaben eine Erhöhung der thermischen Stabilität.
    Notes: The effect of composition and chemical structure of addition polyimides on thermal characteristics was investigated using commercially available allyl nadic-imide resins and phosphorus-containing nadimide resins. Thermogravimetric analysis, in N2 atmosphere, of resins cured at 300°C for 1 h revealed improvement of thermal stability.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052060105
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  • 85
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    Graft copolymers having hydrophobic backbone and hydrophilic branches, 8For Part 6, cf.7, for Part 7, cf.6.. Effect of temperature on the dispersion copolymerization of poly(ethylene glycol) macromonomer with styrene (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 206 (1993), S. 69-75 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Polyethylenglykol-Makromonomere mit Methacryloyl-Endgruppen wurden in Gegenwart von 2,2′-Azo(N,N′-dimethylenisobutyramidin) in einem Ethanol/Wasser-Gemisch (4:1, v/v) bei verschiedenen Temperaturen mit Styrol copolymerisiert. Die Gesamtaktivierungsenergie dieser Dispersionscopolymerisation beträgt 48 kJ/mol.
    Notes: Copolymerization of poly(ethylene glycol) macromonomers with terminal meth-acryloyl groups with styrene was carried out in the presence of 2,2′-azobis(N,N′-dimethyleneisobutyramidine) in ethanol/water mixture (4:1, v/v) at various temperatures. The overall activation energy for the dispersion copolymerization was obtained as 48 kJ/mol.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/apmc.1993.052060107
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  • 86
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    Magnetic bead cellulose (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 212 (1993), S. 147-155 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Magnetische Zellulosepartikel wurden aus Viskose und Eisenpulver mit einer den thermischen Sol-Gel-Übergang nutzenden Suspensionsmethode hergestellt. Die so erhaltenen Teilchen konnen mit einem von außen angelegten, rotierenden Magnetfeld eines üblichen Permanentmagneten durchmischt werden. Die Abtrennung der Partikel von der Reaktionssuspension sollte in einer dünnen Schicht des Materials durch ein starkes Magnetfeld erfolgen. Magnetische Zellulosepartikel, die mit einer SmCoFe-Legierung anstelle des Ferrits hergestellt wurden, besitzen bessere magnetische Eigenschaften.
    Notes: Mangetic bead cellulose was prepared from viscose and ferrite powder by employing the suspension procedure using the thermal sol-gel transition. The particles thus obtained can be stirred if acted upon by an external rotary magnetic field of a common permanent magnet. Isolation of the particles from reaction suspensions should proceed in a thin layer using a strong magnetic field. Magnetic bead cellulose prepared from supermagnetic powder of the SmCoFe alloy shows a better behaviour in the magnetic field than ferrite materials.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052120113
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  • 87
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    Methodological investigations on the thermal stability of polypropylene (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 212 (1993), S. 103-119 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Unterschiedliche Methoden zur Messung der thermo-oxidativen Stabilität von Polypropylen wurden verglichen. Die Induktionszeiten des oxidativen Abbaus wurden mittels Differentialkalorimetrie (DSC) zwischen 160 und 240°C bis zu 10000 min gemessen. Die gleichen Proben wurden bei 130 bis 160°C 13000 h einer Alterung im Heizofen ausgesetzt.Unterschiedlich stabilisierte Proben ergaben bei dynamischen DSC-Messungen unterschiedliche Ergebnisse. Die Übereinstimmung zwischen dynamischen und statischen Experimenten waren bei kleinen Heizraten am besten.Die Arrhenius-Diagramme der isothermen DSC-Messungen unterscheiden sich von denen der Alterungsversuche; die erhaltenen Geraden schneiden sich entweder in der Nähe der Polypropylen-Schmelzpunkte oder verschieben sich bei den durch Temperung gealterten Proben zu längeren Zeiten. Die scheinbaren Aktivierungsenergien aus den Ofen-Temperungsmessungen sind sehr vie1 niedriger als die aus den DSC-Messungen berechneten und liegen bei allen Proben in einem einheitlichen Bereich, während bei den DSC-Experimenten ein Einfluß des Stabilisators zu erkennen ist.Die thermische Stabilität von Polypropylen wird auch von Antistatika und Farbpigmenten beeinflufßt. Besonders Rot-Pigment wirkt als Stabilisator für Polypropylen, was aus den Ofen-Alterungsversuchen hervorgeht; es verliert diesen Effekt aber bei höheren Temperaturen.
    Notes: The correlation between different methods of measuring thermo-oxidative stability of polypropylene has been studied. The oxidation induction times were measured using differential scanning calorimetry (DSC) in the temperature range from 160°C to 240°C up to 10000 min. The same samples were oven-aged in the temperature range from 130°C to 160°C up to 13000 h.The dynamic experiments performed by DSC show different results for differently stabilized samples. At slow heating rates the results of the dynamic experiments corresponded best to the results of the isothermal experiments.The straight-line Arrhenius plots of the isothermal DSC measurements do not correlate with the straight-line Arrhenius plots of the oven-aging tests. The Arrhenius plots obtained by these two methods either intersect close to the melting temperature of polypropylene or show jumps towards longer times when switching from DSC to oven-aging. It was found that the apparent activation energies obtained from the oven-aging tests are much lower than these obtained by DSC measurements. Almost the same activation energies were obtained for all the samples in oven-aging, while for the differently stabilized samples the activation energies from DSC measurements showed different results.Antistatic additives and colour pigments influence the thermal stability of polypropylene. Especially red pigment acts like a stabilizer for polypropylene, which is noticed at oven-aging testing, but at higher temperatures it loses this stabilizing effect.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052120110
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  • 88
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    Announcement (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 212 (1993), S. 201-202 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052120118
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  • 89
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    Removal of escherichia coli from water by systems based on polystyrene-g- and poly(glycidyl methacrylate)-g-amines (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 207 (1993), S. 31-41 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Aktiviertes Aluminiumoxid wurde mit den Produkten der Reaktionen von chlormethyliertem Polystyrol mit Diethylamin, von Poly(styro1-co-chlormethylstyrol) mit Diethanolamin und von Poly(styro1-co-glycidylmethacrylat) mit Diethanolamin belegt und zur Adsorption von Escherichia-coli-Bakterien aus Wasser eingesetzt. 100 mg belegtes Trägermaterial wurden mit einer E.-coli-Suspension (20 ml, 107-8 Zellen/ml) gerührt, wobei die Zahl der lebensfähigen Zellen durch Adsorption abnahm; das Adsorptionsgleichgewicht wurde nach etwa 2 h erreicht. Der Abnahme-Koeffizient D (entspricht der Adsorptionsgeschwindigkeitskonstante) wurde aus der Abnahme der Zahl der lebensfähigen Zellen nach 2 h Adsorption gemessen.
    Notes: Reaction products of soluble chloromethylated polystyrene with diethylamine, poly(styrene-co-chloromethylstyrene) with diethanolamine, and poly(styrene-co-glycidyl methacrylate) with diethanolamine were prepared and supported on activated alumina granules. A study was made of removal of Escherichia coli cells from water by these supported alumina granules. When these granules (0.100 g) were stirred in a viable cell suspension (107-8 cells/ml, 20 ml), the viable cell number decreased by the adsorption of the cells to the granules. The adsorption attained approximately to the equilibrium (saturated adsorption) after about 2 h from the start of the adsorption. The decrease coefficient (D, which corresponds to the adsorption rate constant) was determined from the decrease in the viable cell number in the adsorption for about 2 h from the start.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/apmc.1993.052070104
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  • 90
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    Radical polymerization of mono- and di-methacrylic esters containing bisphenol-S (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 207 (1993), S. 43-52 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die radikalische Polymerisation von Bisphenol-S enthaltenden Mono- und Dimethacrylsaureestern (BPS-M und BPS-DM) wurde bezüglich Polymerisationsgeschwindigkeit, Läsungsmitteleinfluß, Copolymerisation und Kinetik der Photovernetzung untersucht. Es zeigte sich, daß das Lösungsmittel die Polymerisationsgeschwindigkeit signifikant beeinflußt; polare Lösungsmittel wie DMSO und Acetonitril verlangsamen die Polymerisationsgeschwindigkeit. Die Copolymerisation von BPS-M (M1) mit MMA (M1) wurde in Aceton bei 60°C untersucht. Die Copolymerisationsparameter wurden nach der Fineman-Ross-Methode zu r1 = 3,72 ± 0,0l und r2 = 0,80 ± 0,0l berechnet. Die hohe Reaktivität von BPS-M in diesem Copolymerisationssystem kann vermutlich dem „Matrix-Effekt“ zugeschrieben werden. Funktionelle Polymere mit Methacrylat- Seitengruppen wurden erfolgreich modifiziert und durch Bestrahlung in Gegenwart von Benzoinisopropylether photovernetzt. Die Kinetik der Photovernetzung ist zweiter Ordnung.
    Notes: Radical polymerizations of mono- and di-methacrylic esters containing bisphenol-S (BPS-M and BPS-DM) were studied in terms of polymerization rate, solvent effect, copolymerization and kinetic measurements of photocrosslinking. The solvents were found to affect significantly the polymerization rate. Polar solvents such as DMSO and acetonitrile were found to slow down the polymerization rate. Copolymerization of BPS-M(M1) with MMA(M2) was studied in acetone at 60°C. The monomer reactivity ratios were calculated to be r1 = 3.72 ± 0.01 and r2 = 0.80 ± 0.01 by the Fineman-Ross method. The high reactivity of BPS-M observed in this copolymerization system may be due to the “matrix effect”. Functional polymers containing methacrylate side-groups were successfully modified and photocrosslinked by irradiation in the presence of benzoin isopropyl ether. The photocrosslinking process is found to be of second order kinetics.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052070105
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    Supported titanium catalyst for propylene polymerization. Convenient synthesis of unsolvated anhydrous magnesium chloride from MgCl2 · 6 H2OIPCL Communication No. 220. (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 207 (1993), S. 53-63 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Reaktion von Chlorsilanen (Me3SiCl, R2SiCl2, SiCl4; R=Me, Ph) mit MgCl2 · 6 H2O wurde bezüglich der Entfernung des Kristallwassers untersucht. Die Dehydratisierungsgeschwindigkeit hängt von der Art des Chlorsilans ab. Bei der Reaktion mit Dichlordiphenylsilan entsteht in hoher Ausbeute ungelöstes, wasserfreies Magnesiumchlorid, das als Trägermaterial für die Herstellung eines Titan-Katalysators verwendet wurde. Dieser zeigt mit Et3Al und Ph2Si(OMe), als Cokatalysatoren eine hohe Aktivität für die Propylenpolymerisation.
    Notes: Reaction of chlorosilanes (Me3SiCl, R2SiCl2, SiCl4; R=Me, Ph) with MgCl2 · 6 H2O were investigated for the efficiency of removal of water. The nature of chlorosilane is found to govern the rate of dehydration. The treatment of hydrated magnesium chloride with dichlorodiphenylsilane gives unsolvated anhydrous magnesium chloride in high yields. Anhydrous MgCl2 is used as support for the preparation of titanium catalyst. The catalyst in conjunction with Et3Al and Ph2Si(OMe)2 as cocatalyst system shows high activity for propylene polymerization.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052070106
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  • 92
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    Syntheses and reactions of photopolymers, I. New photosensitive azo monomers, photolysis, interfacial polycondensation, viscosity measurements, photodegradation (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 207 (1993), S. 65-79 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wird die Synthese verschiedener, mindestens bifunktioneller Azoverbindungen und deren Einbau in eine Polymerhauptkette mittels Grenzflächenpolykondensation beschrieben. Die thermischen und photochemischen Eigenschaften von Modellverbindungen sowie der Polymeren wurden durch UV-Spektroskopie und DSC-Messungen untersucht. Mit Hilfe von Viskositätsmessungen wurde der Kettenabbau eines Azopolymeren nachgewiesen.
    Notes: The synthesis of new, unsymmetrically functionalized azo compounds and their incorporation into polymers is described. Their photochemical decomposition and thermal stability was studied by UV spectroscopy and differential scanning calorimetry (DSC), respectively. Chemical degradation was followed by viscosity measurements.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/apmc.1993.052070107
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  • 93
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    Linear polythioesters, XXIII. Products of interfacial polycondensation of 4,4′-dimercaptobiphenyl with acid dichlorides (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 207 (1993), S. 173-186 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch Phasengrenzflächenpolykondensation von 4,4′-Dimercaptobiphenyl mit ausgewählten aliphatischen und isomeren Phthalsäuredichloriden wurden neue Polythioester erhalten. Um die optimalen Bedingungen der Phasengrenzflachenpolykondensation zu bestimmen, wurde der Einfluß folgender Faktoren auf die reduzierte Viskosität und Ausbeute der Polythioester ermittelt: Art der organischen Phase, Konzentration der Reagenzien, Verhältnis der wässrigen zur organischen Phase, Art und Konzentration des HC1-Akzeptors, Reaktionstemperatur und -zeit. Die Polykondensation von Dithiol mit Isophthalsäuredichlorid wurde als Modellsystem speziell untersucht. Die Polythioesterstrukturen wurden mittels Elementaranalyse, IR-Spektroskopie und Riöntgenspektroskopie bestimmt. Aus der thermogravimetrischen Analyse wurden die Anfangszersetzungstemperatur, die Gewichtsabnahme bei dieser Temperatur und das Maximum der Zersetzungsgeschwindigkeit erhalten. Es wurden weiterhin einige physikalisch-chemische, mechanische und dielektrische Eigenschaften ermittelt. Aufgrund der geringen Löjslichkeit der Polythioester konnten die mittleren Molekulargewichte nicht bestimmt werden.
    Notes: New polythioesters were obtained by interfacial polycondensation of 4,4′-dimercaptobiphenyl with selected aliphatic and isomeric phthaloyl dichlorides.To determine the optimum polycondensation conditions, the influence of the following factors on reduced viscosity and yield were studied: type of organic phase, concentration of hydrogen chloride acceptor, type of catalyst, reaction temperature and rate of acid dichloride addition.A thorough examination was carried out only for the polycondensation of dithiol with isophthaloyl dichloride chosen as a model system. The structures of polythioesters were determined by elemental analysis, X-ray and infrared spectra. The temperature of initial decomposition, the percentage of its mass loss, and temperature of the fastest decomposition process were determined from curves of differential and thermogravimetric analysis.Some physicochemical, mechanical and electrical properties were determined. The molecular weights were not measured because of the low solubility of the obtained polythioesters.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052070116
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  • 94
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    Electronic Resource
    Announcements (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 207 (1993), S. 215-216 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052070120
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  • 95
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    Electronic Resource
    Cationic surface modification by polyelectrolytes: Polyelectrolyte complex formation at inorganic particle surfaces (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 207 (1993), S. 203-213 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die negativ geladene Oberfläche von feindispersen anorganischen Materialien wie Kieselgur, Perlit, Kaolin oder Glas kann durch die Adsorption von kationischen Polyelektrolyten umgeladen werden. Bei hohen Mengen an adsorbiertem Polykation besitzen die Oberflächen der unterschiedlichen Materialien dann gleiche elektrokinetische Eigenschaften. An den derart modifizierten Grenzflächen können anionische Farbstoffe adsorbiert werden. Bei Zugabe eines Polyanions, resultierend in der Bildung eines Polyelektrolytkomplexes, kann die Zahl der kationischen Zentren in der Grenzfläche und damit die Adsorptionskapazität für den Farbstoff erhöht werden. Die experimentellen Resultate deuten darauf hin, daß das Zetapotential bestimmt wird durch die außeren Bereiche der PEC-Schicht, wahrend die Farbstoffadsorption auch durch die inneren Regionen der Oberfläche mitbestimmt wird. Unmittelbar nach der Modifizierung mit Poly(diallyldimethylammoniumchlorid) und Poly(maeinsäure-co-α-methylstyrol) besitzen die modifizierten Materialien bei einem hohen Überschuß des Poly-anions ein negatives Zetapotential, aber ein positives nach der Abtrennung der überstehenden Lösung. Dieses Verhalten steht in Übereinstimmung mit der Bildung eines nichtstochiometrischen PEC mit Polykation im Überschuß und einer reversiblen Wechselwirkung mit überschüssigem Polyanion in der Lüsung. Die Ergebnisse deuten an, daß die Oberflache als fest-analoger Polyelektrolyt in Konkurrenz zu dem Polyanion an der Reaktion beteiligt ist.
    Notes: The surface charge of inorganic finely dispersed materials like diatom earth, perlite, glass or clay may be changed from negative to positive by the adsorption of cationic polyelectrolytes. Different materials exhibit equivalent electrokinetic surface properties with high amounts of the polycation adsorbed. Interfaces modified this way are able to adsorb anionic dye stuffs. Their adsorption capability for the dye stuff may be enhanced by addition of polyanions due to the formation of a nonstoichiometric polyelectrolyte complex (PEC) and therefore an increased number of cationic centres in the interface. Experimental results indicate that the zeta potential is correlated to the outer PEC layer whereby dye stuff adsorption measurements are sensitive for the more inner surface regions, too. Immediately after modification, materials modified with poly(diallyldimethylammonium chloride) and poly(maleic acid-co-α-methylstyrene) have negative zeta potentials at high excess of added polyanion and a positive one after separation of the solid. This behaviour is attributed to the formation of a nonstoichiometric PEC with polycation in excess and reversible interaction with polyanion in the surrounding solution. Experimental results indicate that the surface may act as “solid-like” polyelectrolyte in competition to the polyanion.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052070119
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  • 96
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    Sulfobetaine polyurethane ionomers, 2. Dielectric relaxation in polyether-based polymer and related compounds with Co2+ (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 207 (1993), S. 195-202 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die dielektrischen Relaxationsprozesse in Sulfobetain-Polyurethanionomeren mit Polyethersegmenten (Co2+ -komplexierte und H,S-behandelte Formen) wurden mit der TSDC-Methode untersucht und mit denen nichtionischer Polyurethane und verwandter Verbindungen verglichen. Vier mit c, βs, β′ und βh bezeichnete Relaxationsprozesse wurden in Polyurethanionomeren im Temperaturbereich von 110 bis 370 K beobachtet und mit möglichen molekularen Bewegungsprozessen korreliert. Die Einflüsse des Gehalts an Hartsegmenten, der Komplexierung sowie der H2S-Behandlung auf die Relaxationsprozesse wurden unter Berücksichtigung der strukturellen Modifikationen der harten und der weichen Mikrophasen erklärt.
    Notes: Dielectric relaxation processes in sulfobetaine polyurethane ionomers based on polyether, were studied comparatively to nonionic polyurethane and related compounds with Co2+ (complexed and H2S-treated forms) by using thermally stimulated depolarization currents (TSDC).Four relaxation processes denoted as γ, βs, β′ and βh in polyurethane ionomers over the 110-370 K range were observed. Molecular origin of these processes was suggested. The effects of the hard segments content, complexation and H2S treatment on the relaxation processes were explained in terms of the structural modifications of the hard and soft microphases.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052070118
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  • 97
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    Metal ion complexation of poly(acrylamide)-supported amines crosslinked with N,N′-methylene-bis-acrylamideSystematic name: N-(acrylamidomethyl)acrylamide. (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 208 (1993), S. 1-15 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Komplexierung von Co(II), Ni(II), Cu(II), Zn(II) und Hg(II) in Amin-funktionalisierten, mit N-(Acrylamidomethyl)acrylamid (NNMBA) vernetzten Polyacrylamiden wurde untersucht. Die Metallionenaufnahme hängt vom Vernetzungsgrad ab und nimmt in der Reihenfolge Hg(II) ≫ Cu(II) 〉 Zn(II) 〉 Ni(II) 〉 Co(II) ab. Die Kinetik der Komplexierung ist erster Ordnung. Die Metallkomplexe wurden mittels IR- und EPR-Spektroskopie charakterisiert. Die Harze können ohne Kapazitätsverlust nach Dekomplexierung mehrmals verwendet werden; die desorbierten Harze komplexieren bevorzugt das vorher gebundene Metallion. Das Quellvermögen der komplexierten ist geringer als das der nichtkomplexierten Harze und hängt vom Vernetzungsgrad ab.
    Notes: The complexation of amino functions supported on poly(acrylamides) with 2-20 mol-% of N-(acrylamidomethyl)acrylamide (NNMBA) crosslinks towards Co(II), Ni(II), Cu(II), Zn(II), and Hg(II) ions was investigated. The metal ion uptake was found to be dependent on the extent of the NNMBA crosslinking. The observed trend in complexation is Hg(II) ≫ Cu(II) 〉 Zn(II) 〉 Ni(II) 〉 Co(II). The kinetics of complexation was found to be of first order. The derived metal complexes were characterised by IR and EPR. The complexed resins can be recycled several times without capacity loss. The metal-desorbed resins showed specificity to the metal ion which was initially present. The extent of swelling of the complexed resins is lower than that of the uncomplexed resins and it varies with the extent of crosslinking.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052080101
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  • 98
    Electronic Resource
    Electronic Resource
    Conduction mechanism of polycarbonate doped with different transition metals (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 208 (1993), S. 17-23 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die elektrische Leitung von mit verschiedenen Übergangsmetallen (Fe, Co, Cu, Cr) dotiertem Polycarbonat (PC) wurde im Temperaturbereich von 293 bis 493 K untersucht. Die Leitfähigkeit von PC mit FeCl, war siebenmal höher als jene der anderen Proben. Die effektive Potentialschwelle Φ wurde zu 0,2 eV berechnet. Weiterhin wurde die Dielektrizitätskonstante bei verschiedenen Temperaturen untersucht.
    Notes: The electrical conduction of polycarbonate (PC) doped with different transition metals was studied in the temperature range of 293-493 K. The conductivity of PC doped with FeCl3 is 7 orders higher in comparison with the other samples. The effective potential barrier (Φ) for pure PC was calculated (0.2 eV). Also, the dielectric constant at different temperatures was studied.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052080102
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  • 99
    Electronic Resource
    Electronic Resource
    Photooxidative ageing of low density polyethylene. Kinetics determined by an electrical method (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 208 (1993), S. 25-38 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Wirkung von Lichtstabilisatoren im ersten Stadium der Alterung von Polyethylen niedriger Dichte (LDPE) wurde mit elektrischen Methoden untersucht. Drei verschiedene UV-Stabilisatoren wurden verwendet: ein Phosphit-Derivat (3,9-Bis[(2,4-di-tert-butyl)phenoxy]-2,4,8,l0-tetraoxa-3,9-diphosphaspiro[5.5]undecane), ein Benzophenon-Derivat (2-Hydroxy-4-octyloxybenzophenon) und ein Chelat [2,2′-Thiobis(4-tert-octylphenolato)(n-butylamino)nickel(II)]. Diese Stabilisatoren, speziell das Chelat, verbesserten die UV-Stabilität von LDPE für elektrische Anwendungen.
    Notes: The efficiency of light stabilizers is investigated by electric methods in the initial stage of photooxidative ageing of low density polyethylene (LDPE). Three types of UV light stabilizers are tried to improve the UV stability of LDPE: a phosphite type (3,9-bis-[(2,4-di-tert-butyl)phenoxy]-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane) a benzophenone type [2-hydroxy-4-octyloxy-benzophenone] and a stabilizer based on chelate salt [2,2′-thiobis(4-tert-octyl phenolato) (n-butylamine) nickel (II)]. LDPE is very susceptible to ultraviolet light. UV light stabilizers improve the stability of low density polyethylene for electrical applications, especially the UV stabilizer based on chelate salt.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052080103
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  • 100
    Electronic Resource
    Electronic Resource
    Volume change by solvent and temperature of poly(vinyl alcohol) crosslinked by electron irradiation (1993)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 208 (1993), S. 39-46 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ein Poly(vinylalkohol)-Film (PVA) wurde nach Erhitzen in siedendem Wasser gequollen und durch Bestrahlen mit Elektronen vernetzt. Das so erhaltene PVA-Hydrogel weist eine höhere Elastizität und bessere mechanische Eigenschaften auf, obwohl es noch quellbar ist. Das Volumen des vernetzten Hydrogels reagiert sehr empfindlich auf einen Wechsel des Quellungsmittels und eine Temperaturänderung. Nach Kontraktion durch Eintauchen in Aceton nimmt die Zugfestigkeit zu. Durch wiederholtes Erhitzen des Hydrogels in siedendem Wasser und anschließendes Abkühlen wurden Kontraktions-Quellungs-Zyklen durchlaufen. Bei Temperaturen oberhalb 40°C nimmt das Quellungsverhältnis stark ab.
    Notes: Responsive poly(vinyl alcohol) PVA hydrogels obtained by electron irradiation after heating of a water-swollen film show higher elasticity and tougher properties even after boiling in water, although some swelling did occur. The volume of the hydrogel after boiling was very sensitive to solvent (acetone) and temperature. The crosslinked hydrogels show higher tensile strength after rapid contraction by immersion in acetone. The crosslinked PVA was boiled and cooled to induce contraction and swelling cycles. The swelling ratio of hydrogel decreased remarkably at temperatures higher than 40°C.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1993.052080104
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