Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1990-1994  (25,439)
  • Polymer and Materials Science  (21,194)
  • Engineering General  (3,144)
  • Genetics  (1,100)
  • Nuclear reactions
Source
Material
Years
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Genetic analysis of a polyembryonic mutant in rye (1994)
    Springer
    Sexual plant reproduction 7 (1994), S. 290-296 
    Details
    ISSN: 1432-2145
    Keywords: Secale cereale ; Polyembryony ; Chromosome mosaics ; Rye ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have obtained one plant regenerated from rye tissue culture which showed a high percentage of polyembryonic seeds in its progeny. The mutation inducing the development of extra embryos is also influencing erroneous cell division, mitosis and meiosis. The genetic analysis indicated that the aptitude for polyembryonic seed formation is a heritable trait controlled by a dominant gene. However, for expression of the phenotype the female parent should have a specific cytoplasm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227712
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Molecular-marker-facilitated investigation of host-plant response to Exserohilum turcicum in maize (Zea mays L.): components of resistance (1994)
    Springer
    Theoretical and applied genetics 88 (1994), S. 305-313 
    Details
    ISSN: 1432-2242
    Keywords: Breeding ; Helminthosporium turcicum ; RFLP ; QTLs ; Disease-resistance ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract RFLPs were used to investigate components of host-plant response to Exserohilum turcicum in 150 unselected F2∶3 lines of a B52/Mo17 maize population. Following inoculation with spore suspensions of the pathogen (race 0), components of disease development were measured and then quantitative trait mapping was performed to identify the location and effects of quantitative trait loci (QTLs) determining host-plant response. Components of interest were the average number of lesions per leaf, the average percent leaf tissue diseased (severity) and the average size of lesions (cm2). Based on a LOD threshold of 2.31 (P〈0.05), the number of lesions appears to be associated with QTLs on chromosomes 1S, 3L, 5S. Severity was associated with analogous regions and, in addition, QTLs on chromosomes 7L and 8L. Most QTLs, for either of these two components, involve additive gene action and partial dominance or overdominance. In contrast, lesion size was associated with QTLs on chromosomes 7L and 5L; recessive gene action may be involved at 7L.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223637
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Chromosome assortment in Saccharum (1994)
    Springer
    Theoretical and applied genetics 89 (1994), S. 959-963 
    Details
    ISSN: 1432-2242
    Keywords: Sugarcane ; Polyploidy ; Genetics ; Evolution ; Breeding ; DNA markers ; Arbitrarily primed PCR ; RAPD markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent work has revealed random chromosome pairing and assortment in Saccharum spontaneum L., the most widely distributed, and morphologically and cytologically variable of the species of Saccharum. This conclusion was based on the analysis of a segregating population from across between S. spontaneum ‘SES 208’ and a spontaneously-doubled haploid of itself, derived from anther culture. To determine whether polysomic inheritance is common in Saccharum and whether it is observed in a typical biparental cross, we studied chromosome pairing and assortment in 44 progeny of a cross between euploid, meiotically regular, 2n=80 forms of Saccharum officinarum ‘LA Purple’ and Saccharum robustum ‘ Mol 5829’. Papuan 2n=80 forms of S. robustum have been suggested as the immediate progenitor species for cultivated sugarcane (S. officinarum). A total of 738 loci in LA Purple and 720 loci in Mol 5829 were amplified and typed in the progeny by arbitrarily primed PCR using 45 primers. Fifty and 33 single-dose polymorphisms were identified in the S. officinarum and S. robustum genomes, respectively (χ 2 at 98%). Linkage analysis of single-dose polymorphisms in both genomes revealed linkages in repulsion and coupling phases. In the S. officinarum genome, a map hypothesis gave 7 linkage groups with 17 linked and 33 unlinked markers. Four of 13 pairwise linkages were in repulsion phase and 9 were in coupling phase. In the S. robustum genome, a map hypothesis gave 5 linkage groups, defined by 12 markers, with 21 markers unlinked, and 2 of 9 pairwise linkages were in repulsion phase. Therefore, complete polysomic inheritance was not observed in either species, suggesting that chromosomal behavior is different from that observed by linkage analysis of over 500 markers in the S. spontaneum map. Implications of this finding for evolution and breeding are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224524
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Familial occurrence of discrete subaortic membrane (1994)
    Springer
    Pediatric cardiology 15 (1994), S. 198-200 
    Details
    ISSN: 1432-1971
    Keywords: Subaortic stenosis ; Congenital heart disease ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The first case of multiple family members with discrete subaortic membrane and no other congenital defects is presented. One family member presents with findings suggesting a forme fruste of this disease. Increased surveillance of family members of individuals with discrete subaortic membrane is warranted, as the clinical findings of mild subaortic obstruction may be indistinguishable from those of an innocent flow murmur.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00800675
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Tricuspid atresia and annular hypoplasia: Report of a familial occurrence (1994)
    Springer
    Pediatric cardiology 15 (1994), S. 201-203 
    Details
    ISSN: 1432-1971
    Keywords: Tricuspid atresia ; Tricuspid hypoplasia ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Occurrence of a similar cardiac malformation in multiple family members has been reported for many lesions. Neither tricuspid atresia nor tricuspid annular hypoplasia and tricuspid atresia and one case of tricuspid annular hypoplasia with an atrial septal defect in siblings. The findings in this family suggest an autosomal recessive pattern of inheritance for abnormal tricuspid valve morphogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00800676
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Myotonic dystrophy and limb girdle muscular dystrophy in one family (1994)
    Springer
    Journal of molecular medicine 72 (1994), S. 409-413 
    Details
    ISSN: 1432-1440
    Keywords: Myotonic dystrophy ; Limb girdle muscular dystrophy ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A family is reported in which a 29-year-old woman showed the clinical features of myotonic dystrophy while her 26-year-old brother presented with the clinical picture of limb girdle syndrome. In the affected female, direct genetic testing for the specific myotonic dystrophy mutation on chromosome 19 revealed abnormal expansion of a repeat unit containing the three nucleotides cytosine, thymine, and guanine (CTG) — typical for myotonic dystrophy — while her diseased brother displayed two normal alleles. This supports the hypothesis of the extremely rare occurrence of two clinically and genetically different myopathies in one family. Genetic analysis of six other family members showed that the father of the diseased siblings as well as all of his three brothers and sisters had a pathological CTG repeat expansion, and that the other two family members tested had a normal allelic pattern. The number of CTG repeats in the diseased women was approximately tenfold higher than in her asymptomatic relatives who revealed an abnormal allelic pattern. The increase in CTG repeats with transmission to a subsequent generation in this family was paralleled by a dramatic increase in the severity of myotonic dystrophy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00252840
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Genetic ecology: A new interdisciplinary science, fundamental for evolution, biodiversity and biosafety evaluations (1994)
    Springer
    Cellular and molecular life sciences 50 (1994), S. 429-437 
    Details
    ISSN: 1420-9071
    Keywords: Genetics ; ecology ; DNA-transfer ; conjugation ; transformation ; transduction ; transposons ; dormant cells ; epilithon ; microbial colonisation ; symbiosis ; virus resistance ; biosafety ; release of genes ; insults to humanity ; evolution ; biodiversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Genetic ecology is the extension of our modern knowledge in molecular genetics to studies of viability, gene expression and gene movements in natural environments like soils, aquifers and digestive tracts. In such milieux, the horizontal transfer of plasmid-borne genes between phylogenetically distant species has already been found to be much more frequent than had been expected from laboratory experience. For the study of exchanges involving chromosomally-located genes, more has to be learned about the behaviour of transposons in such environments. The results expected from studies in genetic ecology are relevant for considerations of evolution, biodiversity and biosafety. The role of this new field of research in restoring popular confidence in science and in its biotechnological applications is stressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01920741
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Familial amyotrophic lateral sclerosis with a mutation in the Cu/Zn superoxide dismutase gene (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 185-188 
    Details
    ISSN: 1432-0533
    Keywords: Key words: Amyotrophic lateral sclerosis ; Neuropathology ; Posterior column involvement ; Genetics ; Superoxide dismutase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Several missense mutations within exons 1, 2, 4 and 5 of the gene for Cu/Zn-binding superoxide dismutase (SOD1) have been discovered to be involved in the development of chromosome 21q-linked familial amyotrophic lateral sclerosis (FALS). We describe here an autopsied patient with FALS, in whom we have recently identified a novel missense mutation in exon 1 of the SOD1 gene. The neuropathological findings were compatible with those described previously in patients with FALS with posterior column involvement. This suggests that mutations of the SOD1 gene may be responsible for this form of FALS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294513
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Mixed desmoplastic primitive neuroepithelial tumor of infancy: a light microscopic, immunocytochemical, ultrastructural and genetic study (1994)
    Springer
    Acta neuropathologica 89 (1994), S. 99-104 
    Details
    ISSN: 1432-0533
    Keywords: Key words     Primitive neuroepithelial tumor ; Desmoplastic small cell tumor ; Brain tumor of infancy ; Immunocytochemistry ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract      We describe a case of a desmoplastic brain tumor which was initially resected from the right fronto-temporal region in a 2 year-old boy. This nodular, calcified tumor was vascularized by the internal carotid artery and the middle meningeal artery branches. Grossly, it contained several mucoid cysts. Light microscopy showed cords or nests of small cuboidal cells surrounded by a loose connective tissue and desmoplasic areas containing fibers and spindle cells. The cuboidal cells expressed epithelial, neuronal and neuroendocrine markers. Some foci of spindle cells showed glial differentiation. The tumor recurred 16 months later and displayed some characteristics of the small cell neuroepithelial component, mitoses being conspicuous. Electron microscopy revealed undifferentiated clear cells, some containing neurosecretory granules. Karyotyping demonstrated the following formula: 〈 15 〉 46, t(8;11) (q13; q11). The chromosome 11 breakpoint was different from that described in Ewing's sarcoma. This isolated translocation has not been previously reported to our knowledge. These unusual features lead us to report this case and to discuss its pathogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050221
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Familial amyotrophic lateral sclerosis with a mutation in the Cu/Zn superoxide dismutase gene (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 185-188 
    Details
    ISSN: 1432-0533
    Keywords: Amyotrophic lateral sclerosis ; Neuropathology ; Posterior column involvement ; Genetics ; Superoxide dismutase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Several missense mutations within exons 1, 2, 4 and 5 of the gene for Cu/Zn-binding superoxide dismutase (SOD1) have been discovered to be involved in the development of chromosome 21q-linked familial amyotrophic lateral sclerosis (FALS). We describe here an autopsied patient with FALS, in whom we have recently identified a novel missense mutation in exon 1 of the SOD1 gene. The neuropathological findings were compatible with those described previously in patients with FALS with posterior column involvement. This suggests that mutations of the SOD1 gene may be responsible for this form of FALS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294513
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Mitochondrial gene defects in patients with NIDDM (1994)
    Springer
    Diabetologia 37 (1994), S. 372-376 
    Details
    ISSN: 1432-0428
    Keywords: Genetics ; diabetes mellitus ; mitochondria ; maternal ; deafness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Non-insulin-dependent diabetes mellitus (NIDDM) has a strong genetic component and maternal factors have recently been implicated in disease inheritance. The mitochondrial myopathies are a group of diseases which often show maternal inheritance as a result of mtDNA defects; some patients have impaired glucose tolerance. Occasional families with maternally inherited diabetes and deafness associated with a deletion or point mutation of mtDNA have been reported. To assess the importance of mitochondrial gene defects in NIDDM, 150 unrelated diabetic subjects from Wales, UK and 68 unrelated patients with diabetes and at least one affected sibling from England, UK were studied. Southern blot analysis did not show any large mtDNA deletions or duplications. One patient had a mutation in the mitochondrial tRNAleu(UUR) gene at bp 3243. This mutation is commonly associated with the syndrome of mitochondrial encephalomyopathy, lactic acidosis and stroke like episodes (MELAS). Study of this patient and his siblings showed a distinct form of late-onset diabetes associated with nerve deafness but no clinical features of the MELAS syndrome. No diabetic subject was shown to have the mtDNA mutation at position 8344 (tRNAlys) which has previously been described in the syndrome of mitochondrial encephalomyopathy and red-ragged fibres (MERRF). The role of other mitochondrial gene defects in diabetes and the pathophysiological basis of glucose intolerance in patients with the MELAS mutation requires further elucidation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408473
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Renal eicosanoids and blood pressure in genetically hypertensive rats of the lyon strain (1994)
    Springer
    Journal of biomedical science 1 (1994), S. 201-203 
    Details
    ISSN: 1423-0127
    Keywords: Hypertension ; Eicosanoid ; Rat ; Genetics ; Kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The present paper reviews the evidence for a possible involvement of renal eicosanoids in the pathophysiology of high blood pressure in genetically hypertensive rats of the Lyon strain. Both in vivo and in vitro experiments suggest that an increased ability to synthesize the vasoconstrictor prostaglandin H2 and/or thromboxane A2 in renal vessels (1) acts as an autocrine amplifier of pressor agents and (2) may contribute to resetting the pressure natriuresis curve which is a prerequisite for the development and maintenance of hypertension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02253302
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Absence epilepsy of early childhood —genetic aspects (1994)
    Springer
    European journal of pediatrics 153 (1994), S. 372-377 
    Details
    ISSN: 1432-1076
    Keywords: Epilepsy ; Absences ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Clinical and EEG family data of 140 cases with early childhood epilepsy with absences are presented. The aim of the study was to evaluate, whether the occurrence of generalized tonic clonic seizures (GTCS) as a presenting symptom might correlate with family data, i.e. whether there are indications of heterogeneity. One hundred and forty cases were selected from the epilepsy family data base of the Neuropaediatric Department. The selection parameter was epilepsy with absences manifesting between the 1 st and 5th year of age. The incidence of seizures was evaluated in siblings, parents and parents' siblings. EEG records were available from 103 parents and 106 siblings. The analysis supports the assumption of heterogeneity within early childhood absence epilepsy. Parents and their sibs of cases manifesting with GTCS had seizures twice as often than parents and their sibs in the non-GTCS group. In the affected relatives of the GTCS group early onset GTCS prevailed, whereas in the relatives of the non-GTCS group absences were found more frequently. The EEG of relatives showed elevated incidences of spikes and waves and photosensitivity in both groups, indicating common genetic factors. In parents of the non-GTCS group, however, EEG pathology was significantly more frequent than in parents of the GTCS group. Comparing EEG pathology in parents with seizure risk in siblings, evidence for maternal preponderance in transmission of the seizure liability was found. Mothers' EEG seems to be the best predictor of the seizure risk in probands' siblings. Early childhood epilepsy with absences can be regarded as an intermediate type, showing overlap with early onset GTCS and myoclonic astatic epilepsy on the one side and with childhood absence epilepsy on the other.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01956423
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    A gene in the HLA class I region contributes to susceptibility to IDDM in the Finnish population (1994)
    Springer
    Diabetologia 37 (1994), S. 937-944 
    Details
    ISSN: 1432-0428
    Keywords: Genetics ; haplotype ; HLA-A ; HLA-DQ ; HLA-DR ; tumour necrosis factor ; diabetes mellitus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In Finland the haplotype A2, Cw1, B56, DR4, DQ8 is the third most common haplotype in insulin-dependent diabetic (IDDM) patients and has the highest haplotype-specific absolute risk for IDDM. Cw1, B56, DR4, DQ8 haplotypes containing HLA-A alleles other than A2 are infrequent in the population and are not associated with IDDM. Comparison of the A2 and non-A2 haplotypes at the DNA level showed that they were identical at HLA-B,-DR, and -DQ loci. Evidence that class I alleles confer susceptibility to IDDM was obtained from the two HLA-C, -B, -DR and -DQ haplotypes most frequently found in IDDM patients in Finland. A24, A3 and A2 on the Cw3, B62, DR4, DQ8 haplotype, and A28, A2 and A1 on the Cw7, B8, DR3, DQ2 were all found to be associated with IDDM. In Finland these seven haplotypes, including A2, Cw1, B56, DR4, DQ8, account for 33% of diabetic haplotypes and 10.3% of non-diabetic haplotypes (p〈0.00001). The contribution of the class I region to IDDM susceptibility was also apparent in those IDDM patients lacking the disease-predisposing class II alleles. Significantly more non-DR3/non-DR4 IDDM patients (47 of 55) possessed two of the IDDM-associated HLA-A alleles compared to non-DR3/non-DR4 control subjects (40 of 58; p=0.038). Moreover, IDDM patients confirmed by oligotyping as unable to form a ‘diabetes-susceptibility’ DQ heterodimer, tended to possess two diabetes-associated HLA-A alleles (12 of 13) compared to control subjects (12 of 20; p=0.056).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400951
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Resistance to potato leaf roll virus multiplication in potato is under major gene control (1994)
    Springer
    Theoretical and applied genetics 88 (1994), S. 754-758 
    Details
    ISSN: 1432-2242
    Keywords: Potato breeding ; Potato leaf roll virus ; Virus resistance ; Major gene resistance ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The concentration of potato leaf roll virus (PLRV), as measured by a quantitative enzyme-linked immunosorbent assay, in the foliage of potato plants (Solanum tuberosum) of cv ‘Maris Piper’ with secondary infection was 2900 ng/g leaf, whereas in clones G7445(1) and G7032(5) it was 180 ng/g leaf and 120 ng/g leaf, respectively. To examine the genetic control of resistance to PLRV multiplication, reciprocal crosses were made between the susceptible cultivar ‘Maris Piper’ and the two resistant clones, and the three parents were selfed. Seedling progenies of these families were grown to generate tubers of individual genotypes (clones). Clonally propagated plants were graft-inoculated, and their daughter tubers were collected and used to grow plants with secondary infection in which PLRV concentration was estimated. The expression of resistance to PLRV multiplication had a bimodal distribution in progenies from crosses between ‘Maris Piper’ and either resistant clone, and also in progeny from selfing the resistant parents, with genotypes segregating into high and low virus titre groups. Only the progeny obtained from selfing ‘Maris Piper’ did not segregate, all genotypes being susceptible to PLRV multiplication. The pattern of segregation obtained from these progenies fits more closely with the genetical hypothesis that resistance to PLRV multiplication is controlled by two unlinked dominant complementary genes, both of which are required for resistance, than with the simpler hypothesis that resistance is conferred by a single dominant gene, as published previously.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01253981
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    A linkage map of diploid Avena based on RFLP loci and a locus conferring resistance to nine isolates of Puccinia coronata var. ‘avenae’ (1994)
    Springer
    Theoretical and applied genetics 89 (1994), S. 831-837 
    Details
    ISSN: 1432-2242
    Keywords: Genetics ; Disease resistance ; Monocots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An F2 oat population was produced by crossing the diploid (n=7) species Avena strigosa (CI 3815) with A. wiestii (CI 1994), resistant and susceptible, respectively, to 40 isolates of Puccinia coronata, the causal agent of crown rust. Eighty-eight F2 individuals were used to construct an RFLP linkage map representing the A genome of cultivated hexaploid oat. Two hundred and eight RFLP loci have been placed into 10 linkage groups. This map covers 2416 cM, with an average of 12 cM between RFLP loci. Eighty-eight F3 lines, derived from F2 individuals used to construct the map, were screened for resistance to 9 isolates of P. coronata. One locus, Pca, was found to confer a dominant resistance phenotype to isolates 203, 258, 263, 264B, 290, 298, 325A, and 345. Pca also conferred resistance to isolate 276; however, an unlinked second gene may also be involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224505
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Genetic analysis of tolerance for phosphorous deficiency in rice (Oryza sativa L.) (1994)
    Springer
    Theoretical and applied genetics 89 (1994), S. 313-317 
    Details
    ISSN: 1432-2242
    Keywords: Genetics ; Rice ; Phosphorousefficiency ; Diallel analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The inheritance of phosphorous (P) — deficiency tolerance in rice was investigated by a sevenparent diallel. The parent materials involved were four P-efficient (IR20, IR54, IR28, and Mahsuri), one moderately P-efficient (TN1), and two P-inefficient (IR31406333-1 and IR34686-179-1-2-1), genotypes. Relative tilering ability (RTA) under P-deficient and P-supplemented soil conditions was the parameter used in determining the tolerance level of the different genotypes. Diallel graph analysis revealed that tolerant parents have an excess of recessive genes, while moderate and susceptible parents possess more dominant genes. Genetic-component analysis suggested that both additive and dominance gene effects are involved in the inheritance of P-deficiency tolerance in rice. The trait exhibited over doiminance as confirmed by the graphical analysis. Narrow-sense heritability of the trait was moderate (0.50) and environmental effects were low. Both the general combining ability (GCA) and the specific combining ability (SCA) were significant, but GCA was more prevalent than SCA. Tolerant parents exhibited a high GCA whereas susceptibles have a very poor GCA, suggesting that tolerant parents were mostly enriched in additive genes and susceptible parents in non-additive genes. Crosses involving two high general combiners showed low SCA effects whereas crosses between poor general combiners manifested highly-significant SCA values.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225160
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Use of doxorubicin and dacarbazine for the management of unresectable intra-abdominal desmoid tumors in Gardner's syndrome (1994)
    Springer
    Diseases of the colon & rectum 37 (1994), S. 260-267 
    Details
    ISSN: 1530-0358
    Keywords: Desmoids ; Genetics ; Chemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: The aim of this study was to describe the natural history and management of surgically unresectable intra-abdominal desmoid tumors in two patients with Gardner's syndrome from two unrelated families, where each had failed on conventional therapy. METHODS: Two patients with Gardner's syndrome were placed on a chemotherapy regimen which included doxorubicin (90 mg/m2) and dacarbazine (900 mg/m2) in divided doses over four days of continuous infusion. Their progress on chemotherapy was assessed by abdominal computerized tomography and laparoscopy. RESULTS: The computerized abdominal tomography scans proved difficult to interpret because of adhesions and matted small bowel resulting from the patients original colectomies. These findings made it difficult to differentiate postoperative changes from residual desmoid tumor. Second-look laparotomy in such patients was contraindicated as this may predispose to further desmoid production. Laparoscopy disclosed a complete response to this chemotherapy. Nevertheless, we had an iatrogenic small bowel perforation in one of these patients. Each patient showed a complete response to chemotherapy. CONCLUSION: Surgical resection remains the first-line treatment of intra-abdominal desmoid tumors. However, doxorubicin/ dacarbazine chemotherapy on a clinical trial basis may be indicated in patients whose intra-abdominal desmoid is unresectable, or who have failed to respond to treatment with hormones (tamoxifen, Toremifene), steroids (prednisone), and nonsteroidal anti-inflammatory agents (Clinoril®; Merck & Co., Inc., West Point, PA).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02048164
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    HLA class II genes and antibodies against recombinant U1-nRNP proteins in patients with systemic lupus erythematosus (1994)
    Springer
    Rheumatology international 14 (1994), S. 63-69 
    Details
    ISSN: 1437-160X
    Keywords: Systemic lupus erythematosus ; Recombinant U1-nRNP proteins ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To investigate a possible involvement of HLA-class II alleles in the genetic predisposition for the formation of anti-U1-nRNP antibody in systemic lupus erythematosus (SLE), genomic DNA of 178 patients was typed for the DRB1, DQA1 and DQB1 alleles using a polymerase chain reaction (PCR) and non-radioactive-oligonucleotide typing. Antibodies against recombinant U1-nRNP proteins (U1-A- U1-C-and 70K-protein) were determined by ELISA. Anti-U1-C antibody was found in 26 (14.7%), anti-U1-A in 34 (19.2%) and anti-70K in 17 (9.6%) patients. A joint occurrence was observed for these antibodies against the recombinant U1-nRNP proteins: anti-U1-C and anti-U1-A antibodies occurred together more frequently than alone and than together with anti-U1-70K antibodies. The frequency of DRB1 * 04 was slightly increased in the patients with anti-U1-C as compared to the patients without anti-U1-C (P〈0.05, Pcorr=n.s., RR=2.4). The DQA1 * 0301 allele, which is in linkage disequilibrium with DRB1 * 04, is found more frequently in anti-U1-C-positive than in antibody-negative patients. The DQB1 * 0303 allele, detected in 12 of 176 SLE patients, was absent in the patients with any of the antibodies against the U1-nRNP proteins. All these deviations may be due to chance alone. We concluded that the presence of antibodies against recombinant U1-nRNP proteins was not significantly associated with any HLA DRB1, DQA1 and DQB1 allele in our group of SLE patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300249
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Multiple sclerosis: genetic versus environmental aetiology: epidemiology in Israel updated (1994)
    Springer
    Journal of neurology 241 (1994), S. 341-346 
    Details
    ISSN: 1432-1459
    Keywords: Multiple sclerosis Epidemiology ; Immigrants Environment ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The incidence and prevalence of multiple sclerosis (MS) were compared, controlling for age, in native-born Israelis of different origins and in immigrants to Israel. This comparison was carried out in two populations, countrywide and in Jerusalem. In the countrywide population, ascertainment was based mainly on hospitalizations; it included 252 patients who were native-born and 150 who had immigrated from Africa-Asia (AA immigrants). The 89 MS patients of Jerusalem also included patients diagnosed in outpatient clinics. In native-born Israelis whose father was born in Europe-America (I-EA), the incidence and prevalence of MS were found to be as high as or even higher than that found previously in immigrants from Europe-America. Among native-born Israelis whose father was born in Africa or Asia (I-AA), the yearly age-adjusted incidence and prevalence rates were found to be 1.4- to 1.8-fold higher than among AA immigrants, pointing to environmental factors. The incidence and prevalence rates in the I-EA were 1.2- to 1.6-fold higher than in the I-AA, pointing to genetic factors. These results seem to point to both environmental and genetic factors in the aetiology of MS. Further research is needed, however, to disentangle the genetic factors from possible environmental differences in the two ethnic groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00868444
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Clinical and genetic aspects of juvenile absence epilepsy (1994)
    Springer
    Journal of neurology 241 (1994), S. 487-491 
    Details
    ISSN: 1432-1459
    Keywords: Juvenile absence epilepsy ; Valproate ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Fifteen patients aged 11–25 years (mean 15.37, SD 3.89) suffering from juvenile absence epilepsy are presented. Only 3 (20%) had absences (AS) as the only seizure type, 12 (80%) had associated generalized tonic-clinic seizures (GTCS) and in the remaining 3 with absences and GTCS there was also sporadic myoclonus. We found a higher frequency of AS in our patients by clinical history and video-EEG than has been previously reported. In our patients the mean age of onset in years was 11.4, SD 1.24 for AS, 13.12, SD 2.31 for GTCS and 12.5, SD 2.18 for myoclonus. The correct diagnosis was not made on referrals for any of the patients. It took an average of 3–5.5 years from the onset of the AS (range: 6–120 months) and 2 years from the occurrence of GTCS (average: 1–72 months) to make the correct diagnosis and institute proper treatment, which was valproic acid (VPA). The GTCS were controlled in all patients whereas AS continued in 6 (40%), but to a significantly lesser degree. The frequency and the duration of the GTCS before the start of VPA treatment seemed to have an adverse effect on AS control. We documented no circadian rhythm in either AS or the GTCS, except in 2 patients who had AS and GTCS mainly when they awoke in the morning. The sample size was too small to perform a proper genetic study, though a positive history of epilepsies of mixed types was obtained in 35.7% of the parents and the siblings of the probands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00919710
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Follow-up and family study of postpartum psychoses (1994)
    Springer
    European archives of psychiatry and clinical neuroscience 244 (1994), S. 138-140 
    Details
    ISSN: 1433-8491
    Keywords: Parity ; Genetics ; Diathesis-stress model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract As part of a follow-up and family study of post-partum psychoses, this episode of illness being the first leading to psychiatric hospitalisation, patients with puerperal episodes (PE) and nonpuerperal episodes (NPE) of illness in the long-term course (n=79) were compared to patients with PE only (n=40). Few differences were found. Relatives of patients with PE only had a lower morbidity risk for functional psychoses than relatives of patients with PE and NPE. A favourable course of illness in the presence of a low genetic predisposition may be expected, according to the diathesis-stress model of functional psychoses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02191888
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    766 cases of oral cleft in Italy (1994)
    Springer
    European journal of epidemiology 10 (1994), S. 317-324 
    Details
    ISSN: 1573-7284
    Keywords: Epidemiology ; Genetics ; Oral clefts ; Registers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Epidemiological and genetic variables for oral clefts were analysed for the years 1981–1989 in a case-control study of congenital malformations in the Emilia Romagna, Veneto, and Friuli regions, and in the Trento and Bolzano hospitals. Birth prevalence for all cases of cleft lip with or without cleft palate (CL(P)) was 8.2 per 10,000 births, and that for cleft palate only (CP) was 6.1 per 10,000. Coexisting abnormalities were found in 23% of CL(P) cases and in 43% of CP. No clusters in time or space were detected. For isolated clefts, a predominance of males among CL(P) and of females among CP was found; epilepsy was the only maternal risk factor correlated with clefts, and an association between clefting and consanguinity was found. Empirical recurrence risks were calculated in both isolated CL(P) and CP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01719356
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Molecular marker-facilitated studies in an elite maize population: I. Linkage analysis and determination of QTL for morphological traits (1994)
    Springer
    Theoretical and applied genetics 88 (1994), S. 7-16 
    Details
    ISSN: 1432-2242
    Keywords: Maize ; Restriction fragment length polymorphisms (RFLPs) ; Qualitative and quantitative inheritance ; Plant breeding ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Restriction fragment length polymorphisms (RFLPs) and one morphological marker were used to investigate quantitative trait loci (QTL) for morphological and physiological traits evaluated on 150 F2∶3 maize (Zea mays L.) lines derived from the cross of elite U.S. Corn Belt inbreds Mo17 and H99. F2∶3 lines were grown in a replicated experiment and evaluated for plant and ear heights and flowering traits. QTL were identified for each trait, and genetic effects were determined. Estimated gene action for the flowering traits was predominantly overdominance. Both parents contributed toward increased values for anthesis and silk emergence. QTL for increased plant and ear heights were usually contributed by the taller parent, Mo17. Estimated gene action for these traits was mainly partial to overdominance. QTL for plant height were located in the vicinity of loci defined by alleles with qualitative effects on plant height.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222387
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Expression of a reporter gene is reduced by a ribozyme in transgenic plants (1994)
    Springer
    Molecular genetics and genomics 245 (1994), S. 465-470 
    Details
    ISSN: 1617-4623
    Keywords: Gene regulation ; Ribozyme ; npt-gene ; Transgenic tobacco ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A chimeric gene encoding a ribozyme under the control of the cauliflower mosaic virus (CaMV) 35S promoter was introduced into transgenic tobacco plants. In vivo activity of this ribozyme, which was designed to cleave npt mRNA, was previously demonstrated by transient expression assays in plant protoplasts. The ribozyme gene was transferred into transgenic tobacco plants expressing an rbcS-npt chimeric gene as an indicator. Five double transformants out of sixteen exhibited a reduction in the amount of active NPT enzyme. To measure the amount of ribozyme produced, in the absence of its target, the ribozyme and target genes were separated by genetic segregation. The steady-state concentrations of ribozyme and target RNA were shown to be similar in the resulting single transformants. Direct evidence for a correlation between reduced npt gene expression and ribozyme expression was provided by crossing a plant containing only the ribozyme gene with a transgenic plant expressing the npt gene under control of the 35S promoter, i.e. the same promoter used to direct ribozyme expression. The expression of npt was reduced in all progeny containing both transgenes. Both steady-state levels of npt mRNA and amounts of active NPT enzyme are decreased. In addition, our data indicate that, at least in stable transformants, a large excess of ribozyme over target is not a prerequisite for achieving a significant reduction in target gene expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302259
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Gel permeation chromatographic analysis of polyurethane prepolymer synthesis kinetics II. The effects of stoichiometry and type of diisocyanate (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 113-120 
    Details
    ISSN: 0887-624X
    Keywords: polyurethane ; chromatography ; stoichiometry ; GPC ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of formation of polyurethane prepolymers is studied by an analytical technique which involves reactive quenching of the isocyanate, separation of the oligomeric species by GPC, and measurement by UV absorbance of the quenched moieties. The precision of the kinetic parameters and the ratios of the oligomers are determined. The effect of changes in reactant stoichiometry on the ratio of oligomers is measured and compared to the value predicted by an equation from Flory. Toluene diisocyanate is shown to give fewer high oligomers than predicted, while methylene diphenylene diisocyanate gives nearly the predicted values. Tetramethylxylene diisocyanate gives more high oligomers than predicted, an unexpected but possibly important result. Catalyst is shown to increase the reaction rate of the last by more than 200 times. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320113
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Whiskers. VII. Homo- and copolyesters of 6-hydroxythioxanthone-2-carboxylic acid (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 159-165 
    Details
    ISSN: 0887-624X
    Keywords: 4-hydroxybenzoic acid ; 6-thioxantone-2-carboxylic acid ; copolyesters ; whiskers ; polycondensation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 6-Hydroxythioxanthone-2-carboxylic acid (HTCA) was prepared from commercial dimethylnitroterephthalate via 2-(4'-hydroxythiophenyl) terephthalic acid. HTCA was acetylated and polycondensed in an inert reaction medium at 350 or 400°C. An insoluble and infusible, highly crystalline polyester was obtained, which did not form whisker-like crystals. Furthermore, copolyesters with 4-hydroxybenzoic acid (4-HBA) were synthesized and whiskers were obtained at a molar ratio of 1 : 9 (in favor of 4-HBA). A meltable, nematic copolyester was prepared by cocondensation of silylated 6-acetoxythioxanthone-2-carboxylic acid and silylated 4-acetoxybenzoic acid in bulk. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320118
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    High modulus polyimide/polyimide molecular composite films that utilize acetylene unit as a crosslink site (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 167-174 
    Details
    ISSN: 0887-624X
    Keywords: polyimide molecular composite ; crosslinking ; internal acetylene ; laminate processing ; high modulus ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyimide/polyimide molecular composite (MC) films comprised of a rigid polyimide derived from biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA) and a flexible polyimide derived from BPDA and bis (3,3'-diaminodiphenyl) acetylene (intA) and/or oxydianiline (ODA) were prepared by blending the polyamic acid solutions in 7 : 3 weight ratio, and then imidizing the blend films. Acetylene content in the flexible polyimide backbone was controlled by the ratio of intA and ODA. Cold-drawing of the blend polyamic acid films, followed by imidization, gives high modulus polyimide/polyimide MC films. The modulus of the MC films increased almost linearly with the draw ratio, reaching 25.5 GPa for the 40% drawn film. Acetylene groups in the flexible polyimide can be thermally cured to crosslink. The onset of exotherm appeared at 340°C on DSC, reaching maximum at 398°C. After the thermal crosslinking, the MC films maintained the high modulus, though elongation became small. Taking advantage of the crosslinkable acetylene units, two MC films were laminated and processed at 400°C for 20 min under 100 kg/cm2 to give a good-quality laminate film. The interface of the two films was strongly bonded through the crosslinking of acetylene groups. Laminate films maintained the high modulus afforded by the cold-drawing. © 1994 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320119
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    New polymer syntheses. LXXV. 2,5-biaryloxyterephthalic acids and rigid-rod polyaramides derived from them (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 355-362 
    Details
    ISSN: 0887-624X
    Keywords: bisaryloxyencephthalic Acids ; polyaramides ; rigid-rod polymers ; molecular blends ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several 2,5-bisaryloxyterephthalic acids were prepared by a new method, namely arylation of diethyl-2,5-bistrimethylsiloxyterephthalate. Rigid-rod polyaramides were prepared by polycondensation of silylated diamines with a terephthaloylchloride with two diphenylsulfone side chains. Another polyamide was prepared from 2,5-bis(4′-cyanophenoxy) terephthalic acid and 1,4-diaminobenzene. None of these polyaramides is meltable and their solubilities differ largely. A copolymer of 1,4-diaminobenzene and 3,3′-dimethoxybenzidine is soluble in various organic solvents including polar vinyl monomers. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320217
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Silolene-Bridged zirconocenium polymerization catalysts (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 149-158 
    Details
    ISSN: 0887-624X
    Keywords: metallocene ; stereoselective catalyst ; propylene polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new silolene-bridged compound, racemic (1,4-butanediyl) silylene-bis (1-η5-in-denyl) dichlorozirconium (1) was synthesized by reacting ZrCl4 with C4H8Si (IndLi)2 in THF. 1 was reacted with trialkylaluminum and then with triphenylcarbenium tetrakis (penta-fluorophenyl) borate (2) to produce in situ the zirconocenium ion (1+). This “constraint geometry” catalyst is exceedingly stereoselective for propylene polymerization at low temperature (Tp = -55°C), producing refluxing n-heptane insoluble isotactic poly(propylene) (i-PP) with a yield of 99.4%, Tm = 164.3°C, δHf = 20.22 cal/g and M̄w = 350 000. It has catalytic activities of 107-108 g PP/(mol Zr · [C3H6] · h) in propylene polymerization at the Tp ranging from -55°C to 70°C, and 108 polymer/(mol Zr · [monomer] · h) in ethylene polymerization. The stereospecificity of 1+ decreases gradually as Tp approaches 20°C. At higher temperatures the catalytic species rapidly loses stereochemical control. Under all experimental conditions 1+ is more stereospecific than the analogous cation derived from rac-dimethylsilylenebis (1-η5-indenyl)dichlorozirconium (4). The variations of polymerization activities in ethylene and in propylene for Tp from -55°C to +70°C indicates a Michaelis Mention kinetics. The zirconocenium-propylene π-complex has a larger insertion rate constant but lower thermal stability than the corresponding ethylene π-complex. This catalyst copolymerizes ethylene and propylene with reactivity ratios of comparable magnitude rE ˜ 4rp. Furthermore, rE.rp ˜ 0.5 indicating random copolymer formation. Both 1 and 4 activated with methylaluminoxane (MAO) exhibit much slower polymerization rates, and, under certain conditions, a lower stereo-selectivity than the corresponding 1+ or 4+ system. © 1994 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320117
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Thermal isomerization of alternating silphenylene-siloxane copolymer (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 187-191 
    Details
    ISSN: 0887-624X
    Keywords: thermal degradation ; polysiloxane ; alternating copolymer ; thermal isomerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320122
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Phosphorus containing polymers. III. Polyimidophosphonates (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 219-227 
    Details
    ISSN: 0887-624X
    Keywords: Polyimidophosphonate ; dihydroxybismide ; phase transfer catalyst ; 31PNMR ; flame retardancy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of dihydroxybisimide monomers and their subsequent polycondensation with dichlorophenylphosphine oxide by use of a phase-transfer catalyst are reported. The monomers were characterized by melting point, elemental analysis, and IR spectroscopy. The polyimidophosphonates were characterized by viscosity measurement, molecular weight determination, elemental analysis, IR, ESCA, 1H-NMR, 31P-NMR, and X-ray diffraction. Thermal stability and glass transition temperature (Tg) of the polymers were evaluated by TGA, DTA, and TMA. These polymers are self-extinguishing and readily soluble in highly polar solvents like DMF, DMSO, DMAC, NMP, HMPA, etc. © 1994 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320202
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Free radical exit in emulsion polymerization. I. Theoretical model (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 605-630 
    Details
    ISSN: 0887-624X
    Keywords: free radical ; exit ; emulsion ; polymerization ; model ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The exit or desorption of free radicals from latex particles is an important kinetic process in an emulsion polymerization. This article unites a successful theory of radical absorption (i.e., initiator efficiency), based on propagation in the aqueous phase being the rate determining step for entry of charged free radicals, with a detailed model of radical desorption. The result is a kinetic scheme applicable to true “zero-one” systems (i.e., where entry of a radical into a latex particle already containing a radical results in instantaneous termination), which is still, with a number of generally applicable assumptions, relatively simple. Indeed, in many physically reasonable limits, the kinetic representation reduces to a single rate equation. Specific experimental techniques of particular significance and methods of analysis of kinetic data are detailed and discussed. A methodology for both assessing the applicability of the model and its more probable limits, via use of known rate coefficients and theoretical predictions, is outlined and then applied to the representative monomers, styrene and methyl methacrylate. A detailed application of the theory and illustration of the methodology of model discrimination via experiment is contained in the second article of this series. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320402
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Synthesis of tert-butyl-substituted poly (ether ketone) by nickel-catalyzed coupling polymerization of aromatic dichloride (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 675-681 
    Details
    ISSN: 0887-624X
    Keywords: nickel ; coupling polymerization ; aromatic dichloride ; tert-butyl-substituted poly (ether ketone) ; de-tert-butylation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: tert-Butyl substituted poly (aryl ether ketone)s with relatively high molecular weights were prepared by the Ni-catalyzed polymerization of tert-butyl substituted aromatic dichlorides containing ether ketone unit. These polymers were amorphous and soluble in common organic solvents, such as THF, dichloromethane, and chloroform. De-tert-butylation of the polymer by the treatment of trifluoromethanesulfonic acid in the presence of toluene proceeded smoothly and produced crystalline poly (aryl ether ketone). © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320406
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Synthesis and thermal properties of liquid-crystalline polyacrylates containing a carbazolyl group in the mesogen (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 711-719 
    Details
    ISSN: 0887-624X
    Keywords: carbazolyl group ; liquid-crystalline polymer ; polyacrylate ; nematic phase ; smectic phase ; electron beam polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new acrylate monomers 4-(ω-acryloyloxyalkyloxy)-N-(9-methyl-2-carbazolylmethylene) anilines containing from 2 to 11 methylenic units in their alkyl group and a carbazolyl group in the mesogenic unit were synthesized and polymerized by azobisisobutyronitrile (AIBN) as radical initiator and by low-energy electron beam (EB) initiation. The thermal properties of the resulting polymers were examined using differential scanning calorimetry and thermal optical polarizing microscopy. The polymer prepared by AIBN with a hexamethylene spacer exhibited a nematic phase from 73 to 170°C and with an undecamethylene spacer exhibited a smectic phase from 55 to 202°C. The isotropization temperature of the polyacrylates increased with increasing the number of carbons of the methylenic spacer. The yield of the resulting polymer was changed by EB irradiation temperature from 4.5 to 41%. The highest yield was obtained when the monomer was polymerized in a liquid-crystalline phase. The same tendency was observed in the molecular weight of the resulting polymers. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320409
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Thermotropic copolyamides from triethyleneglycol bis (4-carboxyphenyl) ether, aromatic diamines, and p-aminobenzoic acid (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 747-752 
    Details
    ISSN: 0887-624X
    Keywords: thermotropic copolyamides ; depression of transition temperatures ; p-aminobenzoic acid ; amide bond structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is proposed that depression of the transition temperatures, especially the melting point (Tm), can be achieved by the introduction of a different amide bond structure into the copolyamides of dicarboxylic acids and diamines by copolymerization of aminocarboxylic acids, such as p-aminobenzoic acid. The effect was examined by the amount and distribution of the structure in the copolylamindes. Copolycondensations of PEG3, p-aminobenzoic acid, and diamines with different chain lengths showed that the structural change of the amide bond in the copolymers, especially its distribution, was more important than its total amount in them. Several types of aminocarboxylic acids were briefly examined to study the effect. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320413
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Spectroscopic study of solid state photoreaction of di n-propyl ester of dicyano p-phenylenediacrylic acid (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 797-801 
    Details
    ISSN: 0887-624X
    Keywords: solid state photopolymerization ; exciton-phonon coupling ; homogeneous and heterogeneous reaction mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photopolymerization reaction in di n-propyl ester of dicyano p-phenylene diacrylic acid crystal is shown to be mediated by exciton-phonon coupling. Raman phonon spectra suggest that at the initial stage of reaction progress, the reactant and the product form a solid solution. In the later stage, the reactant segregates out and forms its own lattice. The polymer lattice is shown to maintain a good degree of order. Infrared and Raman spectra confirm that the polymerization occurs by cyclobutane ring formation. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320501
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Modification of poly(epichlorohydrin) with nadimide derivatives and their curing reaction (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 829-840 
    Details
    ISSN: 0887-624X
    Keywords: chemical modification ; poly (epichlorohydrin) ; nadimide ; polyethers ; DSC ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemical modification of poly(epichlorohydrin) (PECH) with nadimide derivatives using 1,8-diazabicyclo (5.4.0)-7 undecene to catalyze the substitution of the chlorine atom by acid compounds (DBU method) was accomplished. The linear polyethers obtained showed a degree of substitution from 5-80%, depending on time and temperature reaction. The Tg of modified polymers and Ea, calculated in the cure reactions, increases with substitution degree. Residual enthalpies were observed in all cases, which suggests that the curing reaction is incomplete. TGA measurements showed that the degradation has a greater dependence on the modification degree than on the introduced pendant group. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320504
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Block copolymers by polymer modification: Conversion of polyisoprene segment to hydroxylated polyisoprene (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 869-877 
    Details
    ISSN: 0887-624X
    Keywords: polymer modification ; block copolymer ; hydroxylation of polyisoprene ; trifluoroacetylation of polyisoprene ; polymer monolayer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyisoprene (PIP) was found to react with trifluoroacetic acid (TFA) to give an adduct. Saponification of the ester gave a new alternating copolymer of ethylene and α-methyl vinyl alcohol. TFA did not react with polybutadiene (PBD) under these conditions, thus providing a way to produce amphiphilic block copolymers from PBD-b-PIP. TFA addition to the PIP block took place cleanly at an ambient temperature with 2 equiv of the acid in toluene to give block copolymer of PBD and trifluoroacetated PIP. This polymer is very soluble in toluene regardless of molecular weight. Methanolysis with NaOMe cleaved the ester to give PDB-b-(ethylene-alt-α-methyl vinyl alcohol) (PIPOH) in a MeOH/toluene mixture. Low molecular weight hydroxylated diblock copolymer is a viscous liquid when the ratio of PIP/PBD is 0.1 ( \documentclass{article}\pagestyle{empty}\begin{document}$\overline {M_n }$\end{document} = 4100, D = 1.3), but a solid with the ratio 0.5 (\documentclass{article}\pagestyle{empty}\begin{document}$\overline {M_n }$\end{document} = 7170, D = 1.6). High molecular weight polymer (\documentclass{article}\pagestyle{empty}\begin{document}$\overline {M_n }$\end{document} = 114,000, D = 1.4) with PIP/PBD ratio 0.1 is a hazy rubbery material. Block copolymers of PIPOH and poly(methacrylic acid) was also obtained from copolymers of PIP and poly(t-butyl methacrylate). The hydroxylated copolymers showed surface activity by monolayer formation on a Langmuir-Blodgett trough. The transfer of the monolayer on a silicon wafer gave z-type deposition, with the average ellipsometer thickness of the layer being about 40 Å thick per monolayer for \documentclass{article}\pagestyle{empty}\begin{document}$\overline {M_n }$\end{document} = 4100 copolymer. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320508
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of new aromatic polyesters and polyethers derived from 1,2-bis(4-hydroxyphenyl)-1,2-diphenylethylene (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 909-915 
    Details
    ISSN: 0887-624X
    Keywords: high-temperature polyarylates ; dihydroxytetraphenylethylene ; solubility behavior ; thermal behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New polyarylates and aromatic polyethers were synthesized from 1,2-bis(4-hydroxyphenyl)-1,2-diphenylethylene, and aromatic dicarboxylic acid chlorides and aromatic dihalides, respectively. The polyarylates having inherent viscosities of 0.28-1.05 dL/g were synthesized by either the two-phase method or the high-temperature solution method. All the polymers were easily soluble in N-methyl-2-pyrrolidone, N,N-dimethylformamide, pyridine, m-cresol, 1,4-dioxane, and 1,1,2,2-tetrachloroethane. They have glass transition temperatures in the range of 217-250°C and showed no weight loss below 315°C in both air and nitrogen atmospheres. Aromatic polyethers with inherent viscosities of 0.85-1.21 dL/g were obtained by the polycondensation of 1,2-bis(4-hydroxyphenyl)-1,2-diphenylethylene and aromatic difluorides in the presence of potassium carbonate. These polymers having glass transion temperatures of 193-220°C were also soluble in the aforementioned solvents and stable up to around 350deg;C in both atmospheres. © 1994 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320512
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Reduced titanium dioxide as support for Ziegler-Natta catalystsThis work is part of the Ph.D. Thesis of S. Jericó and has been the subject of a patent (see Ref. 1) (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 929-935 
    Details
    ISSN: 0887-624X
    Keywords: reduced titanium dioxide ; supported titanium tetrachloride ; ethylene polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Titanium tetrachloride heterogenized on reduced TiO2 has been studied as a catalyst for ethylene polymerization. The catalyst has good storage stability and exhibits good activity for ethylene polymerization. The polymer chains grow linearly during ca. 1 h, giving an average molecular weight of up to 2.5 × 106 which indicates that practically no β-elimination occurs. The activity of the catalyst at 50°C, based on Ti(III), is 7.6 × 106 PE/mol Ti h bar and based on the quantity of polyethylene formed it is 1.25 × 106 g PE/mol Ti h bar. The molecular weight of the polymer can be controlled with the addition of hydrogen, under 0.5 bar hydrogen, polyethylene with a molecular weight of 411,000 and a relatively low polydispersity index of 2.2 is obtained. The catalyst shows good thermal stability; the Arrhenius activation energy is 31.8 kJ/mol for the polymerization. The catalyst is also active for propylene polymerization, giving 3 × 106 g PP/mol Ti h bar with the high isotacticity of 93%. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320514
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Ring-Opening polymerization of ε-caprolactone by rare earth coordination catalysts. I. Characteristics, kinetics, and mechanism of ε-caprolactone polymerization with nd(acac)3.3H2O-ALET3 system (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 597-603 
    Details
    ISSN: 0887-624X
    Keywords: ε-caprolactone ; ring-opening polymerization ; rare earth coordination catalyst ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ring-opening polymerization of ε-caprolactone has been carried out by using rare earth coordination catalysts for the first time. The rare earth compounds, RE(acac)3.3H2O, Nd(P204)3, Nd(P507)3, Nd(naph)3, Nd(BA)3.2H2O, etc. (where RE = La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Lu, Y; acac = acetylacetone; BA = benzoylacetone), combined with trialkyl aluminum, greatly increased the degree of conversion and the molecular weight of poly(ε-caprolactone) (PCL). The influence of reaction conditions on the polymerization of ε-caprolactone catalyzed by the Nd (acac)3.3H2O-AlEt3 system has been examined in detail. The kinetics indicates that the polymerization rate has the first-order in monomer and a half-order in catalyst. The overall activation energy of the ring-opening polymerization amounts to 59.4 kJ/mol. By IR and UV-Vis spectra, 1H- and 13C-NMR data, it is assumed that the ring-opening polymerization of ε-caprolactone catalyzed by the Nd(acac)3.3H2O-AlEt3 system proceeds via complexation of monomer to catalyst, acyl-oxygen cleavage insertion propagation mechanism. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320401
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    The synthesis and cationic polymerization of multifunctional silicon-containing epoxy monomers and oligomers (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 683-697 
    Details
    ISSN: 0887-624X
    Keywords: hydrosilation ; epoxy monomers ; epoxy functional oligomers ; cationic photopolymerization ; regioselective hydrosilation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several series of multifunctional silicon-containing epoxide monomers and oligomers have been prepared using rhodium catalyzed hydrosilation reactions. Dialkyl and diarylsilanes can be condensed with vinyl epoxides to give high yields of the desired diepoxides while the hydrosilation of alkyl and aryl silanes yields a mixture of di and tri epoxy substituted products. The condensation of αω,—Si—H difunctional compounds with vinyl epoxides can be carried out regioselectively to give α-hydrogen-ω-epoxy intermediates, which can be further reacted with di and tri olefins bearing terminal double bonds to give a series of well characterized epoxy functional oligomers. An investigation of the photoinitiated cationic polymerization of the monomers and oligomers, which were prepared during the course of these studies, was carried out. © 1994 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320407
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Syndioselective propylene polymerization catalyzed by rac-2,2-dimethylpropylidene (1-η5-cyclopentadienyl) (1-η5-fluorenyl) dichlorozirconium (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 661-673 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syndioselective propylene polymerization has been promoted by rac-2,2-dimethylpropylidene (1-η5-cyclopentadienyl) (1-η5-fluorenyl) dichlorozirconium (1). The active catalytic species were generated using either triphenylcarbenium tetrakis (pentafluorophenyl) borate (2) (Zr+ method) or methylaluminoxane (MAO method). The former exhibited much higher activity than the latter, especially at low polymerization temperatures (Tp). Syndiotactic poly (propylene) (s-PP) obtained at Tp = -20°C has Tm approaching 160°C, [rrrr] pentad fraction of 0.92 to 0.95, and 45% crystallinity (Xc). It crystallized in two antichiral unit cells B and C. The C structure is favored by low temperature of polymerization, slow crystallization from melt, and annealing. The s-PP has M̄w/M̄n ranging from 3.6 to 4.4, which can be separated into stereoregular fractions soluble in heptane and hexane and stereoirregular fractions soluble in pentane, ether, and acetone. Therefore, this system cannot be considered to be a single-site catalyst. A parallel study was made on the isopropylidene (1-η5-cyclopentadienyl) (1-η5-fluorenyl) dichlorozirconium (3)/MAO catalyst. Molecular mechanics calculations were performed for all combinations of the configuration of asymmetric centers. The steric energy favors syndiotactic enchainment for both catalysts 1 and 3, with 1 forming the more syndioselective catalyst. © 1994 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320405
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Synthesis of ion-free latex particles composed of polybutadiene and poly (vinyl pyrrolidone) as polymer electrolyte materials (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 767-777 
    Details
    ISSN: 0887-624X
    Keywords: emulsion polymerization ; ion-free ; polybutadiene ; poly (vinyl pyrrolidone) ; polymer electrolyte ; latex ; core-shell ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of polybutadiene (PB) by emulsion polymerization with use of poly (vinyl pyrrolidone) (PVP) stabilizer was investigated. The goal was to prepare flexible latex films that clearly retain particle morphology in the solid state after heat treatment and contain no ionic, hydroxyl, or (primary, secondary) amino groups. The latex particle core composed of PB was nonpolar and rubbery, while the particle shell composed of PVP was polar and glassy. Average particle diameter was measured by the dynamic light scattering technique, and particles were imaged by scanning and transmission electron microscopic analyses. Dialysis of the latices resulted in successful exchange of the dispersion medium without precipitation. © 1994 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320415
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Thermal polycondensation synthesis of biomimetic serine-containing derivatives of polyaspartate: Potent inhibitors of calcium carbonate and phosphate crystallization (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 789-795 
    Details
    ISSN: 0887-624X
    Keywords: polycondensation ; serine ; aspartic acid ; inhibitors ; crystallization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Biocompatable, degradable polymers that are powerful inhibitors of mineral formation were synthesized by automated solid phase and thermal polycondensation techniques. These polymers are analogues of natural proteins isolated from CaCO3 biomineral and consist primarily of polyaspartic acid and serine or modified serine residues. Phosphorylation of the serine residues greatly enhanced the inhibitory activity of the polymers. Synthesis in the presence of orthophosphoric acid resulted in the decomposition and modification of serine. These modified residues when incorporated into the polyaspartic acid also enhanced inhibitory activity of the polymers. © 1994 John Wiley & Sons, Inc.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320417
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Polymers incorporating backbone thiophene, furan, and alcohol functionalities formed through chemical modifications of alternating olefin-carbon monoxide copolymers (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 841-847 
    Details
    ISSN: 0887-624X
    Keywords: ethylene-carbon monoxide copolymer ; propylene-carbon monoxide copolymer ; polythiophene ; polyfuran ; polyalcohol ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of the alternating ethylene-carbon monoxide copolymer with Lawesson's reagent resulted in the conversion of 75% of the carbonyl groups to thiophene units. A few thioketone groups were also present in the derived polymer. A polymer with furan units in the backbone was formed upon treatment of the alternating propylene-carbon monoxide copolymer with P2O5. Depending on the reaction conditions, up to 90% of the carbonyl groups were converted. Finally, 1,4-polyalcohols were prepared from the alternating propylene-carbon monoxide copolymer by reduction. Hydrogenation using Raney nickel as catalyst resulted in the reduction of 60% of the carbonyl groups, whereas reaction with LiAlH4 at room temperature caused the reduction of 85% of the carbonyl groups. The glass transition temperature was found to increase monotonically with increasing concentration of hydroxyl groups in the polymer backbone. © 1994 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320505
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Role of added Lewis base and alkylaluminum halide on living cationic polymerization of vinyl ether (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 879-887 
    Details
    ISSN: 0887-624X
    Keywords: living cationic polymerization ; isobutyl vinyl ether ; added Lewis base ; EtAlCl2 ; Et1.5AlCl1.5 ; polymerization mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the living cationic polymerization of isobutyl vinyl ether (IBVE) by the CH3CH (OiBu) OCOCH3 (1)/EtAlCl2 initiating system in the presence of the added base in hexane at +40°C, the stability of the initiating system 1/EtAlCl2, which form initiating species CH3CH⊕ (OiBu) derived from 1, was investigated. In the presence of the Lewis base such as ethyl acetate or 1,4-dioxane, the active species was stable for 300 min even at +40°C in the absence of IBVE, and the living polymers were quantitatively obtained by adding IBVE. However, the active species was partly consumed by side reactions during the standing time for 60 min in the presence of a less basic additive such as ethyl benzoate, and about 50% of the active species was deactivated in the presence of methyl chloroacetate. Consequently, in the case of a less basic additive such as methyl chloroacetate (which was effective for the fast living polymerization), it can be seen that the careful selection of polymerization conditions was required. The living polymerization rate was dependent on the second order of EtAlCl2 concentration. EtAlCl2 induced the cleavage of 1 into CH3CH⊕ (OiBu) and EtAl⊖Cl2(OCOCH3), and the reactivity of CH3CH⊕ (OiBu) and propagating carbocation may be controlled by EtAl⊖Cl2(OCOCH3) with the aid of other EtAlCl2. Et1.5AlCl1.5 exists as a bimetallic complex of EtAlCl2 and Et2AlCl, and it is expected that the polymers having a bimodal molecular weight distribution will be obtained due to two kinds of counteranions coming from EtAlCl2 and Et2AlCl. However, in the cationic polymerization of IBVE by 1/Et1.5AlCl1.5 in the presence of ethyl acetate, the living polymer exhibiting a unimodal and very narrow molecular weight distribution was obtained. Thereby, it was suggested that the counteranions, EtAl⊖Cl2(OCOCH3) and Et2Al⊖Cl(OCOCH3), exchange rapidly with each other. © 1994 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320509
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    A novel acrylate carrying a hindered phenol moiety as monomer and terminator in radical polymerization (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 917-928 
    Details
    ISSN: 0887-624X
    Keywords: radical polymerization ; stable phenoxyl radical ; intramolecular hydrogen transfer ; termination ; hindered phenol ; copolymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radical polymerizations of methyl methacrylate (MMA), styrene (St), and vinyl acetate (VAc) were carried out in the presence of a novel phenyl acrylate derivative bearing a hindered phenol moiety (HPA). It has been clarified that HPA acts as a retarder and inhibitor for the polymerizations of MMA and VAc, respectively, and that in the polymerization of St it behaves as a monomer to give a copolymer. These additive effects were interpreted in terms of intramolecular transfer of the phenolic hydrogen in competition with propagation of the HPA radical to monomers. © 1994 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320513
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Ethylene-hindered amine copolymer: A self-stabilized polyolefine (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 961-969 
    Details
    ISSN: 0887-624X
    Keywords: ethylene ; copolymerization ; hindered piperidine ; UV stabilizer ; chemically bound antioxidant ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomers having a norbornene as polymerizable group and a 2,2,6,6-tetramethyl piperidine as stabilizing moiety were prepared. This monomer was successfully copolymerized with ethylene using VAc3/AlEt2Cl as the catalytic system. Copolymers exhibited better stability under accelerated aging than polyethylene stabilized by classical blending with commercial hindered amines. Any attempt made to obtain copolymers using a high activity TiCl4/MgCl2 catalyst was unsuccessful. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320517
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Synthesis of new ethynylene-containing aromatic polyamides by palladium-catalyzed polycondensation of aromatic amide monomers having terminal ethynyl and halogen groups (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 987-991 
    Details
    ISSN: 0887-624X
    Keywords: palladium-catalyzed polycondensation ; soluble ethynylene-containing polyamides ; ethynyl-containing amide monomers ; thermal behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320521
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Separation of syn and anti-7-alkylnorbornene isomers by regioselective ring-opening metathesis polymerization (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 993-995 
    Details
    ISSN: 0887-624X
    Keywords: metathesis ; regioselective polymerization ; 7-alkylnorbornenes ; ab initio MO Calculations ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320522
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Fully aromatic thermotropic liquid crystalline polyesters of 3,4′-dihydroxybenzophenone (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 343-354 
    Details
    ISSN: 0887-624X
    Keywords: thermotropic polyester ; nematic ; X-ray diffraction ; synthesis ; characterization ; 3,4′-dihydroxybenzophenone ; 4,4′-bibenzoic acid ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of fully aromatic, thermotropic polyesters, derived from 3,4′-dihydroxybenzophenone and various aromatic dicarboxylic acids, was prepared by the high-temperature solution polycondensation method and examined for thermotropic behavior by a variety of experimental techniques. The aromatic dicarboxylic acids used in this study were 2,6-naphthalenedicarboxylic acid, 4,4′-bibenzoic acid, and terephthalic acid.The two homopolymers of 3,4′-DHB with either 2,6-NDA or 4,4′-BBA formed nematic LC phases at 285°C and 255°C and also exhibited isotropization transitions (Ti) at 317°C and 339°C, respectively. The copolymer of 3,4′-DHB with 50% TA and 50% 2,6-NDA also formed a nematic LC phase and had a broader range of LC phase than that of its respective homopolymers. Two other copolymers of 3,4′-DHB, both containing 50% 4,4′-BBA, also formed nematic LC phases at low Tf values. All of the thermotropic polyesters had high thermal stabilities. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320216
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Syntheses and properties of aromatic polyamides and polyimides based on N-phenyl-3,3-bis[4-(p-aminophenoxy) phenyl] phthalimidine (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 369-382 
    Details
    ISSN: 0887-624X
    Keywords: N-phenyl-3,3-bis[4-(p-aminophenoxy)phenyl] phthalimidine ; N-phenyl-3,3-bis (4-hydroxyphenyl) phthalimidine ; polyamides ; polyimides ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-Phenyl-3,3-Bis[4-(p-aminophenoxy)phenyl] phthalimidine (II) was used as a monomer with various aromatic dicarboxylic acids and tetracarboxylic dianhydrides to synthesize polyamides and polyimides, respectively. The diamine II was derived by a nucleophilic substitution of N-phenyl-3,3-bis(4-hydroxyphenyl) phthalimidine with p-chloronitrobenzene in the presence of K2CO3 and then hydro-reduced. Polyamides IVa-g having inherent viscosities of 0.55-1.64 dL/g were prepared by the direct polycondensation of the diamine II with various aromatic diacids using triphenyl phosphite and pyridine as condensing agents. All the aromatic polyamides were amorphous and readily soluble in various polar solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide, dimethylsulfoxide, and N-methyl-2-pyrrolidone (NMP). Transparent and flexible films of these polymers could be cast from the DMAc solutions. These aromatic polyamides had glass transition temperatures in the range of 293-319°C and 10% weight loss occurred up to 480°C. The polyimides were synthesized from diamine II and various aromatic dianhydrides via the two-stage procedure that included ring-opening polyaddition in DMAc to give poly(amic acid)s, followed by thermal or chemical conversion to polyimides. Most of the aromatic polyimides obtained by chemical cyclization were found to be soluble in NMP, m-cresol, and o-chlorophenol. These polyimides showed almost no weight loss up to 500°C in air or nitrogen atmosphere. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320219
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Absolute rate constants for radical homopolymerization of methyl α-(trifluoromethyl) acrylate (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1389-1392 
    Details
    ISSN: 0887-624X
    Keywords: methyl-(trifluoromethyl) acrylate ; propagation rate constant ; termination rate constant ; rotating sector method ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [no Abstrat]
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320721
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Polyisobutylene-containing block polymers by sequential monomer addition. X. Synthesis of poly(α-methylstyrene-b-isobutylene-b-α-methylstyrene) thermoplastic elastomersAlso Part LVIII of the series “Living Carbocationic Polymerization.” (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 403-412 
    Details
    ISSN: 0887-624X
    Keywords: thermoplastic elastomers ; poly (-methylstyrene-b-isobutylene-b--methylstyrene) ; triblock copolymer ; living carbocationic polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparatory to triblock synthesis experiments, the cationic polymerization of α-methylstyrene (αMeSt) was investigated using the 2-chloro-2,4,4-trimethylpentane (TMPCI)/TiCl4 initiating system in the presence of triethylamine (Et3N) as electron donor (ED) and CH3Cl/n-hexane mixed solvent in the -80 to -40°C range. Conversions are influenced by temperature, [TiCl4], [Et3N], and [αMeSt]. The polymerization of αMeSt is living at -80°C: Both termination and chain transfer to monomer are frozen out, however, initiation is slow relative to propagation. Highly syndiotactic (〉94%) Pα Mest was obtained. At-60deg;C initiator efficiency is ca. 100%, but termination becomes evident. Et3N may act both as Ed and as proton scavenger. Novel poly(α-methystyrene-b-isobutylene-b-α-methylstyrene) (PαMeSt-PIB-PαMeSt) triblocks have been synthesized by adding αMeSt to biliving polyisobutylene carbocations (⊕PIB⊕) in the -80 to -40°C range. The effects of temperature, solvent polarity, and [Et3N] on the block copolymerization have been investigated. At -80°C, the rate of crossover from ⊕PIB⊕ to αMeSt is lower than that of propagation of PαMeSt⊕, so that the triblock is contaminated by PIB and PIB-b-PαMeSt. At -60°C, crossover occurs preferentially. The rate of propagation relative to that of crossover is also reduced by lowering the solvent polarity and increasing the [Et3N]. High crossover efficiency and blocking efficiency can be obtained under optimum blocking conditions. The triblocks are novel thermoplastic elastomers (TPEs). © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320301
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Solid-state polyamidation of hexamethylenediammonium adipate. II. The influence of acid catalysts (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 451-456 
    Details
    ISSN: 0887-624X
    Keywords: hexamethylenediammonium adipate ; solid-state polycondensation (polyamidation) ; acid catalysts ; solid-melt transition ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Loss of diamine and distinct transition phenomena from the solid to the melt state restrain solid-state polymerization (SSP) of nylon salts from industrial application. To depress these phenomena temperatures well below the melting point of the starting material are employed, resulting however in low reaction rates. The need to use catalysts arises and accordingly in this study hexamethylenediammonium adipate (HMA) particles were polymerized containing a strictly controlled amount of uniformly distributed catalyst. The catalysts included boric, sulphuric, and phosphoric acids with boric acid being the most effective in accelerating the reaction while eliminating the tendency to agglomeration. In general, catalyst concentration up to a critical value plays a considerable role in the overall behavior. Furthermore, in agreement with non catalytic processes, the reaction temperature remains an influential parameter. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320306
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Synthesis of new linear polymers containing phosphorus atom in the main chain by the radical polyaddition: Addition polymers of phenylphosphine with 1,4-divinylbenzene or 1,4-diisopropenylbenzene and their properties (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 475-483 
    Details
    ISSN: 0887-624X
    Keywords: polyaddition ; phosphorus-containing polymer ; saturated polymer ; phenylphosphine ; 1,4-divinylbenzene ; 1,4-diisopropenylbenzene ; flame resistance ; thermal stability ; DSC ; TG ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A polyaddition of phenylphosphine (PH) to 1,4-divinylbenzene (DVB) or 1,4-diisopropenylbenzene (DIPB) was carried out by radical initiations or UV irradiation at 60-80°C in toluene under a nitrogen atmosphere. The soluble polymer with higher molecular weight ($\[ \bar M_w = 2 \times 10^4 \]$) was obtained in a high yield with AIBN initiator for 95 h in the presence of 5% excess of PH to DVB (monomer feed ratio [DVB]0/[PH]0 = 1/1.05). On the other hand, a polyaddition of PH to DIPB proceeded much slower than the case of DVB, but the high polymer was obtained in a high yield by choosing polyaddition conditions such as polyaddition temperature and initiator concentration. From 1H-NMR, IR analyses, and phosphorus content of the polymers, it was characterized that both polymers have the alternating structure consisting of PH and DVB or DIPB units in 1 : 1 ratio. The glass transition and decomposition temperatures of both polymers under a nitrogen atmosphere were almost similar: 15-30°C and 380-385°C, respectively; but, the polymers were oxidized by heating under an atmosphere of air. The polymers had a self-extinguishing property and the polymer blend of the flammable polymers such as polystyrene and polyethylene with the phosphorus-containing polymers exhibited an excellent flame resistance. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320309
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Studies on the formation of PEN. I. Kinetic aspects of catalyzed reaction in transesterification of dimethylnaphthalate with ethylene glycol (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1295-1304 
    Details
    ISSN: 0887-624X
    Keywords: poly (ethylene naphthalate) ; transesterification kinetics ; reaction order ; activation energy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The transesterification of dimethyl naphthalate (DMN) with ethylene glycol (EG) was kinetically investigated in the presence of various catalysts at 185°C. The transesterification was assumed to obey first-order kinetics with respect to DMN and EG, and a rate equation was derived. The rate constant of transesterification which was calculated from the quantity of methanol which distilled from the reaction vessel was used to evaluate the activity of each metal compound. The first-order dependence on the catalyst concentration is valid below a critical concentration which was found to be dependent on the catalyst type. The order of decreasing catalytic activity of various metal ions was found to be: Pb ≥ Zn 〉 Co 〉 Mg 〉 Ni ≥ Sb, but in the case of highly basic metal salts, the rate constants were found to be extremely large at the initial stage of the reaction, and then rapidly decreased with the progress of the reaction. Effects of reaction temperature were also discussed. The activation energies for zinc acetate and lead acetate were 97.84 and 108.8 kJ/mol, respectively, which were calculated from the Arrhenius equation. © 1994 John Wiley & Sons, Inc.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320710
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    High flow addition curing polyimides (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1341-1350 
    Details
    ISSN: 0887-624X
    Keywords: addition polyimides ; biphenyldiamine ; benzidine ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new series of high flow PMR-type addition curing polyimides was developed, which employed the substitution of 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (BTDB) for p-phenylenediamine (p-PDA) in a PMR-II formulation. These thermoset polyimides, designated as 12F resins, were prepared from BTDB and the dimethyl ester of 4,4′-(hexafluoroisopropylidene)-diphthalic acid (HFDE) with either nadic ester (NE) or p-aminostyrene (PAS) as the endcaps for addition curing. The 12F prepolymers displayed lower melting temperatures in DSC analysis, and higher melt flow in rheological studies than the corresponding PMR-II polyimides. Long-term isothermal aging studies showed that BTDB-based 12F resins exhibited comparable thermo-oxidative stability to p-PDA based PMR-II polyimides. The noncoplanar 2- and 2′-disubstituted biphenyldiamine (BTDB) not only lowered the melt viscosities of 12F prepolymers, but also retained reasonable thermal stability of the cured resins. The 12F polyimide resin with p-aminostyrene endcaps showed the best promise for long-term, high-temperature application at 343°C (650°F). © 1994 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320715
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Synthesis of graft polymers from an ozonized ethylene vinyl acetate copolymer (EVA). I. Study of the radical polymerization of styrene initiated by an ozonized EVA (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1377-1384 
    Details
    ISSN: 0887-624X
    Keywords: ozonization ; grafting ; kinetics ; radical polymerization ; EVAg-styrene ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymers can be ozonized with an ozone/oxygen mixture to create peroxides and hydroperoxides on the polymer chain. These heat-sensitive functional groups can be used to initiate radical polymerization of vinyl monomers and give graft copolymers. The properties of these copolymers are well described in literature; however, we notice that available data concerning decomposition rate constants are inconsistent. Decomposition rate measurements, time of assay of free radicals and stability of the ozonized polymers do not give the same results. In this work, we studied the kinetics of the styrene polymerization initiated by an ozonized ethylene vinyl acetate copolymer. Consequently, the f·kd product can be calculated (f is the efficiency and kd the decomposition rate constant). The ozonized copolymer is not similar to usual radical initiators. The initial viscosity of the solution has an important effect on the calculation of the kinetic values. Activation energy and Arrhenius coefficient are different than the one obtained for the usual initiators. © 1994 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320719
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Chemical derivatization as a mean to improve contact angle goniometry of chemically heterogenous surfaces (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 699-709 
    Details
    ISSN: 0887-624X
    Keywords: contact angle goniometry ; chemical derivatization ; plasma treatment ; polyethylene ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Plasma-oxidized polyethylene (O-PE) was derivatized with various chemicals and the advancing and receding contact angles with water, formamide, and tricresylphosphate were measured. The contact angles were used to evaluate the surface free energy (SFE) components in terms of the Lifshitz-van der Waals-acid base (LW-AB) model. The derivatization was directed to couple alkyl chains to carbonyl, hydroxyl, and carboxyl groups generated on the surface of O-PE. Carbonyl groups were treated with hydrazine and then reacted with dodecanoyl chloride. Hydroxyl groups were first reacted with reactive dicarboxylic acid dichlorides or cyanuric chloride, respectively, and then with alkylamines because the direct bonding of long-chain alkyl carboxylic acid chlorides proceeds slowly and is, therefore, completed by surface restructuring. Carboxyl groups were chlorinated and in a second step reacted with alkylamines. The bonding of C12-alkyl chains can be sensitively detected by the LW part of the SFE. Concerning the receding contact angles, it is pointed out that the carbonyl groups are present on the surface in a higher concentration than hydroxyl and carboxyl groups. The combination of contact angle goniometry (CAG) and chemical derivatization reactions supplies semiquantitative information about functional groups in the uppermost surface layer. In this way, a major shortcoming of CAG can be overcome. © 1994 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320408
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Mechanistic studies of carbonate macrocyclization (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 741-746 
    Details
    ISSN: 0887-624X
    Keywords: polymerization mechanism ; polymerization kinetics ; carbonate macrocyclization ; polycarbonate ; stopped-flow spectroscopy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of phenylchloroformate (PCF) reactions have been used to model some of the key chemical events in carbonate macrocyclization. Three reactions have been studied using stopped-flow FT-IR spectroscopy: formation of acyl ammonium salt from PCF and three different trialkylamines, the conversion of acyl ammonium salt to urethane, and the condensation reaction between acyl ammonium salt and 4-isopropylphenol. The rate dependence was studied for triethylamine (TEA), diethylmethylamine (DEMA) and tri-n-butylamine (TBA) at 0°C in anhydrous CH2Cl2. The reactivity order for acyl ammonium salt formation for TBA: TEA: DEMA is 1 : 2.7 : 〉444. By contrast, condensation and urethane formation are not sensitive to the structure of the amine. The rate of condensation is comparable to the rate of acyl ammonium salt formation for TEA and TBA, while the rate of urethane formation is the slowest process for all three amines. These results are consistent with the view that the yield of macrocyclic polycarbonates is related to the concentration of the acyl ammonium salt. The optimum amine concentration for obtaining high yields of cyclics varies with the amine structure and parallels the difference in the rates of acyl ammonium salt formation. © 1994 John & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320412
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Role of N,N-dimethyl-para-toluidine and saccharin in the radical polymerization of methyl methacrylate initiated by a redox system. II. Cumene hydroperoxide/iron saccharinate (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1471-1480 
    Details
    ISSN: 0887-624X
    Keywords: methyl methacrylate ; redox polymerization ; kinetics ; mechanism ; additives ; iron saccharinate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The role of N,N-dimethyl-p-toluidine (DMPT) and saccharin as accelerators in the polymerization of methyl methacrylate initiated by the redox decomposition of cumene hydroperoxide (CHP) in the presence of iron saccharinate has been kinetically investigated. DMPT reduces ferric ions to ferrous ions, so that an equilibrium is established between the two oxidation states. With the assumption of a steady-state concentration of propagating radicals, the rate of initiation was deduced from the rate of polymerization and the kinetic orders with respect to each compound involved in the initiation step have been determined. The reaction is first-order in CHP, iron saccharinate, and saccharine and second-order in DMPT. In a proposed scheme, Fe2+ ions, complexed by two DMPT molecules, are much more reactive than uncomplexed Fe2+ and saccharin activates the decomposition of CHP by protonation of the O—O bond. This mechanism, similar to that proposed in the case of copper saccharinate, explains the synergistic effect of both accelerators. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320808
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Amphiphilic graft copolymers with poly(oxyethylene) side chains: Synthesis via activated ester intermediates - properties (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1523-1530 
    Details
    ISSN: 0887-624X
    Keywords: amphiphilic polymers ; graft copolymers ; poly(oxyethylene) ; activated esters ; emulsifying properties ; thermal properties ; crystallinity ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amphiphilic graft copolymers were synthesized via activated ester substitution of derivatives of fumaric acid with amino-functionalized methoxypoly (oxyethylene)s (MPEO-NH2) of different molecular weights. The monomeric activated esters, isopropyl pentachlorophenyl fumarate (PCPFA) and isopropyl succinimido fumarate (SIFA), were copolymerized with styrene (St) or N-vinyl pyrrolidone (VP) at equimolar ratio. The polymeric-activated esters proved to be good precursors for grafting of definite amounts of MPEO-NH2. The aminolysis of the succinimide esters and VP-containing copolymers proceeded with gel formation due to extensive hydrogen bonding. The hydrodynamic behavior, the emulsifying ability, the thermal properties, and crystallinity of the graft copolymers were studied as a function of their molecular characteristics. The length of the PEO grafts and the degree of grafting are the factors which affect the melting parameters and the crystallinity of the side chains. © 1994 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320812
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    The cationic polymerization of N-vinyl-2-pyrrolidone initiated electrochemically by anodic polarization on a Pt surface (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1551-1555 
    Details
    ISSN: 0887-624X
    Keywords: poly(vinyl pyrrolidone) ; cationic polymerization ; electropolymerization ; thin films ; surface modification ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electroinitiated polymerization of N-vinyl-2-pyrrolidone has been investigated. After electrolysis at controlled potential, a thin, covering, and homogeneous film of poly(N-vinyl-2-pyrrolidone) appears on the electrode. The insolubility of the polymer in its classical solvents implies the existence of a true chemical grafting of macromolecules on the platinum surface. Chain propagation occurs by a cationic mechanism initiated by a direct electron transfer leading to grafted cations on the surface, followed by the nucleophilic attack of neutral molecules. The molecular weight of the polymer was estimated by gel permeation chromatography after having mechanically removed the film from the electrode. A molecular weight distribution curve showing an average value of 16,000 was observed. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320816
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Preparation and characterization of functional group gradient surfaces (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1569-1579 
    Details
    ISSN: 0887-624X
    Keywords: functional group gradients ; corona discharge ; graft copolymerization ; water contact angles ; FTIR-ATR ; ESCA ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Functional group gradient surfaces where the density of functional groups changes gradually along the sample length were prepared. The functional group (— COOH, — CONH2, and — OH group) gradient surfaces were produced by the treatment of low-density PE sheets using a corona with gradually increasing power, followed by the graft copolymerization of acrylic acid and subsequent substitution reaction of carboxylic acid groups to amide or hydroxyl groups. The prepared gradient surfaces were characterized by the measurement of water contact angle, FTIR-ATR, and ESCA. The gradient surfaces prepared can be used to systematically investigate the interactions of biological or other species in terms of the surface functional groups and their density of polymeric materials. © 1994 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320818
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Synthesis of novel polymer containing selenium by radical addition polymerization of 1,4-benzenediselenol to 1,4-divinylbenzene (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1609-1617 
    Details
    ISSN: 0887-624X
    Keywords: selenium-containing polymer ; radical addition polymerization ; 1,4-benzene-diselenol ; 1,4-divinylbenzene ; 2,2′-azobisisobutyronitrile ; dimethyl 2,2′-azobisisobutyrate ; 1,1′-azobis(1-acetoxy-1-phenylethane) ; model addition reaction ; side reaction ; properties of polymer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel addition polymerization of 1,4-benzenediselenol (BDSe) to 1,4-divinylbenzene (DVB) was carried out with various azo radical initiators [dimethyl 2,2′-azobisisobutyrate (DAIB), 1,1′-azobis(1-acetoxy-1-phenylethane) (AAPE), and AIBN] in toluene at 65 and 75°C under a nitrogen atmosphere. The polymerization proceded without an induction period, and pale-yellowish powder polymers were obtained in 89% yields for 75 h (DAIB), 89% yields for 24 h (AAPE), and 60% yields for 8 h (AIBN). The molecular weight (Mw) of the insoluble polymers in toluene was about 4000 (IBN) to 14,000 (DAIB or AAPE) by GPC. The polymer had an alternating structure of BDSe to DVB units by 1H-NMR, IR analyses, and selenium contents, but the polymer contained the diselenide linkage by Raman spectroscopy. By AIBN initiator, the yield of the polymers did not increase over 60% and higher molecular weight polymer was hardly obtained. According to the model addition reaction of benzeneselenol to styrene by AIBN, it was found that AIBN was consumed by the side reaction between dimethyl-N-(2-cyano-2-propyl)ketenimine derivedAppl 11 from AIBN and benzeneselenol to give the adduct C, MH+ 295 by DCI MS. On the other hand, DAIB and AAPE initiators, which do not form a ketenimine intermediate, gave the polymers of higher molecular weight in a higher yield. The polymer film exhibited high refractive index (n25D = 1.81) and a reversible phase transition between a transparency and an opaque by thermal mode. © 1994 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320902
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Photomodification of a poly(acrylonitrile-co-butadiene-co-styrene) containing diaryltetrazolyl groups (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1657-1664 
    Details
    ISSN: 0887-624X
    Keywords: photofunctionalization ; photocrosslinking ; synthetic membranes ; permselectivity ; pervaporation ; surface properties ; tetrazole ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new type of membrane polymer, containing a photosensitive moiety, was synthesized. The photochemically induced functionalization and crosslinking of poly [acrylonitrile-co-butadiene-co-styrene-co-2-(4-ethenyl) phenyl-5-phenyl-2H-tetrazole], ABSV, has been studied. A variety of dipolarophiles and phenolic compounds were applied to alter the polarity of the membrane surface. The functionalization and crosslinking were initiated by photoirradiation. DSC and contact angle measurements were used to characterize the modified polymer. Pervaporation experiments with a cyclohexane/benzene mixture (5 wt% benzene) were carried out, with the results showing, that the photochemical treatment significantly effects both permselectivity and flux. Solubility parameters were found to be useful to interpret the pervaporation data. In general, the selectivity towards benzene increases with the polarity of the membrane surface, i.e., with increasing polarity of the modifier. A mechanism to explain the influence of both functionalization and crosslinking on the membrane performance, is proposed. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320907
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Effect of reaction conditions on the grafting of 2-(dimethylamino)ethyl methacrylate onto hydrocarbon substrates (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1691-1702 
    Details
    ISSN: 0887-624X
    Keywords: grafting ; basic functionalization ; free radical polymerization ; methacrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The grafting of 2-(dimethylamino)ethyl methacrylate (DMAEMA) onto two model hydrocarbons, squalane and n-eicosane, and to linear low density polyethylene (LLDPE) has been investigated. The results of the study indicate that a high reaction temperature, 160°C, and a low concentration of monomer, less than 0.3 M, are optimum conditions for the grafting reaction. Reaction products, which consisted of grafted hydrocarbons and poly(DMAEMA), were separated by solvent extraction and vacuum distillation; samples were then analyzed by NMR and FTIR spectroscopy and size exclusion chromatography. 1H-NMR spectroscopy indicates that grafted squalane contained approximately 6 DMAEMA units per squalane residue. 1H- and 13C-NMR and molecular weight studies strongly suggest that the grafts onto the model hydrocarbons consist of single DMAEMA units. Results of the melt grafting of DMAEMA onto LLDPE show that the grafting efficiency and degree of grafting are substantially lower than were expected from the model system. © 1994 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320911
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Quinone-amine polymers. XV. Syntheses and characterization of high-temperature resistant poly(arylamino-quinone)s (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1977-1982 
    Details
    ISSN: 0887-624X
    Keywords: poly(arylamino-quinone)s ; p-benzoquinone ; aromatic diamine ; tetrahydrofuran ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several poly(arylamino-quinone)s (PAAQs) were prepared by the conventional solution polymerization of p-benzoquinone with various aromatic diamines in tetrahydrofuran. Polymers prepared by this method were found to be more soluble in many organic solvents compared to the PAAQs prepared by other reported methods. The poly(arylamino-quinone)s were obtained in 82.3-94.5% yield and had inherent viscosities in the range of 0.073-0.251 dL/g. Among the PAAQs, the polymer prepared from p-benzoquinone and 1,3-bis(3-aminophenoxy)benzene (APB) had demonstrated exceptionally good solubility and thermal stability. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321021
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Kinetics of polyesterification: Effect of diol chain length (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2003-2010 
    Details
    ISSN: 0887-624X
    Keywords: kinetics of polyesterification ; effect of diol chain length ; unsaturated polyesters ; energy of activation ; rate of reaction ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kinetics of polyesterification of maleic anhydride with polyethylene glycol (PEG) of varying molecular weights have been evaluated. The investigations have been carried out by employing heating cycles comparable to those employed in industrial processes and under nonisothermal conditions. The rate of reaction was found to decrease with increase in the chain length of the polyether. The energy of activation was estimated as 26.91, 40.25, and 47.30 Kcal/mol for PEG of molecular weights 200, 300, and 400, respectively. © 1994 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321101
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Novel polystyryl resins for size exclusion chromatography (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2029-2038 
    Details
    ISSN: 0887-624X
    Keywords: 1,2-bis(p-vinylphenyl)ethane ; divinylbenzene ; crosslinker ; network structure ; size exclusion chromatography resins ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New size exclusion chromatography (SEC) resins based on a crosslinker having independent vinyl groups have been produced and compared with SEC resins based on divinylbenzene-55 (DVB). 1,2-Bis(p-vinylphenyl)ethane (p,p-BVPE) and its meta-isomers were suspension-copolymerized with p-methylstyrene in the presence of different porogens to give particles of about 5 μm average diameter. The porous particles were slurry-packed into stainless steel columns for SEC evaluation. Calibration curves were obtained using narrow disperse polystyrene standards with molecular weights ranging from 580 to 3,040,000. The calibration curves for the new BVPE resins covered wider useful molecular weight ranges than those for comparable divinylbenzene resins. Particle size, surface morphology and the properties of pores were studied using a Coulter Multisizer II, scanning electron microscopy, nitrogen adsorption, and mercury porosimetry. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321104
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Synthesis of poly(ether-ketone-amide)s by palladium-catalyzed polycondensation of aromatic dibromides containing ether ketone structure, aromatic diamines, and carbon monoxide (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2065-2071 
    Details
    ISSN: 0887-624X
    Keywords: poly(ether-ketone-amide) ; palladium-catalyzed polycondensation ; aromatic dibromide ; carbon monoxide ; thermal behavior ; tensile properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aromatic poly(ether-ketone-amide)s were prepared by the palladium-catalyzed polycondensation of aromatic dibromides containing ether ketone units, aromatic diamines, and carbon monoxide. Polymerizations were carried out in N,N-dimethylacetamide (DMAc) in the presence of palladium catalyst, triphenylphosphine, and 1,8-diazabicyclo [5,4,0]-7-undecene (DBU), and resulted in poly(ether-ketone-amide)s with inherent viscosities up to 0.82 dL/g under mild conditions. The polymers were quite soluble in strong acid, dipolar aprotic solvents, and pyridine. Thermogravimetry of the polymers showed excellent thermal stability, indicating that 10% weight losses of the polymers were observed in the range above 400°C in nitrogen atmosphere. The glass transition temperatures of the polymers were about 200°C, which are higher than those of poly(ether-ketone) analogues. These polymers also showed good tensile strength and tensile modulus. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321108
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Cationic copolymerization of cyclic carbonate and epoxide via intermediate spiro orthocarbonate (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1393-1397 
    Details
    ISSN: 0887-624X
    Keywords: cyclic carbonate ; epoxide ; cationic copolymerization ; spiro orthocarbonate ; ring-opening polymerization ; poly (ether-carbonate) ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [no Abstrat]
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320722
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Macrothiuram disulfide for the free radical synthesis of PDMS-vinyl triblock copolymers. II. Studies of chain transfer (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1423-1430 
    Details
    ISSN: 0887-624X
    Keywords: block copolymers ; free radical polymerization ; polydimethylsiloxane ; chain transfer ; rate constants for the transfer reactions ; thiuram disulfide ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chain transfer constants (Ctr) for thiuram disulfide (TD) groups, included in the backbone of polydimethylsiloxane (PDMS) of different chain lengths, in methyl methacrylate (MMA) and styrene (St) were determined from measurements of the degree of polymerization. Two methods were used. The first consisted of using the initiation and transfer properties of the thiuram disulfides groups, and the second, of using a more efficient free radical initiator than TD groups, in which case the former behaves only as a transfer agent. In both the methods, the Ctr of TD was evaluated in bulk polymerization of MMA at 60, 70, 80, and 90°C. Using the first method, the Ctr of TD was measured also in solution polymerization of MMA in toluene at 100°C and, with the second one, in bulk polymerization of styrene at 60, 80, and 90°C. PDMS-based macrothiuram disulfide (macroiniferter) behaves as an “azeotropic” transfer agent for MMA and styrene at 125°C and 110°C, respectively. © 1994 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320803
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Synthesis, doping, and processing of high molecular weight poly(o-methoxyaniline) (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2147-2153 
    Details
    ISSN: 0887-624X
    Keywords: polyaniline ; derivatives ; doping ; processing ; films ; gel ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High molecular weight poly(o-methoxyaniline) was synthesized using a novel method in which the polymerization occurs in the presence of a neutral salt. The molecular weight of the polymer was greatly affected by the quenching procedure employed to conclude the polymerization. Conventional doping of the base form of poly(o-methoxyaniline) produced a yellow coloration of the doping solution and polymer degradation. It was found that the molecular weight of the polymer decreased significantly after washing or doping with certain aqueous acid media. The gelation conditions of N-methyl pyrrolidinone (NMP) solutions and film preparation were also investigated for polymers of various molecular weights. The gelation time in NMP decreased drastically with the increase in the polymer molecular weight (the same for solution concentration and temperature), until a critical point was reached after which its decrease was very slow. Flexible, free-standing, and stretchable films were readily obtained from the higher molecular weight polymers. Good quality doped gel films with conductivity of up to 1 S/cm were obtained under optimized doping conditions. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321117
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Photo-initiated base-formation in a polymer matrix (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2177-2185 
    Details
    ISSN: 0887-624X
    Keywords: photo-initiated base-formation ; polymer matrix ; O-acyloxime ; photolysis ; yield of amine ; acyloxyimino group ; thermal crosslinking ; recombination ; cage effect ; 6-membered cyclic intermediate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It was found that amines were formed efficiently by the photolysis of O-acyloximes followed by hydrolysis in polystyrene films and the relationship between structures of O-acyloximes and yields of amines were investigated. O-phenylacetyl acetophenone oxime (PaApO), O-pivaloyl acetophenone oxime (PApO), and O-benzoyl acetophenone oxime (BApO) as monofunctional O-acyloximes and O,O′-succinyl diacetophenone oxime (SDApO) and O,O′-glutaryl diacetophenone oxime (GDApO) as bifunctional O-acyloximes were examined. The yields of amines for PaApO and SDApO under N2 were ca. 70%, which was the highest among O-acyloximes examined in this experiment. On the other hand, the yields for PApO, BApO, and GDApO were less than 15% and it was verified that the hydrogen abstraction by imino radicals via 6-membered cyclic intermediates resulted in the lowering of yields. Although the effect of oxygen under photolysis on the yields of amine for PaApO was negligible under 50% conversion of PaApO, the yield decreased with further increase in the conversion and was 50% at 90% conversion. © 1994 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321121
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Emulsion copolymerization of tetrafluoroethylene and propylene with redox system containing tert-butylperbenzoate. I. Polymerization conditions and components (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2229-2234 
    Details
    ISSN: 0887-624X
    Keywords: tetrafluoroethylene ; propylene ; emulsion redox copolymerization ; fluoroelastomers ; reaction conditions ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Emulsion polymerization of tetrafluoroethylene and propylene with ammonium perfluorooctanoate, initiated by a redox system containing tert-butylperbenzoate (TBPB) was carried out. The effect of the components of the redox system Is (TBPB, FeSO4.7H2O, ethylenediamine tetraacetic acid (EDTA), and CH2(OH)SO2Na.2H2O) on the polymerization rate (R) and molecular weight ($\[ \bar M_n \] $) was studied. Among redox system components, Fe2+ concentration exerts the most significant effect (by power of 0.54) on the polymerization rate. It was found that R ∝ [Is]0.2-0.54 and Mn ∝ [Is]0.0-0.1 and polymerization reaction scheme was suggested for the action of the initiating system. The influence of the copolymerization conditions (pressure, temperature, stirring speed, and pH) is also discussed. The apparent activation energy of the reaction was found to be 46.0 kJ/mol. © 1994 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    NMR investigations of the possible cross reactions between cyanate and epoxy resins (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2203-2221 
    Details
    ISSN: 0887-624X
    Keywords: cyanate ; epoxy ; mixed resins ; curing ; cross reaction ; 13C-, 15N-, and 1H-NMR ; oxazolidinone ; carbamate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The possible cross reactions indicated by solid-state NMR between cyanate functionalized resin and epoxy functionalized resin have been investigated by using both natural abundance and labeled monofunctional model compounds. These soluble products were isolated and purified by silica gel adsorption chromatography and gel permeation chromatography. They were fully characterized by high resolution 1H-, 13C-, 15N-NMR spectroscopy and by mass spectrometry. The major cross-reaction product is a racemic mixture of enantiomers, which contain an oxazolidinone ring formed by one cyanate molecule and two epoxy molecules. However, epoxy consumption lags cyanate consumption in the overall reaction as triazine formation from the cyanate is much faster than the two competing reactions, the cross reaction between cyanate and epoxy, and the self-polymerization of epoxy, under the conditions investigated. The cross reaction between cyanate and epoxy is limited. Approximately 12% of cross reaction between cyanate and epoxy was found in the overall reaction. In addition to the cross reactions of epoxy and cyanate, the reactions of epoxy and the carbamate, which is the major side product for the curing reaction of cyanate resin in solution, have also been investigated, and the mechanism of these reactions discussed. From the reactions of epoxy and carbamate, several products related to cross reaction between epoxy and cyanate have been isolated and identified. It is suggested that the reaction of epoxy and carbamate is one of the pathways in the overall cross reaction between epoxy and cranate resins. Finally, the mechanism of the overall cross-curing reaction between the diepoxy and dicyanate mixed resins is discussed. © 1994 John Wiley & Sons, Inc.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321201
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Elucidation of mechanism for living radical polymerization of styrene with N,N-diethyldithiocarbamate derivatives as iniferters by the use of spin trapping technique (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2241-2249 
    Details
    ISSN: 0887-624X
    Keywords: iniferter ; living radical polymerization ; photopolymerization ; spin trapping ; dithiocarbamate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photodissociation of several N,N-diethyldithiocarbamate derivatives (RDC), i.e., benzyl, 1-phenylethyl, 2-phenylethyl, n-butyl, sec-, and tert-butyl N,N-diethyldithiocarbamates, was investigated by the spin trapping technique to elucidate the polymerization mechanism of styrene (St) with RDC as iniferters. The scission of RDC occured at two different C—S bonds depending on the structure of the alkyl groups of RDC and the cleavage manner was dominated by both resonance and steric effects. It has been confirmed that RDC generating an N,N-diethyldithiocarbamyl radical acts as an effective iniferter and induces the living radical polymerization of St in homogeneous system. The polymerizations of St with tetraethylthiuram disulfide and p-xylylene bis(N,N-diethyldithiocarbamate) were also discussed on the basis of the results of the spin trapping for RDC as the model compounds of the poly(St) chain ends. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321205
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Synthesis and properties of poly(amide-imide)s derived from trimellitic anhydride, ω-amino acids, and aromatic diamines (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1481-1496 
    Details
    ISSN: 0887-624X
    Keywords: aliphatic-aromatic poly(amide-imide) ; trimellitic anhydride ; ω-amino acids ; triphenyl phosphite ; direct polycondensation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Seven imidodicarboxylic acids II-1 to 5, II-10, and II-11 were prepared from trimellitic anhydride and ω-amino acids, such as glycine, β-alanine, 4-aminobutyric acid, 5-aminopentanoic acid, 6-aminohexanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Several aliphatic-aromatic poly(amide-imide)s were prepared by triphenyl phosphite promoted polycondensation reaction from the combination of 3-(4-carboxyphthalimido)propionic acid (II-2) or 6-(4-carboxyphtalimido)hexanoic acid (II-5) with various aromatic diamines and of all the imidodiacids with p-phenylenediamine or 4,4′-oxydianiline. All poly(amide-imide)s were characterized by inherent viscosity, gel permeation chromatography (GPC) measurements, solubility, tensile test, wide-angle X-ray scatting patterns, differential scanning calorimetry (DSC) measurements, and thermogravimetric (TGA) analyses. Effects of structural changes such as polymethylene length and diamine moieties on the properties of poly(amide-imide)s were studied. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320809
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Use of V and V-Cr catalysts interchanged in “Y” zeolites for the polymerization of ethylene (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1539-1542 
    Details
    ISSN: 0887-624X
    Keywords: polymerization ; ethylene ; polyethylene ; catalyst ; zeolites ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ethylene polymerization has been studied in the presence of catalyst based on vanadium or vanadium-chromium supported on a zeolite HY. The effect of vanadium over chromium has been investigated as a function of the sequence of exchange of metals on the support and metal contents. Both effects were investigated in relation to the characteristics of the polyethylene (PE) obtained. Low activity has been found for the V (II) zeolite HY catalyst. Moreover, vanadium acts either as an inhibitor or as a promoter for the polymerizing activity of the Cr (III)/zeolite catalyst, depending on the preparation method. © 1994 John Wiley & Sons, Inc.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320814
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Determination of the reactivity ratios of methyl acrylate with the vinyl acetate, vinyl 2,2-dimethyl-propanoate, and vinyl 2-ethylhexanoate (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2223-2227 
    Details
    ISSN: 0887-624X
    Keywords: bulk ; copolymerization ; reactivity ratios ; methyl acrylate ; vinyl esters ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The course of composition drift in copolymerization reactions is determined by reactivity ratios of the contributing monomers. Since polymer properties are directly correlated with the resulting chemical composition distribution, reactivity ratios are of paramount importance. Furthermore, obtaining correct reactivity ratios is a prerequisite for good model predictions. For vinyl acetate (VAc), vinyl 2,2-dimethyl-propanoate also known as vinyl pivalate (VPV), and vinyl 2-ethylhexanoate (V2EH), the reactivity ratios with methyl acrylate (MA) have been determined by means of low conversion bulk polymerization. The mol fraction of MA in the resulting copolymer was determined by 1H-NMR. Nonlinear optimization on the thus-obtained monomer feed-copolymer composition data resulted in the following sets of reactivity ratios: rMA = 6.9 ± 1.4 and rVAc = 0.013 ± 0.02; rMA = 5.5 ± 1.2 and rVPV = 0.017 ± 0.035; rMA = 6.9 ± 2.7 and rV2EH = 0.093 ± 0.23. As a result of the similar and overlapping reactivity data of the three methyl acrylate-vinyl ester monomer systems, for practical puposes these data can be described with one set of reactivity data. Nonlinear optimization of all monomer feed-copolymer composition data together resulted in rMA = 6.1 ± 0.6 and rVEst = 0.0087 ± 0.023. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321202
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Emulsion copolymerization of tetrafluoroethylene and propylene with redox system containing tert-butylperbenzoate. II. Polymerization mechanism (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2235-2239 
    Details
    ISSN: 0887-624X
    Keywords: tetrafluoroethylene ; propylene ; emulsion redox copolymerization ; fluoroelastomers ; polymerization mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Emulsion copolymerization of tetrafluoroethylene (TFE) and propylene (P) initiated by trilon-rongalite catalytic system containing tert-C4H9OH, initial monomer mixture, emulsifier (C7F15COONH4) concentration, and monomer mixture/water ratio on the polymerization rate (R) and molecular weight (M̄n) was investigated. Both R and M̄n increased considerably with TFE content in monomer mixture up to 75 mol %. Alternating rubber-like copolymers in a wide range of initial monomer mixture (from 55-85 mol %) were obtained. The reactivity ratio was found to be rTFE = 0.005 ± 0.04 and rp = 0.17 ± 0.07. Above the critical miscelle concentration, the effects of the initiating system Is and emulsifier Cs on R and M̄n were found to obey the following relations: \documentclass{article}\pagestyle{empty}\begin{document}$$ {R \propto [Is]^{0.54} \times [Cs]^{0.42} }\quad {{\rm and}}\quad {\bar M}_n \propto [Is]^{ - 0.1} \times [Cs]^{0.1} ,$$\end{document} according to which emulsion copolymerization proceeds by the I case of Smith-Ewart theory. Polymerization mechanism of the reaction studied was suggested. The copolymerization is mainly terminated by degradative chain transfer of the propagating radicals to propylene. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321204
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Spectroscopic evidences for grafting of N-vinyl carbazole on cellulose-acetate film (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2251-2255 
    Details
    ISSN: 0887-624X
    Keywords: grafting ; spectroscopy ; N-vinyl carbazole ; cellulose-acetate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-vinyl carbazole (VCZ) was grafted on cellulose acetate film using simultaneous cobalt-60-γ ray irradiation grafting technique. Absorption, excitation, and emission spectral studies on the grafted film were carried out to ascertain the grafting of VCZ on the polymer matrix. Laser-flash photolysis studies with the solution of grafted film indicate the opening of the double bond of VCZ, which leads to the grafting. On the basis of the observed results, the mechanism of grafting in the system was proposed. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321206
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Synthesis of thiol chelating resins and their adsorption properties toward heavy metal ions (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1877-1883 
    Details
    ISSN: 0887-624X
    Keywords: insoluble chelating polymers ; thiol ligand ; poly(ethylene glycols) chains ; functional polymers ; heavy metal ion recovery ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of chelating resins, derived from a macroreticular styrene-divinylbenzene (2%) copolymer beads grafted with various poly(ethylene glycols) HO—(—CH2—CH2—O—)n—H(n = 0, 4, 9, 13) and containing thiol groups as chelating functions, have been synthesized in a three-step reaction sequence. The structure of the functionalized resins was confirmed by IR spectrophotometry, elemental analysis, and differential scanning calorimetry. The complexation behavior of these thiol resins was investigated towards Hg(II), Cu(II), and Pb(II) ions in aqueous solution by a batch equilibration technique. The influence of pH on adsorption capacity was also examined. The adsorption values for metal ions' intake followed the order Hg(II) 〉 Cu(II) 〉 Pb(II). The affinity of these polymers towards Hg(II) ions was so high that the total mercury level in the liquid decreased from 20 ppm to below 10 ppb after 2 h of treatment. Polymers can be regenerated by washing with a solution of hydrochloric acid (6N) and 10% by weight of an aqueous solution of thiourea. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321008
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Cationic ring-opening polymerization of oxetane derivatives initiated by superacids: Studies on their propagating mechanism and species by means of 19F-NMR (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2543-2549 
    Details
    ISSN: 0887-624X
    Keywords: oxetane ; 19F-NKR ; triflic ; ring opening ; cationic polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nature of ring-opening polymerization of oxetane derivatives initiated by triflic acid and triflic anhydride was investigated via 19F-NMR spectroscopy. Two types of propagating species, which were directly observed from the 19F-NMR spectra, were found to be oxonium macroions and triflic macroesters. These two propagating species established and equilibrium relationship during the polymerization process. The forming of oxonium macroion active species was highly dependent upon the substituents of the oxetane ring, and were enhanced when a more polar solvent was employed. The initiator effect, which occurred primarily in the initiating stage of the polymerization, is also discussed. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321317
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Synthesis and kinetics of polymerization of unsaturated monomers with OH groups in their structure: I.3-hydroxyneopentyl acrylate (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2565-2576 
    Details
    ISSN: 0887-624X
    Keywords: acrylate monomers ; polymerization kinetics ; stereostructure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of new unsaturated monomers containing functional groups has been theoretically analyzed by considering a simple kinetic scheme. In the reactions between acetyl and acryloyl chloride with neopentylglycol, it was shown that the comparison between theoretical and experimental results, does not allow us to conclude that the two rate constants controlling the reactions are equivalent. Kinetic experiments of the polymerization of 3-hydroxyneopentyl acrylate were carried out in benzene and 1,4-dioxane solution at different temperatures. Dilatometric techniques and nonlinear least-squares methods were used to obtain kinetic data and to determine the kinetic constants, respectively. The values of \documentclass{article}\pagestyle{empty}\begin{document}$k_p /k_t^{1/2}$\end{document} for this monomer were found higher in dioxane than in benzene due, probably, to the fact that in the last solvent the polymerization is heterogeneous. The activation energy, determined by using different values of \documentclass{article}\pagestyle{empty}\begin{document}$k_p /k_t^{1/2}$\end{document} was found 7.6 kcal/mol. The stereostructure of the polymers derived from 3-hydroxyneopentyl acrylate and 3-acetoxyneopentyl acrylate was determined by 13C-NMR spectroscopy from the analysis of the resonance signals belonging to the carbonyl groups, obtaining values for the fraction of isotactic dyads in the range 0.36 ± 0.03 for both polymers. Finally, the glass transition temperatures of both polymers, determined calorimetrically, were found 281 and 255 K, respectively. © 1994 John Wiley & Sons, Inc.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321320
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Poly(terephthalic acid anhydride) as a latent monomer in polybenzoxazole synthesis (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1899-1902 
    Details
    ISSN: 0887-624X
    Keywords: poly(p-phenylenebenzobisoxazole) ; poly(terephthalic acid anhydride) ; 1,3-diamino-4,6-dihydroxybenzene ; polyphosphoric acid ; intrinsic viscosity ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High molecular weight poly(p-phenylenebenzobisoxazole) (PBO) was prepared from poly(terephthalic acid anhydride) (PTAA) and 1,3-diamino-4,6-dihydroxybenzene dihydrogenchloride in polyphosphoric acid (PPA). PTAA may react directly with the o-aminophenol groups to form benzoxazoles or react with PPA to generate terephthalic acid (TA) of very small particle size, which dissolves readily in PPA. PTAA provides the advantages of bypassing the requirement of small particle size TA, reducing the amount of water liberated by half, and possibly providing faster kinetics in PBO synthesis. © 1994 John Wiley & Sons, Inc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321011
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Thermotropic copolyamides from triethyleneglycol bis(4-carboxyphenyl)ether, aromatic diamines, and p-aminobenzoic acid modified by the monomer sequences in the copolyamides (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1923-1929 
    Details
    ISSN: 0887-624X
    Keywords: thermotropic copolyamides ; p-aminobenzoic acid ; p-phenylenediamine ; monomer sequence ; triethyleneglycol bis(4-carboxyphenyl)ether ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Copolycondensations of triethyleneglycol bis(4-carboxyphenyl)ether (PEG3), p-amino-benzoic acid (PABA), and p-phenylenediamine (PPD) were studied in order to examine the effect of monomer sequences in the copolyamides upon the transition temperatures of the resulting copolymers. Random copolymerization of these monomers resulted in the copolymers exhibiting a nematic mesophase in a wide range of PABA content. On the other hand, the sequential copolymers composed of PABA/PPD = 1/1 and 2/1, which were prepared from 4,4′-diaminobenzanilide (DABA) and N,N′-bis(4-aminobenzoyl)-p-phenylenediamine (BAB-PPD), respectively, did not show a mesophase. The copolymers of a diamine combination of DABA and PPD exhibited a nematic mesophase, despite the lack of a mesophase for each homopolymer. The combinations of DABA and other diamines were also examined. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321015
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Radical polymerization of alkyl crotonates as 1,2-disubstituted ethylenes leading to thermally stable substituted polymethylene (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1957-1968 
    Details
    ISSN: 0887-624X
    Keywords: radical polymerization ; alkyl crotonate ; 1,2-disubstituted ethylene ; propagation rate constant ; termination rate constant ; substituted polymethylene ; thermal property ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radical polymerization of several alkyl crotonates (RCr) was carried out in bulk or in benzene in the presence of radical initiators. Homopolymerization of RCr bearing bulky ester alkyl groups, e.g. tert-butyl (tBCr), 1-adamantyl (AdCr), and 3,5-dimethyl-1-adamantyl crotonate (DMAdCr) proceeded to give a polymer with molecular weight of several thousands despite of the steric hindrance and chain transfer by the presence of the β-methyl group, while the methyl and ethyl esters gave no polymer. The kinetics of the polymerization was examined in detail and absolute rate constants were evaluated by means of electron spin resonance spectroscopy. The propagation rate constants of RCr were 0.41-1.0 L/mol s, being much smaller than those of the corresponding methacrylates (530-570 L/mol s). The termination rate constants were also determined from the analyses of steady state and non-steady state polymerizations. Radical copolymerizations of AdCr (M2) with several vinyl monomers (M1) were carried out in bulk at 60°C and the rate constants for cross propagations were calculated to examine reactivities of the monomer and its polymer radical. The structure and thermal properties of the resulting poly (AdCr) were also investigated. Onset temperature of decomposition and glass transition temperature of poly(AdCr) were revealed to be much high as 302 and 234°C, respectively. © 1994 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321019
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Synthesis and properties of poly(arylene ether phenyl-s-triazine)s (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2093-2098 
    Details
    ISSN: 0887-624X
    Keywords: high-performance aromatic polyethers ; aromatic nucleophilic substitution polymerization ; aromatic polyethers containing triazine ; thermal behavior ; high-temperature polymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of new poly(arylene ether phenyl-s-triazine)s was prepared by the nucleophilic aromatic substitution polymerization of the potassium salt of bisphenols with 2,4-bis (halophenyl)-6-phenyl-s-triazine in N-methyl-2-pyrrolidone at elevated temperature. The polymers with inherent viscosities exceeding 0.5 were obtained after polymerization for 1 h using 2,4-bis(fluorophenyl)-6-phenyl-s-triazine as a monomer. The glass transition temperatures of the resulting polymers ranged from 200 to 260°C depending on the bisphenol used in the polymer synthesis. The poly(arylene ether phenyl-s-triazine)s demonstrated excellent thermal stabilities in excess of 490°C (5% weight loss in air). The isothermal TGA measurements (400°C under air or nitrogen atmosphere) revealed that the 4,4'-biphenol- and hydroquinone-based poly(arylene ether phenyl-s-triazine)s belong to the most superior class of heat resistant polymers, such as polyimide Kapton™. The mechanical properties of these polymers are also described. © 1994 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321111
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Preparation of poly(phosphate ester)s having bisphenol moieties as mesogenic units in the main chain (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2119-2126 
    Details
    ISSN: 0887-624X
    Keywords: poly(phosphate ester)s ; liquid crystalline polymer ; smectic phase ; thermal stability ; biodegradation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(phosphate ester)s, PPE 1a-d, were synthesized from polycondensation of methyl phosphorodichloridate (MPDC) with various bisphenols such as 4,4′-biphenol 1a, 4,4′-dihydroxyphenylether 1b, bis(4-hydroxyphenyl)methane 1c, and 3,3′-dimethyl-4,4′-dihy-droxybiphenyl 1d. PPE 2a-d with hexamethylene spacers were also obtained from poly-condensation of MPDC with 4,4′-bis(6-hydroxyhexyloxy)biphenyl 2a, 4,4′-di(6-hydroxyhexyloxy)phenyl ether 2b, bis[4-(6-hydroxyhexyloxy)phenyl]methane 2c, and 3,3′-dimethyl 4,4′-di(6-hydroxyhexyloxy)biphenyl 2d. The degree of crystallinity of PPE 1a-1d without hexamethylene spacer was 3.3-17.6%, whereas PPE 2a and PPE 2b which exhibit mesomorphic behavior were 20.1 and 18.6%, respectively. PPE 2a and PPE 2b show the mesophase at 139.6-195.5°C and 42.4-66.3°C, respectively. PPE 2c and PPE 2d were obtained as rubbery. From pyrolysis of PPE in air the temperature corresponding to 5% weight loss was found to be 322-408°C and 284-291°C for PPE 1 and PPE 2, respectively. It was also found that PPE 2a was enzymatically degraded by phospholipase C. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321114
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Model prediction of batch emulsion copolymerization as a function of conversion: A sensitivity analysis (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2161-2168 
    Details
    ISSN: 0887-624X
    Keywords: emulsion copolymerization ; composition drift ; modelling ; sensitivity analysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recently a model has been developed capable of predicting absolute monomer concentrations and their ratios in the polymer, aqueous, and monomer droplet phases as a function of conversion in batch emulsion copolymerizations without using any adjustable parameters. In this article the sensitivity of model predictions of composition drift toward deviations of 10% in all model parameters (maximum swellabilities of monomer in the polymer phase, water solubilities, reactivity ratios, and monomer and polymer densities) was estimated using the monomer combination methyl methacrylate-styrene as an example. From the sensitivity analysis it can be concluded that the reactivity ratios are the most important parameters affecting composition drift. The effects of deviations in maximum swellabilities and monomer and polymer densities on composition drift can be neglected, while the water solubility is important only in those cases where the amount of monomer in the aqueous phase cannot be neglected as compared with the total monomer amount. © 1994 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321119
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Macromolecular engineering of polylactones and polylactides. XV. Poly(D,L)-lactide macromonomers as precursors of biocompatible graft copolymers and bioerodible gels (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2099-2110 
    Details
    ISSN: 0887-624X
    Keywords: polylactide ; macromonomer ; ring-opening polymerization ; graft copolymers ; amphiphilic gel ; biocompatible ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The functional aluminum alkoxide, Et2Al—O—(CH2)2—O-C(O)—C(CH3)=CH2, is a very effective initiator for the (D,L)-lactide (LA) polymerization in toluene at 707deg;C. The coordination-insertion type of polymerization is living and exclusively yields linear P (D,L)-lactide macromonomers of a predictable molecular weight and a narrow molecular weight distribution. IR and 1H-NMR studies show that the methacryloyl group of the initiator is selectively and quantitatively attached to one chain end, whereas the second extremity is systematically a hydroxyl function resulting from the hydrolysis of the living growing site. α,ω-Dimethacryloyl-P(D,L)-lactides, i.e., α,ω-macromonomers, have also been successfully synthesized by the additional control of the termination step, i.e., by reaction of Al alkoxide end groups with methacryloyl chloride. α-Macromonomer and α,ω-macromonomer P(D,L)-lactides are easily free-radical copolymerized with 2-hydroxyethyl methacrylate (HEMA), resulting in a hydrophilic poly (HEMA) backbone grafted with hydrophobic P(D,L)-lactide subchains and a biodegradable amphiphilic network, respectively. © 1994 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321112
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Molecular composite. II. Novel block copolymer and semi-interpenetrating polymer network of rigid polyamide and flexible polyimide (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2629-2639 
    Details
    ISSN: 0887-624X
    Keywords: molecular composite ; liquid-crystalline polymer ; lyotropic polyamide ; polyimide ; semi-interpenetrating polymer network ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,2'-Dimethyl-4,4'-diamino-biphenyl was used to prepare a lyotropic amine-terminated polyamide (PBTA) prepolymer with terephthaloyl dichloride, and an amide oligomer with reactive endcaps of maleimide, respectively. The former was employed in an attempt to increase the solubility of PA/PI block copolymers, and the latter to produce a three-dimensional (isotropic) reinforced molecular composite through the technology of a semiinterpenetrating polymer network (semi-IPN). PBTA prepolymer was copolymerized with an amine-terminated polyimide via a coupling reaction using terephthaloyl dichloride. The resultant block copolymers were characterized by IR, NMR, ηinh and GPC to confirm that the copolymerization reaction was precisely accomplished, as well as to determine their composition and molecular weight. Thermal analysis and lyotropic behavior were also studied for these copolymers. Rigid-rod amide oligomer was crosslinked in the presence of another flexible polyimide. Five sets of semi-IPN films were prepared under varying compositions. The curing conditions were investigated by DSC; in addition, the cured semi-IPNs exhibited a single phase (1 Tg) according to examination by an instrument for thermally stimulated current (TSC). No large-scale phase separation was observed in SEM images of the fractured surfaces. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321404
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Reactivity and catalytic activity of cationic lonomers for the nucleophilic substitution reactions (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2677-2686 
    Details
    ISSN: 0887-624X
    Keywords: polystyrene-based ionomers ; cationic ionomers ; nucleophilicity ; phasetransfer catalysts ; quaternary salts ; triphase catalysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polystyrene-based crosslinked cationic ionomers containing ammonium or phosphonium chlorides (AxRCI and PxBuCI) were reacted with decyl methanesulfonate. The kinetic data were correlated with the swelling behavior of the ionomers and the solution viscosity of the corresponding linear ionomers. The reactivity of the ionomers was independent of the particle size of the ionomer beads, indicating no diffusion control of the reaction. The solvent and the ion content of the ionomers greatly affect the reactivity. In nonpolar solvents with a low acceptor number, AN, such as toluene, the aggregation of ionic groups with an increasing ion content reduces the reactivity. A solvent with a high value of AN, such as chloroform, led a very low reactivity independent of the ion content. Aprotic polar solvent, such as acetonitrila, promoted the dissociation of the ionic groups and furnished a relatively high reactivity independent of the ion content. Several catalytic substitution reactions were carried out under liquid-solid-solid triphase conditions. The kinetic results were accounted for in terms of slow nucleophile transport and fast chemical reaction within the ionomer particles. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321408
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Acid catalyzed fullerenation of carbazole polymer (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2727-2737 
    Details
    ISSN: 0887-624X
    Keywords: fullerenes ; carbazole ; acid catalyzed alkylation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new homogeneous fullerenated carbazole polymer has been synthesized, revealing a new substitution pattern for carbazole and a new photodecomposition-resistant substitution pattern for fullerenes. The synthetic method may be accomplished in one pot via acid catalyzed alkylation. The new polymer has several unusual photovoltaic, charge storage, and photoconductivity capabilities. © 1994 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321413
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Synthesis and photoinitiated cationic polymerization of 1,2,3-tris(1-propenoxy) propane (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2755-2763 
    Details
    ISSN: 0887-624X
    Keywords: photopolymerization ; propenyl ethers ; cationic polymerization ; diaryliodonium salt ; triarylsulfonium salt ; free radicals ; inhibition ; 1,2,3-tris (1-propenoxy) propane ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of 1,2,3-tris (1-propenoxy) propane (GTPE) was carried out by the rearrangement of 1,2,3-tris(2-propenoxy) propane (glycerol triallyl ether, GTAE) and the Z: E isomer composition of the GTPE was determined using gas chromatography and 1HNMR. The photoinitiated cationic polymerization of the GTPE was studied using realtime infrared spectroscopy (RTIR). Employing the data from these studies, rates of polymerization for the respective E and Z propenyl ether double bonds were calculated. The rate of incorporation of Z-double bonds of GTPE into the crosslinked polymer matrix is 1.6 times that of E-double bonds. The effects of oxygen and several other free radical polymerization inhibitors were investigated. An increase in the photogel time and decrease of the gel-content in the presence of these inhibitors implicates the involvement of free radicals in the process of the generation of propagating cationic centers when diaryliodonium salt cationic photoinitiators are used. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321416
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...