Library

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Polymer bulletin 5 (1981), S. 367-372 
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The 1H-NMR-spectra of raw poly (vinyl chloride) obtained at atmospheric pressure (U-PVC) have revealed the presence of high concentrations of branches. The content of labile chlorine was determined by reaction with phenole in order to estimate the branch points with tertiary chlorine. The branch length of reductively dehalogenated U-PVC by13C-NMR analysis have provided evidence for both short chain branches including chloromethyl groups and 2.4-dichloro-n-butyl groups and long chain branching. For a number of U-polymers the total amount of branching ranges from 7.5 to 13.5/1000 C. The 13C-NMR measurements point to a ratio of methyl/butyl branches of 1 ∶ 1 and short chains/long chains of 6 ∶ 1 .
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Monoclonal antibodies against the toxic units ofBacillus thuringiensis delta-endotoxin were raised by the hybridoma technique and detected by an indirect enzyme-linked immunosorbent assay (ELISA). Out of 5 positive clones, I was found to secrete antibodies which inactivate the toxin.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cancer immunology immunotherapy 12 (1981), S. 31-37 
    ISSN: 1432-0851
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Levels of chemiluminescence were measured in peripheral blood mononuclear cells (PBMC) from normal subjects and from solid tumor cancer patients. Patients with advanced malignant disease were found to have significantly elevated baseline chemiluminescence activity in their ‘resting PBMC’ as compared to normal subjects or to cancer patients with, at most, minimum residual disease. Patients with either advanced disease or minimum residual disease, however, were found to exhibit significantly elevated activation of chemiluminescence by treatment of cells with phorbol myristic acetate (PMA). Treatment of surgically resected stage I lung cancer patients with Freund's complete adjuvant alone or emulsified with extracted lung cancer antigens was found to elevate chemiluminescence levels in patient PBMC. Serum from those vaccinated patients was found to elevate chemiluminescence levels of resting PBMC from normal subjects. That serum activity did net correlate with levels of immune complexes measurable in the Clq or Raji cell assay.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 260 (1982), S. 995-998 
    ISSN: 1435-1536
    Keywords: Alternating Copolymerization ; Styrene ; Benzylmethacrylate ; Tacticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Abstract The alternating copolymerization of styrene and benzylmethacrylate shows a different behaviour at the beginning of the reaction and later on. Thus the composition and the intrinsic viscosity of the products as well as the reaction rate become constant only after the initial stage. The1H-NMR-spectra of alternating and statistical copolymers with equal composition show distinct differences. The spectrum of the alternating copolymer confirms the alternating structure as well as an atactic chain configuration.
    Notes: Zusammenfassung Die alternierende Copolymerisation von Styrol und Benzylmethacrylat in Gegenwart von Ethylaluminiumsesquichlorid als Katalysator zeigt im Anfangsstadium der Reaktion ein vom weiteren Verlauf abweichendes Verhalten. So nehmen die Zusammensetzung und die Grenzviskositäten der Produkte sowie die Reaktionsgeschwindigkeit erst nach der Anfangsphase konstante Werte an. Die1H-NMR-Spektren von alternierenden und statistischen Copolymeren gleicher Bruttozusammensetzung zeigen deutliche Unterschiede. Das Spektrum des alternierenden Copolymeren bestätigt die alternierende Struktur und spricht gleichzeitig für einen ataktischen Kettenaufbau.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 258 (1980), S. 376-378 
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Summary Reduced specific viscosities of diluated PVAL solution (1.5 wt.-%) show after ageing and further dilution an increase in viscosity above concentrations of 3 g/l, in contrast to equivalent unaged solutions. The intrinsic viscosity of an aged solution of PVAL reacted with TA shows an increase with concentration and molecular weight above 0.5 wt-%, in contrast to that of a freshly prepared and reacted PVAL solution. This phenomenon is suggested to occur by the association of the resulting microgels in the solution.
    Notes: Zusammenfassung Reduzierte spezifische Viskosotäten einer gealterten und dann verdünnten 1,5 Gew.-% PVAL-Lösung zeigen oberhalb von etwa 3 g/1 eine Viskositätserhöhung gegenüber ungealterten Lösungen. Die Grenzviskositäten von mit TA umgesetzten gealterten PVAL-Lösungen zeigen oberhalb einer Konzentration von etwa 0,5 Gew.-% eine mit der Konzentration und dem Molekulargewicht ansteigende Erhöhung gegenüber den Grenzviskositäten von frisch zubereiteten und dann sofort umgesetzten PVAL-Lösungen. Diese Erscheinung wird auf die Assoziation von in der Lösung enthaltenen Mikrogelen zurückgeführt.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 258 (1980), S. 795-801 
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Summary Reactions competing to form inter and intramolecular networks in the system polyvinylalcohol (PVAL) with terephthal and glutar aldehyde (TA and GA) in water and dimethylsulphoxide (DMSO) were studied. The dependency of the intrinsic viscosity of the reaction product on the initial concentration of PVAL made it possible to assign resulting networks as inter or intramolecular. The reaction products were evaluated using gelchromatography. PVAL acetalisation was found to be reversible only with PVAL that had reacted with very small amounts of GA, other products being only partly hydrolysed. For the reaction proceeding by the pure intramolecular mechanism, leading to a contraction of the coils, the comparison of intrinsic viscosity data with that produced on theoretical grounds by Kuhn and Majer showed only agreement for those reactions with TA. Values of the reactions with GA were much lower than those calculated. The difference in the reaction products of PVAL with TA and with GA could be explained by the greater flexibility of GA in contrast to TA and the appearance of microgels.
    Notes: Zusammenfassung Die Konkurrenz von inter- und intramolekularer Vernetzung bei der Umsetzung von Polyvinylalkohol (PVAL) mit Terephthal- und Glutaraldehyd (TA bzw. GA) in Wasser und Dimethylsulfoxid wurde untersucht. Die Abhängigkeit der Grenzviskosität der Reaktionsprodukte von der Ausgangskonzentration an PVAL erlaubt Rückschlüsse, ob inter- oder intramolekulare Vernetzung stattgefunden hat. Dabei spielen vorhandene Mikrogele eine wichtige Rolle. Die Reaktionsprodukte wurden gelchromatographisch untersucht. Die Acetalisierung ist nur bei den mit sehr wenig GA umgesetzten PVAL reversibel, alle anderen Produkte konnten nur teilweise hydrolysiert werden. Für die unter Knäuelkontraktion verlaufende rein intramolekulare Reaktion zeigt ein Vergleich der experimentellen Ergebnisse mit den nach Kuhn und Majer berechneten theoretischen Werten der Grenzviskositäten nur für Umsetzungen mit TA gute Übereinstimmung. Die Werte für die Umsetzungen mit GA waren erheblich niedriger als die berechneten. Die Unterschiede bei den Produkten aus der Umsetzung von PVAL mit TA und mit GA werden mit der größeren Flexibilität des GA gegenüber dem TA und dem Auftreten von Mikrogelen erklärt.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 260 (1982), S. 1011-1016 
    ISSN: 1435-1536
    Keywords: Copolymers ; Styrene ; Benzylmethacrylate ; Solution properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Abstract Solution properties of equimolar random and alternating copolymers of styrene and benzyl methacrylate were investigated by means of light scattering and viscosity measurements. The two copolymers showed no distinct difference between each other. A special stiffening effect of the aromatic ring of the benzyl methacrylate could not be found. Light scattering data showed a pronounced influence of the third virial coefficient and the conventional interpretation of the data (linear extrapolation toc=0) produced too high molecular weights.
    Notes: Zusammenfassung Die Lösungseigenschaften von äquimolaren statistischen und alternierenden Copolymeren aus Styrol und Benzylmethacrylat wurden mit Hilfe von Lichtstreuungs- und Viskositätsmessungen untersucht. Es ergaben sich keine gravierenden Unterschiede zwischen den beiden Copolymeren. Ein besonderer kettenversteifender Effekt des aromatischen Rings im Benzylmethacrylat konnte nicht nachgewiesen werden. Bei der Lichtstreuung zeigte sich ein deutlicher Einflu\ des dritten Virialkoeffizienten, wodurch die konventionelle Auswertung (lineare Extrapolation aufc=0) zu hohe Molekulargewichte lieferte.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Polymer bulletin 3 (1980), S. 111-114 
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Compared to poly(methyl methacrylate) (PMMA) or other poly(n-alkyl methacrylates), the thermal degradation of poly(2-hydroxyethyl methacrylate) (PHEMA) is rather complex, whereby the generated monomer (HEMA) is accompanied by a variety of other pyrolysis products. Besides HEMA, the dominating compounds were methacrylic acid and acetaldehyde, which could be established by gas chromatography.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Hyperfine interactions 16 (1983), S. 765-766 
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 307 (1981), S. 7-13 
    ISSN: 1618-2650
    Keywords: Analyse von Spaltprodukten, Oligomeren, Methylphenolen, Aromaten in Phenolharz-Abbauprodukten ; Gasanalyse/Chromatographie, DC, GC, GPC, HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Zur chromatographischen Charakterisierung von Abbauprodukten ausgehärteter Phenol-Formaldehyd-Harze mit DC, GC, GPC und HPLC wurden die optimalen chromatographischen Bedingungen erarbeitet. Neben der Pyrolyse wird insbesondere der hydrogenolytische Abbau der vernetzten Kondensate näher untersucht, wobei eine Vielzahl von phenolischen, nichtphenolischen aromatischen und gasförmigen Spaltprodukten gebildet werden. Niedermolekulare phenolische Abbauprodukte können dünnschichtchromatographisch sowohl an formamid-imprägniertem Kieselgel HF254 mit dem Laufmittel Benzol/Methanol (95∶5 Vol.-T.), als auch an Kieselgel 60 F254-Fertigplatten mit Benzol/Diethylamin (85∶15 Vol.-T.) als Eluens befriedigend getrennt werden. Die qualitativen und quantitativen gas-chromatographischen Bestimmungen von Phenol, Kresolen, Xylenolen und anderen nichtphenolischen Aromaten wurden mit einer 2m×1/8 Zoll-Säule, gepackt mit 10 Gew.-% UCON LB-550X auf Chromosorb W NAW (60–80 mesh), durchgeführt; für die Gasanalysen wurde eine 2m×1/4 Zoll-Fertigsäule, gepackt mit einem 5Å Linde-Molekularsieb, eingesetzt. Die Molekulargewichtsverteilungen der Hydrogenolyse-Produkte wurden gel-chromatographisch an Merckogel 6000, einem mit Butandiol-1,4-divinylether vernetzten Poly(vinylacetat), und mit DMF als Eluens ermittelt. Eine alternative Analysenmethode zur chromatographischen Charakterisierung löslicher Phenol-Formaldehyd-Kondensate und niedermolekularer phenolischer Verbindungen ist die reversed phase Hochleistungs-Flüssigkeits-Chromatographie, wobei mit Spherisorb ODS als stationäre Phase und THF/H2O-Mischungen als Eluens eine weitgehende Trennung von Phenol, Methylphenolen und oligomeren phenolischen Spaltprodukten erreicht wird.
    Notes: Summary With chromatographic methods like TLC, GC, GPC, and HPLC it is possible to characterize relatively complex mixtures of phenolic, non-phenolic aromatic, and gaseous degradation products of cured phenolic resins, which have been generated by pyrolytic and hydrogenolytic cleavage. The low molecular weight phenolic compounds were separated with good resolution by thin-layer chromatography on formamideimpregnated silica gel HF254 with the eluent benzene/ methanol (95∶5; vol.), or silica gel 60 F254 precoated aluminium sheets, using the eluent benzene/diethylamine (85∶15, vol.). The qualitative and quantitative gas chromatographic determinations of phenol, cresols, xylenols, and other non-phenolic aromatic compounds were accomplished with a 2 m×1/8 inch column, packed with 10wt.-% UCON LB-550X on Chromosorb W NAW (60–80 mesh), and a 2m×1/4 inch ready packed column with a 5Å Linde molecular sieve for gas analysis. Gel permeation chromatographic investigations with Merckogel 6000, a poly (vinyl acetate) cross-linked with butanediol-1,4-divinylether, as stationary phase and dimethylformamide as eluent, gave information on the molecular weight distributions of the hydrogenolysis products. In addition, good separations of oligomer phenolic compounds, methyl phenols, and phenol are achieved by high performance liquid chromatography in the reversed phase mode, using the stationary phase Spherisorb ODS and THF/H2O-mixtures as eluent.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...