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  • 1975-1979  (6)
  • 1977  (2)
  • 1975  (4)
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  • 1975-1979  (6)
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  • 1
    Electronic Resource
    Electronic Resource
    Thermische Analyse von Poly (1,3,4-oxadiazol-2,5-diyl-1,4-phenylen) und Poly (1,3-phenylen-1,3,4-oxadiazol-2,5-diyl-1,4-phenylen) (1975)
    Springer
    Colloid & polymer science 253 (1975), S. 338-338 
    Details
    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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02352135
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Irradiation of poly(vinyl alcohol) fibers in the presence of chloroform and carbon tetrachloride (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 2913-2920 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Radiolysis of poly(vinyl alcohol) fibers (PVA) in the presence of chloroform and carbon tetrachloride was investigated. Decrease in intrinsic viscosity was observed at lower dosages (up to 2.3 megarads); and above this, an increase was noted. The blank samples irradiated under similar conditions showed a continuous decrease in intrinsic viscosity. A discoloration in the samples irradiated in the presence of CCl4 and CHCl3 was also observed. It is attributed to double bond formation in the backbone. A marginal decrease in the tensile strength of the irradiated fibers was observed. However, the surface characteristics of the fibers did not change on irradiation. The thermogravimetric analysis revealed a better heat resistance in irradiated fibers.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070211107
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Thermal analysis of poly(1,3,4-oxadiazole-2,5 diyl-1,2-ethenediyl) and poly(1,4-phenylene-1,3,4-oxadiazole-2,5 diyl-1,2 ethendiyl) (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 2869-2878 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Poly(1,3,4-oxadiazole-2,5-diyl-1,2-ethendiyl) and poly(1,4-phenylene-1,3,4-oxadiazole-2,5 diyl-1,2-ethenediyl) have been prepared by condensation polymerization using fuming sulfuric acid and different quantities of terephthalic acid (T), fumaric acid (F), and hydrazine sulfate (HS). Homopolymers of F and T and various copolymers of F:T have been prepared. The polymer structure was investigated by IR and visible-range spectra and elemental analysis. The existence of poly(1,3,4-oxadiazole-diylphenylene) and poly(hydrazoterephthaloyl) structures was revealed by these studies. These polymers were thermally stable, and most of them did not show a weight loss below 350°C. The relative thermal stabilities of the various polymers have been evaluated by “integral procedural decomposition temperature” and activation energy measurements.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070191022
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  • 4
    Electronic Resource
    Electronic Resource
    Thermal analysis of poly(vinyl alcohol) and poly(vinyl acetate) fractions (1975)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 46 (1975), S. 1-10 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Handelsprodukte von Polyvinylalkohol (PVA) und Polyvinylacetat (PVAc) wurden einer Fällungsfraktionierung unterworfen. Es wurden neun bzw. sechs Fraktionen erhalten. Die Abhängigkeit der thermischen Stabilität der Polymeren vom Molekulargewicht der Proben wurde thermogravimetrisch in Luft untersucht. Messungen zur Bestimmung der Abhängigkeit des Abbaugrades von der Temperatur sowie zur Bestimmung der Aktivierungsenergie ergaben eine direkte Proportionalität zwischen der Stabilität von PVAc und dem Molekulargewicht der Probe. Für PVA wurde ein Molekulargewichtsbereich ermittelt, für den eine maximale thermische Stabilität besteht. Sowohl für höhere als auch für niedrigere Molekulargewichte war diese Stabilität geringer.
    Notes: The commercially available poly(vinyl alcohol) (PVA) and poly(vinyl acetate) (PVAc) were fractionated by precipitation to give nine and six fractions respectively. The dependence of the thermal stability of the polymer on the molecular weight of the samples was investigated by dynamic thermogravimetry in air. The percentage decomposition temperature, integral procedural decomposition temperature, and activation energy measurements revealed that the stability of PVAc was directly proportional to the molecular weight of the sample. In PVA, there was an optimum polymer size where the stability was at a maximum, and it decreased on increasing or decreasing the molecular weights.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1975.050460101
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  • 5
    Electronic Resource
    Electronic Resource
    Thermal degradation of poly(vinyl acetate) in solution (1975)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 46 (1975), S. 11-21 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der thermische Abbau von Polyvinylacetat wurde in Äthylbenzoat, Benzylbenzoat und Äthylsalicylat unter Stickstoff im Temperaturbereich zwischen 189 und 212°C untersucht. Der Abbau wurde durch Titration der ausgeschiedenen Säure und an Absorptionsspektren vom abgebauten Polymeren verfolgt. Er wurde durch die Lösungsmittel beeinflußt; er war in Äthylsalicylat stärker als in den anderen Lösungsmitteln. Eine breite Absorptionsbande wurde in Benzylbenzoat und Äthylbenzoat gefunden, während in Äthylsalicylat Peaks bei 367, 390, 412 und 435 nm beobachtet wurden. Polyene mit kleiner Zahl von Doppelbindungen waren gegenüber Polyenen mit mehr als 10 Doppelbindungen dominant. Die Aktivierungsenergie für den Abbau lag in diesen Lösungsmitteln zwischen 11 und 15 kcal/mol. Die Ergebnisse werden diskutiert unter Annahme einer Mitwirkung der Lösungsmittel beim Abbauprozeß.
    Notes: The thermal degradation of poly(vinyl acetate) in ethyl benzoate, benzyl benzoate, and ethyl salicylate was investigated in an atmosphere of nitrogen in the temperature range 189-212°C. The degradation was followed by titrating the evolved acid and recording the absorption spectra of the degraded polymer solution. The degradation was influenced by the solvents, and was higher in ethyl salicylate than in other solvents. A broad absorption band was observed in benzyl benzoate and ethyl benzoate while in ethyl salicylate peaks at 367, 390, 412, and 435 nm were observed. Polyenes with a smaller number of double bonds were more predominant than polyenes having more than 10 double bonds. The activation energy varied between 11-15 kcal/mol in these solvents. The results have been explained by proposing the participation of solvents in the degradation reactions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1975.050460102
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  • 6
    Electronic Resource
    Electronic Resource
    Stability of polyamic acids and polyimides (1977)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 64 (1977), S. 101-113 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Polyamidsäuren wurden aus Pyromellithsäuredianhydrid und Benzidin (B) sowie Hydrazin (H) dargestellt und druch Viskositätsmessungen in Dimethylformamid (DMF) charakterisiert. Die Hydrolysestabilitßat wurde nach 20tägige Aufewahrung der DMF-Lösungen an der Luft bei Raumtemperatur ermittelt. Es ergab sich eine Viskositätsabnahme für die B-Polymeren und die Copolymeren mit B und H. Diese Verminderung ist für die Copolymeren geringer.Das thermische Verhalten der Polyamidsäuren und Polyimide wurde mittels thermogravimetrischer und differentialthermoanalytischer Methoden untersucht. Die Copolyamidsäuren wiesen eine größere thermische Stabilität als die Polyamidsären aus B auf, während die Copolyimide eine geringere Stabilität als die Polyimide aus B aufwiesen. Die thermische Cyclodehydrierung der Polyamidsäuren zu den polyimiden fand bei den Copolymeren bei geringeren Temperaturen als bei den B-Polymeren statt.
    Notes: The polyamic acids from pyromellitic dianhydride, benzidine (B) and hydrazine (H) were prepared and characterized by intrinsic viscosity measurements in dimethylformamide (DMF) solutions. The hydrolytic stability of these polymers was determined by keeping the DMF solution in presence of air at room temperature for 20 days. A decrease in ηinh was observed for the B-polymers and copolymers of B and H. This reduction was less in the copolymers.The thermal behaviour of polyamic acids and polyimides was studied by thermogravimetric and differential thermal analysis techniques. The copolyamic acids were found to be thermally more stable than polyamic acid from B at higher weight losses (about 50%), whereas copolyimides were found to be less stable than polyimide from B. Thermal cyclodehydration of polyamic acids to polyimide occurred at lower temperatures in copolymers than the polymer of B.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1977.050640109
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