摘要:

AbstractThe objective of this work was to correlate rheological parameters with basic molecular parameters such as different molecular weights and level of long‐chain branching (LCB) in low density polyethylene. LCB is known to exert a considerable influence on resin's melt flow characteristics which have been useful in predicting resin end‐use properties (especially processability). In the scope of the work steady flow measurements were done with an Instron Rheometer and dynamic oscillatory measurements using a balance rheometer. The molecular weight data were obtained using gel permeation chromatography, light scattering technique, and solution viscosimetry. A correlation matrix was calculated for 34 measured properties. The results showed that good correlations may be obtained especially between LCB‐parameters, die swell and optical properties of the polymer. The LCB properties may also be quite correctly predicted from dynamic viscosity data at low freque

ISSN:0003-3146    

DOI:10.1002/apmc.1979.050750101

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractThe use of tetravalent ceric ions to initiate graft‐copolymerization of methyl methacrylate onto silk has been investigated. The rate of grafting has been determined by varying monomer, cerium (IV), temperature, and nature of silk. The graft yield increases with increasing monomer concentration up to 0.65 mol/l and with further increase of monomer, the graft yield decreases. The percentage of grafting increases with increasing ceric ion concentration up to 0.03 mol/l and thereafter it decreases. The rate of reaction is temperature dependent, with increasing temperature, the graft yield increases. The grafting is considerably influenced by chemical modification prior to grafting. The effect of different species of ceric ion and CuSO4on the rate of grafting has also been investigate

ISSN:0003-3146    

DOI:10.1002/apmc.1979.050750102

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractUntersucht wurde die Verringerung des Reibungswiderstandes (VRW) beim Turbulentfließen der Lösungen von PIB Oppanol B 200 in Toluol und in einer Mischung aus Xylol/Benzol (40:60). In diesen beiden Lösungsmitteln weist PIB gleiche Grenzviskosität auf und die PIB‐Knäueldimensionen sind folglich in beiden Lösungen gleich. Es wurde festgestellt, daß die Werte der VRW in beiden Lösungsmitteln voneinander verschieden sind. Bei kleinen Reynoldsschen Zahlen sind die Unterschiede darauf zurückzuführen, daß die VRW bei der Toluollösung früher beginnt als bei der aus Xylol‐Benzol. Bei großen Reynoldsschen Zahlen sind die Unterschiede der VRW sehr gering und werden durch die kleinen Unterschiede in den physikalischen Eigenschaften der Lösungsmittel bedingt. Berechnet wurden die Werte einer Reihe von Größen, die die Polymerknäueldimensionen in den untersuchten Lösungen bestimmen. Es wurde noch festgestellt, daß die Werte der VRW von der Herstellungsart der PIB‐Lösungen in Toluol (durch Auflösung des Polymeren in der gesamten Lösungsmittelmenge zur Gewinnung der gewünschten Konzentration, durch seine Auflösung in 10‐fach geringerer Lösungsmittelmenge und Verdünnung bis zur gewünschten Konzentration 3–4 h vor der Messung und durch Auflösung in 10‐fach geringerer Lösungsmittelmenge und Verdünnung unmittelbar vor der Messung) praktisch nicht abhängen. Auf Grund dieser Ergebnisse und der Werte des Produkts aus Konzentration c und der Grenzviskosität [η] nimmt man an, daß in den Lösungen der reibungsreduzierenden Polymeren die Makr

ISSN:0003-3146    

DOI:10.1002/apmc.1979.050750103

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractDyeing of polyester materials with disperse dyes at a high temperature in the absence of carriers and at different ranges of dyebath pH was studied. It was found that the behaviour of the dye as well as the magnitude of dye uptake at different pH's are greatly affected by nature and position of the substituents of the dye. Substituents which from lyonium ions in acidic medium produce higher dye uptake in alkaline medium, and those which form lyate ions in alkaline medium bring about higher dye uptake in acidic medium. Substituents which are not able to form neither lyonium ions nor lyate ions yield practically the same dye uptake over a wide range of pH values.

ISSN:0003-3146    

DOI:10.1002/apmc.1979.050750104

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractThe effect of temperature, activator concentration, and polymerization time on the anionic polymerization of 2‐pyrrolidone was studied using the method of statistical planning of the experiments. Sodium tert‐butoxide or sodium dihydrido‐bis(2‐methoxyethoxy)aluminate was used as initiator; N‐acetylpyrrolidone served as activator in both cases. Results obtained with both initiation systems were presented in the form of explicit mathematical

ISSN:0003-3146    

DOI:10.1002/apmc.1979.050750105

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractZetapotentiale geben einen Einblick in die Polymer‐Flüssigkeits‐Phasengrenzfläche. Sie können jedoch nicht auf direktem Wege experimentell ermittelt werden, sondern errechnen sich aus den bei elektrokinetischen Untersuchungen erhaltenen Strömungsströmen, Strömungswiderständen und Ohmschen Widerständen mit Hilfe eines zur Beschreibung des porösen Feststoffpfropfens geeignet erscheinenden Modells.Ziel dieser Arbeit ist es, neben der Beschreibung einer experimentellen Anordnung für elektrokinetische Untersuchungen an Fasern die Anwendung der Methode auf textilchemische Fragestellunge

ISSN:0003-3146    

DOI:10.1002/apmc.1979.050750106

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractThe low stability (both to evaporative concentration and to storage) of polymers terminated with aminooxomethanesulfonate groups (carbamoyl sulfonates) has been investigated. This low stability was induced by spontaneous changes in solution pH. These changes were produced by one of the two alternative reactions: loss of SO2which caused an increase in pH, and oxidation of the free bisulfite which decreased the pH. In this work, excess hydrogen peroxide was found to be the best stabilizer of poly(carbamoyl sulfonates). The optimum stability of poly(carbamoyl sulfonate) solutions was found to occur at pH 2–3 in aqueous ethano

ISSN:0003-3146    

DOI:10.1002/apmc.1979.050750107

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractPVC films were degraded by outdoor exposure, irradiation by a weatherometer and heating by an electric oven. In PVC films subjected to outdoor exposure and to irradiation by the weatherometer at a low temperature, e. g. sample surface temperature of 0°C, photo‐oxidation and scission of the main chain were caused, but dehydrochlorination or formation of solvent‐insoluble substances were not observed. In contrast, PVC subjected to irradiation by the weatherometer at a high temperature, e. g. sample surface temperature of 80°C, showed a degradation tendency similar to that of PVC heated at 200°C in the electric oven, and decomposition of the thermal degradation type characterized by dehydrochlorination, formation of polyenes and formation of solvent‐insoluble substances were

ISSN:0003-3146    

DOI:10.1002/apmc.1979.050750108

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractVarious PVC films containing a thermal stabilizer selected from three kinds of metal stearates and three kinds of organotin compounds were irradiated with ultraviolet rays and the unirradiated samples were subjected to the ESR analysis. Further, these PVC films were subjected to the photodegradation test using a weatherometer at a sample surface temperature of 0°C. By tracing the conversion of methyl radicals to alkoxy radicals or peroxy radicals with the lapse of time according to the ESR, effects of the foregoing stabilizers for stabilizing PVC against actinic rays could be evaluated. Results of the ESR were well in agreement with the results obtained at the photodegradation test using the weatherometer

ISSN:0003-3146    

DOI:10.1002/apmc.1979.050750109

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractSurface topography of polyacrylonitrile based carbon fibres preoxidized under a variety of conditions has been studied in detail. Only those carbon fibres processed under optimum conditions are found to possess defect free surface topography. Changes in surface topography and the tensile strength of carbon fibres with processing conditions have been discussed.

ISSN:0003-3146    

DOI:10.1002/apmc.1979.050750110

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY