摘要:

AbstractProben von unstabilisiertem und mit den Antiozonantien N‐Isopropyl‐N′‐phenyl‐p‐phenylendiamin (IPPD) und Bis‐(1,2,3,6‐tetrahydrobenzaldehyd)‐pentaerithrityl‐acetal (Vulkazon AFS) stabilisiertem Polyoxymethylen wurden unter mechanischer Belastung in einer Klimakammer ozonisiert. Die Schädigungen auf der Oberfläche wurden IR‐spektroskopisch und rasterelektronenmikroskopisch untersucht. Während der Ozonisierung von POM bildet sich eine geschädigte Schicht, deren Dicke mit zunehmender Ozonisierungszeit wächst. Hierbei wird das Polymere an den Acetalbindungen angegriffen, wodurch Ketten gespalten werd

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051560111

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe dependence of glass temperature on the heating rate and the composition for styrene‐zinc acrylate copolymers has been investigated by differential scanning calorimetry. Thermogravimetry was used in order to examine these copolymers undergoing pyrolysis in an atmosphere of air at three different heating rates. Thermal decomposition of ionomers is a three‐stage process. The orders and activation energies have been determined for each stage of decomposition using the computer programs based on the methods of Kissinger, Freeman‐Carrol, and Ozawa. It was found that the heat stability is lowered by the ionic g

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051560112

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractGrafting of unsaturated segmented polyurethanes with some hydrophilic monomers such as N‐vinyl pyrrolidone, 2‐hydroxyethylmethacrylate and acrylamide in N,N‐dimethylformamide have been studied using 2,2′‐azobisisobutyronitrile (AIBN) as initiator. Graft copolymers were isolated from homopolymers by selected solvent extraction using a Soxhlet apparatus. A kinetic study of graft copolymerization reactions showed that the reactions follow the conventional kinetic behaviour of free radical polymerization. The dependencies of the grafting rate on initiator and N‐vinyl pyrrolidone concentrations were of 0.5 and 1.00 order, respectively. However, for the 2‐hydroxyethylmethacrylate, the dependencies of the grafting rate on initiator and monomer concentrations were found to be of 0.5 and 2.00 order, respectively. The overall activation energy for the graft copolymerization of the 2‐hydroxyethylmethacrylate and N‐vinyl pyrrolidone were 21.81 kJ/mol and 16.28 kJ/

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051560113

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe molecular parameters of the flocculation agent from polyacrylonitrile and dicyandiamide (PAN‐DCD) were determined in dimethylsulfoxide. In acidic and alkaline aqueous solutions (0.1 N) PAN‐DCD is weakly aggregated, additionally a small fraction of polymer exists as highly aggregated particle component. A shift of the pH‐value in direction to the neutral range leads immediately to particle growth, which is finished at pH 3, coming from the acidic range and pH 10, coming from the alkaline one. After the passage of the neutral range disaggregation occurs. Flocculation can also be induced by addition of salt.The structural parameters of the particles were determined by a detailed analysis of the light scattering curves. Results obtained give information about the flocculation mech

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051560114

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractUltra fine particles were impregnated by using a finely porous cellulose gel membrane. The impregnated gel membrane is a green transparent one and looks like a solid solution. Highly dispersed Ni catalysts on carbon were obtained from thermal decomposition of these gel membranes. The particle size is in the range of several nm to a few ten nm. They show interesting catalytic properties for hydrogenation of olefins such as cyclooctadiene.

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051560115

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractSelective adsorbent for ethylene is prepared from copper(I) chloride and a macroreticular type polystyrene resin having tertiary amino groups. The adsorbent rapidly adsorbs ethylene at 20°C under 1 atm. The adsorbed ethylene is readily desorbed by subjecting the adsorbent to a reduced pressure (3 mm Hg) at 20°C. The ethylene adsorbing capacity of the adsorbent is 5.5 times as large as the adsorbing capacity for ethane. The present adsorbent exhibits no measurable adsorptions of nitrogen and hydrogen at 20°C under 1 atm, and thus is applicable to selective separation of ethylene from mixtures containing these gases and etha

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051560116

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractStyrene copolymers with low (up to 5 wt.‐%) N‐vinylcarbazol content were prepared. The copolymers showed enhanced thermal stability in comparison with the pure polystyrene. This is explained by a charge transfer complex formation between the carbazol rings as donor and the radicals, formed during the degradation, as accept

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051560117

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

ISSN:0003-3146    

DOI:10.1002/apmc.1988.051560118

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY