氯乙烯-醋酸乙烯酯-乙烯醇共聚物及其与异氰酸酯固化体系的扭辮分析

本工作用扭辫分析法测定了氯乙烯-醋酸乙烯酯(VC-VAc)共聚物及分子量近似相同(乙烯醇含量不同)的四种氯乙烯-醋酸乙烯酯-乙烯醇(VC-VAc-VA)三元共聚物的热力谱。同时还测定了四种(VC-VAc-VA)共聚物与等当量或非等当量的4,4＇-二苯基甲烷二异氰酸酯交联体系的热力谱。(VC-VAc)共聚物水解引入羟基对玻璃化温度有一定的影响;但交联对玻璃化温度影响更大。对于等当量交联体系,交联点密度与玻璃化温度呈线性关系;而对于非等当量交联体系,交联点密度与玻璃化温度的关系更为复杂。

THE TORSIONAL BRAID ANALYSIS OF VINYLCHLORIDE-VINYLACETATE-VINYLALCOHOL TERPOLYMER AND ITS CROSSLINKED SYSTEM WITH 4.4-DIPHENYLMETHANE DIISOCYANATE

The thermo-mechanical spectra for vinylchloride-vinylacetate(VC-VAc) copolymer and four vinylchloride-vinylacetate-yinylalcohol (VC-VAc-VA) terpolymer, in which-the molecular weight is similar, but the VAcontent is different, were determined by torsional braid analysis. At the same time, we also measured the thermo-mechanical spectra for several crosslin-ked systems composed of four terpolymer (VC-VAc-VA) and 4, 4'-diphe-nylmethane diisocyanate with stoichiometric and non-stoichiometric amounts of hydroxyl and isocyanate group. The hydrolysis of (VC-VAc) copolymer, which led to occuring of the hydroxyl group, has -definite effect on the glass transition temperature, but the effect of crosslinking on the glass transition temperature is more strong.For the crosslinked system with stoichiometric amounts of hydroxyl and isocyanate group the crosslinked density presented the linear relation with the glass transition temperature, however for the crosslinked system with non-stoichiometric amounts, the relation between the crosslinked density and the glass transition temperature was more complex.