EVA-g-VC的结构和动态粘弹性

本文研究了聚乙烯-醋酸乙烯酯(EVA,VAc:14％)与氯乙烯(VC)接枝共聚物(EVA-g-VC)的相结构和分子结构。接枝物EVA-g-VC由游离EVA、均聚PVC和EVA-VC接枝高分子三者组成,EVA呈连续相,PVC呈分散微粒。EVA-g-VC中EVA的含量越高,PVC粒子体积越小。实验结果表明,接枝物中“凝胶”的EVA玻璃化温度,随投料比(VC/EVA)的减小而升高;另外随VC/EVA减小,凝胶中PVC的含量和PVC的分子量也减小。这些结果说明,VC/EVA较小时得到的接枝物中,EVA上VC接枝点的数目较多,而PVC接枝链的长度较短。EVA-VC是不相容两相——EVA和PVC的“粘着剂”,其作用表现在:VC/EVA越小,接枝物中EVA和PVC的玻璃化温度越靠近。

STRUCTURE AND DYNAMIC VISCOELASTICITY OF EVA-g-VC

Phase structure and molecular structure of Poly (etheneco-vinyl acetate-g-vinyl chloride) (EVA-g-VC) have been studied in this paper EVA-g-VC consists of free EVA. PVC homopoly-mer and EVA-VC copolymer, in which EVA exists as a continuous phase and PVC particles disperse. The size of PVC particles and the grafting efficiency of EVA all depend on the feeding ratio-VC/EVA (wt/wt) of a graft polymerization. With decreasing the feeding ratio in the graft gel, the Tg of EVA increases, while the molecular weight and PVC content all decrease. One explanation for this could be suggested that the number of VC grafting points in EVA-VC increases with decreasing the feeding ratio. EVA-VC as an adhesion agent exists between two incompatible phases-EVA(14) and PVC, which makes the Tg(EVA) and the Tg(PVC) near to another.