PVC/ABS共混体系的相容性与形态结构研究

Investigation of miscibility and morphology of PVC/Abs blends

采用种子乳液聚合技术在聚丁二烯（PB）乳胶粒子上接枝共聚苯乙烯（St）、α-甲基苯乙烯（α—MSt）和丙烯腈（AN）单体，合成了一系列不同AN结合量的ABS和α—MABS接枝共聚物。将其与聚氯乙烯（PVC）树脂熔融共混制得了PVC／AtkS共混物，利用扫描电镜（SEM）、透射电镜（TEM）和动态力学分析仪（DMA）对共混物的相容性和相结构进行了表征。结果发现，在PVC／ABS共混体系中，尽管改变接枝SAN共聚物的AN结合量，PVC和ABS接枝共聚物均为不相容体系；在ABS接枝共聚物中引入α-MSt后，当接枝SAN共聚物的AN结合量为18．7％～23．6％（质量分数）时，共混物在室温以上只存在1个tanδ峰，共混物成为相容体系，当AN结合量达到32．1％（质量分数）时，共混物成为部分相容体系。共混物的相区尺寸明显地依赖于接枝SAN共聚物中的AN结合量，与动态力学性能结果表现出良好的吻合。

A series of ABS and a-MABS graft copolymers with different acrylonitrile（AN） contents were synthesized by graft co-polymerizing styrene（St） and a-methyl styrene（a-MSt） and acrylo- nitrile（AN） monomer mixture onto polybutadiene（PB） latex rubber particles with seed-emulsion poly- merization technique. By melt blending these copolymers with PVC resin,PVC/ABS blends were prepared. The miscibility and morphology of the blends were investigated by using TEM, SEM and Dynamic mechanical analysis （DMA）. It was found that all PVC/ABS blends are immiscible for SAN copolymer with different AN content. When AN contents were 18. 7%-23. 6% in a-MSAN copolymer, a single tan 3 Peak over room temperature in DMA detection was found. PVC/a-MABS blends became miscible system because of the introduction of a MSt into the SAN copolymer. When AN content was 32.1% in a-MSAN eopolymer, the PVC/a-MABS blends became partly miscible system. The morphology result showed that the phase domain size of the PVC/ABS blends intensively depend on AN content of SAN copolymer in ABS graft copolymer, and it agree well with the results of dynamic mechanical analysis.