SAN共聚物组成对PVC/ABS共混物相容性的影响

采用乳液聚合技术通过改变共聚单体的投料比(St/AN)合成了一系列不同AN结合量的ABS接枝共聚物粉料和SAN共聚物.将其与聚氯乙烯(PVC)和邻苯二甲酸二辛酯(DOP)熔融共混分别制得了PVC/ABS、PVC/SAN、PVC/ABS/DOP和PVC/SAN/DOP共混物,利用SEM、TEM和动态力学粘弹谱仪(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SAN共聚物均为不相容体系;在该共混物中引入增塑剂DOP后,虽然当SAN共聚物AN结合量小于23.4 wt%时,共混物在室温以上只存在一个tanδ峰,但形态结构研究结果表明共混物仍为不相容体系,共混物的相区尺寸明显地依赖于SAN共聚物中的AN结合量,当AN结合量为23.4 wt%时相区尺寸最小.

EFFECT OF COMPOSITION OF SAN COPOLYMER ON THE MISCIBILITY OF PVC/ABS BLENDS

A series of ABS graft copolymers and SAN copolymers with different acrylonitrile(AN) contents were synthesized with emulsion copolymerization technique.By melt blending these copolymers with PVC resin and di-isooctyl phthalate(DOP),PVC/ABS,PVC/SAN,PVC/ABS/DOP and PVC/SAN/DOP blends were prepared.The miscibility and morphology of the blends were investigated by using dynamic mechanical analysis(DMA),TEM and SEM.It is found that in all cases PVC and ABS are immiscible for SAN copolymer with different AN contents.When AN content is less than 23.4% in SAN copolymers,a single tanδ peak over room temperature in DMA detection is found because of the introduction of DOP in the PCV/ABS blends,but the morphological observations show that the PVC and SAN copolymer are immiscible and the phase domain size of the blends intensively depends on the AN content of SAN copolymers in ABS graft copolymers.When the AN content of SAN copolymer is 23.4%,the size of phase domain in the blends is the smallest.