多层核-壳结构橡胶粒子对PVC增韧的研究

Study on Multi-layer Core-shell Rubber Particles Toughened PVC

采用乳液聚合方法,合成了以聚苯乙烯(PS)为内核、聚丁二烯(PB)为中间层,聚甲基丙烯酸甲酯(PMMA)为壳层的3层核-壳结构橡胶粒子(PSBM)。通过改变PS和PB的配比,制得核-壳比分别为23/57/20(质量比,下同)、13/67/20、0/80/20的PSBM,并用于增韧聚氯乙烯(PVC)。并对PSBM的内部结构及其在PVC基体中的分散状态、PVC共混物的力学性能及形变机理进行了研究。结果表明,PSBM在PVC基体中具有良好的分散状态;PS/PB/PMMA为13/67/20时,对PVC具有较高的增韧效率,同时还保持了较高的屈服强度,而且具有很好的透光性;对共混物应力白化区的研究表明,PSBM的内核PS与中间层PB的界面层促进了橡胶粒子发生空洞,提高了增韧能力;PVC/PSBM共混物的增韧机理是PSBM橡胶粒子空洞化促进PVC基体发生剪切屈服。

Three-layer core-shell rubber particles （PSBM） were prepared via emulsion polymerization. The PSBM were designed with a hard inner polystyrene （PS） core, an interim soft polybutadiene （PB） layer, and a hard external poly（methyl methacrylate）（PMMA） layer, with mass ratios of 23/57/20, 13/67/20 and 0/80/20. PSBM were introduced into PVC and the effects of morphology and distribution of PSBM on mechanical, optical properties, and deformation mechanism of the blends were studied. It was found that PSBM dispersed finely in PVC. When the PS/PB/PMMA was 13/67/20, PSBM toughened the PVC matrix effectively and retained high yield strength and transmittance. It also discovered that the interface between the inner core and interim layer could promote the cavitation of the rubber particles. The cavitation of rubber particles and shearing yielding of the matrix were the toughening mechanisms.