苯乙烯在MBS中的结合方式对PVC/MBS性能的影响

以乳液聚合法合成了化学组成恒定的具有核-壳结构的(甲基丙烯酸甲酯/丁二烯/苯乙烯)共聚物(MBS),通过改变原料及其配比,使苯乙烯(St)在MBS中以共聚或接枝方式结合,用动态力学热分析仪研究了MBS内耗与温度的关系。将MBS与聚氯乙烯(PVC)共混,研究了St结合方式对共混物冲击韧性及增韧机理的影响,结果表明,随着MBS核中St含量的增加,PVC/MBS共混物的脆-韧转变向高温移动;当St仅以接枝的方式结合时,橡胶粒子的空洞化及剪切屈服是主要的增韧机理,当St仅以共聚方式结合时,剪切屈服是主要的增韧机理。

INFLUENCE OF ARRANGEMENT OF STYRENE IN MBS ON PROPERTIES OF PVC/MBS BLENDS

Methacrylate/butadiene/styrene copolymer(MBS) of constand chemical composition and core-shell sturcture was prepared by emulsion polymerization.The arrangements of styrene(St) in MBS were altered by grafting and compolymerizing.The relationship between internal loss and temperature of MBS was investigated by DMA.MBS was blended with poly(vinyl chloride)(PVC),and the effects of arrangement of St in MBS on the impact toughness and toughening mechanism of PVC/MBS blends were studied.The results showed that the brittle flexible transition temperature increased with the increase of St content in MBS core;the toughening of PVC/MBS blends owed to rubber cavitation and shear yielding when St was only grafted onto butadiene,and it owed to shear yielding when St was copolymerized with butadiene.