聚苯乙烯和聚乙烯的三维混沌混合

Three Dimensional Chaotic Mixing of Polystyrene with Polyethylene

采用自制的三维混沌混合装置 ,研究了聚苯乙烯 (PS)与少量低密度聚乙烯 (LDPE)进行共混时 ,共混物中少相LDPE的结构演化及其对共混物韧性的影响 .扫描电子显微镜 (SEM )和透射电子显微镜 (TEM )的分析表明 ,随着混合周期数的增加 ,少相经历了由宏观颗粒→层片→纤维→微观颗粒的演化过程 ,最终形成了高长径比的纤维和大量尺寸均匀的颗粒 ,而增容剂聚苯乙烯 聚乙烯 丙烯 (SEP)的加入 ,对这一结构的形成是有利的 .冲击强度测试表明 ,在不加入增容剂时 ,LDPE对PS没有增韧作用 ,原因在于相间界面结合很差 ,当加入少量的增容剂后 ,可以获得显著的增韧效果 .

Polystyrene(PS) was blended with low density polyethylene(LDPE) in a self made three dimensional chaotic mixer. Evolvement of the minor phase and its effect on toughness of the blend were investigated. Examination by scanning electron microscopy (SEM) and transmissing electron microscopy (TEM) show that minor phase changed from macroscopical droplets to sheets of varied thickness, then to fibrils and to microcosmic droplets as the period numbers increases. Ultimately, there are fibrils of high aspect ratio and many uniform sized droplets in the blend. Compatibilizer polystyrene/polyethylene propylene (SEP) tend to enhance the formation of this structure. Impact strength tests showed that no improvement would be achieved without compatibilizer due to badly interface adhesion. However significant improvement of toughness can be achieved with a little compatibilizer (0.45% by weight). The maximum impact strength was 90.9% higher than that of pure PS.