多单体接枝聚丙烯对PBT/PP共混体系的形态结构及力学性能影响研究

研究了甲基丙烯酸缩水甘油酯 (GMA)和苯乙烯 (St)多单体熔融接枝聚丙烯 (PP g (GMA co St) )对聚对苯二甲酸丁二酯 (PBT) 聚丙烯 (PP)共混物的形态结构和力学性能的影响 .利用双螺杆挤出机对PBT PP合金进行共混挤出 ,使用DSC、FT IR和SEM、TEM等手段对共混物进行了分析和相形态观察 ,并测试了力学性能 .实验证明 ,熔融共混过程中PP g (GMA co St)的环氧基团可以与PBT的端羧基发生化学反应 ,就地生成了PBT g PP共聚物 ,该共聚物可对PBT PP合金起到良好的增容剂作用 ,使共混物的相区尺寸显著减小 ,共混物的拉伸强度和冲击强度等力学性能同时得到明显改善 ,达到了弹性体系或小分子增容所难以达到的力学性能平衡的效果 .此外 ,TEM的研究还在PBT PP g (GMA co St)共混物中发现了特殊的微相分离结构

EFFECT OF ADDITION OF PP-g-(GMA-co-St) ON MORPHOLOGIES AND PROPERTIES OF PBT/PP BLENDS

Multi\|monomer grafted polypropylene (PP g (GMA co St)) was used as a precursor of in\|situ compatibilizer for incompatible blend of poly(butylene terephthalate) (PBT) and polypropylene(PP).The formation of PBT g PP copolymer with addition of PP g (GMA co St) was confirmed by means of MFR and FT\|IR measurements because the epoxy group in glycidyl methacrylate (GMA) of PP g (GMA co St) reacted with the terminal carboxylic acid group in PBT.Thus the PBT g PP copolymer acted as a compatibilizer between PBT and PP during the melt blending.The changes in morphologies of PBT/PP/PP g (GMA co St) blends with different contents of PP g (GMA co St) were investigated using scanning electron microscopy (SEM).The addition of PP g (GMA co St) markedly improved the morphologies of the blends,and uniform and fine dispersed phase was observed with size being about 0.2 μm for PBT/PP g (GMA co St) (70/30) blend.Micro\|phase separated structure formed in the blend was found by means of transmission electron microscopy (TEM).The addition of PP g (GMA co St) also greatly improved the mechanical properties of PBT/PP blends,particularly for PBT/PP/PP g (GMA co St) (70/20/10) blend.It should be noted that the tensile strength of the blend was kept with the increasing of the Izod impact strength and elongation at break.