抗冲聚丙烯/聚对苯二甲酸乙二醇酯共混物的结构表征与抗应力发白性能的研究

Structure characterization and anti-stress-whitening property of Hi PP/PET blend

采用抗冲聚丙烯(hi PP)和聚对苯二甲酸乙二醇酯(PET)为原料进行共混得到hi PP/PET共混物。利用DSC,DMA,SEM等方法分析了PET的冷结晶行为,研究了hi PP/PET共混物中各组分的相区,探讨了分散相体积收缩对共混物性能的影响。表征结果显示,hi PP/PET共混物在注塑成型过程中,PET结晶不完善,在120℃时即可完成冷结晶。hi PP/PET共混物中,橡胶、聚丙烯和PET各自具有独立的相区,橡胶和PET形成各自的独立颗粒。未经退火处理的hi PP/PET共混物的抗应力发白性能较好,共混物中的橡胶颗粒尺寸与hi PP相比有所降低,共混物中PET颗粒的收缩程度与基体差异不明显。退火之后PET颗粒的体积发生收缩,共混物中的内应力增大,聚丙烯/PET两相界面分离的趋势增加,使hi PP/PET共混物的抗应力发白性能显著降低。

A blend of high impact polypropylene（hiPP） and polyethylene terephthalate（PET） were prepared and were characterized by means ofDSC, DMA and SEM. The cold crystallization and phase separation behavior of the blend were studied and the effects of volume contraction on the properties of the blend were discussed. It was found that the crystallization of PET in the injection-molded blend was incomplete or imperfect and the cold crystallization could finish at 120 %. In the blend, PP, PET and rubber are immiscible, and PET and rubber form dispersed phases in the PP matrix separately. The blend without annealing owns better anti-stress-whitening ability and smaller particle size than hiPP, in which the difference between the contraction degrees of both PET and the PP matrix is not so apparent. After annealing, the cold crystallization of PET leads to the volume contraction of the PET particles and the internal stress in the blend increases correspondingly. This induces a departure trend at the interface between PP and PET, which results in the apparent decrease of the anti-stress-whitening ability of the blend.