基本断裂功方法表征PP及弹性体增韧PP的冲击韧性

IMPACT TOUGHNESS CHARACTERIZATION OF PP AND ELASTERMER TOUGHENED PP BY EWF METHOD

将基本断裂功(EWF)方法应用于聚丙烯(PP)、PP/(乙烯/丙烯/二烯)共聚物(EPDM)和PP/(乙烯/1-辛烯)共聚物(POE)共混体系的冲击韧性表征。结果表明,加入EPDM或POE后,共混物的比基本断裂功we和比塑性形变功βwp均有提高,说明弹性体的加入提高了材料抵抗裂纹扩展的能力和发生塑性形变的能力。含质量分数8%EPDM或POE的PP共混物的we和βwp高于含1%EPDM或POE的PP共混物。通过对试样冲击断面和应力发白区域的观察证实了EWF方法表征的结果。EWF方法为评价聚合物材料的断裂行为提供了更多的数据,是一种表征材料冲击韧性的极好的方法。

Essential work of fracture （EWF） method was applied to characterize impact toughness of polypropylene （PP） and PP/ethylene-propylene-diene rubber （EPDM） blends and PP/（ethylene/1-octene） copolymer （POE） blends. It was shown that the specific essential work （we） and specific plastic work （βwp） increased with the addition of EPDM and/or POE, which suggested that the elastermer had improved the material＇ s ability to resist crack propagation and produce plastic deformation. The we and/βwp of PP containing 8% EPDM or POE were higher than those of PP containing 1% EPDM or POE. The results above were verified by scanning electron microscopy （SEM） observation and stress whitening observation. EWF method provided more information for determining the fracture behavior of polymer materials. Thus it was a superior method to characterize the materials＇ impact toughness.