聚丙烯/POE共混组成对材料断裂行为的影响

采用基本断裂功(EWF)方法对聚丙烯(PP)/聚烯烃弹性体(POE)共混物的注射双边缺口拉伸试样的断裂行为进行了研究,比较了不同POE含量对共混物各断裂参数的影响.结果表明,PP和用量为5phr POE的共混物都可完全满足EWF方法的要求,共混物的断裂韧性-比基本断裂功we,较PP有显著提高;POE用量为10phr以上的共混物则出现明显的成颈现象而限制了EWF方法的应用;PP和各种POE用量的共混物都得到了其屈服所需要的比基本断裂功we,y和比塑性功β′wp,y.

FRACTURE BEHAVIOR OF POLYPROPYLENE/POE BLENDS WITH DIFFERENT MIXED RATIOS

The influence of polyolefin elastomer (POE) content of polypropylene (PP)/POE blends on fracture behavior has been studied using the essential work of fracture (EWF) method.Each material was injected for preparing double edge-notched tensile (DENT) specimens of about 1.3 mm thickness.It was established that the essential work of fracture approach worked well for the PP and PP/POE (100/5) blend.The specific essential work of fracture,w_e,increased remarkably with adding POE.Some limitations of the EWF method was found with PP/POE (100/10 and 100/15) blends,which showed the necking phenomenon with DENT specimens studied.The specific essential work and plastic work of fracture required for yielding,w_e,y and β′w_p,y ,of each material were obtained.It was found that the w_e,y values of the PP/POE blends all increased remarkably,over two times larger than that of pure PP,and the β′w_p,y values increased gradually with increasing content of POE for the PP/POE blends.