热处理对β成核聚丙烯结晶结构及力学性能的影响

采用广角X衍射(WAXD)研究了热处理对β成核聚丙烯(β—PP)结晶结构的影响，并考察了不同热处理条件下的力学性能。研究表明，随着热处理温度的升高，β—PP的结晶度增大，结晶形态由β晶型逐渐转变为α晶型。当PP完全转化为α晶型时，其拉件强度及弯曲强度提高，而悬臂梁缺口冲击强度和断裂伸长率却降至最低，由韧性材料转变为刚性材料。该结果说明了在生产工艺中控制合适温度的必要性。

INFLUENCE OF THE THERMAL TREATMENT ON THE CRYSTALLINE STRUCTURE AND THE MECHANICAL PROPERTY OF β-NUCLEATED POLYPROPYLENE

The influence of the thermal treatment on the crystalline structure of B-nucleated polypropylene (PP) was studied by means of wide angle X-ray diffraction (WAXD). Also its mechanical property under different conditions was investigated. The results showed that with the increase of the temperature in the thermal treatment, the crystalline degree increased and the initial B crystalline converted to a crystalline gradually. When PP was totally composed of a crystalline at high temperature, the tensile strength and flexural strength were both very high, and the break elongation and the notched impact strength were the lowest, which meant the tough material had turned to be brittle. The results verified the necessity of the temperature controll during the molding process.