聚丙烯/热致液晶聚合物/玻璃纤维混杂复合材料的制备及性能研究

Preparation and Properties of PP/TLCP/GF Hybrid Composites

提出了一种制备原位混杂复合材料的新途径。将聚丙烯 (PP)、热致液晶聚合物 (TLCP)与玻璃纤维 (GF)在高于TLCP熔点的温度下熔融共混挤出 ,经适当拉伸 ,然后造粒 ,得到TLCP成纤良好的PP/TLCP/GF复合材料粒料。将其在不同温度下注射成型 ,考察了成型温度对所得混杂复合材料中TLCP组分的形态及材料力学性能的影响。结果表明 ,注射成型温度对最终复合材料中TLCP形态及材料的力学性能有明显的影响。当注射温度为 2 0 0℃和 2 2 0℃ ,即低于TLCP的熔融温度较多时 ,所得混杂复合材料中TLCP组分保持了较好的微纤结构 ,复合材料具有良好的力学性能。注射成型温度为 2 40℃时 ,复合材料中TLCP相开始出现熔融回缩 ;而当加工温度高于 2 60℃后 ,TLCP分散相主要成球形。随注射成型温度升高 ,混杂复合材料的力学性能逐渐下降。在基体中加入聚丙烯接枝马来酸酐 (PP g MAH)作为增容剂 ,可以同时改善PP与TLCP、PP与GF之间的界面黏结 。

A new route for the fabrication of in-situ hybrid composites is proposed.The PP/TLCP/GF hybrid composite was prepared by melt extrusion at a temperature higher than the melting temperature of TLCP.A well-developed TLCP fibrils structure was formed in-situ by post-drawing after the extruder die.The extrudates were injection-molded at different temperatures,and the effect of temperature on the morphology of TLCP phase and the mechanical properties of the composites was investigated.The results showed that the morphology of dispersed TLCP phase and the mechanical properties of the materials were strongly dependent on molding temperature.At molding temperatures of 200 ℃ and 220 ℃,which were far below the melting temperature of TLCP,it was observed that the injection-molded in-situ hybrid composites contained TLCP fibrils and exhibited maximum mechanical strength.The TLCP fibrils in the composites appeared somewhat retracted when the molding temperature was 260 ℃.But above 260 ℃,the TLCP component in the form of spheres resulted with decreased mechanical properties.The mechanical properties of the hybrid compostites decreased gradually with increasing molding temperature.The incorporation of maleic anhydride grafted polypropylene (PP-g-MAH) in the matrix improved the interfacial adhesion between PP and TLCP,between PP and GF and the mechanical properties were found to be enhanced.