PP/EPDM反应挤出共混制备高熔体黏度PP的研究

High-melt-viscosity polypropylene prepared by PP/EPDM reactive extrusion blending method

采用反应型双螺杆挤出机,用过氧化物(BPO)为交联剂、不饱和烯烃为交联助剂,对PP/EPDM体系进行反应增容,一步实现聚丙烯(PP)与少量EPDM的共混、接枝与交联,制备出了具有高熔体黏度的发泡用聚丙烯。对改性材料熔体流动性能、力学性能和发泡性能研究结果表明:当交联剂、交联助剂的质量比约为0.78∶1时,可以获得最佳的改性效果,改性后体系的熔体流动速率(MFR)下降92.9%;改性PP的多项力学性能都有显著改善,其中拉伸强度提高12.9%,缺口冲击强度提高93%;改性使材料的发泡性能得到显著提高,采用反应共混改性PP可获得泡孔大小约100μm,泡沫密度在0.44g/cm3左右,且分布均匀,闭孔率高的发泡材料。

A high-melt-viscosity modified polypropylene （PP） for foaming was prepared by blending copolymerized PP with EPDM through reactive extrusion. The crosslinking was initiated and promoted in the system using peroxides （BPO） as primary cross-linking reagent and unsaturated olefin as cross-linking coagent. Melt flow rate, mechanics capability and foaming of the modified polypropylene （PP） were studied. The results showed that the optimal effect was achieved when the weight ratio of primary cross-linking reagent （BPO） to the coagent was 0.78 ： 1. Melt flow rate descended 92. 9%. Many kinds of mechanics capability of the modified polypropylene （PP） were improved. Tensile strength was improved 12.9%, and impact strength was improved 93%. High-quality foam with uniform, closed and independent cells can be fabricated with the modified polypropylene PP foam diameter achieved about 100μm, and foam density achieved about 0. 44g/cm^3.