【摘要】 以过氧化物为引发剂,不饱和硅烷为接枝单体,不饱和烃类为接枝助剂,并加入交联催化剂,通过反应型双螺杆挤出机一步实现共聚型聚丙烯的接枝和交联;制备出了可用于发泡的高熔体粘度聚丙烯。通过熔体质量流动速率(MFR)和凝胶含量的变化,研究试剂体系对接枝交联改性的作用。结果显示,改性后PP的MFR可降低至0．1 g／ 10min以下,凝胶含量可高达48％以上,体系中各组分都显著影响改性材料熔体的流动性和凝胶含量,缺一不可。随引发剂和硅烷单体含量的增加,体系熔体流动性逐渐降低,凝胶含量增加。而硅烷单体与接枝助剂的最佳量之比为1 :1。通过PP改性前后的力学性能和发泡性能对比研究表明,接枝和交联使改性后PP的耐热性、抗冲击性、拉伸性能均有所改善;而且用改性PP发泡可以获得泡孔均匀、细密,且具有独立泡孔的高质量泡沫塑料。更多还原

【Abstract】 Foamable propylene was prepared by one-step silane-grafting and cross-linking of co-polymerized polypropylene (CPP) with a reactive extruder, using peroxide as initiator, unsaturated silane with long chain as a grafting monomer, unsaturated hydrocarbon as grafting co-agent in the presence of crosslinking catalyst. The effects of the agent system on the CPP modification were investigated by testing the change of the MFR and gel content. The results showed that the MFR of the modified PP decreased obviously to below 0.1 g/10 min and the gel content was up to more than 48 wt % . Each agent in the formulation had effect on the MFR and gel content of the modified PP, and all of the contents were effective and necessary. The more the contents of initiator and monomer, the lower the MFR, and the more the gel content. The optimum molar ratio of co-agent to silane was 1:1. The results of the comparison of the mechanical and foaming properties of the PP before and after modification indicated that the heat resistance, impact resistance and tensile strength of the modified PP were all improved. Furthermore, a high qualified foam with uniform, closed, fine and independent cells could be fabricated from the modified CPP.更多还原