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采用不饱和硅烷为接枝单体,不饱和烯烃为共单体,在双螺杆挤出机上实现均聚型聚丙烯的接枝交联,制得了高熔体强度聚丙烯。实验通过熔体指数(MFR)和凝胶含量的变化研究原材料对改性PP的影响。结果显示,体系中的试剂均严重影响材料的熔体流动性能。在硅烷和共单体共存的条件下,材料的熔体流动性能随引发剂A含量的增加而下降。共单体起到稳定大分子自由基的作用,增加了硅烷的接枝效率和接枝速率,共单体与硅烷最佳摩尔比为1∶1。改性后材料的耐热性、力学性能等均有较大提高。
Adopting unsaturated silane as grafting monomer and unsaturated olefin as comonomer, graft copolymerization of homopolypropylene was carried out on twin-screw extruder to obtain polypropylene with high melt strength. The effect of raw materials on the modified PP was studied through the changes of melt index (MFR) and gel content. The results show that the reagents in the system seriously affect the melt flow properties of the material. Under the coexistence of silane and comonomer, the melt flowability of the material decreases with the increase of initiator A content. The monomer plays the role of stabilizing the free radical of the macromolecule, increasing the grafting efficiency and the grafting rate of the silane, and the optimal molar ratio of the monomer to the silane is 1: 1. Modified materials, heat resistance, mechanical properties, etc. have greatly improved.