【摘要】 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。更多还原

【Abstract】 High-melt-strength PP was silane-grafted and cross-linked of isotactic PP with atwm screw extruder,using unsaturated silane as grafting monomer,unsaturated olefin as co-agent.The effects of the agents on modified PP were investigated by testing the changes of melt-flow-rate (MFR) and gel percentage.The results showed that each agent of the system had great effect on the melt-flow-rate and gel percentage.The fluidity of modified PP decreased with the increasing content of initiator A.The introduction of co-agent increased the degree and rate of silane grafting and cross-linking by stabilizing macromolecular radical.The optimum molar ratio of co-agent to silane was 1∶1.The modified PP indicated better heat resistance and excellent mechanical properties.更多还原