【摘要】 通过辐照法制备了长支链型高熔体强度聚丙烯(LCB-HMSPP),采用高级流变扩展系统(ARES)表征了其熔体黏弹性,采用毛细管流变仪研究了其在高剪切速率下的流变行为。讨论了敏化剂用量、超高相对分子质量聚乙烯 (PE-UHMW)对PP熔体黏弹性、流动曲线和黏流活化能的影响。动态剪切流变数据表明,辐照改性制备的LCB- HMSPP具有较好的熔体黏弹性,并且其熔体弹性随敏化剂用量的增加而增强,表现在低频端剪切储能模量明显提高,内耗正切变小,零切黏度增大,特征松弛时间变长;辐照过程中添加极少量PE-UHMW也可提高PP的熔体黏弹性。静态毛细管剪切流变测试表明,线形PP和长支链PP的流动曲线较相似,LCB-HMSPP的黏流活化能较线形PP 有显著提高,其剪切黏度具有较高的温度敏感性。更多还原

【Abstract】 High-melt-strength polypropylene with long chain branching (LCB-HMSPP) was prepared via irradiation. The rheological behavior of LCB-HMSPP was investigated using an advanced rheometric expansion system (ARES) and a capillary rheometer. The dynamic rheological test indicated that the melt elasticity increased with increasing sentilizer content, reflected as increase in G′, zero-shear-viscosity, and reflaxation time, and decrease in tanδ. Introducing a small amount of PE-UHMW also enhanced the elasticity. The capillary rheological test revealed that LCB-HMSPP exhibited higher flow activation energy and temperature sensitivity compared with PP devoid of irradiation.更多还原