【摘要】 采用组合式转矩流变仪研究了聚丙烯(PP)熔体在等径异长毛细管流道(长径比L/D为20,30,40)的流变行为。结果表明,非牛顿指数随着长径比的增加而减小,即熔体的非牛顿性增强,剪切速率对黏度敏感性增加;熔体黏流活化能随剪切速率的增大而减小,表现为低剪切速率范围黏度对温度较敏感,其中又以L/D=30情况下的敏感性最高。更多还原

【Abstract】 The rheological properties of polypropylene(PP) melt were studied by Haake combined-typed torque rheometer in different capillary length die among ratio of length to diameter(L/D=20,L/D=30 and L/D=40). The results show that non newtonian index decreases with the increases of the capillary flow length,thus non newtonian property and shear rate dependence of viscosity enhance. Viscous flow activation energy decreases with the increase of shear rate,which indicates viscosity is sensitive to temperature in low shear rate range,and the highest sensitivity appear in the case of L/D=30.更多还原