相对分子质量对全同聚1-丁烯熔体流变行为的影响

摘要

The steady-state shear flow rheological properties of isotactic poly(1-butene)(iPB)with differ-ent relative molecular mass were studied by constant-speed double capillary rheometer within a wide range of the shear rate.The effects of the shear rate,temperature and relative molecular mass on the melt viscoelasticity,non-Newtonian index,viscosity flow activation energy and the appearance of the extrudate were explored. The results indicate that iPB melt is typical pseudo-plastic fluid within the experimental range of the shear rate. The non-Newtonian index decreases with the increase in the relative molecular mass. The iPB melt with higher relative molecular mass shows larger viscosity flow activation energy and melt viscoelasticity and lower critical shear rate of the extrudate. The melt viscoelasticity is decreased with the rise in the temperature. Moreover the change rules of non-Newtonian index with the temperature and the viscosity flow activation energy with the shear rate have slight difference for iPB melts with different relative molecular mass.%采用恒速型双筒毛细管流变仪研究了不同相对分子质量的全同聚1-丁烯（iPB）在较宽剪切速率范围的稳态剪切流变行为。讨论了剪切速率、温度及相对分子质量对iPB熔体黏弹性、非牛顿指数、黏流活化能及挤出物表观的影响。结果表明：在实验剪切速率范围内，iPB是典型的假塑性流体，相对分子质量越大非牛顿指数越小，熔体的黏弹性和黏流活化能越大，挤出物临界剪切速率越小；升高温度能降低熔体的黏弹性。iPB熔体的非牛顿性随温度变化及黏流活化能随剪切速率变化均因相对分子质量的不同而略有差异。