剪切应力场对聚丙烯等温结晶的影响

Effect of Shear Stress on Isothermal Crystallization of PP

在等温条件下,通过考察不同剪切应力条件下聚丙烯(PP)的储能模量,并将其储能模量与PP的结晶行为相联系,研究了剪切应力条件下PP的等温结晶行为,研究了各种剪切应力条件对PP结晶的影响。结果表明:剪切应力施加的时间延迟长和应力施加速率的变快均能缩短PP结晶诱导时间、加快结晶速率。此外,应力场作用下消除热历史后的降温速率越快,会延迟结晶出现的时间。

Based on previous studies,the isothermal crystallization induced by shear flow with rheological method was futher studied in the paper.The effects of different shear flow on the variation of storage modulus and crystallization during iPP isothermal crystallization were investigated.The variation of storage modulus and the relative crystallinity;and analyzed was related directly,and the reason of no storage modulus platform during PP crystallization was discussed.The results showed that there was obvious promotion of shear flow to crystallization in polymers,but rheological behaviors of crystallization process could vary by material.