关键词: 流动诱导结晶, 结晶动力学, 晶体取向, 标准化黏度

Abstract:

A numerical simulation for the isothermal flow-induced crystallization of polymer in a simple shear flow is presented. The effect of flow on crystallization is considered through the simple mathematical relationship between the additional number of nuclei induced by shear and the first normal stress difference.Leonov viscoelastic model and Avrami model are used to describe the normal stress difference and the crystallization kinetics, respectively.The orientation factor and the shear viscosity are also calculated through the evolution of the relative crystallinity.It is found that the short-term shear has a large effect on the crystallization dynamics of polymer.The effect of the intensity of shear flow will approach some limit, namely, the acceleration degree of crystallization tends to level off when the shear rate or shear time is large enough.

Key words: 流动诱导结晶, 结晶动力学, 晶体取向, 标准化黏度