科研之友
微信
新浪微博
Facebook
分享链接
摘要
Aim to explore the polymer crystallization during the cooling stage, a multiscale model in which macroscopic temperature and microscopic crystal morphology are related with each other is built up. On the one hand, the variation of macroscopic temperature can bring in changes of nucleation number and growth rate of crystal, and thus results in changes of microscopic crystal morphology. On the other hand, the latent heat released by crystallization can cause significant rise of temperature with the evolution of the crystallization. According to this multiscale model, the algorithm of coupling finite volume method with pixel method is proposed. The finite volume method is used on the coarse grid to calculate the macroscopic temperature and the pixel method is employed on the fine grid to capture the morphology of crystallization. A 2-D polymer melt with its boundaries experiencing the constant cooling rate operation is studied and the temperatures, relative crystallinity as well as the evolution of crystal morphology are given. In addition, the roles of cooling rate and initial temperature are also discussed. The results indicate that cooling rate is a significant factor for the temperature,relative crystallinity as well as the morphology. In the case of higher cooling rate, the plateau of temperature turns on earlier and lasts shorter, and so does the relative crystallinity; the temperature which begins with the crystallization does not change, however, the range of temperature becomes wider; due to this wider temperature change, nucleation number becomes more, thus result in the smaller average crystal size. The initial temperature only affect the time of showing up of temperature plateau and crystallization, and is almost independent on the lasted time.
- 出版日期2010-6-20
- 单位西北工业大学
