半结晶聚合物非等温结晶结构演化模拟

Numerical simulation of structure evolution in non-isothermal crystallization for semi-crystalline polymers

在半结晶聚合物加工中,材料的结晶决定了结构形态的形成,而形态对最终制品的性能起着重要的作用,因而对聚合物结晶形态演化进行模拟具有重要意义。本文基于非等温结晶的微分控制方程组,采用龙格-库塔法,在matlab上实现了聚合物非等温结晶过程的模拟。模拟不同结晶条件下整体结晶动力学、晶核生成和晶体长大过程,并在此基础上计算晶体尺寸演化及分布。将等温和非等温结晶模拟结果与解析解和实验结果对比,结果吻合很好,验证了模拟程序。数值分析了结晶温度和冷却速率对晶体尺寸分布的影响,获得等温和非等温结晶中晶体尺寸分布规律。

In polymer processing,crystallization plays a major role on the structure development of polymer,and structure development has important influence on the final properties of the products.It is significant to simulate crystallization morphology evolution.In this work,a general differential system was adopted to describe the crystallization morphology evolution,and the simulation of the crystallization process under non-isothermal conditions was implemented using Rounge-Kutta method by Matlab.The overall crystallization kinetics,the potential nuclei number and the crystal entities number can be predicted,and the size evolution and final size distribution of the crystal entities can be calculated.The simulation results were compared with analytical values and experimental results,the comparison result showed a perfect agreement and verified the program.The influence of crystallization temperature and cooling rate on size distribution was studied by numerical analysis,and the influence laws were obtained.