自由基聚合反应挤出过程的化学流变分析

进行了甲基丙烯酸正丁酯在异向旋转双螺杆挤出机内的自由基聚合反应过程数值模拟,描述了单体转化率、重均分子量、流体粘度等物理量的变化特点,分析了其影响因素,获得了材料体系的化学流变规律.模拟结果与实验结果基本吻合.

CHEMORHEOLOGICAL ANALYSIS OF FREE RADICAL POLYMERIZATION PROCESSES DURING REACTIVE EXTRUSION

In order to optimize reactive processing conditions and synthesize polymer materials according to requirements a kinetic model of free radical polymerization of n-butylmethacrylate(n-BMA) in counter-rotating twin screw extruders was constructed mainly on the basis of the entanglement theory,and then the numerical calculation expressions of the monomer concentration,the monomer conversion,the average molecular weight and the apparent viscosity were deduced.Consequently,the free radical polymerization process of n-BMA in counterrotating twin screw extruders was numerically simulated by means of the finite volume method and an uncoupled semi-implicit iterative algorithm,and then the evolution characteristics and the influencing factors of different variables like monomer conversion,average molecular weight and fluid viscosity were discussed in detail.A comparison of the monomer conversion as well as the weight-average molecular weight between the simulated results and the experimental results shows a nearly good agreement,which indicates that the constructed model is reasonable.