聚对苯二甲酸乙二醇酯切片溶胀聚合过程的模拟

摘要

Considering polycondensation,degradation and vinyl end group polycondensation, a poly (ethylene terephthalate) (PET) particle diffusion model was set up and used to simulate swollen-state polymerization (SwSP) of PET chips in tetradecane and their solid state polymerization ( SSP) in nitrogen. The experimental and simulative results showed that both SwSP and SSP processes for preparation of high relative molecular mass PET indicated similar polymerization rule that the intrinsic viscosity of the produced PET increased with increasing reaction time and temperature. The rate constants of the polycondensation and the vinyl end group polycondensation (kp and kt) are larger during SwSP than those during SSP, while the degradation rate constant(Jkd) during SwSP is lower. The diffusion coefficient(DEG) for SwSP is greater than that for SSP due to the honeycomb formation of the PET produced by SwSP. The factors of kp, kt, kd and DEG make the reaction rate increase in SwSP.%在考虑缩聚、降解及端烯基缩聚反应的基础上,建立了聚对苯二甲酸乙二醇酯(PET)颗粒反应扩散模型,模拟了PET切片在十四烷中的溶胀聚合及在氮气中的固相聚合反应过程.实验和模拟结果表明,溶胀聚合和固相聚合制备高相对分子质量PET具有相同的聚合反应规律,即PET的特性黏数随聚合时间的延长、反应温度的升高而增大；与PET切片固相聚合相比,PET 切片溶胀聚合的缩聚、端烯基缩聚反应速率常数(k.和k1)均较大,降解反应速率常数(kd)较小；溶胀聚合时的试样呈蜂窝状结构,其内扩散系数(DEG)大于固相聚合时的DEG.k.,kt,Kd,DEG等因素的综合效应使得溶胀聚合具有增速效应.