氯化聚乙烯/氯乙烯悬浮溶胀接枝共聚聚合温度-压力-转化率模型

Temperature-Pressure-Conversion Model for Chlorinated Polyethylene-Vinyl Chloride Suspension-Swelling Graft Copolymerization

根据氯乙烯(VC)在气相、水相、聚氯乙烯(PVC)富相、氯化聚乙烯(CPE)相和单体富相的分配,建立了CPE/VC悬浮溶胀接枝共聚聚合温度-压力-转化率模型。该模型可用于共聚体系VC临界转化率和临界转化率后VC转化率的预测,实现聚合终点的控制。模型和实验结果表明,随着聚合体系中CPE含量增加,VC临界转化率和一定压降时的转化率减小,这是由于VC在单位质量CPE中的溶胀量大于VC在PVC中的溶胀量所致。实验测定的不同CPE含量或压降时的VC聚合转化率与模型结果吻合较好。

Based on the monomer distribution balance of VC in vapor, poly(vinyl chloride)-rich, monomer-rich, water and CPE phases, an equilibrium model relating temperature, pressure, content of chlorinated polyethylene (CPE) and vinyl chloride (VC) conversion for CPE-VC suspension-swelling graft copolymerization is proposed This model can be used to determine VC conversion at the pressure drop point (Xf) and conversion beyond the pressure drop, and thus to control the end of polymerization. The model simulation results show that Xf and conversion beyond the pressure drop decrease as CPE feed content increase and it is caused by the higher swelling capacity of VC in CPE than that in PVC. A series of CPE-VC suspension copolymerizations were carried out in a 5L autoclave to evaluate the model. VC conversion at different CPE content or pressure drop determined by experiments fit well with the model results.