氯乙烯悬浮聚合过程中pH值调节剂的应用研究

Study on the application of pH regulator in the suspention polymerization of vinyl chloride

通过10L釜小试研究了氯乙烯悬浮聚合体系pH值的变化,并探索了pH值调节剂的种类、用量及加入时间对聚合反应和PVC树脂质量的影响。结果表明:在氯乙烯悬浮聚合过程中,添加pH值调节剂能提高聚合反应速率;在聚合1.0h或1.5h时开始流加pH值调节剂后,聚合分散体系较稳定;添加含NH+4的pH值调节剂有利于改善PVC树脂的颗粒皮膜结构、提高PVC树脂的氯乙烯脱吸性能、增塑剂吸收性能、塑化性能及热稳定性能。

The change of pH of the vinyl chloride suspension polymerization system was studied in a 10 L polymerizer,and the influences of the kind,adding amount and adding time of pH regulator on polymerization and the quality of PVC resins were investigated.The results showed that:(1)the addition of pH regulators could increase the rate of polymerization;(2)the dispersing system in polymerization was more stable if continuously adding pH regulators 1.0 h or 1.5 h after the beginning of polymerization;(3)the addition of NH^+_4-containing pH regulators helped improve the skin film structure of resin particles,vinylchloride-desorping property,plasticizer-absorping property,plasticizing property and heat resistance.