提高PVC树脂热稳定性的研究

通过采用缓冲剂对聚合体系的pH值进行控制、在聚合配方中添加热稳定剂、控制聚合转化率等措施提高了PVC树脂的热稳定性能。结果表明：聚合开始添加用量为0．14％(或0．12％)(以VCM质量分数计)的碳酸氢铵pH值缓冲剂与聚合1．5h后流加用量为0．13％的氢氧化钠能有效地控制聚合体系pH值呈中性状态；采用加料方式2添加0．06％的PVC树脂改进剂或添加0．04％液体锌热稳定剂(或0．04％液体锌与新型耐热终止剂SPJ-KHZ复合使用)能有效提高PVC树脂的热稳定性能。

Research on improving the heat stability of PVC resin

The heat stability of PVC resin was improved by means of controlling the pH value of polymerization system with buffering agent,adding heat stabilizer to polymerization composition and controlling the polymerization conversion.The results showed that:(1)the pH value of polymerization system could be efficiently controlled at neutral by adding 0.14 wt%(or 0.12 wt%)(based on VCM) ammonium acid carbonate buffering agent at the beginning of polymerization and continuously feeding 0.13 wt% NaOH 1.5 hours after polymerization;(2)the heat stability of PVC resin could be efficiently improved by adding 0.06 wt% improver for PVC resin or adding 0.04 wt% liquid zinc heat stabilizer (or 0.04 wt% compound system of liquid zinc and new heat-resistant terminator SPJ-KHZ) by charging method 2.