α-酮戊二酸镧的制备、复配及对PVC热稳定性能

以α-酮戊二酸、硝酸镧、氢氧化钠为原料，水为溶剂，经两步法制备了α-酮戊二酸镧。采用元素分析、ICP-OES和FTIR对产物结构进行了表征。通过刚果红试纸法测试产品对PVC的静态热稳定性，转矩流变仪法测试产品对PVC的动态热稳定性，TGA研究产品对PVC热降解动力学的影响，并将产品与β-二酮、PDOP、PER、ESO等辅助热稳定剂复配，考察其协同性能，采用SEM观察热降解不同时间的PVC的微观表面形貌。结果表明，α-酮戊二酸镧对PVC具有较好的热稳定作用，添加3 wt%时，静态热稳定时间可达13min，动态热稳定时间可达1820s，可将PVC热降解过程的平均活化能提高15.78 KJ/mol，其与PER之间协同作用最佳，复合热稳定剂对PVC的静态热稳定时间达37min，动态热稳定时间达3480s。SEM观察发现复合热稳定剂能较好的抑制PVC团聚。

Preparation and Composition of Lanthanum Alpha-Ketoglutarate and Its Thermal Stability to PVC

Lanthanum alpha-ketoglutarate was prepared by two-step method using alpha-ketoglutarate, lanthanum nitrate and sodium hydroxide as raw materials and water as solvent. The structure of the product was characterized by elemental analysis, ICP-OES and FTIR. The static thermal stability of the product to PVC was tested by Congo red test paper, the dynamic thermal stability of the product to PVC was tested by torque rheometer, and the effect of the product on the thermal degradation kinetics of PVC was studied by TGA. The synergistic properties of the product were investigated by compounding with auxiliary thermal stabilizers such as beta-dione, PDOP, PER and ESO, and the microscopic surface morphology of PVC degraded at different time was observed by SEM. The results showed that lanthanum alpha-ketoglutarate has good thermal stability for PVC. When 3 wt% was added, the static thermal stabilization time could reach 13 min and the dynamic thermal stabilization time could reach 1820 s. The average activation energy of PVC thermal degradation process could be increased by 15.78 KJ/mol. The synergistic effect between PER and the composite thermal stabilizer was the best. The static thermal stabilization time of composite thermal stabilizer for PVC was 37 min and the dynamic thermal stabilization time was 3480 s. SEM observation showed that the composite heat stabilizer could better inhibit the agglomeration of PVC.