PVC用三元复合羧酸镧热稳定剂的制备及其性能研究

Preparation and Properties of Ternary Composite Carboxylic Lanthanum for PVC

以月桂酸、十四烷二酸、柠檬酸和硝酸镧为原料,制备了一种复合羧酸镧热稳定剂,采用刚果红法及转矩流变仪法对聚氯乙烯(PVC)进行了静态和动态热稳定性测试,并通过红外光谱和紫外光谱分析了复合羧酸镧及其组成对PVC的热稳定机理。结果表明,复合羧酸镧对PVC具有较好的热稳定性,且与辅助热稳定剂有较好的协同效应,其对PVC静态热稳定性可达47min,动态热稳定性可达2340s;复合热稳定剂在与PVC共同受热的过程中,镧离子的配位作用是减缓PVC热降解的主要因素,同时还伴有羧酸盐吸收HCl的作用;月桂酸镧的前期热稳定性较好,而十四烷二酸镧和柠檬酸镧的长期热稳定性较好。

Using lauric acid,tetradecane diacid,citric acid and lanthanum nitrate as precursors,a composite carboxylic lanthanum was synthesized,which was used in PVC as a thermal stabilizer.By Congo red and torque rheometer,the static and dynamic thermal stability of PVC was tested.The stabilizer rendered good thermal stability to PVC and had good synergistic effect with additives.The static and dynamic thermal stability for PVC were 47 min and 2340 s,respectively.FTIR showed that,when heated,coordination of lanthanum ion was the major factor for reducing degradation of PVC.Meanwhile,the carboxylate also could absorb HCl.UV test showed that lauric acid lanthanum was a early stage thermal stabilizer,but tetradecane diacid lanthanum and citric acid lanthanum provided a long-term thermal stability.