复合羧酸镧对PVC热稳定作用研究

以常见的一元、二元及三元羧酸为原料，制备了6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，并通过傅里叶红外光谱分析对复合羧酸镧对PVC的热稳定机理进行了探讨。结果表明，长链二元酸与短链一元酸或二元酸复合所得的羧酸镧产品对PVC具有较好的热稳定性，而与短链三元酸复合所得产品对PVC的热稳定性相对较差；复合热稳定剂在与PVC共同受热的过程中，镧离子可以和PVC链上的Cl发生配位作用，使Cl趋于稳定，减缓了PVC的热降解，同时镧还可以吸收PVC降解释放出来的HCl。

Thermal Stabilization Effect of Composite Carboxylic Lanthanum on PVC

Using lanthanum nitrate, monocarboxylic acid, dicarboxylic acid and tricarboxylic acid as the precursors, six carboxylic lanthanums were synthesized, which were used in PVC as thermal stabilizers. By Congo red and torque rheometer, the static and dynamic thermal stability of the modified PVC was tested. It showed that the thermal stabilizers based on mono or di carboxylic acid behaved better than those based on tricarboxylic acid. FT IR showed that when heated, lanthanum ion could coordinate with the chlorine atoms and thus the thermal stability was provided. In addition, HCl released during the degradation of PVC could be absorbed by lanthanum.