PVC用衣康酸镧复合热稳定剂的制备与应用研究

采用皂化法合成了衣康酸镧，利用刚果红法考察了与其他热稳定剂的多元复配效果，得到PVC衣康酸镧复合热稳定剂, 通过傅里叶变换红外光谱探讨了复合热稳定剂对聚氯乙烯（PVC）的热稳定机理，并用转矩流变仪、动态力学谱仪测定其加工性能和力学性能。结果表明，衣康酸镧、季戊四醇、硬脂酸钙、β二酮质量比为35∶1∶1∶1时协同效果最佳，可使PVC试样的静态及动态热稳定时间达到66.0 min和36.8 min，并能较好地抑制初期着色性, 其加工性能和力学性能与铅盐体系、硬脂酸镧复合热稳定体系相当，优于钙锌复合热稳定体系；复合热稳定剂在加热初期可减缓PVC脱除HCl的反应速率，抑制共轭多烯的形成，提高热稳定性能。

Preparation and Application of Lanthanum Itaconate Compound Thermal Stabilizer for PVC

Lanthanum itaconate was synthesized by saponification method, which was mixed with other components forming a compound thermal stabilizer for PVC. Thermal stability mechanism of PVC containing the compound stabilizer was studied by Congo red testing and FTIR. Processing performance and mechanical properties of the PVC compounds were determined by torque rheometer process tests and dynamic mechanics spectrometer. It showed that the best ratio was lanthanum itaconate∶pentaerythritol∶calcium stearate∶β diketone was 3.5∶1∶1∶1. The static and dynamic thermal stability time reached 66.0 and 36.8 min, respectively, the early coloring of PVC was restrained. Processing performance and mechanical properties were similar to those of lead salt and lanthanum stearate compound systems and better than those of calcium zinc complex system. The FTIR showed that the compound thermal stabilizer could lower the reaction rate of HCl eliminating, and inhibit the formation of conjugated polyene at the beginning of the heating, and thus the thermal stability was improved.