多元醇对聚氯乙烯热稳定作用的影响

采用静态热老化法、动态热老化法、刚果红变色法、红外光谱分析(FT-IR)、热失重分析(TGA)等现代仪器分析方法,评价了多元醇单独使用以及与硬脂酸锌(ZnSt2)复配使用时,对聚氯乙烯(PVC)的热稳定作用,并研究其协同作用机理。结果表明,多元醇单独使用时,能吸收聚氯乙烯受热分解产生的氯化氢(HCl),改善PVC的初期着色性,随着多元醇含量的增加,PVC热稳定时间延长。当硬脂酸锌与山梨糖醇复配含量为(0.7/0.4)份时,PVC的静态热稳定时间从15 min增加到21 min,热失重第一阶段试样残留量由44.97%增加到49.78%,表明山梨糖醇与ZnSt2复配能与降解产生的ZnCl2络合,缓解"锌烧"现象,改善了PVC的长期热稳定性。

Effect of Polyols on Thermal Stability of Polyvinyl Chloride

The evaluation on the static thermal stability of PVC and exploration of its synergistic mechanism when polyol was used alone and in combination with zinc stearate(ZnSt2)had been done by using the static thermal stability method,dynamic heat aging method,Congo Red test,FT-IR,Thermogravimetric analysis(TGA)and other modern instrumental analysis methods.The results showed that polyol can absorb the HCl generated by thermal decomposition of PVC and improve the initial coloration of PVC when it’s used alone.PVC thermal stability time increased with the increased of the polyol content.When the content of zinc stearate and sorbitol was(0.7/0.4),the static heat stability time of PVC increased from 15 mins to 21 min,and the residual amount of sample in the first stage of thermal weight loss increased from 44.97%to49.78%.It indicated that the complexation of polyol sorbitol and ZnSt2 can be complexed with ZnCl2 produced by degradation,alleviating the phenomenon of"zinc burning"and improving the long-term thermal stability of PVC.