STUDIES ON THE RELATION BETWEEN THE STRUCTURAL DEFECTS AND THERMAL INSTABILITY OF POLY (VINYL CHLORIDE) I. THE SYNTHESIS OF PVC AT MONOMER UNSATURATION VAPOR PRESSURE AND RELATION BETWEEN ITS IN STABILITY AND MOLECULAR WEIGHT
聚氯乙烯结构缺陷和热不稳定性之间关系的研究——Ⅰ.在单体不饱和蒸汽压下聚氯乙烯的合成及其热稳定性与分子量之间的关系

Five PVC samples (U-PVC) were prepared in water suspended system at monomer unsa-turation vapor pressure. The molecular weigh's and dehydrochlorination rates (De-HCl) of these samples and five commercial PVC samples (S-PVC) were determined. Experimental data showed that the thermal stabilities and molecular weights of U-PVC samples decreased wifh decreasing the monomer unsaturation vapor pressure (Pm/Po) in the preparation process. It was found also that there was a good linear correlation between 1/Mm, De-HCl and Pm/Po This result indicated the important role of the terminal structural defect in the dehydrochlorination of PVC.The mechanism of formation of terminal structural uefects was discussed.