The study of the thermal stability of poly (vinyl- chloride) with different molecular weight

This study investigated the influence of the molecular weight on the thermal stability of poly (vinyl chloride) (PVC) under nitrogen atmosphere was studied by bromometry titration at various temperatures (160-190oC).The extent of dehydorchlorination (%conversion) was calculated from the ratio of the HCl evolved to the amount available in the polymer. The intrinsic viscosities of solutions to deduce the effect of the molecular weight on the degradation of polymer were calculated.In addition to the course of the dehydrochlorination, the spectral changes in the visible and infrared regions have been investigated. It was found that the number- average molecular weight (45.000, 104000) slightly affected the thermal dehydrochlorination.The experimental results also indicated the relationships between molecular weight and structural defects.