Effect of segment structure on the thermal stability ofCPVCin theGas–Solid PVCchlorination process

Abstract

The chlorination of the polyvinyl chloride resin with different ratios of CH2, CHCl2, and CCl2 was carried out through a gas–solid process by varying the temperature, reaction time, and chlorine concentration. The rheological properties and thermal stability of the resin were characterized. 13C NMR was used to characterize the segment structure of the resin. In addition, conjugated diene structure was determined by UV–Visible to study its chlorination process. The results show that CCl2 units in the structure promote the dehydrochlorination of CPVC, forming a conjugated diene structure and reducing the rheological properties and thermal stability. In contrast, the formation of CHCl in the chlorination process increased the thermal stability of the resin. Moreover, a structure‐effect relationship between the structure and performance has been established, and a stepwise process of chlorination was obtained by analyzing the changes of the structure segment content at different stages.