Thermal Degradation and Stabilization of Polyvinyl Chloride

Abstract

st widely produced plastic formed by the polymerization of vinyl chloride and has tremendous applications all around. It is thermally degraded by dehydro- chlorination, in the absence of oxygen and evolves HCl. Thermogravimetry (TG/DTG) coupled with evolved gas analysis (MS de- tection) of volatiles was used to characterize the thermal behavior of commercial PVC cable insulation material during heating in the range 20-800°C in air and nitrogen, re- spectively. In addition, simultaneous TG/FTIR was used to elucidate chemical processes that caused the thermal degrada- tion of the sample. There are two general approaches to the stabilization of polymers by modification of molecular structure and the use of additives. This degradation must be controlled by the addition of stabilizers. The mainly used stabilizers are Schiff bases, Alkyltin Stabilizers, Mixed Metal Stabilizers, Alkyl Phosphites Stabilizers, ? -Diketones Stabilizers, Epoxidized Fatty Acid Esters Stabilizers, Hydrotalcites Stabilizers, Tin Stabilizers, Organotin Mercaptides and Or- ganotin Sulfide Organotin Carboxylates. The heat stabilizer must prevent the dehy- drochlorination reaction. Among these Schiff bases were find best regarding envi- ronmental effects.