Investigating the role of different stabilizers of PVCs by using a torque rheometer

Abstract

Poly(vinyl chloride) (PVC) is one of the versatile thermoplastic materials that have tremendous applications almost everywhere but it is thermally unstable at high temperatures. Processing of PVC at elevated temperatures requires the use of thermal stabilizers that are considered crucial additives for the protection of PVC during both processing and useful life usage. Several thermal stabilizers are available commercially that mostly obstruct the dehydrochlorination reaction. Choosing appropriate stabilizer systems for a specific application is cumbersome. A Brabender torque rheometer at a constant temperature of 180°C and variable shear stress was used to evaluate the stabilizing efficiency of 12 different stabilizer systems combined with PVC. Fusion time, induction period, minimum torque, and rheological stability time were determined in order to evaluate the investigated stabilizer systems. It was found that dibutyl tin mercaptide was the best stabilizer, while the mixture of lead stabilizers was the worse one.

Keywords

• poly(vinyl chloride)
• stabilizers
• thermal degradation
• dehydrochlorination