EFFECT OF PREPARED HEAT STABILIZER MIXTURES ON THE PROPERTIES OF POLYVINYL CHLORIDE

Abstract

Nowadays, problems related to degradation and stabilization of polymer are getting more and more important. Poly vinyl chloride is one of the most frequently used thermoplastic polymers. Its big advantage is the high variability of properties which allow the application in rigid or soft products; there is no other polymer which shows such broad variety of changes in modificatious by plasticization like PVC. However, all polymers of vinyl chloride are quite unstable against heat and light, which leads to extensive changes in the polymer structure. This so- called degradation is caused by the elimination of hydrogen chloride and is characterized by discoloration of the polymers and in turn by unfavourable effects on mechanical, optical and electrical properties. This study aims to prepare some thermal stabilizer mixtures and study their effect on the properties of PVC. Six different stabilizer mixtures were prepared from calcium stearate and potassium stearate together with other additives, each was added to polyvinyl chloride in the following percentages: 1.8%, 2%, 2.2%, 3%. The effect of the different mixtures on the mechanical, thermal and electrical properties of the polymer was studied to determine the optimum amount which can be used as a heat stabilizer from each mix. Most of the prepared mixtures showed a positive effect on the delayed decomposition of PVC.

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