Journal of the University of J.Chemical Blazevska-Gilev, Technology D. Spaseskaand Metallurgy, 40, 4, 2005, 287-290 THERMAL DEGRADATION OF PVAc J. Blazevska-Gilev, D. Spaseska Faculty of Technology and Metallurgy, Received 20 October 2005 Ss Cyril and Methodius University, Accepted 15 November 2005 P.O. Box 580, MK-1001 Skopje, Republic of Macedonia, E-mail:
[email protected] ABSTRACT The kinetics of decomposition of plastics are interesting from different points of view, i.e. evolution of harmful substances during fires or waste incineration, recovering of chemical raw materials from plastic refuses and designing of recycling procedures. Non isothermal or dynamic thermogravimetry (TGA) has been used for kinetic study of the thermally activated process of polyvinyl acetate (PVAc), heating by two different rates up to around 723 K. As the easily measured weight changes of the samples in the defined thermal conditions are a suitable sensor for their structural and chemical changes, by means of some methods like Gropjanov-Abbakumov,s one, the useful information for identifying the formal kinetic parameters of the investigated processes taking place in the course of thermal treatment have been obtained. The thermal variation of the rate constant as well as the kinetic equations for the examined process depending on the investigated parameters have been derived. Keywords: polyvinyl acetate, thermal degradation, degradation kinetics. INTRODUCTION mally degrades under vacuum at an appreciable rate at temperatures above 500 K. The mechanisms of ther- Polyvinyl acetate (PVAc) is known to be one of mal degradation of PVAc is very complex process in- the most important commercial polymers as a result cluding, among others, the following reactions: chain of its low cost and high performance of the products, fission, radical recombination, carbon hydrogen single combined with the wide range of properties.