THE THERMAL-DEGRADATION OF COPOLYMERS OF GLYCIDYL METHACRYLATE AND VINYLACETATE

The thermal degradation of copolymers of glycidyl methacrylate (GMA) a nd vinyl acetate (VAc) was studied by thermal volatilisation analysis (TVA), thermogravimetry (TG), differential thermal analysis (DTA), and pyrolysis mass spectrometry. The apparent activation energies for the decomposition of the copolymers were calculated from the results of T G experiments. The condensable volatile products from the TVA experime nts have been identified after separation by subambient thermal volati lisation analysis (SATVA). The cold ring fraction (CRF) was examined b y FTIR spectroscopy, and the structural changes in the residue in the course of degradation were also examined. Non-condensable products for med during TVA degradation were identified by mass spectrometry. These copolymers display a new reaction not found in either of the homopoly mers, namely adjacent unit lactonisation. Particular features which di stinguish the behaviour of the copolymers from the homopolymers are: ( a) the low yield of GMA, and (b) the appearance of glycidyl acetate as one of the major products. A mechanism of thermal degradation has bee n suggested.