Studies on the thermal and oxidative polymer degradation have been presented in monographs by Grassie' and Jellinek.The general consensus in the majority of these studies is that thermal and oxidative degradation of polymers is a radical reaction. Unlike the case of degradation of polymer products, the thermal decomposition of condensation resins has received virtually no attention, despite the fact that these resins have been widely used up to the present time in industry.In the present work we have investigated the thermal and oxidative degradation of epoxy resins. The kinetics of the thermal degradation of epoxy resins was evaluated on the basis of the increase in pressure in the system which is caused by gas evolution. The gases that appear during the degradation process are collected in a preliminary evacuated trap, where they are frozen with liquid nitrogen.During the degradation of the original epoxy resins, which were obtained on a base of epichlorohydrin and diphenylolpropane and designated ED-6 and ED-15 (molecular weight 500 and 2000, respectively) we found that at relatively low temperatures (2W250°C.), a small quantity of gaseous products slowly evolves from the resin, and a transparent colorless liquid distills off. At higher temperatures both the rate of formation and the amount of these gaseous products sharply increases; the liquid which distills off is yellowish brown in color. The quantity of infusible and insoluble residue is reduced with increased ' temperature. Also, with increasing temperature, there is a gradual increase in the amount of liquid which distills over.In the case of the degradation of hardened resins, even at low temperatures (25OOC.) the liquid is colored a dark hue.Curves showing the increase in gaseous pressure at different temperatures for the original and hardened resins are given in Figures 1-3. We can see from Figure 1 that the degradation of the epoxy resins begins at 240-25OOC. For resins that have been hardened with maleic anhydride (Fig. 3), this process begins at higher temperatures.

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1. In special apparatus (a laboratory modifier and a continuous modifier) block polymers are produced from condensation resins and various starting polymers by a mcchanochemical method. 2. It is demonstrated that the physicochemical properties of the resulting block polymers differ essentially from the properties of a mechanical mixture of homopolymers, which makes it possible to produce polymers with new properties.

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