The kinetics of the thermal degradation of the synthetic styrenated polyester, laminac 4116

The kinetics of the thermal decomposition of the polyester, Laminac 4116, were investigated in air and argon at atmospheric pressure by means of a continuous recording thermobalance and by differential thermal analysis. Samples were heated from ambient temperature to 600°C. at rates of 5°/min. and 15°/min. In air and argon, decompostion commences at 200°C. and is complete at 550 and 450°C., respectively. Four modes of degradation in oxygen and two in argon are indicated from derivative plots of the thermogravimetric curves. The kinetics of reaction were evaluated by the method of Freeman and Carroll. In the presence of air, the initial stage of reaction appears to involve formation of an unstable hydroperoxide intermediate which undergoes rearrangement and degradation. The energy of activation was calculated to be 19 kcal./mole. An exotherm corresponding to this first stage of degradation is observed by differential thermal analysis. The second and third stages of reaction in air correspond approximately to the two stages in argon with respect to their endothermal nature and to the temperature regions over which they occur. Mass spectrometric and infrared analysis were employed for identification of gaseous and volatile products. The fourth stage of reaction in air appears to involve the oxidation of carbon to carbon dioxide. Mechanisms of reaction are proposed and discussed.