Thermokinetic studies of dicumyl peroxide

A synchronized thermal analyzer was used to measure heat-flow and weight-loss of dicumyl peroxide (DCP) at various heating rates. Numerical models of DCP thermo-kinetic parameters were developed. The data show that DCP first fuses and then decomposes. The DCP melting point is 39.5°C with an enthalpy for the phase transition of 110 J/g. The maximum temperature of decomposition is 165 °C with an enthalpy of 500 J/g. As the heating rate increased the temperature for the onset of decomposition shifted to higher temperatures. The thermal profile of the decomposition also extends to higher temperatures. The kinetic parameters for DCP decomposition were determined by the Borchardt-Daniels method. The reaction was first order and had an activation energy of 140 kJ/mol. The gravimetric curves show that the thermally induced weight loss occurs in one phase. The temperature of maximum weight loss is 170°C and the total loss is about 90%. As the heating rate is increased the loss curve shifts to higher temperatures but the total weight loss becomes smaller. A model free kinetic method was used to calculate kinetic parameters from the weight loss curves. At a conversion of 0.3 to 0.9 the apparent activation energy is approximately constant with a mean value of 102.8 kJ/mol.