A kinetic analysis of thermogravimetric data of radically polymerised N-phenylmaleimide

Abstract The thermal behaviour of the radically polymerised poly( N -phenylmaleimide) was studied, adopting the thermogravimetric method at heating rates of 1, 5, 10 and 50°C min −1 in a nitrogen atmosphere. The kinetic parameters, such as activation energy, reaction order, Arrhenius pre-exponential factor etc., have been calculated using different mathematical approximations available in the literature. It is observed that the energy of activation values and pre-exponential factors estimated for the degradation of poly( N -phenylmaleimide) from a single heating thermogram using different approximations decrease with increase in heating rate, whereas nearly constant values are observed in the Dharwadkar and Kharkhanavala approximation irrespective of the variation in sample size and heating rate. It is also observed that the different approximations, when applied to multiple heating data, give nearly constant values for the kinetic parameters. These values are broadly similar to that calculated using the Dharwadkar and Kharkhanavala approximation from a single heating thermogram.