Determination of the thermal degradation kinetic parameters of carbon fibre reinforced epoxy using TG

In this work, a kinetic study on the thermal degradation of carbon fibre reinforced epoxy is presented. The degradation is investigated by means of dynamic thermogravimetric analysis (TG) in air and inert atmosphere at heating rates from 0.5 to 20 degreesC min(-1). Curves obtained by TG in air are quite different from those obtained in nitrogen. A three-step loss is observed during dynamic TG in air while mass loss proceeded as a two step process in nitrogen at fast heating rate. To elucidate this difference, a kinetic analysis is carried on. A kinetic model described by the Kissinger method or by the Ozawa method gives the kinetic parameters of the composite decomposition. Apparent activation energy calculated by Kissinger method in oxidative atmosphere for each step is between 40-50 kJ mol(-1) upper than E-a calculated in inert atmosphere. The thermo-oxidative degradation illustrated by Ozawa method shows a stable apparent activation energy (E(a)approximate to 130 kJ mol(-1)) even though the thermal degradation in nitrogen flow presents a maximum E-a for 15% mass loss (E(a)approximate to 60 kJ mol(-1)).