THERMAL OXIDATIVE-DEGRADATION OF EPOXY-RESINS - EVALUATION OF THEIR HEAT-RESISTANCE USING INVARIANT KINETIC-PARAMETERS

The thermal degradation of two epoxy resins was studied using a nonisothermal thermogravimetric technique. This work applies the invariant kinetic parameter (IKP) method in order to describe the degradation of the resins. The kinetic parameters (pre-exponential factor and activation energy) are independent of the experimental conditions and are computed without any hypothesis on the form of the kinetic degradation function. Moreover, the method allows us to compute the distribution of the probabilities associated to kinetic functions and to predict the degradation mode of the material. The kinetic model which best describes the decomposition of epoxy resins is that corresponding to a diffusion mechanism. Invariant activation energies of the degradations of TGDDM/DDS and TGDDM/DDA systems allows the comparison of their heat resistances in air and shows that the resin cured using the aromatic diamine is the more stable.