THERMOOXIDATIVE DEGRADATION OF SOME NITRILE BUTADIENE RUBBERS

Accelerated thermal ageing of some nitrile-butadiene rubbers has been studied, by measuring the residual deformation under constant deflexion in air. The results have been analysed by means of the Dakin kinetic equation and the Arrhenius equation. Thermal analyses (TG, DTG and DTA) have been performed at different rates of heating, the non-isothermal kinetic parameters of the thermooxidative degradations being estimated. The thermal analysis results have been correlated with those obtained in studying the variations of the residual deformation under constant deflexion, showing that mechanical ageing is due to the formation of oxidation products of the polymer.