ACCELERATED THERMAL AGING OF NITRILE-BUTADIENE RUBBER UNDER AIR-PRESSURE

Accelerated thermal degradation of nitrile-butadiene rubber was studied (a) in air, at atmospheric pressure, and temperatures of 90, 105 and 120 degrees C; (b) in air, at 90 degrees C and 5 arm, at 105 degrees C and 3 atm and 5 atm, and at 120 degrees C and 3 atm and 5 atm. The changes of elongation at break as a result of the accelerated thermooxidative degradation were studied, and the importance of air pressure as a thermooxidative degradation accelerator is pointed out. On the basis of the experimental results, kinetic equations of thermal degradation of nitrile-butadiene rubber in an oven with forced air circulation and in pressurized air are derived.