Compatibility investigation of microwave irradiated acrylonitrile butadiene/ethylene propylene diene rubber blends

The physicomechanical properties, infrared spectra, and dielectric relaxations of acrylonitrile butadiene/ethylene propylene diene rubber (NBR/EPDM) blends with different compositions were studied. Microwave irradiation with different powers and different exposing time was used to improve the compatibility of such blends. The structure of NBR, EPDM, and NBR/EPDM blends before and after exposing to microwave irradiation were characterized by Fourier transform infrared-attenuated total reflection (ATR-FTIR) spectroscopy. The dielectric loss epsilon" data for the blends under investigation were fitted in the frequency domain by three Frohlich terms. The first term in the lower frequency range could be attributed to the Maxwell Wagner effect. The second and third terms could be ascribed to the reorientations of large and small aggregates caused by the movement of the main chain, which are expected to be formed by the addition of peroxides to rubber. The increase in the relaxation times associated with both terms is ascribed to the formation of crosslinks between NBR and EPDM at the boundaries of phases. A further proof was obtained from the crosslinking density (1/2M(c)) calculated from the Flory-Rehner relation and confirmed by the physicomechanical data of these blends. The effect of thermal aging on such blends was also studied.