Effect of gamma irradiation on some properties of reclaimed rubber/nitrile–butadiene rubber blend and its swelling in motor and brake oils

Reclaimed rubber powder (RRP) was treated by the addition of glycidyl methacrylate (GMA) to impart desired properties suitable for oil resistance applications. The produced GMA-RRP was mixed with nitrile–butadiene rubber (NBR) in various compositions. The blends were irradiated with gamma radiation doses of 50–250 kGy. The compounding of the blend factors has been elaborated using Fourier transform infra-red spectroscopy and scanning electron microscopy (SEM). Different properties of the synthesized unirradiated and irradiated blends such as tensile strength, elongation at break, hardness, swelling behavior in motor and brake oils and thermal stability were investigated with respect to the RRP content. Results show that the tensile strength, hardness and swelling resistance increase with increasing NBR content in the blend. It has been shown that the tensile strength increased with dose. Similarly, hardness values, reported for the same composition, apparently increased with dose within the range of 50–250 kGy. The residual mass percentage of blends obviously increased upon the incorporation of incremental RRP. The swelling percentage steadily decreases with increasing radiation dose due to the radiation-induced cross-linking.