VULCANIZATION OF NITRILE RUBBER .3. FORMULATION AND STUDY OF OIL-RESISTING VULCANIZATION, BASED ON ACRYLONITRILE BUTADIENE RUBBER

Acrylonitrile butadiene rubber (Krynac, 803) with the best system of vulcanization in presence of accelerators, and coaccelerators, is further modified by the addition of different quantities of melamine-formaldehyde resin. As compared with the blank sample without this resin, the values of optimum cure time and scorch time decrease with the addition of resin. The rate of vulcanization increases and then begins to decrease gradually at higher quantities. Higher values of tensile strength, modulus, and hardness are obtained for vulcanized samples. The elasticity and elongation at break, respectively, remain at 28% and 260% till 3.0 pphr. Even higher quantities of the added resin lead to slight decreases in the studied properties. Better properties were also obtained upon aging in fuel and in hydraulic oil.