Preparation and characterization of butyl/NBR vulcanizates

To obtain rubber compounds with satisfactory thermal and oil resistance pro perties, blends of butyl rubber (IIR) with nitrile rubber (NBR) were prepar ed on a laboratory open mill. Cure behaviour of the blends, physico-mechani cal properties and ageing and oil resistance properties of the vulcanizates were determined. For electric insulation application, dielectric constant, dielectric loss and tans were measured. The results indicate that the vulc anizates of IIR/NBR blends of the ratios (70:30), (30:70) and (20:80), show superior thermal stability upon ageing, compared to individual rubbers and other blend compositions. Blending of IIR with NBR (main component) improv es swelling behaviour of NBR in brake fluid and toluene. However, blending of NBR with IIR (main component) improves swelling resistance of IIR in mot or oil and gasoline. Thus, the results obtained reveal effective improvemen t in thermal and oil resistance upon blending. (C) 1998 Elsevier Science Li mited. All rights reserved.