The effects of compatibility on the mechanical properties and fatigue resistance of butyl/EPDM rubber blends

Abstract In this study, compatibility of butyl/ethylene‐propylene‐diene rubbers in different ratios was investigated byviscometric technique. For evaluating polymer compatibility, the parameters Δb suggested by Krigbaum&Wall, ΔB and μ that were suggested by Chee were calculated. Data obtained from viscometric study were used for preparing new compound recipe. Mechanical and rheological properties of the new compounds were measured and the changes in the properties before and after thermal aging were determined. Replacement of ethylene‐propylene‐diene rubber with butyl rubber in appropriate ratio improved the fatigue resistance of the vulcanizates. Improvement of dynamic mechanical properties of polymer blends is expected only in the case of blending compatible polymers in appropriate ratios. The compatibility of blends in different ratios has been studied by viscometric technique and mechanical measurements and obtained very similar results. It has been concluded that viscometric determination of butyl/ethylene‐propylene‐diene rubbers compatibility could be used as a simple technique for predicting the mechanical properties of the same rubber blend that was related with solid phase compatibility. POLYM. COMPOS., 31:1869–1873, 2010. © 2010 Society of Plastics Engineers.