Nitrile-EPDM Polymer Blends Fundamental Considerations for Development of Key Properties

The method of polymer-carbon black addition to the Banbury has a very definite effect on the development of the NBR-EPDM blend features. The conventional mix provides excellent dispersion, the best balance of properties and the best economics. The cure system has an important influence on the blend properties. Sulfur-accelerator cures designed for co-vulcanization of NBR-EPDM develop uniform physical properties through the entire blend range. Peroxide cures also provide uniform physical properties, better oil resistance and better ozone resistance at low levels of EPDM. The EPDM polymer composition has a dramatic effect on the blend properties. An EPDM polymer with equivalent viscosities and high unsaturation has good development of the essential blend properties. However, an EPDM polymer which is higher in viscosity and ethylene with normal unsaturation, the physical properties are constant through the entire blend range.