CROSSLINKING OF EPDM AND NBR/EPDM BLENDS WITH POLYFUNCTIONAL ALLYL AND/OR VINYL COMPOUNDS

Abstract

Polyfunctional allyl and/or vinyl compounds as a crosslinking promoter were prepared by a ring-opening addition of allylglycidyl ether or glycidyl methacrylate and polyfunctional alcohols or carboxylic acids, and then, thier compounding effects were examined for pure EPDM and NBR/EPDM blends. These unsaturated compounds were viscous liquids containing three and four allyl and/or vinyl groups in their molecules.As the results, the higher values of tensile strength and elongation at break were obtained with EPDM and NBR/EPDM vulcanizates when these polymerizable unsaturated compounds were blended in theirs. Especially, in the case of sulfur-accelerator vulcanizing system, while the initial tensile modulus decreased with incresing of the amounts of these compounds, the tensile stress showed the remarkable rising like as the limited chain effect at just before the break. From the results of swelling and extraction tests of vulcanizates, it was suggested that these unsaturated compounds contributed to a formation of crosslinking for EPDM and NBR/EPDM vulcanizates.