Anisotropy of Ultimate Properties in Vulcanizates of EPDM/High-Diene-Rubber Blends

Abstract

Abstract It can be concluded from this work that the ultimate mechanical properties of NR/EPDM blends are indeed anisotropic, but that the tendency towards anisotropy (and, thus, the tendency towards weakness in certain directions, e.g., a tendency to tear with the processing-flow direction or grain) is greatly reduced when one uses the dynamic vulcanization technique. This technique improves cut-growth resistance (in the grain direction), peel strength, and interply adhesion. Also, because of the modification of the EPDM to give reactive sites (pendent succinic-anhydride groups) for vulcanization to occur by a means other than sulfur, the cure-rate incompatibility problem is greatly ameliorated. Thus, improvements in permanent set, hysteresis, and rebound are obtained by using the techniques of this report.