AFM STUDIES ON SILICA DISPERSION IN EPDM RUBBER

EPDM rubber formulations filled with precipitated silica and cross-linked by peroxide vulcanization have been investigated with the objective of realizing better processing characteristics and vulcanizate properties.  Dispersion of silica in EPDM rubber in presence of conventional coupling agents and in presence of an epoxy resin has been investigated using Atomic Force Microscopy and Scanning Electron microscopy. AFM results of EPDM rubber compounds containing silica fillers in presence of the epoxy resin have exhibited improved silica dispersion in terms of scanned height distribution. The latter has been found be in the range of maximum around 100nm for EPDM rubber- Silica systems with epoxy resin while in the absence of the resin, height distribution has been found to be more than 700nm. The significant reduction in the distribution of the scanned height in presence of epoxy resin is an indication of good dispersion of silica in the rubber. Morphological studies using SEM, mechanical properties and Mooney-Rivlin constants all have shown significant improvement in performanceproperties of EPDM Rubber–Silica compounds containing epoxy resin and vulcanized with dicumyl peroxide.