In situ preparation and properties of rubber/inorganic oxide nanocomposites

Abstract

The present paper is concerned with the preparation of a filled elastomer by means the non-conventional bottom-up approach to polymer composites, alternatively with the conventional mechanical compounding of preformed filler particles with rubber. EPDM rubber was modified with in situ generated silica particles prepared by means of a sol-gel process adopting a solution process. The used synthetic procedure permitted the preparation of highly filled rubbers (up to 40 wt% of silica) with silica particle dimensions ranging from 0.2 to 2 μm. Equilibrium swelling and extraction tests indicated a hindering effect of the presence of in situ generated silica on the vulcanization process which reduced the cross-linking degree of the rubber matrix. Both tensile tests and dynamic-mechanical analysis showed a significant improvement in the mechanical properties due to the presence of the reinforcing filler, with an enhancement more significant than that expected from a simple hydrodynamic reinforcing mechanism.