Surface modified silica fillers have been developed by coating these with a silane coupling agent, triethoxyvinyl silane (TEVS) followed by electron beam irradiation at room temperature. These have been incorporated in an ethylene-octene copolymer rubber. Rheometric, mechanical, volume swelling and aging properties of the gum as well as the filled elastomers have been studied in details. A significant improvement in the above properties has been noticed for these vulcanizates, which clearly emphasizes that novel surface modified silica improves polymer-filler adhesion by the introduction of covalent bonds between the filler surface and the rubber chains. Filler-filler and polymer-filler interactions have been quantified with the help of a mathematical model correlating the modulus and the volume concentration of filler. The influence of electron beam treatment on silanized silica filler has also been demonstrated from the above model. (C) 2003 Kluwer Academic Publishers.