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Incorporation of silica into styrene butadiene rubber (SBR)–reclaim rubber (RR) blend system was carried out by sol–gel technique and conventional method. A well known silica coupling agent bis(3‐triethoxysilyl propyl) tetrasulfide was found to affect the curing characteristics and mechanical properties of SBR/RR vulcanizate. Here, the effect of RR on silica reinforcement was studied for different SBR/RR blend system. Silica incorporation by conventional mechanical mixing in absence of TESPT showed a much higher tensile properties than that of silica incorporated by the in situ sol–gel reaction of tetraethoxy silane both in presence and absence of TESPT. Studies of equilibrium swelling in a hydrocarbon solvent were also carried out. ATR study indicates that RR forms bond with silica particles due to the presence of active functional site on RR. The amount of silica incorporated by sol–gel reaction was determined through thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the silica filled SBR/RR vulcanizate. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 957–968, 2006

The present study aims to enhance EPDM rubber–silica interaction by employing a special technique called Two‐Stage Vulcanization, with the help of a multifunctional rubber additive, bis diisopropyl thiophosphoryl disulfide (DIPDIS). In this process EPDM rubber was heated along with rubber additives up to the time just before the commencement of cure and then filler was incorporated to the preheated rubber to get the final mix. The efficiency of this novel technique is evaluated by the enhancement of physical properties of the silica‐filled vulcanizates. This novel technique is also employed to investigate the effect of a silane‐coupling agent, viz., bis (3‐triethoxy silyl propyl) tetrasulphide (TESPT), in addition to DIPDIS, on the rubber–filler interaction. The positive role of this technique in enhancing the rubber–filler interaction is evidenced by the dynamic mechanical analysis and scanning electron microscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1132–1139, 2006

The effect of addition of chloroprene rubber (CR) on the dispersion of silica in EPDM (ethylene–propylene–diene terpolymer) was studied. It was observed that physical properties of the vulcanizates could be significantly increased at the EPDM : CR blend ratio of 92.5 : 7.5. SEM micrographs also indicated that incorporation of CR into EPDM improves the network structure of the resulting vulcanizates. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 196–200, 2004