CONTRIBUTION OF MECHANICAL ENGAGEMENT AND ENERGETIC INTERACTION IN REINFORCEMENT OF SBR-SILANE–TREATED SILICA COMPOSITES

Abstract

ABSTRACT We evaluated the significance of mechanical engagement and energetic interaction between a polymer and a filler as two reinforcing mechanisms in SBR composites containing silica modified by short- and long-chain silanes. To exclude mechanical contributions of reinforcement from that of energetic contributions, surface energy of silica particles was systematically adjusted to prepare fillers of identical and diverse surface energies. Having analyzed interactions using a temperature sweep in a small-strain oscillatory test and a uniaxial tension test, results indicated that the chain length of the silane has remarkable influence on energetic filler–filler and filler–polymer interactions, but no detectable difference associated with filler–polymer mechanical engagement was observed from these experiments. However, dynamic strain sweep experiments showed that the rate of breakage of the filler network (Payne effect) is less for the composite having long-chain silane compared to that having short-chain silane. It was hypothesized that this behavior could be correlated to mechanical engagements of long-chain silanes existing on the filler structure.