Influence of hydroxyl-terminated polybutadiene liquid on rheology of fumed silica filled cis-polybutadiene rubber

Hydroxyl-terminated polybutadiene (HTPB) liquid is used to mediate the dispersity of fumed silica in cis-poly-butadiene rubber (BR) to prepare nanocomposites. The introduction of HTPB promotes the dispersion of both hydrophilic and hydrophobic silicas (A200 and R974), which improves the reinforcement efficiency, delays the onset strain amplitude of nonlinear softening and enlarges the high-order harmonics in the nonlinearity region. Influence of HTPB on the linear and nonlinear rheological responses are well accounted for by data superposition on the basis of the rheological responses of the matrix. It is evidenced for the first time that the rheological nonlinearity may be enhanced in the case of improved filler dispersity. This is understandable taking the intrinsic nonlinearity of the matrix and the strain amplification effect induced by filler into consideration.