AbstractWithout the use of any curatives, silica filled BIMS compounds can achieve tensile strength and bound rubber level close to conventional crosslinked elastomer compounds. This outstanding tensile performance of silica filled BIMS compounds results from the strong interaction between BIMS polymer and silica filler. Silica filled BIMS compounds can be reprocessed and still retain their high tensile strength performance. The good compatibility between BIMS and silica also leads to better filler dispersion and inhibition of filler‐filler interaction. This in turn leads to the lower processing viscosity observed. We speculate that BIMS can interact with silica via nucleophilic substitution reaction between benzylic bromide of the polymer and surface silanol group of silica.