The Filler—Elastomer Chemical Link and the Reinforcement of Rubber

Abstract The results confirm the rationale which guided the experiments. The mechanical properties of the vulcanizate prepared without any milling and containing a carbon black chemically grafted to part of the elastomer are definitely superior to those of the blank, prepared under the same conditions with an ungrafted black. This indeed proves that merely creation of a chemical bond between the carbon black and the rubber brings about reinforcement and that, therefore, the reinforcement mechanism cannot be solely accounted for by physical interactions. Of course, optimum reinforcement as would be observed by classical mixing is not attained, since in this case complementary effects intervene. We believe that, for the first time, we have given absolute proof that the establishment of a chemical link between the carbon black and the elastomer induces reinforcement. New experiments are in progress with SBR; they should accentuate the differences in mechanical properties taking into account the very low values for nonreinforced vulcanizates.