Methacrylamide grafted elastomer composites reinforced with biobased particles

Abstract

Modulus of rubber can be improved with grafting of unsaturated monomers. To increase the modulus of bio-based rubber composites, methacrylamide was grafted onto natural rubber composites reinforced with bio-based hydrophilic particles. Rubber particles in water were modified with methacrylamide using redox free radical initiator. Modified rubber composites have higher crosslinking density, bound rubber, and modulus than the unmodified rubber composites. Without methacrylamide, initiator modified rubber composites have poor tensile strength and elongation. The modified rubber has a greater stress relaxation rate than the unmodified rubber because of interactions between methacrylamide grafts. Relaxation behaviors of modified and unmodified rubber composites are similar because the effect of filler dominates the dissociation process. The rapid increase of reinforcement factors with filler content can be described by the modified Mooney equation. At small strain, the reinforcement factors for both modified and unmodified rubber composites indicate the association of poly(methacrylamide) grafts is the main contribution to the increase of modulus in the modified rubber composites.

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