Study of crosslink structure and dynamic mechanical properties of magnetorheological elastomer: Effect of vulcanization system

Magnetorheological elastomers are a kind of intelligent and smart materials which are mainly composed of rubbery polymers and soft magnetic particles. The role of various vulcanization systems on the crosslink structures, curing properties, and dynamic mechanical properties of natural rubber–based magnetorheological elastomer was investigated. Conventional, semi-efficient, and efficient vulcanization systems were used and compared. It was found that the content of polysulfide linkages decreased and the monosulfide linkages increased when the vulcanization system was changed from conventional to semi-efficient and efficient vulcanization systems, respectively. The crosslink density has the same tendency with the content of polysulfide linkages. In all vulcanization systems, the zero-field modulus, magnetic-induced modulus, controllability of damping, and the degree of the influence of Payne effect of the samples had an increasing trend when the crosslink density decreased. Evidence from micrographs of scanning electron microscope showed that this was because the particle chains in the low crosslink density composites were longer and more aligned. As the proportion of monosulfide linkages increased, the value of the loss factor increased and the modulus of the composites was more affected by the increasing frequency.