Investigation of the durability of anisotropic magnetorheological elastomers based on mixed rubber

Magnetorheological elastomer (MREs)-based devices often operate at cyclic loading and high temperature conditions, which may cause fatigue and aging problems of MRE materials. This paper investigates the durability properties of MRE materials based on a mixed matrix: cis-polybutadiene rubber (BR) and natural rubber (NR). Six MREs samples were fabricated and their mechanical properties under cyclic loading with a constant strain amplitude of 50% and different aging temperatures were measured. The absolute MR effect, storage modulus (G') and loss modulus (G'') of MRE samples after cyclic loading and aging were evaluated by a modified dynamic mechanical analyzer (DMA). The results revealed that the MR effect, G' and G'' of all samples depended on the number of loading cycles, but samples which contained different ratios of two rubbers showed distinct properties. G' and G'' of all samples which contained only BR change little, but G' and G'' of samples which contained NR was large and decreased with the increment of the cycle number. Meanwhile, all their MR effects increased after cyclic loading. The results also revealed that the MR effect, G' and G'' of all samples were dependent on the time of aging at different aging temperatures. G' and G'' of all samples increased with the increment of aging time, but the properties of samples which contained more NR had better durability properties because their MR effect was higher and decreased more slowly than that of samples which contained more BR. The relationship between the durability properties, and cyclic loading and aging conditions were also analyzed.