Magnetorheological elastomer (MRE) specimens were prepared to find the optimum compressive characteristics using different types and amounts of iron powder. A magnetic field of up to 2 T was applied during vulcanization. Among the four types of iron powders, the specimen with round‐shaped carbonyl iron powder and small grain size shows higher magnetic effects than that with bigger and irregularly shaped electrolyte iron powder. However, the compressive modulus of the rubber with electrolyte iron powder is higher without magnetic treatment at a given amount. In general, the bigger and irregularly shaped iron particles tend to move slowly and produce nonuniform distribution when a magnetic field is applied. The experimental results show that the mechanical properties are better when applying a magnetic field of 1.5 T compared with 2.0 T during the specimen vulcanization. Applying a magnetic field of 300 mT during the compression test enhanced the compressive modulus by 12% to 15%. The rate of increase of the modulus decreased exponentially with prestrain.

Rubber nanocomposites were prepared by mixing room-temperature-vulcanized (RTV) silicone rubber and nanofillers such as graphitic nanofillers (GRs), carbon nanotubes (CNTs), and carbon black (CB) for industrial applications. The possible correlations were examined between the properties and morphology of the fillers. The vulcanizates based on the CNT hybrid showed higher reinforcement with as an elastic modulus of 5.3 MPa compared to 3.2 MPa for GR flakes and 3.1 MPa for the CB hybrid at 8 phr. Similarly, lower resistances of 17 kX at 4 phr and 0.7 kX at 12 phr were obtained for the CNT hybrid. A correlation was determined between the mechanical and electrical properties in enhancing the displacements of the nanocomposites when used in actuators. Such improvements might be useful for flexible electrodes, energy harvesting, or actuators. POLYM.

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Conductive films were prepared on stretchable substrates by mixing sonicated multiwall carbon nanotubes (MWCNTs) with room‐temperature‐vulcanized silicone rubber. Microscopic investigations show a broad range of MWCNT particles with diameters in the range 15–17 nm, lengths from a few nanometers to a few micrometers, and thus a high aspect ratio of 55–70. The sonicated MWCNTs have 40 wrapped graphene layers and an out‐of‐plane correlation length of 13 nm. Also, the grain size of the dispersed sonicated MWCNTs is around 35 nm, and the roughness is around 13.5 nm. At 3 phr, the modulus is higher for the MWCNTs (5.95 MPa). The electrical resistance of the MWCNTs is as low as 180 Ω at 3 phr. These improvements were introduced in an actuator and energy harvester for industrial applications. The actuator shows a displacement of 2.18 mm at 10 kV. At 60% strain, the energy harvesting is 1.07 V during compressive strain and 0.015 V during tensile strain. From durability tests under 30% compressive strain, the voltage drops from the energy harvesting device are negligible for up to 3000 cycles. © 2018 Society of Chemical Industry