Magneto-mechanical properties of polydimethylsiloxane composites with a binary magnetic filler system

Polymer composites embedded with ferromagnetic particles are widely applied in many engineering areas and have been extensively investigated for the past decade because of their outstanding magneto-dependent properties. In this article, a series of addition cured polydimethylsiloxane (PDMS) composites with a mixture of carbonyl iron and cobalt particles at a given weight amount were prepared for the first time. Influences of the mass ratios of two additives on thermal stability, magnetic, mechanical properties, and magnetic actuating performance were studied experimentally. Experiment results demonstrated that the PDMS composite reinforced by carbonyl iron granule has a high thermal stability and saturation magnetization, and there is an optimal mixture ratio for the large and small particles. However, the loss factor is increased with an increase in Co contents for the binary blend system of RDE/Co and RXE/Co, respectively. For a comprehensive evaluation, the magnetoelastic ratios of all samples are obtained to demonstrate that the samples filled with carbonyl iron particles are easy to produce bending deflection in a uniform magnetic field. Under the influence of gradient magnetic field, the bending deflection of rectangular magnetized samples including Co particles show dependence on the direction of applied magnetic field, even, bidirectional and reversible responsive behavior are possible appearing for some special cases. These obtained results will provide some basic guidelines for selecting the proper materials to develop novel actuators. POLYM. COMPOS., 40:337-345, 2019. (c) 2017 Society of Plastics Engineers