Reinforced, Extruded, Isotropic Magnetic Elastomer Composites: Fabrication and Properties

Abstract

The study involves the development of isotropic magnetorheological elastomer composites (i-MREs) with improved mechanical properties, their preparations, and properties characterizations. The novelty of the research is the use of extrusion process in the preparation of composites containing two different fillers: carbonyl iron powder (CIP) as magnetic filler and carbon black (FEF, N550) as reinforcing one. So far, the process of extrusion has been used to prepare magnetic composites without filler that improve mechanical properties. It is worth mentioning that the polymer matrix (ethylene-octene copolymer, EOR) offers excellent performance in extrusion applications. In this research, two methods of magnetic composites preparation were reported: traditional, during two-roll mill, and a new one using extrusion process. It was found that the usage of new processing technology allowed forming more homogenous dispersion of particles in elastomer matrix and oriented polymer chains, resulting in an improved rheometric characteristic, increased crosslink density, and decrease of the storage modulus (Payne effect). Based on both static/dynamic mechanical properties and damping properties under the influence of compression stress, the positive influence of extrusion process on material characteristics was confirmed. Moreover, all composites proved very good magnetic properties and resistance to thermooxidative ageing.

Thermal Aging Rheological Behavior of Magnetorheological Elastomers Based on Silicone Rubber

“…Cvek et al [20] investigated the degradation process of thermoplastic elastomers (TPEs) and TPE-based MRE with an operating twin-screw counter-rotating temperature of 185 • C. They found out that thermo mechanical degradation did enhance the stiffness of the TPE based MREs, but at the same time resulted in the 10% decrement of MR effect. Masbowski et al [21] studied the thermooxidative aging on MRE samples of ethylene-octene copolymer filled with carbonyl iron particles (CIPs) and carbon black. The samples were subjected to a conventional drying oven with an air circulation at an elevated temperature of 70 • C for 14 days.…”

Silane Treatment as an Effective Way of Improving the Reinforcing Activity of Carbon Nanofibers in Nitrile Rubber Composites

“…Rheological tests were performed under the following conditions: force 5 N, temperature 25 °C, sample deformation rate 10 rad/s, and stress from 0.1% to 150%. The Payne effect of the composites was determined based on Equation (3) [ 23 ]: where G′ min ( lim 10 −1 ) is the composite storage modulus determined under deformation of 10 −1 % and G′ max (∞) is the composite storage modulus determined under the max deformation. The resistivity of the NBR composites was measured using an insulation MIC-1000 resistance meter (SONEL S.A., Poland) coupled to EP-1 measuring electrodes.…”

Recent Progress in Isotropic Magnetorheological Elastomers and Their Properties: A Review

“…Isotropic MREs provide significant properties for a wide range of industrial applications at a low cost compared to anisotropic MREs. Due to these advantages, isotropic MREs are achieving great industrial importance nowadays [ 85 ]. Depending upon the applied magnetic field strength, the moduli of MREs immediately alter due to strong magnetic forces between magnetic filler particles.…”