Electroactive Alumina Particles Embedded in an Acrylic Elastomer

Composites of alumina particles embedded in a polar acrylic rubber polymer matrix are being investigated as potential electroactive polymer actuators. The measured FTIR spectra, XRD patterns, and SEM micrographs suggest that the alumina particles with an average diameter of 9.873 +/- 0.034 mu m having the rhombohedral form of the corundum phase are intercalated homogeneously within the acrylic rubber matrix. At an Al2O3 volume fraction of 0.144, the electrical conductivity increases from 10(-9) to 10(-8) (Omega m)(-1) at 500 Hz. The storage modulus without applied electrical field, G'(o), increases from 9,533 to 105,540 Pa, an order of-a single-magnitude increase, as the particle volume fraction is varied from 0 to 0.144. The increase in the matrix rigidity of the hybrid organic-inorganic composites are because of the stress transfer from matrix to the reinforcement particles, the partial substitution of a soft matrix with a stiffer filler, and the segmental immobilization caused by the interaction between the matrix polymer chains and the filler surface. Under an applied electric field, induced dipole moments and particle-particle interaction are generated, leading to an increase in the matrix rigidity. Under an applied electrical field, G'(2) (kV/mm) increases from 9,775 to 139,080 within the same volume fraction range, a difference of more than 30% is observed because of presence of an electrical field. POLYM. COMPOS., 32:44-51, 2011. (C) 2010 Society of Plastics Engineers