Effect of annealed titania on dielectric and mechanical properties of ethylene propylene diene monomer-titania nanocomposites

Flexible ethylene propylene diene monomer (EPDM)-titania nanocomposites of different compositions were prepared by room temperature mixing using both neat and annealed titania. All these composites showed composition-dependent dielectric and mechanical properties, and composites with controlled dielectric properties could be made through judicial adjustment of the composition. The effect of moisture/filler heat treatment was also studied and found that composites with annealed titania showed lower dielectric constant than composites with normal titania. There was a significant improvement in mechanical properties, where composites with 60 parts per hundred parts of titania gave the optimum tensile strength. The particle size of titania particles was analyzed by high-resolution transmission electron microscopy (HRTEM) and a dynamic light scattering technique. The morphology and dispersion of titania particles in the EPDM matrix were studied by field emission scanning electron microscopy and HRTEM. Finally, different dielectric models were compared with experimental data, and the best match was achieved by the Lichtenecker model, which can be used as a predictive rule for different volume contents of titania filler in the EPDM matrix.