Development of poly(dimethylsiloxane)-titania nanocomposites with controlled dielectric properties: Effect of heat treatment of titania on electrical properties

Polymerceramic composites were prepared using poly(dimethylsiloxane) as base matrix and normal as well as heat-treated titania as fillers. Dielectric and mechanical properties of the composites were measured and found that dielectric constant of the composites was increased dramatically with the addition of filler, whereas resistivity was decreased. Hardness and modulus were found to increase but tensile strength, % elongation at break, and tear strength were decreased with the filler loading. Neat titania contains some moisture (physisorbed and chemisorbed) as revealed from thermogravimetric analysis. Both electrical and mechanical properties of the composites were affected by filler heat treatment. Further, untreated titania contains Ti3+ and Ti4+, which on heat treatment, increases the concentration of Ti4+, as a result electrical properties were affected. Filler dispersion in the composites was studied by field emission scanning electron microscopy and high resolution transmission electron microscopy. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012