Dielectric properties of blends of silicone rubber and tetraflouroethylene/propylene/vinylidene fluoride terpolymer

Dielectric studies show that the blends of silicone rubber and fluororubber based on tetrafluoroethylene/propylene/vinylidene fluoride terpolymer are immiscible. Dielectric loss factor at any temperature increases with increase in concentration of the fluororubber phase in the blend composition. The activation energy of the relaxation of the vinylidene fluoride segment of the fluororubber is influenced by the presence of silicone rubber in the composition. The higher the concentration of silicone rubber in the composition, the higher is the activation energy of the fluorine-containing segment of the fluororubber. The interfacial polarization of the blends is dependent on the domain size of the fluororubber dispersed in the silicone rubber matrix. Higher degree of polarization at fine dispersion of fluororubber in the blend composition of 75/25-silicone rubber/fluororubber makes the dielectric constant higher than that of the neat silicone rubber and raises the energy barrier for the free rotation of vinylidene fluoride segment, causing maximum activation energy for the dipolar relaxation. (C) 2001 Published by Elsevier Science Ltd.