The influence of particle shape on the ac electrical stress relieving behaviour of barium titanate polymer composites

The addition of barium titanate to a polymer has previously been found to produce a composite material with an enhanced electrical field dependent permittivity. The electrical field dependent behaviour arises due to a process of spontaneous domain alignment within the barium titanate crystals. Previous investigations have indicated that composites using larger particle sizes of barium titanate produce composites with higher field dependent permittivity characteristics, for comparative filler levels. Particle size can also influence a dependency on particle shape, due to the milling processes which are involved in the manufacture. This paper now looks at how the filler particle shape influences the field dependent permittivity nature of an acrylic composite resin for a variety of particle sizes.