Poly(Isobutylene-co-Isoprene) Composites for Flexible Electronic Applications

Abstract

Flexible, bendable, and stretchable dielectrics which can cover even curved surfaces are important for applications in electronic control systems, consumer electronics, heart pacemakers, body-worn antenna, etc. The requirements for a material to be used as a flexible dielectric are good mechanical flexibility, low dielectric loss, high thermal conductivity (TC), low coefficient of thermal expansion (CTE), etc. It is very difficult to identify a single material which possesses all these properties simultaneously. There are a number of ceramic materials with high relative permittivity and low dielectric loss that are available but are brittle in nature. Butyl rubber has low dielectric loss with good mechanical flexibility and stretchability, but they have low relative permittivity, low TC, and high CTE. Therefore, the practical applications of an elastomer or a ceramic alone are limited. By integrating the flexibility, stretchability, and low processing temperature of butyl rubber with high relative permittivity and low loss of ceramics, a composite may be formed, which can deliver improved performances. In this review, the preparation, characterization, and properties of butyl rubber composites with several ceramics such as Al2O3, BaTiO3 on the microwave dielectric properties, thermal properties, moisture absorption, and mechanical properties are discussed.