Epoxy composites with glass bubbles for electrical application

The main goal of the study is to explore epoxy composites with a low permittivity and acceptable other properties, especially mechanical properties and dielectric strength, for electric power applications. The influence of filler surface treatment and filler content on mechanical, thermal and dielectric properties of epoxy composites was systematically investigated. Epoxy composites were prepared with both silanized and non-silanized glass bubbles. The different filler treating methods had a significant effect on mechanical properties and only a minor effect on thermal properties and dielectric permittivity. The filler content has an important influence on epoxy composites preparation and mechanical and dielectric properties. With the increasing glass bubble content up to 35 wt.% (52.4 vol.%), the following results were obtained: 1) the mechanical properties decreased with the filler content, while the specific strength and modulus increased or remained the same; 2) the permittivity decreased with the filler content; 3) the dielectric strength was similar to that of the unfilled epoxy resin, while compared with high loading silica flour filled epoxy composites, there is an obvious dielectric strength decrease. This could limit the application of glass bubble filled epoxy material in specific cases. Further research is required to improve the dielectric strength of the material.