Hybrid composites of polyamide-imide and silica applied to wire insulation

Abstract

Aromatic polyamide-imide resins (PAI) based on trimellitic anhydride and diphenylmethane-4,4'-diisocyanete, were modified by an oligo-alkoxysilane compound to lead to novel silane-modified PAIs. Then, PAI-silica hybrid films were prepared by drying and curing the silane-modified PAIs. With increasing silica unit content, the hybrid films have higher elastic modulus and tensile strength of the original PAI film, however maintain maximum elongation. Furthermore, they have much lower moisture absorption than the PAI film under wet conditions. Moreover, this hybrid film found that a difference was in a dielectric constant as compared with the usual film. This report describes the characteristic about the enameled wire used for the silane-modified PAI varnish as an insulation layer.