Ceramic / inorganic-organic nano-hybrid composites for thermally stable insulation of electrical wires. Part I: Composition and synthetic parameters

Composite coatings comprising of particulate ceramic and silicon containing inorganic-organic nano-hybrids are synthesized and applied as high temperature capable coatings for electrical wire insulation. The nano-hybrids are synthesised from organosilanes bearing non-hydrolysable methyl, glycidyloxypropyl and phenyl groups. The molar ratios of organosilanes, acid catalysts and synthetic conditions are optimised to offer suitable mechanical and thermal performance to the composite coatings. Different particulate ceramics are tested in regard to their effects on mechanical stiffness of the resultant composite coatings. Vermiculite platelet is finally selected for its lower hardness. The mass ratio of nano-hybrids to platelets of 70:30 to 60:40 are found optimal for balanced performance in respect to thermal, mechanical and dielectric properties. Uniform composite coatings are produced on conductor wires using a reel-to-reel continuous coating process. Initial tests showed insulated wires have moderate mechanical flexibility, dielectric strength and excellent thermal stability, capable of withstanding over 1100V AC potential after 500°C heating.