Coating carbon fiber using polyimide-silica nanocomposite by electrophoretic deposition

Polyamic acid-silica hybrid colloidal emulsion with an average particle size of 200 nm was prepared by dispersing nano-silica into polyamic acid colloidal particles. The polyimide-silica hybrid nanocomposite coating was fabricated onto carbon fiber through electrophoretic deposition. The properties of polyamic acid-silica hybrid colloidal emulsion and polyimide-silica hybrid nanocomposite coating onto carbon fiber were characterized using laser diffraction, ZetaPlus Particle Sizing, transmission electron microscopy, field-emission scanning electron microscope, Fourier transform infrared spectroscopy and thermal gravimetric analysis. The results indicated that the small amount of nano-silica would be effectively dispersed in polyamic acid colloidal particles without aggregation and the nano-silica played an important role on keeping stability of polyamic acid-silica hybrid colloidal particles. The polyimide-silica hybrid nanocomposite coating carbon fiber displayed an excellent thermal stability up to 600 degrees C in the air (less than 5% weight loss for 8 h). (C) 2011 Elsevier B.V. All rights reserved.