Effect of TiO2 on thermal and adhesive characteristics of poly(imide siloxane)/TiO2 hybrid films

Abstract

A novel poly(imide siloxane)/titania (PIS/TiO2) hybrid film was fabricated by sol-gel process via in situ formation of TiO2 within PIS matrix. Poly(amic acid siloxane) (PAAS) was prepared from 4,4'-oxydiphthalic anhydride, 2,2-bis [4-(4-aminophenoxy) phenyl] propane, and alpha,omega-bis(3-aminopropyl)polydimethylsiloxane (APPS). Chelating agent, acetylacetone, and catalyst-free polymerization were used to reduce the rate of hydrolysis of titanium alkoxide in the PAAS. X-ray photoelectron spectroscopy data showed that the presence of APPS promotes the Ti surface composition of PIS/TiO2 hybrid film. The effects of TiO2 and APPS contents on the characteristics of surface, thermostability, coefficient of thermal expansion (CTE), and the strength of adhesion were investigated. The presence of TiO2 on the surface of the hybrid films enhanced the adhesive strength at the interface of PIS/TiO2 hybrid film and copper foil. When more TiO2 was incorporated into the PIS matrix, the PIS/TiO2 hybrid film exhibited lower CTE while retaining favorable mechanical and thermal properties. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012