Preparation and properties of poly(imide siloxane) segmented copolymer/silica hybrid nanocomposites

Abstract

AbstractA series of Poly(imide siloxane) (PIS)/silica (SiO2) hybrid nanocomposites with C‐Si covalent bonding between the homogeneous PIS copolymer and SiO2 have been successfully synthesized. The PIS copolymer synthesized in this study is characterized by the coexistence of two segments: the polyimide segment and polydimethyldiphenylsiloxane segment, and the latter are specially featured with the introduction of a diphenyl group for improved homogeneity. The PIS/SiO2 hybrid nanocomposites were prepared from 3,3′,4,4′‐bezonphenone tetracarboxylic dianhydride (BTDA), 2‐2′‐bis[4(3‐aminophenoxy)phenyl] sulfone (m‐BAPS), and vinyl‐containing α,ω‐bis‐(aminopropyl)polydimethyldiphenyl siloxane (APPPVS) oligomer to form vinyl siloxane‐containing poly(amic acid) (PAAVS). This copolymer was further reacted with trimethoxyvinylsilane (TMVS), 2,2′‐azobis‐isobutyronitrile (AIBN), and tetraethoxysilane (TEOS). The PIS/SiO2 hybrid nanocomposites exhibited a series of properties unlike traditional composites, and the nano sized inorganic particles have resulted in a transparent hybrid when the SiO2 content was less than 12 wt %. The Young's modulus and tensile strength of the PIS/SiO2 hybrid nanocomposites increased with increasing SiO2 content, whereas, the elongation at break was only slightly affected. The structure of the hybrids was characterized by FTIR, 29Si‐NMR, 1H‐NMR, and 13C‐NMR, as well as SEM and TEM. The thermal properties of the PIS/SiO2 hybrid nanocomposites were investigated with DSC, TGA, and DMA studies. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007