Polyimide‐silica nanocomposites exhibiting low thermal expansion coefficient and water absorption from surface‐modified silica

Abstract

Abstract In this study, a commercially available nano‐sized silica (SiO 2 ) was surface‐modified via esterification with oleic acid (OA), a relatively inexpensive and hydrophobic modifier, and characterized by FTIR, NMR, SEM, EDS, and TGA measurements. Various amounts of the surface‐modified silica nanoparticles (SiO 2 ‐OA) were dispersed in a poly(amic acid), which were then cyclized at high temperatures to form a series of PI/SiO 2 ‐OA nanocomposite films (PISA). The effect of the addition of the SiO 2 ‐OA nanoparticles on the properties of the as‐prepared polyimide nanocomposite was studied. The results indicated that, comparing with pure PI and PI/pristine‐SiO 2 composite film (PISI), the as‐prepared PISA films had enhanced dynamic mechanical properties and thermal stability, as well as reduced water absorption and thermal expansion. The as‐prepared PI/SiO 2 ‐OA nanocomposites have potential for applications in high performance microelectronic devices. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104, 4096–4105, 2007