Synthesis and properties of silica-polyimide hybrid films derived from colloidal silica particles and polyamic acid

A series Of SiO2/polyimide hybrid films with different contents and sizes Of SiO2 particles were prepared by blending polyamic acid (PAA) and SiO2 nanoparticles obtained from Stober method, followed by a step thermal imidization process. The size and content effect of SiO2 particles on the mechanical and thermal properties was studied. It was found that as the silica particles were introduced into polyimide matrix, T(g)s of hybrid films increased on the whole and there was a maximum value of T-g for the hybrid film with 10-nm SiO2 particles. TGA indicated that the thermal stability for hybrid films decreased with the increasing content and size Of SiO2 particles. Dynamic mechanical thermal analysis (DMTA) indicated that the modulus of hybrid films increased, while the tensile strength and elongation at break decreased as the size Of SiO2 particles increases from 10 to 25 nm and to 65 nm. All polyimide hybrid films were amorphous according to X-ray determination. (c) 2008 Wiley Periodicals, Inc.