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

Abstract A series of SiO 2 /polyimide hybrid films with different contents and sizes of SiO 2 particles were prepared by blending polyamic acid (PAA) and SiO 2 nanoparticles obtained from Stöber method, followed by a step thermal imidization process. The size and content effect of SiO 2 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 SiO 2 particles. TGA indicated that the thermal stability for hybrid films decreased with the increasing content and size of SiO 2 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 SiO 2 particles increases from 10 to 25 nm and to 65 nm. All polyimide hybrid films were amorphous according to X‐ray determination. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008