Physical and electrical properties of polyimide/ceramic hybrid films prepared via non-hydrolytic sol-gel process

In this study, TiO2 and SiO2 were chosen as ceramic fillers in the 3,3',4,4'-benzophenone tetracarboxylic dianhydride-4,4'-oxydianiline (BTDA-ODA) polyimide matrix. Physical properties of hybrids with up to 30 wt% SiO2 and 7 wt% TiO2 were evaluated and discussed. Nano-size ceramic particles were prepared by non-hydrolytic sol-gel (NHSG) process. SEM micrographs show that both films have nano-sized ceramic particles with a narrow size distribution. Thermal conductivities of the hybrids increase from 0.12 to 0.21 W/m-K, as the SiO2 and TiO2 in the hybrid increases from 0 to 30 and 7 wt%, respectively. Electrical surface resistivity slightly decreases with increasing ceramic filler content. Dielectric constant of the hybrid increases from 2.45 to 2.72 with the incorporation of the 7 wt% (5.4 vol%) TiO2. Water absorption decreases considerably with increasing filler content. With 30 wt% (20.2 vol%) SiO2 addition, the water absorption of the hybrid film reduces by 85% from that of pure polyimide.