A series of polyether-urethane-imide(PUI)/silica(SiO2) hybrid composite materials with different silica content were successfully prepared by the Sol-Gel process．The properties of in-situ synthesized PUI/SiO2 hybrid materials weFe characterized by NMR

FTIR．SEM

DSC and TG measurements．The FTIR analysis revealed that the reaction of imidization of PUI in the organic phase and the reaction of SiO2 sol-gel transformation in the inorganic phase are simultaneously completed in this system at 100℃ The TG and the SEM results indicated that PUI/SiO2 composite materials with appropriate silica contents (approximately 9 wt％) possessed outstanding thermal stability

in these cases silica particles with diameters around 0.2～1.0μm were observed．The result showed that with increasing silica content the silica particles grew larger

resulting in obvious separation of the organic and inorganic phases The DSC results suggest that Tg of the soft segment rich phase of PUI/SiO2 hybrid materials is not Influenced obviously by introducing SiO2 to PUI systems．