A siloxane-grafted new diamino monomer DBPDMS has been prepared and used as a co-monomer in combination with the fluorinated diamine monomer TFBB to prepare siloxane-grafted polyimides. The polymers have been characterized by means of GPC, IR, and NMR. Their thermal, mechanical, and surface properties have been evaluated and compared with the homopolyimide and with polyimides where polysiloxane is incorporated in the main chain. DSC revealed melting of the grafted siloxane chain at sub-ambient temperature and a glass transition corresponding to the main polymer chain at high temperature. Isothermal gravimetric analysis at 350 degrees C indicated that grafted siloxane moiety can be removed thermally from the polymer chain without affecting the polymer backbone.