Preparation and Characterization of Porous Carbonized Films by the Pyrolysis of Poly (urethane-imide) Films

Abstract

Porous carbonized films were prepared by the pyrolysis of poly (urethane-imide) films that were prepared by reacting polyurethane prepolymer and poly (amide acid), a precursor of polyimide. The reaction between the two prepolymers gave poly (urethane-imide) films that have network structure. By treating the poly (urethane-imide) films at 300-400°C thermally labile urethane domains decomposed, leaving porous polyimide films. The average macropore size of the films was 0.6-51-μm depending on the ratio of the urethane and imide components. The porous polyimide films were then pyrolyzed at 900°C to give porous carbonized films maintaining the pore structure at the porous polyimide films. It was revealed fromthe nitrogen adsorption isotherm study for the macroporous carbonized films that the films also contain micropores that are developed during the pyrolysis of the macroporous polyimide films.