USE AS ION-EXCHANGE MEMBRANES AND BATTERY SEPARATORS

EXFLUOR RESEARCH CORPORATION ALONG WITH PROFESSOR RICHARD J. LAGOW AT THE UNIVERSITY OF TEXAS AT AUSTIN HAVE DEVELOPED A NEW SYNTHETIC METHOD FOR PREPARING FLUOROCARBON MEMBRANE MATERIAL. THE PROCEDURE CONSISTS OF FIRST SYNTHESIZING A HYDROCARBON PRECURSOR, INTRODUCING CROSS-LINKS AND THEN FLUORINATING WITH ELEMENTAL FLUORINE. THIS METHOD PERMITS WIDE FLEXIBILITY IN THE STRUCTURAL FEATURES OF THE MEMBRANE. WE HAVE PREPARED MEMBRANES WITH BOTH ISOLATED AND VICINAL CARBOXYLIC ACID FUNCTIONS BY THIS METHOD. IN THIS EXAMPLE A POLYETHYLENE MATRIX WITH THE APPROPRIATE FUNCTIONAL GROUPS WAS PREPARED, CROSS-LINKED WITH RADIATION AND FLUORINATED TO CONVERT C-H TO C-F BONDS. THE MEMBRANES OBTAINED FROM THIS PREPARATION AFTER HYDROLYSIS IN AQUEOUS ACID WERE SHOWN TO BE CONDUCTIVE. CONDUCTIVITIES OF 5 OHM/CM(1) HAVE ALREADY BEEN OBTAINED VALUES OF 3 OHM/CM(1) ARE THOUGHT TO BE READILY ATTAINABLE. THE SUCCESS OF THE "OXYFLUORINATION" PROCESS FOR MAKING FUNCTIONALIZED POLYMERS HAS ALREADY BEEN DEMONSTRATED IN PROFESSOR LAGOW'S ACADEMIC LABORATORY. USING FURTHER TECHNOLOGY DEVELOPED AT EXFLUOR RESEARCH CORPORATION, NEW CANDIDATES FOR ION-EXCHANGE MEMBRANES WILL BE EXAMINED. FILMS ALREADY PREPARED BY THIS METHOD HAVE BEEN SHOWN TO HAVE RESISTANCES OF LESS THAN 5 OHM-CM(2) AND ARE STABLE IN AGGRESIVE ENVIRONMENTS. THE DEGREE OF CROSS-LINKING WILL BE VARIED AND THE EFFECTS ON MEMBRANE PERFORMANCE WILL BE DETERMINED. ADDITIONAL ATTENTION WILL BE GIVEN TO THE FILM-FORMING CHARACTERISTICS OF THE FUNCTIONALIZED POLYMERS. BONDING PROPERTIES TO TEFLON WILL ALSO BE EXAMINED FOR USE IN INCREASING THE MECHANICAL STRENGTH OF THE POLYMER FILM.