The present invention provides an anisotropically porous membrane which is obtained according to a wet process, which comprises a substantially non-sulfonated aromatic polyether ketone having a crystallinity of 10 percent by weight or higher, and which has open pores having an average pore diameter of 0.02 to 30.00 .mu.m on both surfaces of said membrane at an open pore ratio of 7 to 90 percent. In accordance with the present invention, a porous crystalline aromatic polyether ketone membrane is provided which is excellent in heat resistance, chemical resistance, water resistance, water permeability and a balance of water permeability and fractionating characteristics.
This application is the national phase under 35 U.S.C. .sctn.371 of prior PCT International Application No. PCT/JP 96/00495, which has an International filing date of Mar. 1, 1996, which designated the United States of America, the entire contents of which are hereby incorporated by reference.
The invention concerns a proton exchange membrane comprising a perfluorosulfonic acid having silica particles embedded therein in a concentration by weight comprised between 0.01 and 50% by weight and dimensions comprised between 0.001 and 10 micrometers, characterized in that said membrane comprises both an amorphous and a crystalline phase and the ratio thereof is adjusted by means of a controlled thermal treatment at a temperature higher than the glass transition temperature, controlled by an X-ray spectrometer. The invention further concerns an electrochemical cell using said membrane, in particular a fuel cell and the method of operating the same.
Membranes comprising an aromatic ether ketone polymer (e.g. polyetherketone) in sheet or hollow fibre form are made by preparing at least a 12 wt % solution of the polymer in a solvent which is chemically inert to the polymer (e.g. concentrated sulphuric acid); forming a film of the solution in sheet or hollow form; and contacting the film with a non-solvent (e.g. more dilute sulphuric acid or acetic acid) thereby to precipitate the film.
Porous poly(aryl ether ketone) (PAEK) articles are prepared from PAEK/polyimide blends by selective chemical decomposition and subsequent removal of the polyimide phase. Porous PAEK articles exhibit highly interconnected pore structure and a narrow pore size distribution. The porous PAEK articles of the present invention can be utilized as a porous media for a broad range of applications, including membranes for fluid separations, such as microfiltration, ultrafiltration, nanofiltration, and as a sorption media.
Functionalized porous poly(aryl ether ketone) articles are prepared by reacting ketone groups in the backbone of poly(aryl ether ketone) polymer with a primary amine reagent. Preferred functional primary amines are primary aliphatic amines or substituted hydrazines containing one or more target functional groups including polar groups, such as hydroxyl groups, .about.OH, amino groups, .about.NH.sub.2, .about.NHR, .about.NRR', and ethylene oxide groups, .about.OCH.sub.2CH.sub.2--, negatively or positively charged ionic groups, such as .about.SO.sub.3.sup.-, .about.COO.sup.-, and .about.NH.sub.4.sup.+ groups, hydrophobic groups such as siloxane or perfluorcarbone groups, and non-polar groups, such as linear or branched hydrocarbon groups. The functionalized porous poly(aryl ether ketone) article can be prepared by reacting primary amine with a pre-formed, shaped porous poly(aryl ether ketone) article or by functionalizing the surface of a non-porous precursor article that is subsequently converted into a porous article.
Functionalized porous poly(aryl ether ketone) articles are prepared by reacting ketone groups in the backbone of poly(aryl ether ketone) polymer with a primary amine reagent. Preferred functional primary amines are primary aliphatic amines or substituted hydrazines containing one or more target functional groups including polar groups, such as hydroxyl groups, .about.OH, amino groups, .about.NH.sub.2, .about.NHR, .about.NRR', and ethylene oxide groups, .about.OCH.sub.2CH.sub.2--, negatively or positively charged ionic groups, such as .about.SO.sub.3.sup.-, .about.COO.sup.-, and .about.NH.sub.4.sup.+ groups, hydrophobic groups such as siloxane or perfluorcarbone groups, and non-polar groups, such as linear or branched hydrocarbon groups. The functionalized porous poly(aryl ether ketone) article can be prepared by reacting primary amine with a pre-formed, shaped porous poly(aryl ether ketone) article or by functionalizing the surface of a non-porous precursor article that is subsequently converted into a porous article.
