Ballard Power Systems Corporation

Alfred E Steck

Charles Stone

Jinzhu Wei

Robert D Lousenberg

Biswajit Choudhury

Graft polymeric membranes and methods for making graft polymeric membranes have one or more trifluorovinyl aromatic monomers that are radiation graft polymerized to a polymeric base film. The membranes comprise a polymeric base film to which has been graft polymerized substituted &agr;,&agr;,&bgr;-trifluorostyrene and/or &agr;,&agr;,&bgr;-trifluorovinylnaphthylene monomers, which are activated towards graft polymerization. As ion-exchange membranes, the membranes are suitable for use in electrode apparatus, including membrane electrode assemblies in, for example, fuel cells. The membranes can also be crosslinked.

Graft polymeric membranes and ion-exchange membranes formed therefrom

A composite membrane is provided in which a porous substrate is impregnated with a polymeric composition comprising various combinations of &agr;,&bgr;,&bgr;-trifluorostyrene, substituted &agr;,&bgr;,&bgr;-trifluorostyrene and ethylene-based monomeric units. Where the polymeric composition includes ion-exchange moieties, the resultant composite membranes are useful in electrochemical applications, particularly as membrane electrolytes in electrochemical fuel cells.

&agr;,&bgr;, &bgr;-trifluorostyrene-based composite membranes

Graft polymeric membranes in which one or more trifluorovinyl aromatic monomers are radiation graft polymerized to a preformed polymeric base film are provided, as well as ion-exchange membranes prepared therefrom. Preferred monomers include substituted &agr;, &bgr;, &bgr;-trifluorostyrenes and trifluorovinyl naphthalenes which are activated towards the grafting reaction or facilitate the introduction of more than one ion-exchange group per monomer unit in the grafted chains. The ion-exchange membranes are useful in dialysis applications, and particularly in electrochemical applications, for example as membrane electrolytes in electrochemical fuel cells and electrolyzers.

A composite membrane is provided in which a porous substrate is impregnated with a polymeric composition comprising various combinations of &agr;, &bgr;, &bgr;-trifluorostyrene, substituted &agr;, &bgr;, &bgr;-trifluorostyrene and ethylene-based monomeric units. Where the polymeric composition includes ion-exchange moieties, the resultant composite membranes are useful in electrochemical applications, particularly as membrane electrolytes in electrochemical fuel cells.

&agr;,&bgr;,&bgr;-trifluorostyrene-based composite membranes

A composite membrane is provided in which a porous substrate is impregnated with a polymeric composition comprising various combinations of .alpha.,.beta.,.beta.-trifluorostyrene, substituted .alpha.,.beta.,.beta.-trifluorostyrene and ethylene-based monomeric units. Where the polymeric composition includes ion-exchange moieties, the resultant composite membranes are useful in electrochemical applications, particularly as membrane electrolytes in electrochemical fuel cells.

.alpha., .beta., .beta.-trifluorostyrene-based composite membranes

Substituted .alpha.,.beta.,.beta.-trifluorostyrene-based composite

Polymeric compositions are derived from copolymers of .alpha.,.beta.,.beta.-trifluorostyrene with a variety of substituted .alpha.,.beta.,.beta.-trifluorostyrenes. These compositions are suitable for use as membranes, particularly as ion-exchange membranes, and most particularly as solid polymer electrolytes in electrochemical applications, such as, for example, electrochemical fuel cells.

Trifluorostyrene and substituted trifluorostyrene copolymeric

Sulfonyl fluoride substituted .alpha.,.beta.,.beta.-trifluorostyrene monomers are disclosed. The monomers are incorporated into polymeric compositions which are conveniently hydrolyzed to produce polymeric compositions which include ion-exchange moieties. The resulting compositions which include ion-exchange moieties are particularly suitable for use as solid polymer electrolytes in electrochemical applications, such as, for example, electrochemical fuel cells.

Substituted trifluorostyrene monomeric compositions

Substituted trifluorostyrene compositions

Polymeric compositions are derived from copolymers of .alpha.,.beta., .beta.-trifluorostyrene with a variety of substituted .alpha.,.beta.,.beta.-trifluorostyrenes. These compositions are suitable for use as membranes, particularly as ion-exchange membranes, and most particularly as solid polymer electrolytes in electrochemical applications, such as, for example, electrochemical fuel cells.

A gasketed membrane electrode assembly for electrochemical fuel cells employs gasketing material at the periphery of the ion exchange membrane, rather than the membrane itself, as a gasket. The gasketing material may be formed from an elastomeric material suitable for cold bonding or bonding by heat and pressure. A nonhydrophilic thermoplastic elastomer is the preferred gasketing material. The gasketed membrane electrode assembly provides a seal between the electrically conductive separator plates that is more effective and economical than assemblies employing the membrane itself as the gasketing material. In an alternative embodiment, a gasketed membrane assembly for use in the humidification portion of a fuel cell employs gasketing material at the periphery of a water permeable membrane.

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Vancouver, Canada

Alfred E Steck