摘要:
All electrocatalytic gas diffusion electrode for fuel cells and a process for its preparation is disclosed. The electrode comprises an anistropic gas diffusion layer and a catalytic layer. The gas diffusion layer is made of a porous carbon matrix through which carbon particles and poly(vinylidene) fluoride are distributed so that the matrix is homogeneously porous in a direction lateral to gas flow and asymmetrically porous to gases in the direction of the gas flow. The porosity of the gas diffusion layer decreases in the direction of gas flow. The catalytic layer is made of a coagulated ink suspension containing catalytic carbon particles and a thermoplastic polymer selected from polyethersulfone, poly(vinylidene fluoride) and sulfonated polysulfone and covers the small pore surface of the gas diffusion layer. The gas diffusion layer has a thickness between 50 .mu.m and 300 .mu.m. The catalytic layer has thickness between 7 .mu.m and 50 .mu.m and a metal catalyst loading between 0.2 mg/cm.sup.2 and 0.5 mg/cm.sup.2.
摘要:
A rechargeable zinc halide electrochemical cell comprises a laminate of the sequence:a. an electrically conducting chemically inert material;b. a matrix supporting a zinc halide; andc. an electrically conducting layer adapted to absorb and adsorb halogen. Inert and ion specific separation layers can be added to the laminate.Because of the laminate construction of the cell, the cell of the present invention can be made in an extremely thin configuration.
摘要:
This invention relates to a novel family of phosphorylated polysiloxanes which are non-ionic and water soluble. When these polysiloxanes are dissolved in water, the resulting solutions exhibit low surface tensions. The invention also relates to phosphorylated polysiloxanes which are gels or hydrogels. The invention further contemplates methods of synthesizing the phosphorylated polysiloxanes.
摘要:
Novel radiopaque materials comprise heavy metal salts, such as bismuth and uranium salts complexed with a polymer. The metallic complexes which are permanent, nonleachable and have radiopacities at least equivalent to that of aluminum do not adversely affect the mechanical and physical properties of compositions. They are useful as medical and dental resins, in fabricating medical and dental appliances, prosthetic devices, radiation shielding devices and radiopaque polyester fabrics for clothing.
摘要:
Radiopaque polymeric materials comprising halogenated barium salts, homogeneously distributed at the molecular level, provide permanent, nonleachable radiopacities at least equivalent to pure aluminum without adversely affecting mechanical or physical properties of compositions in which they are employed.
摘要:
The invention relates to a modified polybenzimidazole (PBI), membranes that are fabricated from these polymers, and their use in electrochemical applications. These membranes have high ionic conductivity and are suitable for solid polymer electrolytes in electrochemical applications, especially for high temperature polymer electrolyte membrane (PEM) fuel cells.
摘要:
The invention relates to a new method for the separation of gaseous paramagnetic species from diamagnetic or weakly paramagnetic gaseous species by contacting the mixture of such species with a high Tc superconductive material in permeable form, so that one of the species is enriched respective of the other one by permeation through such porous barrier.
摘要:
Novel radiopaqaue materials comprise heavy metal salts, such as bismuth and uraniuim salts complexed with a polymer. The metallic complexes which are permanent, nonleachable and have radiopacities at least equivalent to that of aluminum do not adversely affect the mechanical and physical properties of compositions. They are useful as medical and dental resins, in fabricating medical and dental appliances, prosthetic devices, radiation shielding devices and radiopaque polyester fabrics for clothing.
摘要:
A method for forming blends of polydiorganosiloxanes and solid, sulfonated polyolefins and novel blends prepared by the method. In the present method the solid, sulfonated polyolefin is swollen with a diorganosiloxane oligomer whose rearrangement to high molecular weight polydiorganosiloxanes is catalyzed in situ by the sulfonic acid substituents of the polyolefin.
摘要:
A process for the rearrangement of polyorganosiloxanes using solid sulfonated polyethylene as a rearrangement catalyst. The process comprises contacting polyorganosiloxanes at a temperature within a range of about 20.degree. C. to 110.degree. C. with a rearrangement catalyst consisting essentially of a solid sulfonated polyethylene. In a preferred process, the solid sulfonated polyethylene is in the form of hollow fibers through which the polyorganosiloxanes are passed to effect rearrangement.