Abstract: A dispersion composition comprising 100 parts by weight of a specific perfluorocarbon-based copolymer containing functional groups and 10 to 10,000 parts by weight of a specific liquid fluoro-oligomer(s). The composition of the present invention is useful as a material for producing, for example, a fluorine-containing cation-exchange membrane having excellent functions imparted thereto.

Abstract: An ionomer and a process for forming the ionomer such that the ionomer has (1) low equivalent weight; below 950, preferably between 625 and 850, and most preferably between about 700 and about 800; and (2) high conductivity, (greater than 0.15 S/cm). In an alternative embodiment, the ionomer has (1) low equivalent weight; below 950, preferably between 625 and 850, and most preferably between about 700 and about 800; and (2) acceptably low hydration, (less than about 75 weight percent). These ionomers are adapted to be processed into thin films that have acceptable physical stability. They are thus extremely well-suited for low humidity or high temperature fuel cell applications.

Abstract: An ion exchange composition membrane is made up of dispersed natural clay and/or organized clay in ion conducting polymeric film as a methanol barrier material. The membrane exhibits low methanol crossover, high proton conductivity and is thus suitable for use in direct methanol fuel cells with low costal advantage.

Abstract: An ionomer and a process for forming the ionomer such that the ionomer has (1) low equivalent weight; below 950, preferably between 625 and 850, and most preferably between about 700 and about 800; and (2) high conductivity, (greater than 0.15 S/cm). In an alternative embodiment, the ionomer has (1) low equivalent weight; below 950, preferably between 625 and 850, and most preferably between about 700 and about 800; and (2) acceptably low hydration, (less than about 75 weight percent). These ionomers are adapted to be processed into thin films that have acceptable physical stability. They are thus extremely well-suited for low humidity or high temperature fuel cell applications.

Abstract: An electrochemical cell includes a first electrode, a second electrode, and a proton exchange membrane disposed between and in intimate contact with the electrodes. The proton exchange membrane is configured to be integral with a frame structure and includes a substrate disposed in contiguous contact with the frame structure and a proton exchange material disposed at the substrate.

Abstract: A solid polymer electrolyte membrane and a catalytic layer are properly assembled even when the solid polymer electrolyte membrane and an ion exchange resin in the catalytic layer are formed of different materials. In a fuel cell, a solid polymer electrolyte membrane 20 is provided with a first solid polymer electrolyte membrane 200, and second solid polymer electrolyte membranes 202 and 204 provided at respective sides thereof. The second solid polymer electrolyte membranes 202 and 204 are formed of the same material as the ion exchange resin (not shown) included in a catalytic layer 26 and a catalytic layer 30.

Abstract: Thin films of inexpensive composite polymer electrolyte membranes containing inorganic cation exchange materials including various clay based fillers are fabricated by solution casting. The membranes exhibit higher ion exchange capacity, proton conductivity and/or lower gas crossover. In general, the composite membranes exhibit excellent physicochemical properties and superior fuel cell performance in hydrogen oxygen fuel cells.

Abstract: The present invention provides a fluorinated cation exchange membrane comprising at least two layers, a first layer made of a fluoropolymer having sulfonic acid groups and a second layer made of a fluoropolymer having carboxylic acid groups on the cathode side thereof, wherein when an electrolytic soda process is conducted using the cation exchange membrane as a diaphragm between an anode compartment and a cathode compartment, the water transport number through the cation exchange membrane is at least 4.8 mol/F (F: Faraday) under operating conditions such that the brine concentration in the anode compartment is 200 g/L, the sodium hydroxide concentration in the cathode compartment is 32 mass %, the current density is 5 kA/m2, and the temperature is 90° C. The fluorinated cation exchange membrane of the present invention gives an excellent effect such that a uniform catholyte concentration can be maintained even when installed in an electrolytic cell having no special circulating means.

Abstract: A polymer electrolyte having, in a main chain, a structural unit represented by the following formula (1): —[Ar1—(SO2—N?(X+)—SO2—Ar2)m—SO2—N?(X+)—SO2—Ar1—O]—??(1) wherein Ar1 and Ar2 independently represent a divalent aromatic groups, m represents an integer of 0 to 3, and X+ represents an ion selected from hydrogen ion, an alkali metal ion and ammonium ion, which is excellent in proton conductivity, thermal resistance and strength. The polymer electrolyte is soluble in solvents and has excellent film forming property and recycling efficiency.

Abstract: A process for producing a bipolar membrane is described in which a cationic membrane undergoes a treatment with a salt from a group 8 metal, an anionic membrane undergoes a treatment with a salt of a transition metal not belonging to group 8, and then the two membranes are conjoined and, before and/or after having been conjoined, the membranes are brought into contact with a treatment solution selected from alkaline aqueous solutions, aqueous metal sulphate solutions and aqueous metal sulphite solutions.

Abstract: Porous hydrophilic membranes comprising a porous inert support on which an ionomer is deposited, said membranes being characterized in that they have an ionic conductivity and a water permeability higher than 1 l/(h.m2.Atm).

Abstract: Embodiments of the invention generally provide an electrochemical plating cell having a cell body configured to contain a plating solution therein. An anode assembly is immersed in a fluid solution contained in the cell body, the anode being positioned in an anode compartment of the cell body. A cathode assembly is positioned in a cathode compartment of the cell body, and a multilevel diffusion differentiated permeable membrane is positioned between the anode compartment and the cathode compartment. The multilevel diffusion differentiated permeable membrane is generally configured to separate the anode compartment from the cathode compartment, while allowing a fluid solution to flow therethrough in a direction from the anode compartment towards the cathode compartment.

Abstract: A water electrolyte cell can be used with a high energy efficiency over a long period of time. The water electrolyte cell has a pair of catalytic layers and an electrolyte membrane sandwiched between the catalytic layers. The catalytic layers includes an anode catalytic layer which contains a catalyst comprising an alloy of ruthenium, iridium, and at least one metal selected from the group consisting of iron, nickel, and cobalt, or an oxide of the alloy, or a mixture of the alloy and an oxide thereof. The at least one metal has a molar ratio with respect to ruthenium and iridium in the range from 0.05 to 0.13 mol with respect to 0.8 to 2.2 mols, preferably 1.8 to 2.2 mols, of ruthenium and 0.8 to 1.2 mols of iridium. The electrolyte membrane comprises a solid polymer electrolyte membrane.

Abstract: The invention is an electrochemical cell for the separation of hydrogen and oxygen from water made of a fuel plenum with a fuel inlet, a oxidant plenum, a porous substrate, an undulating channel with walls, a support member between the walls, an anode and a cathode in the walls, an electrolyte contacting the anode and the cathode forming a barrier preventing transfer of fuel and oxidant to the cathode or to the anode, a two separate coatings on the porous substrate to prevent fuel or oxidant from entering the porous substrate, a sealant barrier to divide the two plenums, and a negative electrical and a positive electrical connection on the side of the porous substrate for flowing current from an outside source to the porous substrate.

Abstract: An ionomer and a process for forming the ionomer such that the ionomer has (1) low equivalent weight; below 950, preferably between 625 and 850, and most preferably between about 700 and about 800; and (2) high conductivity, (greater than 0.15 S/cm). In an alternative embodiment, the ionomer has (1) low equivalent weight; below 950, preferably between 625 and 850, and most preferably between about 700 and about 800; and (2) acceptably low hydration, (less than about 75 weight percent). These ionomers are adapted to be processed into thin films that have acceptable physical stability. They are thus extremely well-suited for low humidity or high temperature fuel cell applications.

Abstract: It is an object to provide a high ion conductive solid electrolyte which uses organic and inorganic complex compound having water absorption and water resistance and to provide an electrochemical system using the high ion conductive solid electrolyte. The high ion conductive solid electrolyte is composed of a complex compound including water that has zirconic acid compound and polyvinyl alcohol. An aqueous solution in which zirconium salt or oxyzirconnium salt and polyvinyl alcohol are dissolved is neutralized by alkali. After removing water used as solvent, unnecessary salts are removed from the neutralized solution. The high ion conductive solid electrolyte is obtained which is composed of the complex compound having zirconic acid compound, polyvinyl alcohol, and water. Various electrochemical systems are obtained each of which use the high ion conductive solid electrolyte.

Abstract: The present invention relates to a high crystalline polypropylene microporous membrane and a preparation method of the same, and it provides a preparation method of a polypropylene microporous membrane comprising the steps of preparing a precursor film using high crystalline polypropylene having a crystallinity of 50% or more and a very high isotacticity, annealing, stretching at a low temperature, stretching at a high temperature, and heat setting, and a polypropylene microporous membrane having superior permeability and mechanical properties prepared by the preparation method.

Abstract: An ion-exchange membrane having excellent resistance against organic fouling by high molecular weight organic ions etc. and showing low electric resistance is provided. Said ion-exchange membrane is characterized by that a polyether compound containing polyalkylene glycol chain, such as polyethylene glycol, polypropylene glycol, their derivatives, etc., is fixed on the surface and/or inside of the membrane. As examples of the mode of the fixation there are mentioned fixation by entanglement of the molecules forming the membrane and the molecules of the polyether compound, physical fixation of both molecules by the anchor effect, and chemical fixation of both molecules by the formation of covalent bond or ionic bond. Said ion-exchange membrane can be preferably used in case of removing low molecular weight electrolytes from an aqueous solution containing low molecular weight electrolytes and high molecular weight organic ions etc. through electrodialysis.

Abstract: The invention includes novel anion exchange membranes formed by in situ polymerization of at least one monomer, polymer or copolymer on a woven support membrane and their methods of formation. The woven support membrane is preferably a woven PVC membrane. The invention also includes novel cation exchange membranes with or without woven support membranes and their methods of formation. The invention encompasses a process for using the membranes in electrodialysis of ionic solutions and in particular industrial effluents or brackish water or seawater. The electrodialysis process need not include a step to remove excess ions prior to electrodialysis and produces less waste by-product and/or by-products which can be recycled.

Abstract: A process for the preparation of a membrane includes forming a porous substrate and then impregnating the porous substrate with a polymeric material. The porous substrate is made by first dispersing fibres in water to form a slurry, then depositing the slurry onto a mesh bed to form a fibre network, drying and compacting the fibre network, and, either before or after drying and compacting, applying to the fibre network a dispersion of a binder of silica and a fluorinated polymer.

Abstract: A gas diffusion structure for polymer electrolyte fuel cells having a sheet-like carbon substrate made hydrophobic and having two main opposing surfaces and a contact layer on one of these surfaces. The contact layer is formed of an intimate mixture of at least one hydrophobic polymer, which can be polyethylene, polypropylene or polytetrafluoroethylene, and finely divided carbon particles, wherein the weight percentage of the carbon particles relative to the total weight of the contact layer amounts to 40 to 90 wt. %. The gas diffusion structure is a carbon substrate made hydrophobic by at least one hydrophobic polymer and the hydrophobic polymers are restricted to two layers extending from both opposing surfaces into the carbon substrate down to a depth of from 5 to 40 &mgr;m and the hydrophobic polymers fill of from 20 to 60% of the pore volume within those layers.

Abstract: The invention relates to a method for producing polymer-electrolyte membranes using plasma-assisted deposition in a gaseous phase. Said method simplifies the process in relation to prior art by the selection of its starting materials, carbon or fluorocarbon compounds and water. The invention also relates to a polyazol membrane coated by plasma-polymerization.

Abstract: A method for producing a bridged polymer membrane includes the steps of: obtaining a liquid medium comprising a basic polymer having an amino group in a repeating unit, a bridging agent, and a solvent; shaping the liquid medium into a membrane configuration to obtain the shaped membrane; and bridging the basic polymer by the bridging agent in the shaped membrane. A fuel cell has the bridged polymer membrane. The mechanical strength of the polymer electrolyte membrane is improved.

Abstract: PFSAs having CO tolerances greater than 500 ppm at temperatures above 100° C. are provided by decreasing the equivalent weight and thickness of the membrane and impregnating the membrane pores with an oxide, e.g., a hydrophilic siloxane polymer or TiO2. This was accomplished by either impregnating an extruded PFSA film via sol-gel processing of tetraethoxysilane, or by preparing a recast film, using solubilized PFSA and an oxide source.

Abstract: A releaseable membrane structure for producing a free membrane containing a substrate, a release stratum on the substrate and a membrane stratum on the release stratum. The release stratum and the membrane stratum contain oppositely-charged polyelectrolytes that are associated. The oppositely-charged polyelectrolytes of the release stratum are selected to dissociate upon application of stimulus whereas those of the membrane stratum are selected to remain associated upon application of the stimulus. Thus, when the stimulus is applied the polyelectrolytes in release stratum dissociate and the membrane stratum is released from the substrate and is a free membrane.

Abstract: The invention relates to an electrolysis cell comprising an anode compartment which comprises an aqueous solution of at least one alkali metal salt, a cathode compartment and a solid electrolyte which separates the anode compartment and the cathode compartment from one another, wherein that part of the surface of the solid electrolyte which is in contact with the anode compartment and/or that part of the surface of the solid electrolyte which is in contact with the cathode compartment has/have at least one further ion-conducting layer.

Abstract: Embodiments of the invention provide an electrochemical plating cell. The plating cell includes a fluid basin having an anolyte solution compartment and a catholyte solution compartment, an ionic membrane positioned between the anolyte solution compartment and the catholyte solution compartment, and an anode positioned in the anolyte solution compartment, wherein the ionic membrane comprises a poly tetrafluoroethylene based ionomer.

Abstract: An electrochemical cell includes a first electrode, a second electrode, and a proton exchange membrane disposed between and in intimate contact with the electrodes. The proton exchange membrane is configured to be integral with a frame structure and includes a substrate disposed in contiguous contact with the frame structure and a proton exchange material disposed at the substrate.

Abstract: A polymer electrolyte membrane is provided having a thickness of 90 microns or less and comprising a polymer, said polymer comprising a highly fluorinated backbone and recurring pendant groups according to the formula:

Abstract: A dispersion composition comprising 100 parts by weight of a specific perfluorocarbon-based copolymer containing functional groups and 10 to 10,000 parts by weight of a specific liquid fluoro-oligomer(s). The composition of the present invention is useful as a material for producing, for example, a fluorine-containing cation-exchange membrane having excellent functions imparted thereto.

Abstract: Composites comprising porous polymeric membrane films meeting the following equation: 75 MPa<(longitudinal membrane tensile modulus+transverse membrane tensile modulus)/2, wherein at least a portion of the porosity of the membrane is imbibed with resin and methods for making the same. The composites have unusually high resistance to fracture and catastrophic failure.

Abstract: The present invention provides an ozone generating system that combines single-use elements or segments with an extended use fixture that is used to activate the single-use elements. One embodiment of the invention consists of a strip of proton exchange membrane (PEM) having the ozone producing catalyst applied directly onto one side of membrane. Optionally, the application of this catalyst may be divided into segments or patches, wherein each segment represents the limited-use portion of the ozone generator. Each segment may be advanced into a fixture that provides the balance of the electrochemical system required for operation of the ozone generator. This balance of system may include additional subsystems, with a power supply, water source, electrical contacts, electronic controllers, sensors and feedback components, being typical examples.

Abstract: Composites comprising porous polymeric membrane films meeting the following equation: 75 MPa<(longitudinal membrane tensile modulus+transverse membrane tensile modulus)/2, wherein at least a portion of the porosity of the membrane is imbibed with resin and methods for making the same. The composites have unusually high resistance to fracture and catastrophic failure.

Abstract: A heat-resistant separator composed of a non-woven fabric of high-melting resin, 1 to 20 &mgr;m in average fiber diameter, 5 to 300 g/m2 in basis weight, 1 to 200 cc/cm2/sec in air permeability, and 0.01 to 1.0 mm in thickness, or a laminated heat-resistant separator composed of a laminate having a melt-blown, non-woven fabric layer of high-melting resin, 1 to 20 &mgr;m in average fiber diameter, 5 to 300 g/m2 in basis weight, 1 to 200 cc/cm2/sec in air permeability, and 0.01 to 1.0 mm in thickness is more resistant to heat, and hence safer, and is suitable for batteries and electrical double-layer capacitors serviceable at high temperature.

Abstract: A membrane electrode assembly comprising a composite membrane having a first major surface area and a second major surface area comprising a porous polymeric matrix containing ionically conductive solid and ionomeric binder, at least one protective layer disposed adjacent to the porous polymeric matrix membrane comprising an ionomeric binder and an ionically conductive solid, an anode comprising an oxidizing catalyst adjacent said first major surface area of said composite membrane and a cathode comprising a reducing catalyst adjacent said second major surface area of said composite membrane, and a method for manufacturing the same.

Abstract: It is an object to provide a high ion conductive solid electrolyte which uses organic and inorganic complex compound having water absorption and water resistance and to provide an electrochemical system using the high ion conductive solid electrolyte. The high ion conductive solid electrolyte is composed a complex compound including water that has zirconic acid compound and polyvinyl alcohol and compound having carboxyl group or metal salt of the compound having carboxyl group. An aqueous solution in which zirconium salt or oxyzirconnium salt and polyvinyl alcohol and compound having carboxyl group or metal salt of the compound having carboxyl group are dissolved is neutralized by alkali. After removing water used as solvent, unnecessary salts are removed from the neutralized solution. The high ion conductive solid electrolyte is obtained which is composed of the complex compound. Various electrochemical systems are obtained each of which use the high ion conductive solid electrolyte.

Abstract: An organic electroluminescent device comprising: a pair of electrodes; and at lest one organic layer provided between the pair of electrodes, at least one of the at lest one organic layer being a light emitting layer, wherein the light-emitting layer comprises a compound represented by the formula (I) as defined herein.

Abstract: This invention provides an assembly comprising a sensing electrode and a counter electrode in contact with a membrane body formed from a solid polymer electrolyte system comprising a fluorinated polymer matrix and a charge carrying component which is dispersed in the matrix the electrodes and membrane being housed in a housing having a gas diffusion barrier through which gas may flow. The charge carrying components are fluorinated organic proton conductors (such as heptadecafluorooctane sulphonic acid, bis-trifluoromethane sulphonamide, N-(2,6-diethylphenyl)-1,1,1-trifluoromethane sulphonamide, N-benzyltrifluoromethane sulphonamide and N, N-1,2-cyclohexanediylbis (1,1,1-trifluoromethane sulphonamide)). The polymer matrix is a homopolymer or copolymer of vinylidene fluoride preferably with fluorinated comonomers. The solid polymer electrolyte system preferably contains plasticising additive(s) and is cast as a coating onto one or more electrodes eg.

Abstract: Membrane-electrode assembly consisting of a cationic exchange membrane which contains fluorine (made of hydrolyzed copolymer of tetrafluoro-ethylene and vinyl ether which contains perfluorosulfur with PE=900-1300) and porous layers of electrode material (made of electrocatalyst), inactive electroconductor material and fluoropolymer agglutinating material arranged on both surfaces of the cationic exchange membrane. The cationic exchange membrane which contains the fluorine is made of hydrolyzed copolymer of tetrafluoroethylene with vinyl ether which contains perfluorosulfur, having a crystallinity grade between 2 and 8%; porous layers of the electrode material are obtained which have a porosity comprised between 40 and 70% and decreasing in the direction of the cationic exchange membrane surface with a porosity gradient from 5 to 15% par 1&mgr;. Said membrane-electrode assembly is used in fuel cells, in water electrolysis and in other electrochemical process.

Abstract: An electrochemical gas sensor is provided which can be assembled economically and in a few steps. The electrodes (1, 2, 3) with associated electric lines are applied in a planiform manner to a membrane strip, which is impermeable to the electrolyte but permeable to gases. The membrane strip (6) is deposited in the sensor housing in a zigzag-folded pattern, so that the membrane strip limits the opening of the sensor housing for the entry of the measured gas. The electrodes (1, 2, 3) are arranged stacked in the sensor housing (5, 7) at spaced locations from one another due to the membrane strip (6) deposited in a zigzag-folded pattern.

Abstract: This invention relates to an electrochemical cell having a high-temperature low-hydration (HTLH) ion exchange membrane serving as an electrolyte layer. The membrane may be a non-fluorinated ionomer membrane, such as an acid-doped polybenzimidazole (PBI) membrane. The HTLH membrane is sandwiched by an anode having a hydrogen-carrying fluid feed chamber with an inlet for receiving a hydrogen-carrying fluid, and a cathode having a hydrogen product chamber with an outlet for discharging a hydrogen product gas. The anode and cathode are electrically couplable to an electric current source for powering the electrochemical cell to produce hydrogen gas in a reduction reaction at the cathode. The hydrogen-carrying fluid may be water, in which case the electrochemical cell serves as an electrolyzer; or, the hydrogen carrying fluid may be a hydrogen gas, in which case the cell serves as a hydrogen pump.

Abstract: A composite comprises at least one layer which includes a composite comprising (a) from 1 to 99% by weight of a solid (I) with a primary particle size of from 5 nm to 100 &mgr;m or a mixture made from at least two solids, (b) from 99 to 1% by weight of a polymeric binder (II) which includes: (IIa) from 1 to 100% by weight of a polymer or copolymer (IIa) which has, along the chain, terminally and/or laterally, reactive groups (RG) which are capable of crosslinking reactions when exposed to heat and/or UV radiation, and (IIb) from 0 to 99% by weight of at least one polymer or copolymer (IIb) which is free from reactive groups RG, where the at least one layer has been applied to at least one second layer comprising at least one conventional separator.

Abstract: An inexpensive composite electrolyte for use in electrochemical fuel cells includes (i) an inorganic cation exchange material, (i) a silica-based binder; and (ii) a polymer-based binder. The cation exchange material includes aluminosilicate clays. The composite electrolyte can be fabricated with a tape casting apparatus.

Abstract: A polymer electrolyte for an electrochemical half cell, in particular for a reference half cell, contains a polymer which as a first monomer component contains at least one alkyl methacrylate. The alkyl methacrylate has a substituted alkyl group with from three to seven carbon atoms and at least two substituents. The aforementioned substituents are selected from the group comprising OR1 and NR2R3, in which R1, R2 and R3 are selected from the group comprising hydrogen, methyl, and ethyl, on the condition that the substituted alkyl group contains the substituent OH at most once.

Abstract: An integral composite membrane comprised of an expanded polytetrafluoroethylene having a morphological structure comprising a microstructure of very highly elongated nodes interconnected by fibrils is imbibed with ionomer. This composite membrane shows a surprising increase in hardness and thereby reduces electrical shorting and improves fuel cell performance and durabiity.

Abstract: It is an object to provide a high ion conductive solid electrolyte which uses organic and inorganic complex compound having water absorption and water resistance and to provide an electrochemical system using the high ion conductive solid electrolyte. The high ion conductive solid electrolyte is composed of a complex compound including water that has zirconic acid compound and polyvinyl alcohol. An aqueous solution in which zirconium salt or oxyzirconnium salt and polyvinyl alcohol are dissolved is neutralized by alkali. After removing water used as solvent, unnecessary salts are removed from the neutralized solution. The high ion conductive solid electrolyte is obtained which is composed of the complex compound having zirconic acid compound, polyvinyl alcohol, and water. Various electrochemical systems are obtained each of which use the high ion conductive solid electrolyte.

Abstract: A bipolar membrane which exhibits a low water dissociation voltage for an extended period of time under a high current density condition, and a high current efficiency, without developing blister. The bipolar membrane comprises a cation-exchange membrane and an anion-exchange membrane which are joined together, wherein ion-exchange resin particles having ions exchanged with ions of a metal of an atomic number 20 to 90, such as titanium, zirconium, tin, iron, ruthenium or palladium, or with complex ions of said metal are existing on the junction interface between the cation-exchange membrane and the anion-exchange membrane.

Abstract: The invention concerns a microporous diaphragm obtainable by filtering through a porous support, an aqueous dispersion free of asbestos fibres and titanate fibres, comprising organic fibres, at least a binding agent selected among halogenated polymers, at least a pore-forming agent and mineral particles with non-fibrous structure. The invention also concerns a combination comprising said diaphragm and a fibrous mat obtainable by filtration deposit through a porous support of a dispersion comprising fibres whereof part is electrically conductive, at least a binding agent selected among halogenated polymers, at least an electrolytic agent, at least a pore-forming agent. The invention further concerns the preparation of the diaphragm and the combination, and the use thereof to obtain an alkali metal hydroxide solution by electrolysis of aqueous alkali metal halide solutions.

Abstract: A hydrophilic cross-linked polymer obtainable by copolymerisation of hydrophobic and hydrophilic monomers that give a cross-linked hydrophilic polymer on polymerisation; a monomer including a strongly ionic group; and water is useful as the membrane in an assembly that can be used in an electrolyter or fuel cell.

Abstract: Crosslinked sulphonic fluorinated ionomers having an equivalent weight 380-1300 g/eq, comprising: (A) monomeric units deriving from one or more fluorinated monomers containing at least one ethylene unsaturation; (B) fluorinated monomeric units containing sulphonyl groups —SO2F in an amount such as to give the above indicated equivalent weight.