Abstract:
A method for the preparation of a graft polymer membrane comprising an inactive polymer film having TFS as a graft chain. The inactive polymer film is irradiated with ionizing radiation, and the resulting irradiated film is graft-polymerized by contacting said film with TFS.This product may then be sulfonated to provide a cation exchange membrane; or the obtained graft polymer may be haloalkylated, and quarternary aminated to provide an anion exchange membrane; or the graft polymer membrane may be used to prepare a weakly acidic cation exchange membrane by substituting at least part of the benzene rings of the graft polymer by one of the groups among hydroxyl groups, carboxylic acid groups, phosphoric acid groups and phosphorous acid groups.The polymeric membrane products are also disclosed and claimed.
Abstract:
Pre-swelled ion exchange membranes formed from one or more layers of fluorinated polymer having carboxylic or sulfonic acid functional groups and which polymer contains about 8 to 30% by weight of a swelling agent of the formula HO(CH.sub.2 CHYO).sub.n H where Y=H or CH.sub.3 and n=2, 3 or 4 are disclosed. Also disclosed are processes for preparing these membranes, electrochemical cells utilizing these membranes, and methods of preparing said cells for use in chloralkali processes.
Abstract:
An electrolytic cell is described which has a spacing means positioned between the anode and cathode faces. The present spacing means comprises a plurality of longitudinally elongated, electrically non-conductive spacers fabricated of a chemically resistant material being inert to the conditions existing within an operating electrolytic cell. The present spacers are positioned on the face portion of a foraminous anode. The spacers are secured on the anode face by extention of a portion of the spacer through an opening in the anode and are secured at the back portion of the anode.
Abstract:
The invention concerns a NiO-based ceramic oxide diaphragm for the alkaline water electrolysis. The diaphragm, in accordance with the invention, contains 0.5 to 10% by weight (estimated as Ti based on the oxide mass) of titanium oxide in the porous NiO layer. Diaphragms of this type are obtained, in particular, by the oxidative sintering of a mass of nickel powder which has been applied under pressure to a nickel support, especially one consisting of nickel wire gauze. In the process the titanium is in the form of titanium metal, titanium oxide or a titanium compound which is added to the initial nickel powder. The titanium is present in the form of its oxide after the oxidation sintering treatment. In an alternative embodiment of the process, an already sintered porous mass of nickel or nickel oxide can be impregnated with a titanium compound and calcined to convert the titanium compound to its oxide.
Abstract:
An unreinforced ion exchange membrane which comprises fluorinated polymer which has carboxylic functional groups, which has a hydrogen bubble release layer on the cathode-facing side thereof, and which has channels open to the outer surface of the anode-facing side thereof, is described. Precursor membrane, which may contain partially embedded sacrificial members, and from which the unreinforced ion exchange membrane is made, is also described. The unreinforced ion exchange membrane can be used to separate the compartments of a chloralkali cell, and such a cell operates at low voltage, high current efficiency, and low power consumption.
Abstract:
A method for repairing perfluorocarbon copolymeric cation exchange membranes. A quantity of a perfluorocarbon copolymer having a desired pendant cation exchange functional group is partially solvated in a solvating dispersion media, applied to areas of the membrane to be repaired, and the dispersion media removed.
Abstract:
Treating a sheet of ion-exchange membrane in order to decrease the voltage of operation of an electrolytic cell containing the membrane by swelling the membrane in a liquid medium, the extent of swelling on the anode side being greater than the extent of swelling on the cathode side, and the extent of swelling on the anode side being greater than that effected by contacting the membrane with the electrolyte to be electrolyzed.
Abstract:
A fluorocarbon cation exchange membrane containing a sacrificial reinforcement for tear resistance which, in use as a cation exchange membrane for alkali metal chloride electrolysis, degrades to provide low voltage operation of the electrolytic cell.
Abstract:
The process relates to the formation of diaphragms, for example those used for alkali chloride electrolysis in an aqueous solution. The formation of a layer-type diaphragm, accreted on a hollow diaphragm support from a slurry having a high solids content of diaphragm material, is made uniform.During the accretion step, the diaphragm support is periodically lifted and lowered in the slurry (frequency 0.1-10 min.sup.-1 ; amplitude 10-100 cm; velocity 2-20 cm/sec); its topside, at the upper reversal point of the oscillating motion, has a certain spacing (10-25 cm) from the constantly measured height of the level of slurry in the accretion tank and its underside cannot reach below a minimum distance (30 cm) from the bottom of the basin. The suction pressure of the slurry through the hollow diaphragm support is maintained at a constant value and is controlled (10-500 mbar below the atmospheric pressure of the surroundings).The accretion step can be subdivided into time intervals between which the frequency and the suction pressure are increased stepwise.The electrolysis process becomes more economical with the use of the diaphragm produced according to this invention.
Abstract:
A method of cladding a separator, that is a diaphragm or membrane, to a cathode box of the pocket type comprising a plurality of foraminate walls, the method comprising positioning a separator in the form of a sleeve in each pocket of the cathode box with the ends of the sleeves projecting beyond the ends of the pockets and heat sealing by means of radio frequency heating those parts of the sleeves projecting beyond the ends of adjacent pockets, either to each other or to additional heat sealable material. Also a cathode box clad with separator, and an electrolytic cell comprising a cathode box clad with separator.