Patent GB-918626-A (GB)
Title: Membranes and shaped articles prepared from polyelectrolytes
IPC: H01M50/414
Filed: 1959-06-23
Abstract: Mechanically and chemically stable membranes and shaped bodies having numerous, substantially straight, parallel and circular cross-section capillaries of equal size, are made by producing from a sol of a polyelectrolyte by the action of multivalent cations a gel having capillaries of the type referred to, soaking the gel with a polymerizable monomeric material, removing excess monomeric material from the capillaries and polymerizing the monomeric material in the walls of the capillaries. Polyelectrolytes specified are soluble salts of polyuronic acids such as alginic, pectinic, cellulose carboxylic, cellulose glycollic, carrageenic and arabinic acids as well as derivatives, partial esters, amides and amphions thereof; also specified are polyglucosamine, chondroitinosulphuric acid, hyaluronic acid and keratosulphate and mixtures and mixtures with proteins.  In modifications, the gel may be soaked with a solution of the monomeric material, or a solution of partially polymerized monomeric materials may be used.  Suitable monomeric materials include methacrylic acid methyl ester, a mixture of phenol and formaldehyde, a mixture of urea and formaldehyde, polyesters, styrene and di-isocyanates.  The polyelectrolyte may be subsequently dissolved out of the consolidated membrane, but if retained the activity of its ions and ion-groups is sufficiently unimpaired for the consolidated membrane to act as an ion-exchanger.  In Example 1, a porous membrane is produced from an aqueous solution of sodium alginate by the use of copper cations, and in Examples 2-6 consolidated membranes are produced by polymerizing in the capillaries of the porous membrane (2) and (3) methacrylic acid methyl ester using a benzoyl peroxide catalyst (4) phenol and formaldehyde (5) urea and formaldehyde (6) hexamethylene di-isocyanate-in this last case consolidation of the membrane takes place by floating it on water whereupon carbon dioxide is evolved.ALSO:Mechanically and chemically stable membrane and shaped bodies having numerous, substantially straight, parallel and circular cross-section capillaries of equal size, are made by producing from a sol of a polyelectrolyte by the action of multivalent cations a gel having capillaries of the type referred to, soaking the gel with a polymerisable monomeric material, removing excess monomeric material from the capillaries and polymerising the monomeric material in the walls of the capillaries. Polyelectrolytes specified are soluble salts of polyuranic acids, such as alginic, pectinic, cellulose carboxylic, cellulose glycollic, carragenic and arabinic acids as well as derivatives, partial esters, amides and amphions thereof; also specified are polyglucosamine, chondroitino-sulphuric acid, hyaluronic acid and keratosulphate and mixtures thereof and mixtures with proteins.  In modifications, the gel may be soaked with a solution of the monomeric material, or a solution of partially polymerised monomeric materials may be used.  Suitable monomeric materials include methacrylic acid methyl ester, a mixture of phenol and formaldehyde, a mixture of urea and formaldehyde, polyesters, styrene and di-isocyanates.  The polyelectrolyte may be subsequently dissolved out of the consolidated membrane, but if retained the reactivity of its ions and ion groups is sufficiently unimpaired for the consolidated membrane to act as an ion-exchanger.  In Example 1, a porous membrane is produced from an aqueous sodium alginate solution by the use of copper cations, and in Examples 2-6 consolidated membranes are produced by polymerising in the capillaries of the porous membrane (2) and (3) methacrylic acid methylester using a benzoyl peroxide catalyst (4) phenol and formaldehyde (5) urea and formaldehyde (6) hexamethylene di-isocyanatein this last case consolidation of the membrane takes place by floating it on water whereupon carbon dioxide is evolved.