GB1056202A - Polymers - Google Patents

Abstract

Alkylene, arylene and aralkylene polycarbo-diimides are prepared by heating an organic diisocyanate with a catalyst <FORM:1056202/C2/1> -(-R-N=C=N-)-x+XCO2 where R is a bivalent organic radical and x is an integer greater than 1. Preferred catalysts include phospholines, phospholine oxides and sulphides, and phospholidine oxides and sulphides. Mixtures of two or more organic diisocyanates may be used, so as to produce recurring units in which the radical R is different. Specified diisocyanates (d) are 2,4-tolylene-d; m-phenylene-d; 1,3-diisopropylene-phenylene-2,4-d; 1-methyl-3,5-diethyl-phenylene-d; 4,41-methylene-d; 4-chloro-1,3-phenylene-d; 4,41-biphenylene-d; 1,5-naphthylene-d; tetramethylene-d; hexamethylene-d; decamethylene-d; 1,4 - cyclohexylene - d; 4,41 - methylenedi-cyclohexylene-d and 1,5-tetra-hydro-naphthylene diisocyanate-the aromatic diisocyanates being preferred. Organic triisocyanates such as 2,4,6-triisocyanatotoluene and p-isocyanatophenyl 2,4-diisocyanatophenyl ether may also be used. In an example 1,6-diphenylthiourea hexane prepared by refluxing hexamethylene diamine with phenylisothiocyanate in benzene, is refluxed with mercuric oxide and sodium sulphate in tetrahydrofuran yielding 1,6-diphenylcarbodiimidohexane.ALSO:A process for cross-linking an organic acid-containing polymer comprises reacting the polymer and a polycarbodiimide. The organic acid-containing polymer may be an inter-polymer of at least one unsaturated monomer, at least one of which is an alpha-beta olefinically unsaturated acid. Specified polymers are carboxylic-terminated polybutadiene, carboxylic terminated butadiene-methacrylic acid, carboxylic-terminated butadiene-acrylonitrile, carboxylic-terminated butadiene-acrylonitrile-methacrylic acid, polyacrylic acid, partially hydrolysed polyacrylonitrile having at least 0.005 equivalent of carboxyl hydrogen and inter-polymers of acrylate esters and acrylic acid, acrylate esters and methacrylic acid, acrylate esters and methacrylic acid and acrylic acid, butadiene and acrylic or methacrylic acid, butadiene and methacrylic acid and styrene or acrylonitrile, chloroprene and acrylic or methacrylic acid, butadiene and acrylonitrile and ethylene sulphinic acid and polyalphasulphonylated acrylic acid. In examples (1) a carboxylic butadiene-acrylonitrile polymer containing 0.09 ephr of carboxyl in 50% solution in tetrahydrofuran is treated with 1,6-diphenylcarbodiimido hexane; (2) an ethyl acrylate/acrylic acid/methacrylic acid, 92/2.5/2.5 terpolymer in 50% solution in methylethylketone is cross-linked by poly-(1-methyl-3,5-diisopropyl-2,4-phenylcarbodiimide); (3) a carboxylic polyethylacrylate in similar solution is so cross-linked in the presence of dibutyl phthalate as plasticizer; (4) a liquid carboxyl terminated (both terminals) polybutadiene is cross-linked (a) with a poly-(trialkyl-1,3-phenyl-carbodiimide) in which the alkyl groups are methyl, ethyl and isopropyl with the major proportion-isopropyl and (b) with a poly-(1-3-dialkyl-2,4-phenyl carbodiimide in which the alkyl groups are methyl and isopropyl the major proportion being isopropyl in the presence of dibutyl phthalate; (5) a solid carboxyl modified butadiene-acrylonitrile copolymer analysing 0.065 ephr 20% solid in methylethylketone is cross-linked with the polycarbodiimide of 4(a); (6) a carboxyl-terminated polyethyl acrylate and polybutyl acrylate are cross-linked with the above polycarbodiimide; and (7) a solid carboxylic polymer of butadiene-acrylonitrile and methacrylic acid analysing 0.065 ephr mixed with carbon black and poly-(trialkyl-1-3-phenyl-carbodiimide in which the alkyl groups are methyl and isopropyl, the major proportion being isopropyl.