GB1348321A - Production of shaped polymeric articles - Google Patents

Abstract

1348321 Articles of polymers containing methacrylimide groups; the introduction of such groups ROHM GmbH 20 Aug 1971 [22 Aug 1970] 39232/71 Heading C3P Shaped articles of small doss-sectional thickness, such as films, foils, fibres and filaments, and comprising a polymer containing a substantial proportion of methacrylimide units, are prepared by a process which comprises heating to an elevated temperature to effect methacrylimide unit formation, a composition in the form of a pre-shaped article of small crosssectional thickness and comprising (A) a polymer of methacrylic acid or a methacrylamide; a copolymer of methacrylic acid with methacrylonitrile and/or a methacrylamide; or a copolymer of a C 1-4 alkyl methacrylate with a methacrylamide and/or methacrylic acid; said polymers and copolymers optionally containing up to 20 mole per cent of units of acrylic monomers replacing units of the corresponding methacrylic monomers and/or a minor proportion of units of one or more other copolymerizable monomers, and (B) a primary amine or diamine boiling at a temperature above that to which the article is heated and/or a compound which decomposes on said heating to produce ammonia or one or more primary amines and/or one or more diamines and volatile by-products, the nitrogen in said latter compound being in the form of an amide group derived from a carbonic acid or carboxylic acid. The amine(s) or diamine(s) produced from said compound may be volatile or non-volatile at the heating temperature, which is preferably from 130- 250‹ C. The mechanism of the reaction is not fully understood and it is essential to point out that when the polymer is substantially composed of all methacrylamide and/or methacrylonitrile with or without acid groups, some imide groups may form intramolecularly, without the compound (B) reacting. In such a case, the volatile amine(s) and/or diamine(s) released, escape, and the less volatile ones form some imide groups, and also have a temporary plasticizing effect. When diamine(s) are present or released from the amide, cross-linking also occurs to some extent. Amines and diamines which boil above the heating temperature are, for example, aniline, toluidine, octylamine and (in Example 3) hexamethylene diamine. Amides releasing NH 3 , amine(s) and/or diamine(s) are for example urea, urethan, N-methyl urethan, N,N-dimethyl urea, formamide and monomethyl formamide. When methacrylamide units are present in the polymer, they may be N-substituted, such as N-methyl-, N-butyl- and N- isopropyl-methacrylamide. The amide compounds may be present during the production of the polymer or may be added afterwards. The non-volatile amine or diamine is preferably added afterwards, since these tend to interfere with the polymerization.