Relates to copolymers of (a) a derivative of an aliphatic copolymerizable acid, which contains at least one functionally converted carboxylic acid group in which the <FORM:0864311/IV (a)/1> group of the acid residue is bound to a heteroatom and the latter atom is bound through a bridge of at least two carbon atoms to a tertiary or quaternary nitrogen atom, and any other residues bound to such a basic nitrogen atom contain at most as many  <FORM:0864311/IV (a)/2> group as are present in the first-mentioned residue of the functionally converted carboxylic acid groups, (b) an N-substituted acrylic acid amide of the formula:-  <FORM:0864311/IV (a)/3> in which R represents a hydrogen atom or an alkyl group containing one or two carbon atoms, R1 represents a hydrogen atom or an organic substituents, and R2 represents an organic substituent, and in which, when R1 represents a hydrogen atom, R2 is bound to the amide nitrogen atom through a secondary or tertiary carbon atom, and, if desired, (c) another copolymerizable ethylenically unsaturated compound, which, if it contains a nitrile group, is present in a proportion amounting to at most 30% calculated on the total weight of the monomers.  The invention also relates to amine salts and quaternary ammonium compounds of the above copolymers.  Preferred monomers (a) are N-(g -diethyl aminopropyl)-acrylamide, N-(b -dimethylaminoethyl)-acrylamide, para-dimethylaminophenyl-acrylamide and b -dimethylaminoethyl methacrylate.  The substituted amide (b) may be N-isopropyl, N-cyclohexyl, N-bornyl, N-isobornyl, N-phenyl or N-tertiary butyl-acrylamide, N-tertiary butylmethacrylamide or N-diethyl, p  N-di-isobutyl, N-di(2-ethyl-hexyl), or N-diphenyl-acrylamide. Monomer (c) may be vinyl acetate, formate, butyrate, benzoate, chloride or fluoride, vinylidene chloride, styrene, ethyl, butyl or dodecyl acrylate, acrylonitrile, isobutylene, butadiene, 2-chlorobutadiene or vinyl-pyridine.  The copolymer may be rendered hydrophilic by partial hydrolysis of ester groups or by converting amino groups into salt form by neutralization with an acid or into quaternary ammonium groups by treatment with a quaternising agent.  The polymerization may be carried out in bulk, in solution or water or organic solvents or in aqueous emulsion in the presence of conventional ionic or non-ionic emulsifying agents, in the presence of a catalyst such as a  : a 1-azo-isobutyrodinitrile, peracetic acid, acetyl peroxide, benzoyl peroxide, benzoyl acetyl peroxide, lauryl peroxide, cumene, tertiary butyl or paramenthane hydroperoxide, hydrogen peroxide, percarbonates, persulphates or perborates, and if desired in the presence of activators such as sulphur dioxide, sodium bisulphite, ammonium bisulphite, sodium hydrosulphite, sodium thiosulphate, triethanolamine, diethyl-ethanolamine, or a complex cyanide of iron, mercury, molybdenum, mercury, zinc, copper, or silver, or a mixture of such complexes.  The copolymers may be hardened by treatment with an acid hardening catalyst. Solutions of the copolymers may be hardened by treatment with an acid hardening catalyst.  Solutions of the copolymers may be used for treating textile materials and as fixatives for the hair, the hair fixatives being preferably used as aerosol sprays, the polymer being neutralized with an acid such as stearic or lactic acid and dissolved in an alcohol such as ethanol or isopropanol and admixed with a halogenated hydrocarbon propellant such as trichloromonofluoromethane, dichlorodifluoromethane and dichlorotetrafluorethane; other additives such as softening agents, perfume, dyestuffs, agents imparting gloss, substances retarding evaporation, silicone oil or silicone wax may also be incorporated.ALSO:Textiles of synthetic fibres such as cellulose acetate, polyamides and polyacrylonitrile are provided with an antistatic dressing by treatment with solutions of the copolymers of the invention, which are derived from certain substituted acrylic acid amides and certain derivatives of polymerizable aliphatic acids (see Group IV(a)).  In examples nylon fabric is impregnated with (a) an aqueous alcoholic solution of a copolymer of tertiary butyl acrylamide and N-(b -diethylaminoethyl)-methacrylate which has been neutralized with acetic acid, (b) an aqueous solution of a copolymer of N (g -diethylaminopropyl)-acrylamide quaternated with para-toluenesulphonic acid methyl ester and di-hydroxyethylmethacrylamide, the liquor also containing dimethylolurea and ammonium chloride, and (c) an aqueous emulsion of a copolymer of N (g -diethylaminopropyl)-acrylamide quaternated with triethyl phosphite and N-cyclohexyl-N-(g -hydroxypropyl)-acrylamide. In each case the impregnated fabric is then squeezed and dried.ALSO:Hair fixatives are prepared from copolymers of the invention (see Group IV (a)), preferred copolymers being those derived from tertiary butyl acrylamide, N-(g -diethylaminopropyl)-acrylamide and ethyl and/or methyl acrylate and/or methacrylate, or from tertiary butyl acrylamide, N - (g  - diethylaminopropyl) - acrylamide and octadecylacrylamide, the basic amino groups being converted into hydrophilic amino salt groups by neutralization with stearic or lactic acid, and any acrylic acid ester groups being partially hydrolysed.  The copolymers are dissolved in a low molecular weight aliphatic alcohol such as ethanol or isopropanol with additions such as softening agents, perfume, dyestuffs, agents importing gloss or substances retarding evaporation; the compositions preferably contain a silicone oil or silicone wax.  Compositions suitable for use as aerosol sprays are made by adding a propellant such as trichloromonofluoromethane, dichlorodifluoromethane or dichlorotetrafluoromethane.