In examples a copolymer is prepared from N.N. diethylaminoethyl vinyl sulphide, acrylonitrile, and ethyl acrylate. The copolymer may be used in the form of an aqueous dispersion for coating tiles, fibre boards and pressed boards.ALSO:Vinyl sulphides (thio ethers) having an amino group, of general formula CH2=CH-S-A-N-R1R2 where A represents a phenylene group, a phenylene group having non-functional ring substituents, or an alkylene group having at least two carbon atoms between the nitrogen and sulphur atoms, and R1 and R2 together represent a saturated divalent aliphatic chain with which the nitrogen atom forms a heterocyclic group having five or six cyclic atoms, or R1 and R2 each represent hydrogen or a C1-C5 alkyl group, are prepared by reacting acetylene and an amino-containing thiol of the formula R1R2N-A-S-H together at elevated temperature and pressure, in the presence of a strongly basic catalyst, such as potassium hydroxide, sodium ethoxide, potassium ethoxide, or potassium butoxide (1 to 10% by weight of the thiol), and an organic solvent, e.g. C1-C5 alkanols, e.g. ethoxyethanol, butoxyethanol, ethoxy ethoxy-ethanol or butoxyethoxy-ethanol, or ether alcohols alone or with, e.g., the dimethyl ether of ethylene glycol or diethyl acetal. The organic solvent used is one which is a solvent for the thiol and for the catalyst. The acetylene is passed into the solution under pressure and heated to 100-200 DEG C. at 100-700 p.s.i.g. Suitable aminocontaining thiols are substituted or unsubstituted aminobenzenethiols, aminotoluenethiols or aminoalkanethiols. Examples are given of the reaction between acetylene in the presence of potassium butoxide and n-butyl alcohol and (1) 2-aminobenzenethiol to produce 2-aminophenyl vinyl sulphide; (2) 2-aminoethanethiol to produce 2-aminoethyl vinyl sulphide; (3) b -N-N-dimethylaminoethanethiol to produce N,N-dimethylaminoethyl vinyl sulphide. Examples also describe the production of 2-morpholinoethyl vinyl sulphide from 2-morpholinoethanethiol, 2-piperidinoethyl vinyl sulphide from 2 - piperidinoethanethiol, 2 - pyrrolidinoethyl vinyl sulphide from 2-pyrrolidinoethanethiol, pyrrolidinoisopropyl vinyl sulphide from pyrrolidinoisopropanethiol, and acetylene in the presence of potassium hydroxide, butanol, and methyl formal. Other starting materials specified are N,N-dibutyl aminobenzenethiol, b -aminoethanethiol, diethyl-aminoethanethiol, dibutylaminoethanethiol, morpholinopropanethiol, pyrrolidinobutanethiol, aminobutanethiol, dimethylaminobutanethiol, diethylaminohexanethiol, dimethylaminododecanethiol, and o -aminododecanethiol.ALSO:Compounds of the general formula CH2 = CH-S-A-NR1R2 where A is a phenylene group, a phenylene group having non-functional ring substituents or an alkylene group having at least two carbon atoms between the nitrogen and sulphur atoms, and either R1 and R2 together represent a saturated divalent aliphatic chain with which the nitrogen atom forms a heterocyclic group having five or six cyclic atoms, or R1 and R2 each represent hydrogen or C1-C5 alkyl group, are subjected to polymerization treatment to form homopolymers or copolymers. The amino-containing vinyl sulphides form homopolymers under the influence of cationic agents in about molar proportions or more, e.g. boron trifluoride, and its co-ordination complexes with oxygenated organic compounds, such as ethers, alcohols, aldehydes and carboxylic acids, zinc chloride, or stannic chloride, or in the presence of relatively small amounts of azo free-radical catalysts such as azodiisobutyronitrile, dimethyl azodiisobutyrate or azodiisobutyramide. Examples are given of the polymerization of 2-aminoethyl vinyl sulphide, 2-aminophenyl vinyl sulphide and N,N-dimethylaminoethyl vinyl sulphide, and of the copolymerization of 3-aminopropyl vinyl sulphide and sulphur dioxide. The poly - (N,N - dimethylaminoethyl vinyl sulphide) is quaternized with hexamethylene dibromide to give an ion-exchange resin. The compounds of the invention may be copolymerized with, e.g., acrylonitrile, acrylamide, methyl, ethyl, butyl, octyl, dodecyl, methoxyethyl or benzyl acrylates, methacrylonitrile, methacrylamide, methyl, ethyl, butyl, cyclohexyl, benzyl, butoxyethyl, octyl or dodecyl methacrylate, ethylene diacrylate or dimethacrylate, vinyloxyethyl-acrylate or methacrylate, allyl acrylate or methacrylate, ethyl, butyl, octyl, ethoxyethyl, and ureidoisobutyl vinyl ethers, ethyl vinyloxyethylcarbamate, N-vinylpyrrolidone, alkyl vinyl sulphides, N-vinyl ethylene urea, N-vinyl succinimide, N-vinylphthalamide, styrene, p-methylstyrene, p-chlorostyrene, vinyltoluene, divinylbenzene, trivinylbenzene, vinyl acetate, vinyl propionate, dimethyl or dibutyl itaconate, dialkyl maleates, mesaconates and nitraconates. Examples are given of copolymers of b -aminoethyl vinyl sulphide and divinylbenzene (an ion-exchange resin), N,N-dimethylaminoethyl vinyl sulphide and N-vinylpyrrolidone, and of N,N-diethylaminoethyl vinyl sulphide, acrylonitrile and ethyl acrylate. The homopolymers may be used as additives to cellulose acetate spinning dopes.ALSO:A pesticidal composition comprises 2-aminophenyl vinyl sulphide incorporated in a dust in proportions of 1, 3 and 5%.