Patent GB-580514-A (GB)
Title: Sulphur-containing polymers
IPC: C08F8/34
Filed: 1944-09-22
Abstract: Sulphur-containing polymers are prepared by reacting an ethylenically unsaturated polymer having an iodine number of at least 25 with a thiol-carboxylic acid in the presence of a peroxy catalyst, until at least one mol. of the thiolcarboxylic acid is introduced per four ethylenic linkages in the polymer.  Specified unsaturated polymers are the glycerol-phthalic anhydride-linoleic acid condensates, methallyl alcohol - para - amylphenol - formaldehyde condensates and polyesters, polyethers, polysulphides, polyamide-polyesters and polyacetals, and the products obtained by polymerizing butadiene 1 : 3, isoprene or dimethyl-2 : 3-butadiene-1 : 3 with pinene, camphene, monovinyl acetylene, vinylethinyl alkyl carbinols, vinyl acetate, vinyl chloride, unsaturated aldehydes and ketones such as acrolein and methyl vinyl ketone, acrylic and methacrylic esters such as butyl acrylate, a -chloracrylic acid and its esters such as methyl a -chloroacrylate, furylacrylic acid and its esters such as methyl furyl acrylate and esters of 1 : 4-butenedioic acid such as dimethyl fumarate.  The preferred thiolacid is thiolacetic acid, though thiolpropionic, thiolbutyric, thiolcaproic or thiolbenzoic acid may be used.  The peroxy catalysts may be ascaridol, peracetic acid or perbenzoic acid.  The process is preferably carried out in a non-reactive solvent such as dioxane, benzene, xylene, gasoline or other aromatic or aliphatic hydrocarbon at a temperature between 15 DEG  C. and the boiling point of the solvent at atmospheric pressure. The product, which is soluble in dioxane and acetone, may be rendered insoluble by treatment with an alcoholic solution of sodium methylate followed by exposure to air.  The product may also be partially or wholly hydrolysed by acids or alkalis to give polymer thiols which are insolubilised by oxidation to form disulphide cross-linked polymers which are more solvent resisting than the original polymers. Specification 339,255, [Class 2 (iii)], is referred to.ALSO:Sulphur-containing polymers are prepared by reacting an ethylenically unsaturated polymer having in iodine number of at least 25, such as natural or synthetic rubber, with a thiocarboxylic acid in the presence of a peroxy catalyst, until at least one mol of the thiolcarboxylic acid is introduced per four ethylenic linkages in the polymer.  Specified synthetic rubbers are those obtained by polymerizing butadiene 1:3, isoprene or dimethyl-2:3-butadiene 1:3, either alone, intermixed, or admixed with styrene isobutylene, acrylic or methacrylic acid or their esters including the nitriles. The preferred thiol acid is thiolacetic acid, though thiolpropionic, thiolbutyric, thiolcaproic or thiolbenzoic acid may be used.  The peroxy catalysts may be ascaridol, peracetic acid or perbenzoic acid. The process is preferably carried out in a non-reactive solvent such as dioxane, benzene, xylene, gasolene or other aromatic or aliphatic hydrocarbon at a temperature between 15 DEG C. and the boiling point of the solvent at atmospheric pressure.  In an example, rubber in benzene solution is treated with thiolacetic acid in the presence of ascaridol, oxygen is intermittently bubbled through over a period of 6 days, and then the solution allowed to stand 10 days after which the white solid which separates out is washed with methanol and dried.  This product which is soluble in dioxane and acetone may be rendered insoluble by treatment with an alcoholic solution of sodium methylate followed by exposure to air.  The product may also be partially or wholly hydrolysed by acids or alkalis to give polymer thiols which are insolubilised by oxidation to form disulphide-cross-linked polymers which are more solvent resisting than the original polymers.  In a further example, a butadienestyrene copolymer prepared according to Specification 339,255, [Class 70], is treated in a similar manner.