| 摘要 |
A method for the manufacture of high molecular weight hydrophilic copolymers of hydroxyl group-containing non-ionic polymeric substances in the form of gel grains in which the hydroxyl group-containing polymer is reacted in the presence of alkali with a bifunctional organic substance capable of reacting with hydroxyl groups with the formation of ether bridges in the molecular proportion of 1 mole of the hydroxyl group-containing substance to at least 10 moles of the bifunctional substance, comprises mixing a liquid solution of the non-ionic polymer with a dispersing medium capable of forming a two phase system therewith, under sufficient agitation to transform the liquid solution into drops suspended in the medium, reacting the bifunctional compound with the non-ionic polymer in the presence of alkali until gel formation has taken place and separating the gel grains formed from the drops. Specified polymers are dextran, starch, dextrin, cellulose, polyglycose, methyl dextran, ethyl dextran, hydroxypropyl dextran, methyl cellulose, ethyl cellulose, ethylhydroxyethyl cellulose and polyvinyl alcohol. Specified bifunctional compounds are epichlorhydrin, dichlorhydrin, 1, 2-3, 4-diepoxybutane, bis-epoxypropyl ether, ethylene glycol-bis-epoxypropyl ether and 1, 4-butanediol-bis-epoxypropyl ether. Specified alkalis are the hydroxides and carbonates of alkaline earth and alkali metals and quaternary ammonium compounds. The polymer may be dissolved in water, alcohols, ketones or mixtures thereof, and the dispersing medium may be an aliphatic or aromatic hydrocarbon or halogenated hydrocarbon. Stabilizing agents, e.g. polyvinyl acetate, polystyrene, polyisobutylene and cellulose acetate-butyrate may be added to the dispersing medium, and surfactants may also be present. Examples describe the reaction of (1-6, 14 and 15) dextran with epichlorhydrin, (7) dextrin with epichlorhydrin, (8) dextran with the diglycidyl ether of ethylene glycol, (9) hydroxypropyl dextran with epichlorhydrin, (10) ethyl hydroxyethyl cellulose with epichlorhydrin, (11) dextran with 1, 2-3, 4-diepoxybutane, (12) starch with 1, 3-dichloropropane-2-ol, and (13) polyvinyl alcohol with epichlorhydrin.
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