Synthesis of a Biopolymeric Form of Vinylsulfone Dye for Dyeing Polyamide Fibers

A method for preparing a chitosan derivative modified by a vinyl-sulfone dye intended for use in dyeing of polyamide fibrous materials and its synthesis conditions are proposed. The dye added to chitosan during its precipitation by base from HOAc solution. The polymeric form of the dye was prepared in NaOH solution at pH = 8.5. The dye was simultaneously activated to form a vinyl-sulfone group and a covalent bond of the dye to deprotonated chitosan amines. The reaction product of chitosan and the dye precipitated and could be isolated from the reaction mixture. The obtained chitosan derivative could be used to dye polyamide yarn or fabric and to produce colored solutions or films. The film-forming properties of the chitosan derivative were studied.