Method for modifying a yarn or textile fabric

A method for modifying a textile yarn or textile fabric by immobilising on said yarn or fabric a cyclodextrin derivative comprising a group reactive towards organophosphorus agents,

• said cyclodextrin derivative having the following formula (I):
• in which:
• n is 1, 2 or 3;
• Y is a linker selected from the following groups:
• —O—(CH2)m—, m being 1, 2, or 3;
• —NH—C(═O)—(CH2)p—, p being 0, 1, or 2;
• —CONH—(CH2)q—, q being 1, 2, or 3;
• —C(═O)O—(CH2)r—, r being 1, 2, or 3;
• —OC(═O)—(CH2)s—, s being 0, 1, or 2;
• and
• —O—CH2—C≡C—(CH2)t—, t being 1, 2, or 3;
• Nu has the following formula (II):
• in which:
• either R is COOH and X is C—I═O, wherein a corresponding functional group exists in two forms in equilibrium in an aqueous solution as follows:
• such that this corresponding functional group is represented by the following formula (III):
• or R is CH═N—OH and X is N or N+—(C1-C6)alkyl,
• or R is CO—NH—OH and X is N,
• said method comprising a step (a) of contacting said textile yarn or fabric with the cyclodextrin derivative of formula (I) and with a bridging agent selected from the group consisting of 1,2,3,4-butanetetracarboxylic acid, succinic acid, citric acid, oxalic acid and mixtures thereof,
• to obtain a textile yarn or fabric on which the cyclodextrin derivative of formula (I) is immobilised.