Crosslinking of rayon fibers with co-oligomer of maleic acid and methylacrylate and their responses to water

A co-oligomer of maleic acid and methylacrylate (COMM) was used to crosslink rayon fibers. It was shown to be a more effective polycarboxylic crosslinking agent than 1,2,3,4-butanetetracarboxylic acid (BTCA) as judged by the enhancement of mechanical properties. Similar to BTCA, COMM formed a five-membered cyclic anhydride intermediate by anhydridisation of a carboxyl group pair, and subsequently the anhydride intermediate reacted with cellulose in the amorphous regions to form an ester linkage. Apparent crosslinking degree (ACD) of the crosslinked rayon fibers was proposed to quantify the crosslinking efficiency of COMM. The water sorption isotherm was not strongly affected by crosslinking whereas water retention after swelling in excess water decreased with the degree of crosslinking.