The Cross-Linking of Cotton Cellulose by Aliphatic Dicarboxylic Acids

Abstract

Cross-linked, fibrous, cellulose diesters have been prepared using trifluoroacetic anhydride as a condensation agent for reaction of cotton fabric with eleven different, terminally-substituted, dicarboxylic acids ranging from malonic acid (C 3) to eicosane- 1,20-dicarboxylic acid (C22). In the range C2 to C5, only malonic acid reacts readily, oxalic acid being unreactive, while succinic and glutaric acids have qnly slight reactivity. With diadds from C6 to C 22, reaction occurs readily and a decrease in reactivity with chain length is observed. The reaction products are predominantly cellulose diesters containing a relatively small number of acid-ester residues. For each acid, the effect of varying the degree of cross-linking on the crease recovery, moisture regain, and water imbibition of the fabric has been determined. Crease recovery angles increase with the extent of reaction and, at equivalent degrees of cross-linking, longer chain acids effect more improvement in crease recovery than acids of shorter chain length. In geheral, both the nioisture regain and water imbibition of the fabric are decreased by esterification, the effect being greater the longer the acid chain length. Possible reasons for the observed effects are discussed.