Cross-Linking Cotton Cellulose by the Combination of Maleic Acid and Sodium Hypophosphite. 1. Fabric Wrinkle Resistance

Durable press finishing agents used to produce wrinkle-resistant cotton garments are cross-linking agents for cotton cellulose. Polycarboxylic acids have been the promising durable press finishing agents to replace the formaldehyde-based reagents when sodium hypophosphite (NaH2PO2) was used as the catalyst. In our previous research, we found that a polycarboxylic acid esterifies cotton cellulose by first forming a five-membered cyclic anhydride as a reactive intermediate. Maleic acid (MA) is a bifunctional carboxylic acid, therefore is not able to form the second cyclic anhydride intermediate once it forms the first ester linkage with cotton. However, we discovered that MA imparted wrinkle resistance to cotton fabrics when NaH2PO2 was present, thus indicating that MA was able to cross-link cotton. Sodium hypophosphite functions as the catalyst for the esterification of cellulose by MA, and the esterification takes place at relatively low temperatures (≥130 °C). Esterification of MA forms single esterlinka...