Synthesis of a Quaternary Ammonium Derivative of Chitosan and Its Application to a Cotton Antimicrobial Finish

A quaternary ammonium derivative of chitosan, N-(2-hydroxy)propyl-3-trimethy lammonium chitosan chloride (HTCC), is synthesized as an antimicrobial finish for cotton using a reaction of glycidyltrimethylammonium chloride (GTMAC) and chitosan. Results indicate that the degree of substitution (DS) in HTCC calculated by chloride content is a function of the reaction temperature and mole ratio of GTMAC and NH ₂ in chitosan. Excess amounts of GTMAC are generally needed to obtain a water-soluble fraction of HTCC. A minimum DS of 0.6 is needed to yield water-soluble HTCC. Syn thesized HTCC is analyzed by FTIR, H ¹ -NMR, TGA, and x-ray diffraction techniques. At very low concentrations, such as 0.025% owb, HTCC shows superior antimicrobial ac tivity indicated by an almost 100% bacterial reduction, whereas 1 % owb chitosan shows only 30% bacterial reduction. Since HTCC is soluble in water, we have examined several methods to increase the laundering durability of cotton treated with HTCC. Among them, application of a nonionic binder considerably improves the laundering durability of HTCC-treated cotton.