Comparative multifunctional properties of partially carboxymethylated cotton gauze treated by the exhaustion or pad-dry-cure methods.

A commercial cotton gauze was modified by partial carboxymethylation using both exhaustion and pad-dry-cure methods, and varying the reaction time and concentration of monochloroacetic acid and sodium hydroxide to obtain the relative degree of carboxymethylation differently. For each experiment, relative value of the degree of substitution (DS) of the modified cotton was evaluated and compared with whole blood clotting time, absorption and retention of chitosan and silver nitrate solutions, antibacterial activity, and physical properties of whiteness, bursting strength and water absorption. Carboxymethylated cotton gauze with a higher DS value showed a better absorption of chitosan and silver nitrate solutions and retained these two solutions for a much longer time than those of unmodified cotton gauze or carboxymethylated cotton gauze at a lower DS. Carboxymethylated cotton gauzes obtained from exhaustion method showed significant antibacterial activity and higher bursting strength and less affected whiteness index than those treated by pad-dry-cure method.