This research was to modify cotton gauze by carboxymethylation to obtain the different degrees of substitution (DS), and then the modified cotton gauze was treated with silver agent and dried under UV irradiation at different intensities. After that, antibacterial activity, blood clotting and physical properties, e.g. bursting strength, saline absorption and whiteness, of all the modified and/or treated cotton gauzes were examined. For antibacterial results, cotton gauze and the modified cotton gauze by carboxymethylation with different DS values without treating with silver agent did not show any antibacterial activity against S. aureus and E. coli. In contrast, when the cotton gauze and the modified cotton gauze with different DS values were treated with silver agent and then exposed or not exposed to UV irradiation, they all showed good antibacterial activity. For the hemostatic or blood clotting results, carboxymethylated cotton gauze with a higher DS value showed faster blood clotting, compared to the unmodified cotton gauze. The carboxymethylated cotton gauze treated with silver agent and dried under UV irradiation at intensity either 300 or 500 mJ/cm² showed much faster blood clotting than the untreated carboxymethylated cotton gauzes. But the silver treated carboxymethylated cotton gauze exposed to UV at intensity of 700 mJ/cm² showed slower blood clotting rate than those exposed to lower intensity UV irradiation. For the bursting strength result, it could be concluded that the carboxymethylated cotton gauzes with different DS valued showed higher bursting strength than the unmodified cotton gauze. This was due to the shrinkage of the cotton gauze during the modification. For saline absorption, the carboxymethylated cotton gauze with different DS values showed better saline absorption than the unmodified cotton gauze. For the whiteness result, the unmodified cotton gauze had the highest whiteness index compared with the carboxymethylated cotton gauze and silver treated carboxymethylated cotton gauze.
