Synthesis And Antibacterial Activity Of Groups Chitosan Derivatives With Dual-Functional Groups

The chemical modification of chitosan was studied, to obtain chitosan derivatives bearing dual-functional groups, the optimal synthesis conditions were explored. The structures of products were characterized. The finishing conditions and antimicrobial properties of the cotton fabrics, which treated with the obtained chitosan derivatives, were discussed.Through the schiff reaction of amino groups, quaternization of C-6 hydroxyl group and ethylation, three types of chitosan derivatives with dual-functional groups, O-quaternized-N-chitosan Schiff base (O-HTCCS), O-quaternized-N-benzyl chitosan (O-HT CC-Bn), O-quaternized-N-Diethyl-benzyl ammonium chitosan chloride (O-HTCC-DEBn) were obtained. The impact factors on the quaternization of C-6 hydroxyl groups was discussed by the orthogonal test. The optimal conditions for synthetic of O-HTCCS were as follows: chitosan schiff base / GTMAc (mol/mol) was 1:5; reaction time was 24h; reaction temperature was at 70℃. Under these conditions, the yield was 78.5 %, and the degree of quaternization was 89.7 %. Water-solublility of chitosan derivatives was tested and resulets showed that O-HTCC-DEBn was best, it soluble in water at rt, O-HTCC-Bn was the second, it can soluble under tepidity condition, while O-HTCCS was a little worse, it can be soluble in water at 50℃. In addition, the water-solublility of O-HTCCS increases with increase of quaternization degree. The solubility of the three derivatives in organic solvents is still poor.Cotton fabrics were finished with synthesized chitosan derivatives by cross-linking agent. The fiber's adsorptive capacity of chitosan derivatives was tested through the fixation of acid dyes of treated fabrics. The effects of finishing process, amount of cross-linking agent, concentration of finishing agents and cure conditions on the adsorbance of dye, were all investigated. The best finishing results cameout under the following conditions: finished with citric acid two-bath process, 14 % citric acid, 3 % O-HTCCS and cured at 140℃for 3 min.Antibacterial test of finished fabrics show that three kinds of derivatives all revealed strong antibacterial activity against E.coli and S.aureus. The inhibiting efficiency of E.coli and S.aureus were all close to 100 %. Especially for the O-HTCCS treated samples, the antibacterial activity against S.aureus reached 100%. Durability test found that finished fabrics with O-HTCCS maintained about 75% of the antibacterial rate, after 20 consecutive home launderings.