Preparation Of Amphoteric Grafted Chitosan And Its Long-term Antibacterial Finishing On Wool Fabric

With the severe situation of world environmental health and the improvement of people’s health awareness,people’s demand for antibacterial properties of daily life articles is gradually increasing,especially textiles.In the preparation process of antibacterial textiles,antibacterial agents should not only have long-term antibacterial effect,but also be non-toxic to the organism and harmless to the environment to ensure safety,while not affecting the wearability of textiles in the process of treatment.Based on these,a new type of antibacterial agent was synthesized in the paper,which took the natural biomass-based antibacterial agent chitosan as raw materials and modified it to enhance its water solubility and antibacterial properties.Firstly,reactive cationic antibacterial monomer was synthesized,and zwitterionic grafted chitosan CMCS-g-PDHBr with both anion and cationic groups was prepared by carboxymethylation of chitosan and free radical graft copolymer in"one pot"method.The citric acid,as a crosslinking agent,and CMCS-g-PDHBr was added to the wool fabric by two dipping and two rolling process to give the wool fabric a long-term antibacterial effect and retain the wear performance of the fabric.The research results are as follows:The reaction antibacterial monomer DHBr was synthesized from dimethylaminoethyl acrylate and bromoheptane.FTIR and ¹³C-NMR showed that the target product was successfully synthesized.The MIC values of DHBr against E.coli and S.aureus were 0.05mg/m L and 0.04mg/m L,respectively.The zwitterionic chitosan derivative CMCS-g-PDHBr was prepared by one pot method by carboxymethylation of chitosan and free radical graft copolymerization of antibacterial monomer.Taking CMCS-g-PDHBr graft rate as dependent variable,The optimum reaction condition was obtained based on the single factor and orthogonal experiments:mass ratio of DHBr to CS of 4:5,temperature of 45℃,initiator concentration of 0.03mol/L,initiator mole ratio of 3:1,respectively.FTIR,¹³C-NMR,XRD and SEM showed that CMCS-g-PDHBr was successfully synthesized.Solubility test showed that CMCS-g-PDHBr was soluble in a larger p H range,and Zeta potential test showed that its isoelectric point was 7.04.The MIC to E.coli and S.aureus were 2mg/m L and 1.5mg/m L,respectively.CCK8 assay showed that CMCS-g-PDHBr had low cytotoxicity and was an ideal antibacterial agent.By using citric acid as a crosslinking agent,the antibacterial agent CMCS-g-PDHBr was treated into wool fabric via"two dipping and two rolling"processes.Taking the antibacterial effect as the index,the optimal process was obtained based on single factor experiments:concentration of CMCS-g-PDHBr was 0.5%,concentration of citric acid of 0.3%,soaking temperature of 45℃,pre-baking temperature of 80℃,baking temperature of 120℃,respectively.The results of SEM and FTIR showed that CMCS-g-PDHBr finished wool fabric successfully.The results showed that the antibacterial rate against E.coli and S.aureus of CMCS-g-PDHBr treated wool fabric was 100%,and had a long-term antibacterial effect.The material properties of antibacterial wool are retained,the air permeability is slightly decreased,the moisture permeability is improved,and the thermal stability is not significantly changed.