By utilizing vanillin to form Schiff bases with the C2 amino group of chitosan in order to protect the amino group,and then grafting 2,3-epoxypropyl trimethylammonium chloride(GTA)quaternary ammonium salt on C6 site in chitosan,O-quaternary ammonium chitosan(O-HACC)was synthesized after removing Schiff-base from the solution of dilute HCl and ethanol.Subsequently partial groups at C2 and C3 positions in O-HACC were selectively oxidized into dialdehyde groups with KIO4,so the O-quaternary ammonium salt-oxidized chitosan(O-HAOCC)was finally obtained,which possessed the fiber-reactive and dual antibacterial activities,and then grafted with cotton fabric to obtain O-HAOCC modified cotton fabric.The characterizations of Fourier-transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),proton nuclear magnetic resonance spectroscopy(1H NMR),scanning electron microscopy(SEM)and differential scanning calorimetry(DSC)displayed that,major amino groups were retained while introducing the structure of quaternary ammonium salt and active dialdehyde groups in O-HAOCC molecules,and the crystal morphology was destroyed,as well as thermal stability reduced.Furthermore,the test results showed that the water solubility of O-HAOCC oxidized for 3 h achieved 23.7 g/100 mL,and the 2,2'-azinobis(3-ethylbenzo-thiazoline-6-sulfonic acid)diamine salt(ABTS)radical scavenging rate after 40 min was 65.58%.The graft ratio of O-HAOCC modified cotton fabric arrived at 9.84%when the mass fraction of O-HAOCC was 2%,the reaction time was 2 h and the graft temperature was 80℃.The antibacterial rate of modified cotton fabrics against Staphylococcus aureus and Escherichia coli was 98.63%and 93.38%,respectively,furthermore the antibacterial rate maintained above 90.75%after 50 times of washing,manifesting extensive application in antibacterial textile and garment,home textile and medical and sanitary products,etc.
关键词
季铵盐壳聚糖/香草醛/选择性氧化/结构性能/抗菌织物
Key words
Quaternary ammonium salt chitosan/Vanillin/Selective oxidation/Structure and property/Antibacte-rial fabric