Synthesis And Application Of Quaternized Carboxymethyl Chitosan Assisted With Ultrasonic Irradiation

Chitosan has good performance such asbiodegradation, non-toxic, antibacterial activities, which are widely used in many fields. However, its function is greatly restricted in the medical treatment sanitation, composite materials, biological engineering, nowing to the fact that chitosan is insoluble in water. Therefore, people took a variety of chemical modifications of chitosan. There were many problems in traditional methods, such as toxic reagent and cleaning pollution. Through a rapid, efficient and pollution-free utrasonic-assisted chemical modification, carboxymethyl and quaternary ammonium salt group which hads hydrophilic and antibacterial were introduced into chitosan. This synthesis method of quaternary ammonium salt of carboxymethyl chitosan, offers a new ideas of chemical modification of chitosan.Carboxymethyl chitosan (CMC) was synthesized by ultrasonic irradiation with chitosan (CTS) and chloroacetic acid in NaOH-ethanol. The degree of substitution (DS) of carboxymethyl and amino retained amount (NH2%) were determined by potentiometric titration. The alkali, reaction temperature, chloroacetic acid, reaction time and solvent were studied by single factor experiment. The condition was optimized by orthogonal experiment. The optimum condition was m(NaOH)/m(CTS)=1.5(m means solid mass), m(chloroactic acid)/m(CTS)=1.5, reaction temperature for50℃, reaction time for2h, and the DS was0.56, the NH2%was87.2%. QCMC was synthesized by ultrasonic irradiation with CMC and GTA in isopropyl alcohol solution. The substitution degree of quaternary ammonium salt (QDS) was determined by AgNO3titration. In the preparation of QCMC, reaction temperature, reactant ratio, reaction time and ratio of solvent were studied. The reaction condition was optimized by the same way. The optimum condition was reaction temperature for75℃, m(GTA)/m(CMC)=4.0, reaction time for5h, the volume fraction of isopropyl alcohol for70%. The structure of the products was charcatterized by FTIR and SEM. Finally, the products were applied to antibacterial agent, dyeing, wrinkle proofing, and the performance was evaluated.The antibacterial properties of the products were evaluated against Escherichia coli and Staphylococcus aureus. The minimum inhibitory concentration (MIC) value of QCMC was8times lower than CMC. The cotton fabric which was finished by QCMC had good bacterial resistance, the antibacterial rate to Escherichia coli reached97.3%and Staphylococcus aureus99.2%. After washing for40times, the antibacterial rate still remain at about75%. X-3B type reactive dyes and4BS type direct dye were used for dyeing cotton fabric which was finished by QCMC. The QDS, finishing agent concentration, rolling rate, curing temperature and curing time were studied. The optimum condition was the concentration for0.4-0.5%, rolling rate for100%, curing temperature for100℃, curing time for4mins. In this way, the salty quantity of the cotton dyeing can be cut by half and hyperchromic effect was better than the one with traditional consumption. However, the color fastness declined slightly. The crease recovery angle of the cotton which was anti-wrinkle finished by QCMC had obviously increased. However, the disadvantage was the fabric feel became downgrade.