Application Of Silver Salt On Antibacterial Finishing Of Textile By Sol-Gel Technique

The inorganic silver salt has widely used as anti-bacterial agent in recent years.In this paper, the sol-gel technique had been used for anti-bacterial finishing of cotton fabric.Through physical adsorption,Silver thiosulphate complex（STS） was imported into cotton fabric.The application of STS on cotton fabric as anti-bacterial agent had been studied.The research included three parts.The preparation and stabilization of the modification of silicate sol were first studied.The silicate gel layer formed on fabric could adsorb anti-bacterial agent to give the anti-bacterial function on cotton textile.The smaller of the size of particles in silicate sol is,the SiO₂ particles could more easily permeate into fabric.The addition of polyethylene glycol（PEG） into silicate sol could reduce the size and distribution range of particles in silicate sol at appropriate pH range.When 0.2%PEG400 was added into 5%silicate solution in pH10.6,the size of silicate sol could be reduced to less than 100nm.The second part studied the treatment process of anti-bacterial agent and the color change of this anti-bacterial cotton.The silver salt anti-bacterial agent（such as silver nitrate） could lead to the color change of fabric.Silver thiosulphate complex（STS） had been used as anti-bacterial agent in this paper in order to improve the brightness stability.The results showed that good antibacterial performance could be obtained through dipping cotton fabric into silver nitrate solution firstly and then sodium thiosulfate solution.The result showed that the antibacterial ratio to coliform is still more than 99%even washed for 20 times.The anti-bacterial cotton fabric could have satisfactory brightness stability after solarization for 12h.The determination of concentration of silver thiosulphate complex（STS） was also studied due to no report about this kind of ion.Different methods,such as potassium permanganate spectrophotometric method,ammonium molybdate spectrophotometric method and diphenylthiocarbazone-CCl₄ liquid-liquid extraction spectrophotometric method,had been used to determinate the concentration of STS.The first and second method of oxidation-deoxidization reactions could not be used for the determination of thionate ion,which were not easy to control due to the slowly release of thionate ion from the complex.The diphenylthiocarbazone-CCl₄ liquid-liquid extraction spectrophotometric method could be used in this experiment since a stable complex could form by complexation of diphenylthiocarbazone with silver in CCl₄ solution.