The Study On Betaine Modified Cotton Fabric And Their Antibacterial Performances

The industrial finishing processes of antibacterial fabrics are relatively complex.They not only need toxic chemicals,but also generate a large amount of rinsing wastewater.To develop green finishing technology with a reduced pollution,many attentions have been paid to the naturally occurred antibacterial agents having low toxicity.Betaine(Bet)is a quaternary ammonium alkaloid,non-toxic and harmless,and has rich resources.This research studies the antibacterial properties of betaine modified cotton fabric.In the first part,betaine modified cotton fabric(Bet-Co)was prepared by esterification reaction of the carboxyl functional group of Bet and the hydroxyl groups of cellulose molecules on cotton fiber surface,and the quaternary ammonium groups grafted on the surface of the cotton fiber impart antibacterial function to the cotton fabric.The finishing process of the antibacterial cotton fabrics has two steps:padding cotton fabrics with a betaine solution and heating at 180? for 5 minutes.By analyses such as infrared spectrum,X-ray diffraction spectrum,and X-ray photoelectron spectroscopy,it was confirmed that a certain number of Bet molecules were grafted onto the fiber surface of cotton fabric.Antibacterial experiments and anti-protein adsorption tests verified that the modified cotton fabric has both good antibacterial and anti-protein adsorption functions.In addition,cytotoxicity assess proved that the modified cotton fabric are safe for human skin,but wearing comfort properties like water absorbability,water transmission rate,softness and tensile strength of the cotton fabric show insignificant different from the original cotton fabric.The second part aims to further improve the antibacterial effect of Bet by a synergistic effect with carboxymethyl chitosan(CMC).We first prepared carboxymethyl chitosan modified cotton fabric(CMC-Co)by esterification of CMC with the cellulose molecules on fiber surface,then Bet molecules were grafted onto the modified cotton fabric by a pad-dry-cure method similar to the first part to obtain the antibacterial cotton fabric,CMC-Bet-Co.This CMC-Bet-Co fabric was proved to be of excellent antibacterial effect without compromise on the desired cotton features such as water absorbability,water transmission rate,softness and tensile strength.Using Bet,a naturally occurred product,as an antibacterial agent to prepare antibacterial cotton fabrics,the safe risk for users,discharges of wastewater,and impacts on the environment from the traditional dyeing and finishing textile industry can be relieved.This study can provide new research ideas and good examples for the manufacture of antibacterial textiles.