Study On Antibacterial Finishing Agent For Fabrics Based On Chitooligosaccharides

As the Natural alkali polysaccharide, Chitooligosaccharides (COS) has good solubility in water and broad spectrum antibacterial activity.Active groups in the constitutional unit of COS make it possible to be modified and applied in fabrics antibacterial finishing. In this research, we study on the antibacterial function of COS and quaternize it to get quaternary ammonium salt of COS which has better antibacterial function. In order to get antibacterial fabrics, we used quaternary ammonium salts of COS in antibacterial finishing. Those fabrics obtain antibacterial function. The specific research results are as following:Based on previously preliminary study, we choose COS (in molecular weight of3500) to be experimental object and set, strain, pH value as variable factors in the research of antibacterial function.0.1%,0.5%,1.0%,1.5%,2.0%and2.5%,3.0%are set as concentration gradient, the result show that COS has a better inbibitional effect against Staphylococcus aureus than Escherichia coli. A trend is that COS promote the growth of bacteria at low concentration level and restrain the growth of bacteria at high concentration level. COS at0.1%and0.5%can promote the growth of bacteria.While,the inhibition effect which transform promptly into restraining the growth of bacteria start from1.0%.And the inhibition rate increase with the rising of concentration gradually. The inhibition rate of COS at2.5%for those two strains can reach to96%at least. Compared with the test results for COS at pH value of5.5,6.0,6.5and7.0, we find that the pH value also have a effect of COS’s antibacterial function. COS show the best antibacterial result at pH6for those two strains.Further more, quaternary ammonium salts of COS (in molecular weight of800,1000,2500,3500,5000-10000and more than10000) is prepared in the80℃heat with CTA as etherifying agent in alkaline condition. Yields of the quaternized products are spreading from36.66%to50.61%, the majority of them are between40%and50%; The degree of substitution of the products decreases from51.34%to23.32%with the molecular weight of COS increasing. The quaternary ammonium salts of COS have great solubility in water which can reach to97%at least. Regardless of the solution pH value is6.0or7.0or8.0, quaternary ammonium salts of COS (in molecular weight of3500) have better antibacterial effect than COS (in molecular weight of3500). The aqueous solution of quaternary ammonium salts of COS at3%can be well decolorized by H2O2at0.6%, the best decolourization ratio is96.62%. The antibacterial result of those fabrics which are antibacterial finishing by those quaternary ammonium salts of COS shows that the quaternized product of COS (in molecular weight of2500) has the best antibacterial effect. Further more, the method of antibacterial finishing leads to different result. Decolorization weaken the function of antibacterial in a small extent. More over, the fabric which is antibacterial finished by quaternary ammonium salts of COS (in molecular weight of2500) not only has inhibitory effect on Escherichia coli, but also on Staphylococcus aureus and Bacillus subtilis (thallus).