Study On Surface Modification Method Of Cotton Fiber Via Esterification And Its Application For Fabricating Functional Fabrics

Nowadays,people desire textiles with developed functions,especially for the multifunctional cotton fabrics.The cotton fabrics with single function are gradually replaced by multifunctional ones.The cotton fabrics combining antibacterial,washable,conductive and more other functions have a great potential market demand.The first work of this thesis attempts to establish a methodology using esterification reaction on the fiber surfaces to impart cotton fabric with antibacterial function,exploring a technology that is suitable to the simple dip-pad-dry process.The cotton fabric is immersed in an aqueous solution of oligomeric polyacrylic acid(PAA),heated at 180°C for 5 min to esterify the hydroxyl groups of cellulose on the cotton fiber surfaces.Then silver nanoparticles(Ag NPs)are synthesized on the resulting cotton fabric via an in-situ reduction reaction.The PAA oligomers grafted on the cotton fibers show positive effect on enhancing affinity of the Ag NPs to the fibers,and improving the dispersion of Ag NPs on the fiber surfaces.Therefore,the prepared modified cotton fabrics can achieve good antibacterial effect and washing resistance by loading a very small amount of silver(about 1/10 of reported dosage)).Antibacteriostatic rate(BR)of the treated fabric against both Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli)after 50 simulated washing cycles is more than90%.Cytotoxicity tests cleared that the antibacterial fabric is safe to human skin.Moreover,important cotton properties such as breathability,water absorption and flexibility were largely preserved when comparing with the original cotton fabrics.This thesis further demonstrates a simple strategy for preparing conductive cotton fabrics via the esterification on fiber surfaces.First,the hydroxyl groups of the cellulose on the fiber surfaces is esterified using glycocyamine,resulting in a cationic surface of guanidine group.The resulting fabric is further immersed into a DNA aqueous solution,leading the DNA chains fixed on the fiber surfaces by ionic bonds,then an in-situ polymerization of aniline is carried out on the DNA templates to prepare conductive cotton fabric.By evaluating the electrical conductivity and caloricity of the fabric,it is found that the conductive fabric has excellent electrical conductivity(142 Ω/sq)and anti-deformation property.Even experienced 4000 bending and 4500 torsion fatigue tests,the fabric surface conductivity reduced only by 60%,indicating the remarkable anti-deformation stability.Moreover,the fabric temperature rises to 37.8℃ by charging a voltage of 6V for 30 seconds,and the heating capability keeps stable after 5000 bending cycles.After comparing and summarizing the effects of various factors on the conductive fabric during the preparation process,it can be concluded that DNA molecules is the most important factor in the anti-deformation property of the conductive fabric.