Preparation Of Chitosan Polyether Derivatives And Their Application In Salt-free Dyeing Of Cotton Fabric Reactive Dyes

Reactive dyes are the most important dyes for cotton fiber owing to their advantages of variety of hue,brilliance,low-cost and so on.In order to enhance percentage of dye utilization a lot of electrolytes are needed to add when dyeing cotton with reactive dyes.As a result,there were a large number of inorganic salts in dyeing wastewater that are very difficult to be treated.In this paper,water-soluble chitosan polyether derivative PEG-CS was successfully synthesized and applied to dye cotton with reactive dyes aiming to solve the problem of inorganic salt in dyeing wastewater.The chitosan polyether derivatives PEG-CS was synthesized by using chitosan and polyethylene glycol,then the structure of the chitosan polyether derivatives was characterized PEG-CS by IR,NMR and amino content survey.The pretreatment of cotton fabrics with PEG-CS was done by dip-pad-bake process.The effects of pretreatment to the properties of cotton fabrics were studied by SEM,amino content survey,whiteness test and tensile strength test and so on.The results showed that the whiteness and the tensile strength of the pretreated cotton fabric decrease slightly,and the antibacterial ability was obtained after pretreatment.The effects of PEG-CS concentration,pH value,impregnation temperature and baking temperature on the dyeing properties of cotton fabrics were investigated.The optimum pretreatment conditions were determined: PEG-CS concentration of 40 g/L,pH 6,immersing at 80 ? for 10 min with two-dip-two-pad process,and then drying at 80 ?,curing at 110 ? for 3 min.The results showd that the dyeing performance of the pretreated cotton fabric is closed to that of the unpretreated cotton fabric dyeing with salt,which is obviously better than that of the unpretreated cotton fabric using salt-free.The mechanism of salt-free dyeing process for pretreated cotton fabric was studied to determine the thermodynamic model as Langmuir model and the kinetic model aspseudo-second-order kinetic model.PEG-CS pretreated cotton fabric,reducing dyeing activation energy of cotton fabric,making it easier for the dyes to spread in the cotton fiber,dyeing process easier to achieve,achieving salt-free dyeing.