Study On Improving Levelling Property Of Modified Cotton Fabric Based On Catanionic Vesicles

The traditional dyeing method of cotton fabric with reactive dyes has some disadvantages, such as the addition of a large amount of salts to improve dyeing properties、the low usage of dyes and serious environmental pollution caused by dyeing effluent, then cationic modification process was used to improve dyeing properties. Cationic groups can be directly attached to the fabric by using chemical or physical means, charges of the surface of the modified fabric could be changed into positive which could improve the affinity of negatively charged dyes to cotton fabric.but cationic modification process also caused new issues, which is poor levelling property,so it’s very necessary to find out a method to improve levelling property.Vesicles, which are creatively used to improve levelling property, were prepared by mixing appropriate cationic surfactant(CTAB) and anionic surfactant(SDS), the special structure of vesicle could make sure that it could entrap reactive dyes into its interior’water pool’, so dye concentration outside of vesicles decreases to some extent and the initial uptaking rate decreases accordingly, which have a positive effect on dyeing properties. Firstly, TEM technology and dynamic light scattering technology were used to confirm the formation of vesicles in dyeing bath and the effects of molar ratio of the two surfactants、temperature、dye concentration、 time of ultrasonic processing and concentration of Na2CCO3on average size&PDI of vesicle were investigated. Secondly, based on K/S value and the degree of unevenness, the effects of exitence of vesicle on the traditional dyeing factors, such as initial dyeing temperature、 concentration of Na2CCO3.etc, were researched and the optimal dyeing factors were determined. Thirdly, based on K/S value and the degree of unevenness, the optimal concentration&molar ratio of the two surfactants was figured out by doing experiments. Fourthly, by testing the uptaking rate curve and dyeing properties,the mechanism of the vesicle to improve levelling property was studied. Fifthly, some other kind of reactive dyes were used to test the applicability of the vesicle and other dyeing properties were also studied.The results of experiments showed that firstly when the molar ratio of the two surfactants is5:5, the largest average vesicle size was obtained and the average size of vesicles is about290nm; the average size increases with the increase of molar ratio of cationic surfactant in anionic-rich side; the average size increases with the increase of molar ratio of anionic surfactant in cationic-rich side. Secondly, the best dyeing properties, especially the levelling property, were reached when the total concentration of the two surfactants is4×10-3mol/L and the molar ratio is6:4,the levelling property improved a lot. Meanwhile the mechanism of the vesicle to improve levelling property was investigated by testing uptaking rate curve、dyeing properties、mechanical properties and the variation of the average size of vesicles. Thirdly, the applicability of the vesicle to other reactive dyes was studied by testing dyeing properties of other dyes, the results showed that the vesicle can be applicable for other reactive dyes as well.