| Tea polyphenols (TP) are the most important ingredients in tea, which have many good characteristics, such as antibacterial actions, deodorization and UV protection function, etc.. TP has great prospects if it is used for the dyeing and finishing of textiles and endow them natural functional properties. The researches on their sorption and mordant dyeing properties on fibers and their applications in functional finishing provide both a theoretical basis for the applications and a guideline for solving the problems during practical production. In this paper, the adsorption and mordant dyeing properties of a commercial TP on wool, silk and nylon were investigated. And the ultraviolet protection and deodorization behaviors of treated fibers were also discussed. From these basic researches, the important conclusions were drawn as follows:(1) The stability of TP in the process of dyeing and finishing: TP solution exhibited good stability under acidic condition, whereas it had comparatively poor stability in alkaline medium, and its color became darker as it was oxidated and ionizated. The speed of the oxidation became faster as the temperature of TP solution was higher. After fabrics were subjected to pad-dry-cure finishing with TP alkaline solution under high temperature, their whiteness was decreased obviously.(2) The adsorption properties of TP on silk, wool and polyamide fibers: The uptake of TP by three fibers was sensitive to the pH of its solution, which was higher in acidic buffer, and decreased with increasing pH in the range of neutral to alkaline, along with the changes in the color of treated fabrics. The effect of temperature on the adsorption of TP was different according to the nature fibers. The uptake of TP by wool increased with increasing temperature, whereas the trend of silk was opposite. The uptake of TP by nylon increased with increasing temperature, and reached to maximum at 60℃and then decreasd slightly with further increasing temperature. TP showed good building-up property for the three fibers.(3) The adsorption mechanisms of TP on silk, wool and polyamide fibers: The equilibrium value and half-time of TP adsorption on the three fibers decreased with increasing temperature, while the rate constant of adsorption increased. In comparision with Langmuir and Freundlich models, the Langmuir-Nernst model had the best fitting to all of the adsorption isotherms of TP on the three fibers at pH 4.1. The contribution of Langmuir adsorption to total adsorption decreased with increasing temperature and initial TP concentration, while the contribution of Nernst increased. The adsorption of TP on silk and polyamide fiber was exothermic, while it was endothermic on wool.(4) The mordant dyeing properties of TP for wool, silk and polyamide fibers: The colors of the fibers mordanted with ferrous sulphate and copper sulphate were violetish iron grey and bright bronze brown, the color of wool and silk was deeper than that of polyamide fiber after mordant dyeing with TP 5%owf at pH 4.1 and 90℃for 60min. The staining fastness grades of the three fibers were all 5, and the rubbing fastness grades were 4, whereas the washing and light fastness were poor. The washing and light fastness of the three fibers mordanted with copper sulphate were better than that with ferrous sulphate.(5) Functional properties of TP-treated fabrics: The ultraviolet protection and deodorization behaviors of the three fibers finished and mordanted with TP were greatly improved. The ultraviolet protection factors of dyed fibers increased obviously with increasing TP concentrations. The deodorization percent of the silk fibers can reach to 80% and 90% for ammonia and methanol, respectively. The ultraviolet protection and the deodorization behaviors of the treated fibers with mordants were better than those of the untreated fibers.
|
PDF Full Text Request