The Property Of Oxygen Bleaching Activator TAED And Its Application In Bleaching

Hydrogen peroxide/tetraacetylethylennedianime(TAED) activating system achieves the efficient oxidative bleaching under low temperature, and low-temperature oxygen bleaching agent TAED has only been produced commercially, peracetic exerts textile bleaching effect which is the formation of activating reaction between TAED and hydrogen peroxide. So the systematic study of the performances of TAED and its application in related textile bleaching will provide a theoretical supervise for auxiliary enterprises to improve its performance and guide the actual bleaching processing.In the research of this paper, the structures of several TAED products were characterized by WAXD, FT-IR, and UV. The solubility of a high purity TAED powder was determined. The stability of TAED in the different temperature and pH values as well as the hydrolysis of TAED and its activation to hydrogen peroxide under alkaline condition were researched by spectral analysis.The key factors of the hydrogen peroxide/TAED activating system applied in the bleach of cotton, bamboo viscose/cotton blends and modal/AN-g-caien blends were determined. The results of these researches listed as follows:(1) The solubility of a high purity TAED powder (content 99%) is 17g/L at 70℃. The bleaching effect was irrespective of TAED formulation. The stability of TAED was good in the acidic solution. TAED was easily hydrolysed by alkali, and the degree of its hydrolysis became larger with the increased alkali concentration. The rate of activating reaction between TAED and hydrogen peroxide was fast in the weakly alkaline condition, so the prophase of the reaction should be controlled slowly in order to improve the utilization of TAED. (2) In the hydrogen peroxide/TAED activating bleaching system of cotton and bamboo viscose/cotton blends, the most important factors of bleaching effect were found to be the amount of hydrogen peroxide and its molar ratio to TAED. The scouring and bleaching one-step process at nearly neutral medium as well as the high whiteness and good wettability of bleached fabrics were achieved, if the bleaching was performed at 70℃for 30min under the conditions of 30% H₂O₂ 4⁷g/L, H₂O₂/TAED mol ratio 2:0.75¹, sodium carbonate 1²g/L.(3) In the activating bleaching system of modal/AN-g-Caein blends, the most important factors of bleaching effect were found to be the amount of sodium carbonate and hydrogen peroxide/TAED. Compared with the conventional alkaline bleach, the weak acid conditions provided by the activating system markedly reduced the loss of caein in AN-g-Caein. However the oxidation of amino groups in caein induced the decrease in the dyeability of bleached fabrics with acid and neutral dye.