Jiangang Qu

Light and perspiration stability of triazinylstilbene fluorescent brighteners on cotton fabrics

Light and perspiration stability of triazinylstilbene fluorescent brighteners (TFBs) for cotton fabrics was investigated and many factors affecting the photo-fading of TFBs viz. substituent groups, artificial perspirations and their components were discussed. The experimental results indicated that the TFB with morpholine groups appeared to be the most sensitive one under simultaneous exposure to light and perspiration, whereas the TFBs containing sulfonic acid and diethanolamine groups exhibited the best stability. Among the three selected standards of artificial perspiration, the alkaline Association for Textile Technical Study standard perspiration retarded the photo-fading of TFBs on cotton fabrics remarkably. Furthermore, the study on the contribution of artificial perspiration components disclosed that the sodium salt played the predominant role in decelerating the photo-reaction of TFBs on cotton fabrics, while the influence of lactic acid was usually depended on two factors: the pH value and its reducibility.

Effect of NaCl concentrations on the photodecoloration of reactive azo-dyes and their cotton dyeings

The color fastness of reactive cotton dyeings under simultaneous exposure to light and saline water, as well as light and perspiration, is one of the most important characteristics especially for summer-time sportswear. In order to illustrate the dual effects (i.e. favorable or adverse) of saline water on the photofading of reactive azo-dyes, the degradation mechanism and reaction kinetics of dye photodecoloration in the presence of various NaCl concentrations were investigated in simulated experiments. Experimental results indicated that the photodecoloration of dye solution was mainly attributed to the hydroxyl radical. Due to the quenching of the hydroxyl radical by the chloride ion, the dye photodecoloration rate decreased with low NaCl concentration (<10 g/L). Nevertheless, higher NaCl concentration (>50 g/L) was beneficial to produce reactive chlorine species, resulting in a significant increase of the photodecoloration rate. Moreover, reaction kinetic analysis demonstrated that the observed first-order rate constant for the photodecoloration of dye solution consistently increased with the increasing NaCl concentration.

Environmental impact on the light and perspiration stability of triazinylstilbene fluorescent brighteners on cotton fabrics

The fading of the triazinylstilbene fluorescent brighteners (TFBs) on cotton fabric under the conditions of exposure to sunlight and human sweat may reduce the visual quality and added value of the garment and also produce many toxic substances, which could threaten human health due to direct contact with skin. In order to investigate the light-fastness and perspiration stability of TFBs on cotton fabrics, three environmental factors of affecting the photo-fading of TFBs, i.e., ultraviolet irradiation, wet condition, and atmospheric constituents, were discussed according to AATCC standard. The results indicated that the effect of ultraviolet irradiation was more significant than its visible counterpart on the light and perspiration stability of TFBs on cotton fabrics. The light stability of TFBs was susceptible to the wet environment, and the presence of moisture accelerated the rate of photo-fading of TFBs. Furthermore, the study on the contribution of atmospheric constituents disclosed that the oxygen in the air together with the moisture of perspiration would make the synergistic effect on the fading of TFBs.