Mordant-free dyeing of sheep wool using apple bark extraction : Observation of the adsorption state and quantitative analysis of the dyeing dynamics of natural dyes(Natural Science)

We studied the adsorption process of the dye, which was extracted from apple bark, into wool serge without mordant, and interpreted the dynamics of the dyeing. The result of pH dependence of the UV-vis spectra showed that the dye was assigned to polyphenols, and that it adsorbed on wool fibre as phenolate-anion-like species. The concentration of dye molecules which distributed to ca two micrometers from the wool fibre surface was under the detection sensitivity of the ATR method, according to the comparison of IR spectra between undyed wool and the dyed one. The result of the time dependence of the dyeing process showed that the dyeing reaction constants and the equilibrium adsorption concentration increased over the double with an increase in dyeing temperature from 55℃ to 80℃. The adsorption isotherm plot of the dyeing showed that the number of dye-sites increased with an increase in dyeing temperature. We propose the quantitative analysis method of the dyeing using natural dyes.Article信州大学教育学部紀要. 116: 193-201 (2005)departmental bulletin pape