In order to investigate the influence of urea on the diffusion of polyethylenimine(PEI) into human hair,cross sectional samples of white human hair treated with PEI solutions containing urea and no urea,were prepared.In particular,a method for analyzing the diffusion behavior of PEI in the bleached human hair was developed,in which the PEI parts in the cross-sectional samples were dyed with orange orange II and the cross sections were examined at a wavelength of 487 nm (λmax of orange II) with a microspectrophotometer. The penetration of PEI into virgin hair and bleached hair clearly increased by adding 20 wt % urea in all cases despite varying PEI molecular weights (600-20000) except for the virgin hair sample treated with PEI (Mw: 20000). Also, the diffusion pattern of PEI at pH 11.1 showed Fickian type characteristics regardless of adding urea or not. The diffusion coefficient of PEI (Mw: 600), with urea added, increased 2 times in comparison with that of PEI, with urea not added. From these experiments, it was demonstrated that urea acts as a penetration accelerator for PEI.
In order to investigate the penetration of thioglycolic acid (TG) and L-cysteine (CYS), into human hair, cross-sectional samples of white human hair treated with TG and CYS were prepared. In particular, a method for analyzing the diffusion behavior of TG and CYS in human hair was developed. The TG parts and CYS parts in the cross-sectional samples were dyed with methylene blue and the cross sections were examined at a wavelength of 664 nm (λmax of methylene blue) with a microspectrophotometer. In our method, the penetration of TG in human hair clearly increased by increasing the treatment time and pH. On the other hand, the penetration of CYS in human hair almost unchanged by increasing the treatment time, and by raising pH. Also, the diffusion pattern of TG showed Fickian type characteristics. While, the diffusion pattern of CYS was Non-Fickian. By calculating the diffusion coefficient from the TG concentration profile, the apparent diffusion coefficient of TG at pH 9.0 was found to be the order of 10-9 cm2 ⁄s.
The characteristics of the running of color (“nijimi”) were quantitatively analyzed in order to elucidate the difference of natural indigo dyeing and conventional synthetic indigo dyeing. The luminance distribution curves and half-widths of the running of color were evaluated for the clothes tie-dyed with traditional natural indigo and conventional synthetic indigo. A single Gaussian function fits to the profile of the running of color produced by natural indigo reduced by fermentation, while the running of color produced by synthetic indigo prepared with sodium hydrosulfite was approximately represented by a linear sum of two Gaussian functions. The half-width profile of the running of color is in the following order : synthetic indigo ⁄ reduction method (sodium hydrosulfite) > synthetic indigo ⁄ reduction method (zinc powder) > natural indigo ⁄ reduction method (fermentation). The running of color is thus concluded to be due to the mode of indigo penetration into fiber, which depends on dyebath preparation. A critical difference in dyeing process is the speed of reduction of indigo, and could not be attributed to a small amount of impurity contained in natural indigo.
PET fabric aminolyzed initially by ethylenediamine were reacted with various sugar-lactone in order to increase their hydrophilicity. The adsorption-desorption isotherm and amount of water vapor adsorption on the fabrics were investigated concerning with aminolysis time of initial treatment and reaction times with sugar-lactones. Effects of the unit number and difference of sugar-lactones were discussed on the basis of water vapor adsorption results. Mechanical strength of PET fabrics treated here was also investigated by relating to the reaction times.
The use of hiba oil (cypress oil) as a safe and natural antimicrobial agent for textiles is on the rise. For investigating the hiba oil content of commercially available textiles, the authors developed an analytical method using thujopsene, the main ingredient of hiba oil, as an index. First, standard fabrics were prepared by fixing microcapsules filled with hiba oil. Using these fabrics, detection of thujopsene by gas chromatography mass spectrometry (GC⁄MS), extraction of thujopsene from textiles, and purification of the extract were studied, and then an analytical method for finding thujopsene on the level of ng⁄g-fabric was established. Next, in order to estimate the survivability of thujopsene in marketed products, the JIS color fastness test was performed for the hiba-oil-treated fabrics, and the survival rate of thujopsene in those fabrics was observed. It was proven that thujopsene continued to remain on the level of ng⁄g-fabric. Furthermore, analysis of thujopsene was carried out for 23 kinds of textile products labeled “processed with hiba oil or hinokitiol,” which were purchased in the past five years. As a result, thujopsene was detected in 21 products, proving that most commercially available products had been processed with hiba oil. This analytical method is considered effective in determining whether a textile product was actually processed with hiba oil.
Recently washable wool is strongly requested in order to avoid dry cleaning with chlorinated solvents such as perchloroethylene. So far wool top has been chlorinated for shrink proofing. However chlorination will be prohibited for AOX zero emission in the near future. In this article wool fibers and fabrics were treated by pulse corona discharge, followed by two kinds of enzymes, protease and keratinase. The effects of pulse corona discharge pretreatment and enzyme concentrations on the shrinkage, strength, weigh loss, surface property, and handle of the fibers were investigated. It was found that the treatment of enzyme, in particular the keratinase, after the pulse corona discharge is very effective for shrinkage, weight loss, and strength compared to the enzyme treatment alone. Scanning electron micrographs of wool surface after the treatment showed that the wool surface is treated uniformly with the enzymes, in particular the keratinase, after the pulse corona discharge, and the fibrillation of the fabrics reduces significantly. The dual treatment improves the shrinkage with little change of the strength and handle of the wool fabrics.