Kazuya Sawada

Dyeing of protein fiber in a reverse micellar system

Dyeing of protein fiber in non-aqueous media has been investigated using a reverse micellar solution as a dye bath. Conventional acid dye and direct dye solubilized in the interior of reverse micelle was satisfactorily adsorbed on silk even without the presence of auxiliary. It has become obvious that adsorption manner of anionic dye on silk in this system is similar to that in aqueous system. On the other hand, dyeing property of wool with anionic dye in a reverse micellar system was found to be lower than that of silk because of the low fiber swelling. We have found that reactive dyes also have a high ability to adsorb on fiber in a reverse micellar system. Further, fixation of reactive dye on fiber could be attained in reverse micellar system. Fixing ratio of reactive dye on fiber in this system was almost perfect.

Adsorption behavior of direct dye on cotton in non-aqueous media

Abstract Solubilization and adsorption behavior of direct dye on cotton in Aerosol-OT (AOT) revere micellar system has been investigated. Cotton fabrics could be dyed in deep shade with direct dye from reverse micellar system without adding auxiliaries. Exhaustion of dye was almost perfect and was very superior to that in aqueous system. High exhaustion of the dye in reverse micellar system was attributed to the very low bath-ratio (water–fabric ratio) compared to the conventional aqueous dyeing process. It has become obvious that adsorption of direct dye on cotton in reverse micellar system is similar to that in aqueous system and follows a Freuindrich manner.

Solubilization of ionic dyes in supercritical carbon dioxide: a basic study for dyeing fiber in non-aqueous media

Solubilization of ionic dyes in supercntical carbon dioxide has been investigated using the reverse micellar system. The reverse micelle composed of pentaethylene glycol n-octyl ether and co-surfactant provided suitable solubilizing space for ionic dyes in supercritical carbon dioxide. The effect of the co-surfactant, alcohol, on the stability of the reverse micelle was also investigated. It was found that stability of the reverse micelle and capacities to dissolve water and ionic dyes in the system are greatly dependent on the chain length of alcohol.

Modification of Polylactic Acid Fiber with Enzymatic Treatment

Enzymatic modification of polylactic acid fibers is investigated using various kinds of protease and lipase. The effects of enzymes on the hydrolysis of polylactic acid fibers is evaluated by means of fiber weight loss, fiber strength and fiber surface observation. It is found that proteases derived from Bacillus subtilis and Bacillus licheniformis had remarkable activities on polylactic acid fibers. It is also observed that the hydrolysis of polylactic acid fibers with these enzymes causes a serious drop in fiber strength, although fiber weight loss is lower.

Hydrophilic Treatment of Polyester Surfaces Using TiO2 Photocatalytic Reactions

Photocatalytic hydrophilic treatment of polyester surfaces is investigated using TiO2 as a photocatalyst. The hydrophilicity of photocatalyzed polyester film and fabric is evaluated by means of water absorbency, contact angles, and XPS analyses. Irradiation of uv light with an approximate wavelength of 352 nm produces effective photocatalytic action of TiO2 on polyester. The surface properties of photocatalyzed polyester materials significantly improve and show high hydrophilicity. XPS analysis also indicates that the photocatalytic reaction of TiO2 generates C—O and C==O groups on the surface of polyester.