Takeru Ohe

Chemical Introduction of Sugars onto PET Fabrics Using Diamine and Cyanuric Chloride

Polyethylene terephthalate (PET) fibers having reactive cyanuric groups were synthesized by reaction of cyanuric chloride with PET fibers aminolyzed by ethylenediamine. In subsequent reaction with D-glucose, the hygroscopicity of PET fibers was further enhanced. The mechanical strength of PET fibers was not influenced by the reactions other than aminolysis, but their dyeing abilities were greatly affected by each of the reactions. When various sugars other than D-glucose were examined, it was found that reaction with D-maltose imparted the highest hygroscopicity to PET fibers. Interestingly, nonreducing sugars of low reactivity such as D-trehalose could also be made to react with PET fibers using the same methods.

Coloration of polyamide fibers in an aqueous solution by Maillard reaction

Polyamide fibers, such as wool, silk, and nylon fibers, could be colored in an aqueous solution containing reducing sugars, similar to the coloration of various foods containing both protein and reducing sugars, by the Maillard reaction. For example, the color of the wool fibers reacted with xylose, one of the reducing sugars, was changed in succession from beige to yellow to orange with the reaction time. Further examination of the reaction conditions, such as reaction time, reaction temperature, types of reducing sugar and their concentration, enabled deep coloration, such as brown. Furthermore, the properties of the colored fibers, such as mechanical strength and hygroscopicity, were also investigated here.

Coloration of different textile fibers using glycerol oxides

We have investigated new applications of the Maillard reaction in textile industries as an alternative to conventional dyeing methods. Our previous paper indicated that only textile fibers having amino groups, such as wool, silk, and nylon fibers, were colored by chemical reactions with reducing sugars, such as d-glucose and d-xylose, but these coloration reactions were very slow compared with conventional dyeing methods. Recently, we obtained important results from our preliminary studies that trioses, such as glyceraldehyde, imparted deeper coloration to the textile fibers than other reducing sugars. However, these trioses are too expensive to be used as raw colorant materials for the textile industry. In this paper, the coloration reactions of the textile fibers having amino groups with glycerol oxides, which were obtained from low-cost glycerol by the Fenton reaction, were investigated. Interestingly, the obtained fibers were observed to be more deeply colored by the glycerol oxides than the reducing sugars mentioned above, including glyceraldehyde. Furthermore, when the wool fibers were heated in neutral or basic solutions containing glycerol oxides, the color of the fibers quickly became dark brown or almost black.

Effect of Surfactant Pretreatment on Enzymatic Hydrolysis of Wool Fiber

Abstract: The effect of surfactant pretreatment on enzymatic hydrolysis of a wool substrate was studied. It was found that surfactant pretreatment with anionic surfactants accelerated the enzymatic hydrolysis of a wool substrate by protease. Below the critical micelle concentration, the dissolution rate of the wool fabric increased with the amount of surfactant adsorbed. In particular, alkaline fatty acid surfactants strongly accelerated the enzymatic hydrolysis of wool. They caused extensive damage to the wool surface with the elution of scales and a change in the internal fiber structure. This damage aids enzyme action on the inside of the wool, thus resulting in an increased dissolution rate.