Abstract
Six kinds of subtropical plant fibers taken from the Hibiscus, Pineapple, Okra, Plantain, Banana and Agave were treated with sodium hydroxide aqueous solution and liquid ammonia using a commercial plant. Cross section of the fibers were observed with microscope. Furthermore, in order to investigate the internal structure, X-ray diffraction measurement was carried out and the crystallinity of the treated fibers was obtained. From the observation of the cross section, it is clear that every fiber forms honey comb structure which consists of several to many cells, and each cell has a void in the cell. The void is comparably larger than that of the cotton lumen, and the void generally became smaller by the NaOH treatment. Furthermore, X-ray diffraction profile was measured for each fiber. Most of the fibers were changed from cellulose I to cellulose II by the NaOH treatment, whereas the fibers unchanged to cellulose III by the NH3 treatment. After the three times NH3 treatment, the cellulose III intensity increased comparably, although the cellulose I remains not a little for all samples. On the other hand, cotton fiber completely changed to the cellulose III structure by the NH3 treatment. Hereafter, it is necessary to investigate the void structure including the effect of lignin and cell-wall as a multicelluar plant fiber.
