Morphology of high-pressure steamed cellulose fabrics were investigated using viscose rayon fabrics.Viscose rayon fabrics were steamed at several conditions without (dry-condition) and with (wet-condition) excess water.X-ray diffractometry revealed that the total crystallinity increased with generating cellulose Ⅳ.There were no dependences whether dry- or wet-steaming in their crystal forms.It is suggested that cellulose Ⅳ is generated from paracrystalline structure in the amorphous region.Further, steamed rayons were dyed by 5 kinds of reactive dyes to analyze the amorphous region.The relative color depths (K⁄S value) compared with the control were much decreased in dry-steamed viscose rayons whereas there was a slight difference in wet-steamed ones.The excess water at steaming showed a strong role to control the structure of the amorphous region.
The chemical and physical characteristics of kenaf plants (Zhejiang No.1 cultivar from China) grown in Japan, 1996 and their cellulosic materials of different plant ages were investigated, and their bast (outer bark) was compared with their inner core. The ash content of the bast and the core of the kenaf plant of different ages decreased with the plant aged, however, the percent of the holocellulose content for the bast and the core of the kenaf plants at different ages was almost constant, similar to the kenaf plants grown in U.S.A., though its weight was different. The alpha-cellulose content, the sorption of basic dye, the degree of polymerization and the birefringence for the bast pulp fibers were higher than those for the core pulp fibers, however, the content of lignin, hot water extract, 1% NaOH solution extract and carboxyl group for the bast fibers was lower than that for the core fibers. The content of the hot water extract and 1% NaOH solution extract for the bast and core fibers increased with plant ages. However, there were only slight effects of the kenaf plant ages and the differences between the bast and the core fibers on the moisture content, the sorption of direct dye, the crystallinity, the crystallite size and the orientation. Therefore, these results indicate that kenaf (Zhejiang No.1) can be harvested at about 140-150 days in Japan.
We have investigated in the structural properties of xyloglucans extracted from four kinds of seeds(Afzelia, Detarium, Jatoba, Tamarind) by static and dynamic light scattering measurement(SLS and DLS, respectively) and small angle X-ray scattering measurement(SAXS). The primary aim of this study is to clarify the origin of differences of the physiological activities or physicochemical properties shown by the xyloglucans extracted from different sources in term of the structure of xyloglucan in aqueous solution. From the experimental results of SLS and DLS measurements, the structure of xyloglucans extracted from all seeds is essentially the same and assumes random coil conformation. SAXS measurements confirm a rod-like structure common to xyloglucans. We propose the molecular model on the basis of a blob model. The scattering function of our model (I(q)) is described as a linear sum of two term as; I(q) = A(q)²[2(exp( - Rg²q²) - 1 + Rg²q²)⁄ (Rg²q²) + cξ²q²⁄(1 + cξ²q²)], where q is the magnitude of a scattering vector, A(q) is a scattering amplitude from xyloglucan single helix, Rg is the gyration radius of xyloglucan chain, c is a constant and ξ is a diameter of a blob. The scattering function proposed here can reproduce the experimental scattering profiles in whole measured q region including SLS and SAXS measurements. The significant differences are observed in the value of ξ among xyloglucans extracted from different seeds. Since ξ corresponds to Kuhn length according to the definition of ξ, the difference in the value of ξ indicates that the flexibility of xyloglucan extracted from different seed should be different. Thus, the differences in flexibility may be one of the origins for the different physiological activities or physicochemical properties shown by the xyloglucan extracted from different sources.
Lipase from Candida antarctica was entrap-immobilized in cellulose acetate-zirconium butoxide gel fiber by the sol-gel process. Synthesis of citronellyl acetate catalyzed by the fiber-immobilized lipase was studied in hexane solution. Conversion reached 70% for citronellyl acetate after 150h, and this value was close to those of native lipase, although the reaction rate was decreased by immobilization. The activity of the immobilized lipase was decreased to about 1⁄10 that of native lipase, however the fiber-immobilized lipase retained a high level of activity after 8 repeated uses, and almost no enzyme leakage from fiber was observed. It was considered that the esterification occurred in the neighborhood of the fiber surface.
For the utilization of chitinous materials in various fields, depolymerization has been one of the important subjects. Chitin and chitosan are easily hydrolyzed with concentrated hydrochloric acid or hydrolase (chitinase, chitosanase, lysozyme), and decomposed with hydrogen peroxide and so on. Therefore, transformation of chitin and chitosan into their low molecular weight homologs usually needs some catalysts or reagents. Recently, it has been proposed that cellulosic materials are decomposed in super critical water or subcritical water. But it is too difficult to control the reaction conditions for decomposition of chitin and chitosan in supercritical water and subcritical water. Furthermore the experimental device is very expensive. In this study, the decomposition of amorphous chitin, deacetylated chitin (partially deacetylated chitin prepared under the homogeneous conditions) and amorphous chitosan was performed under the hydrothermal conditions (120-180 degrees centigrade) without any catalysts. The degradability of amorphous chitin and amorphous chitosan were compared with that of powdered chitin and chitosan which have rigid crystal structure. As the results, amorphous chitin and amorphous chitosan were decomposed under the hydrothermal conditions at 120-180 degrees Centigrade. But powdered chitin and chitosan were not almost decomposed under these conditions.
Cyclic compounds such as lactones and N-carboxy α-amino acid anhydrides (NCAs) were graft-polymerized on cellulose dissolved in tetrabutylammonium fluoride ⁄ dimethyl sulfoxide (TBAF ⁄ DMSO). ε-Caprolactone was grafted on cellulose with grafting of 64% in this solvent system. NCAs were also grafted with grafting of over 100%. It is thought that an increase in the nucleophilicity of hydroxyl groups of cellulose by the interaction with TBAF was related to this polymerization.
As an organic solid catalysis, blend films of chitosan or PEG-Chitosan derivative with PVB were prepared. The palladium adsorption ability of the blend films depended on the blend ratio (chitosan contents). The surface condition of Chitosan⁄PVB blend film was rough as a result of phase separation while that of PEG-Chitosan⁄PVB blend film was flat and homogeneity.