ABSTRACT:Specific interactions between cellulose and hydrophobic solvents were studied using highly planar oriented cellophane and X-Ray diffraction analysis. The planar orientation index ( f kð1 1 10Þ ) was found to decrease considerably by hydrophobic solvent treatment. Toluene, a hydrophobic solvent, caused decrease at specific concentration in f kð1 1 10Þ at toluene content of ca. 20-40 wt % to cellulose with keeping its crystallinity and the degree of intermolecular hydrogen bonding. The molecular sheet-like assembly (corresponding to sh relaxation), proposed previously by Yamane et al. [Polym. J., 28, 1039(1996] may be a plausible explanation of the result. Analysis of X-Ray diffraction intensity of cellulose/solvent systems might give some information on the extent of interaction between cellulose and solvent in question. However, whether such change in specific solvent concentration with orientation index is related to the long-periodicity change, as observed for water, should be studied. [DOI 10.1295/polymj.36.478] KEY WORDS Cellulose / Planar Orientation / Hydrophobic Solvent / X-Ray Diffraction / Crystal Plane / Molecular Sheet / Water causes a sudden long-periodicity change of regenerated cellulose fiber at ca. 30 wt %.1 Such concentration-specific structural change for natural cellulose was also observed indirectly by T 1 measurement of water in cellulose.2 Ago et al. also showed that amorphous cellulose is reorganized to cellulose II crystals by ball-milling preferentially when water content is ca. 30%.3 Hydrophobic solvents such as hexane, toluene and dichloromethane are captured in cellulose domain even after some severe vacuum drying.4 Such nonpolar solvents have been frequently utilized as heterogeneous reaction media for converting cellulose to its derivatives. Marchenko et al.5 studied structural changes in cellulose (wood pulp, cotton) caused by dichloromethane (DCM) by using X-Ray diffraction, IR, and SEM analyses, and noted intrafibrillar swelling, no practical change in X-Ray crystallinity, some changes in CH 2 vibration (IR; 1380 cm À1 ) absorption, a loosening of cellulose structure by penetration of DCM into nonordered region and formation of rigid cellulose structure after removal of DCM. Such studies are quite important, although not much research seems to have been done. Recently, we have reported the mechanical molecular alloy preparation of cellulose/thermoplastics in the presence of such a nonpolar solvent.6,7 The method is based on the facts that 1) such solvents lowers the temperature (a kind of T g ) considerably, representing sh relaxation mode (inner phase relaxation of cellulose main chains on molecular sheet-like assembly 8,9on tan -T curves, from ca. 170 C to less than room temperature 9 and 2) such solvents might induce concentration-specific mobilization of cellulose chains. Therefore, more detailed studies on the interaction of cellulose with nonpolar solvents are immediately required. Recently, a concentration-specific interaction between cellulose with hydrophobic ...

Several composites of bacterial cellulose and inorganic compound were obtained by cultivation of a noble bacterial cellulose producing Entero-bactor species under the presence of inorganic substances. It was found that the presence of non-soluble inorganic substances gave considerable influence on bacterial cellulose production itself. Observation of SEM and X-ray diffraction patterns of the obtained composites revealed that cellulose microfibril became narrower and thinner, and the degree of the planner orientation of the microfibril became larger in the some compounds with specific inorganic material species. Above such results might open a new way to prepare the new materials with noble and potential functions.(