STRUCTURE OF ALKALI-SWELLING BACTERIAL CELLULOSE-BRIGHTENER COMPLEX

The structure of alkali-swelling samples for cellulose-brightener complexes, which were prepared from the Acetobacter-culture in the presence of a fluorescent brightener, was examined. The X-ray diffraction diagram of 10.4% alkali-swelling complex of the brightener content of 0.095 mol (per mol of glucose residue) did not show diffraction patterns of the Na-Cell I, but those of the complex. With the decrease of the brightener content in the complex, the formation of Na-Cell I is facilitated. The complex of the brightener content of 0.059 mol was not transformed into Na-Cell I when treated with aqueous NaOH solution below 8.2wt%, but it formed Cell II after regeneration. In the case of alkali concentration of 9.0%, however, Na-Cell I was yielded in this complex. On alkali-treatment above 10.4wt%, the formation of Na-Cell I is facilitated still more. Even when this complex was treated with an alkaline solution of 4.3 and 5.0%, production of Na-Cell I could not be confirmed althrough Cell II was yielded. It became clear from this examination that Na-Cell I is not formed during the alkali-swelling process possibly due to the cross-linking of the brightener with the cellulose sheets, although Cell II produces by the regeneration. These facts strongly suggest that in the alkali-swelling process, Cell II is only formed by the change in the conformation of the chains without significant change in the apparent shape of the microfibril. Therefore, the direction of chains in it is the same as that of chains in conventional bacterial cellulose.