Swelling and dissolution of cellulose in amine oxide/water systems

摘要: The swelling behavior and the dissolution process of various cellulosic fibers, both native regenerated, in N-methylmorpholine N-oxide (MMNO), dimethylethanolamine (DMEAO), mixtures thereof were studied presence amounts water. principal tools this investigation optical microscopy wide-angle X-ray scattering (WAXS). two amine oxides could either dissolve or only swell cellulose, depending on water concentration, which was found to be critical importance. Three domains concentration important. When a few percent present, cellulose such as ramie, cotton, rayon, etc., dissolved readily without noticeable oxide/water system brought above its melting point. At relatively high (e.g., 18% w/w for MMNO), fibers exhibited an extensive (up sevenfold increase fiber diameter) but no dissolution. In that case, removal agent showed initial converted into unoriented II structure. With still greater content 20% more MMNO 15% DMEAO), partial observed, recovered their oriented I structure after ofmore » medium. investigations provided evidence forthe formation cellulose/solvent complexes swollen fibers. A large decrease (110) reflection WAXS patterns gels. This is interpreted due preferential cleavage crystals along corresponding plane when are exposed forces systems. 29 references, 13 figures, 1 table.« less