Hydrothermal Transformation of Wood Cellulose Crystals into Pseudo-Orthorhombic Structure by Cocrystallization.

The ultrastructural transformation of wood cellulose crystals by hydrothermal treatment was followed by synchrotron and standard X-ray scattering experiments. When treated at 200 °C for 2 h in the presence of an excess of water, a significant sharpening of the equatorial reflections of crystalline cellulose was observed, and the average crystallite size, estimated from the X-ray line broadening, was twice as large as that of untreated wood cellulose. During the treatment, the cellulose structure was converted from the native monoclinic form of cellulose I into a pseudo-orthorhombic system, coined as cellulose I', a transformation occurring only with an excess of water, above 180 °C and after more than half an hour. In situ experiments indicated that the increase of crystallite size was likely due to cocrystallization of individual crystallites rather than to the crystallization of the amorphous domains of cellulose.

[1]  C. Gourdon,et al.  Study of solid chemical evolution in torrefaction of different biomasses through solid-state 13C cross-polarization/magic angle spinning NMR (nuclear magnetic resonance) and TGA (thermogravimetric analysis) , 2016 .

[2]  M. T. Pimenta,et al.  Cellulose co-crystallization and related phenomena occurring in hydrothermal treatment of sugarcane bagasse , 2015, Cellulose.

[3]  Jeremy C. Smith,et al.  Common processes drive the thermochemical pretreatment of lignocellulosic biomass , 2014 .

[4]  P. Langan,et al.  Structural coarsening of aspen wood by hydrothermal pretreatment monitored by small- and wide-angle scattering of X-rays and neutrons on oriented specimens , 2014, Cellulose.

[5]  Dick Sandberg,et al.  Thermo-hydro and thermo-hydro-mechanical wood processing: An opportunity for future environmentally friendly wood products , 2013 .

[6]  Helena Pereira,et al.  Wood modification by heat treatment: a review. , 2009 .

[7]  M. Pétrissans,et al.  XPS characterization of wood chemical composition after heat‐treatment , 2006 .

[8]  K. Imada,et al.  Crystallographic aspects of sub-elementary cellulose fibrils occurring in the wall of rose cells culturedin vitro , 1979, Protoplasma.

[9]  H. Militz,et al.  Chemical changes in hydrothermal treated wood: FTIR analysis of combined hydrothermal and dry heat-treated wood , 2005, Holz als Roh- und Werkstoff.

[10]  Hanne Wikberg,et al.  Characterisation of thermally modified hard- and softwoods by 13C CPMAS NMR , 2004 .

[11]  T. Viraraghavan,et al.  Treatment of pulp and paper mill wastewater--a review. , 2004, The Science of the total environment.

[12]  J. Sugiyama,et al.  Structural details of crystalline cellulose from higher plants. , 2004, Biomacromolecules.

[13]  G. Irvine.  The significance of the glass transition of lignin in thermomechanical pulping , 1985, Wood Science and Technology.

[14]  S. Maunu,et al.  Magnetic Resonance Studies of Thermally Modified Wood , 2002 .

[15]  Paul Langan,et al.  Crystal structure and hydrogen-bonding system in cellulose Ibeta from synchrotron X-ray and neutron fiber diffraction. , 2002, Journal of the American Chemical Society.

[16]  M. Wada,et al.  Lateral thermal expansion of cellulose Iβ and IIII polymorphs , 2002 .

[17]  T. Okano,et al.  Intracrystalline deuteration of native cellulose , 1999 .

[18]  J. Sugiyama,et al.  Transformation of Valonia cellulose crystals by an alkaline hydrothermal treatment , 1990 .

[19]  Hiroyuki Yamamoto,et al.  Structural changes of native cellulose crystals induced by annealing in aqueous alkaline and acidic solutions at high temperatures , 1989 .

[20]  S. R. Allen,et al.  Preparation of cellulose triacetate I from solution , 1986 .

[21]  A. Sarko,et al.  Packing analysis of carbohydrates and polysaccharides. 16. The crystal structures of celluloses IVI and IVII , 1985 .

[22]  L. Segal',et al.  Preparation of cotton cellulose IV from cotton cellulose III , 1954 .