title: Concomitant changes in viscoelastic properties and amorphous polymers during the hydrothermal treatment of hardwood and softwood.
abstract: The aim of this study was to understand how the molecular structures of amorphous polymers influence wood viscoelastic properties. Wood from oak and spruce was subjected to hydrothermal treatments at 110 or 135 degrees C. Wood rigidity, reflected by the wood storage modulus, showed different modification patterns according to the wood species or the temperature level. Because viscoelasticity is dependent on wood amorphous polymers, modifications of lignins and noncellulosic polysaccharides were examined. Hemicellulose degradation occurred only at 135 degrees C. In contrast, lignins displayed major structural alterations even at 110 degrees C. In oak lignins, the beta-O-4 bonds were extensively degraded and wood rigidity decreased dramatically during the first hours of treatment. Spruce lignins have a lower beta-O-4 content and, relative to oak, the wood rigidity decrease due to treatment was less pronounced. Wood rigidity was restored to its initial value by prolonged treatment, probably due to the formation of condensed bonds in cell wall polymers.
authors.affiliation: INRA, UMR 1092 LERFOB, ENGREF, 14 rue Girardet, F-54042 Nancy cedex, France. assor@nancy-engref.inra.fr
authors.forename: Carole
authors.initials: C
authors.lastname: Assor
authors.forename: Vincent
authors.initials: V
authors.lastname: Placet
authors.forename: Brigitte
authors.initials: B
authors.lastname: Chabbert
authors.forename: Anouck
authors.initials: A
authors.lastname: Habrant
authors.forename: Catherine
authors.initials: C
authors.lastname: Lapierre
authors.forename: Brigitte
authors.initials: B
authors.lastname: Pollet
authors.forename: Patrick
authors.initials: P
authors.lastname: Perré
mesh_terms: D001704:Biopolymers / Q000737:chemistry; D004548:Elasticity; D006358:Hot Temperature; D008031:Lignin / Q000737:chemistry*; D028222:Picea / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D029963:Quercus / Q000737:chemistry*; D014783:Viscosity; D014934:Wood / Q000737:chemistry*
chemical_list: D001704:Biopolymers; D011134:Polysaccharides; C007916:hemicellulose; D008031:Lignin