Assor Carole, Placet Vincent, Chabbert Brigitte, Habrant Anouck, Lapierre Catherine, Pollet Brigitte, Perré Patrick
INRA, UMR 1092 LERFOB, ENGREF, 14 rue Girardet, F-54042 Nancy cedex, France.
J Agric Food Chem. 2009 Aug 12;57(15):6830-7. doi: 10.1021/jf901373s.
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.
本研究的目的是了解无定形聚合物的分子结构如何影响木材的粘弹性。将橡木和云杉木在110或135摄氏度下进行水热处理。由木材储能模量反映的木材刚度，根据木材种类或温度水平呈现出不同的变化模式。由于粘弹性取决于木材无定形聚合物，因此对木质素和非纤维素多糖的变化进行了研究。半纤维素降解仅发生在135摄氏度时。相比之下，即使在110摄氏度时，木质素也显示出主要的结构变化。在橡木木质素中，β-O-4键被大量降解，并且在处理的最初几个小时内木材刚度急剧下降。云杉木木质素的β-O-4含量较低，相对于橡木，处理导致的木材刚度下降不太明显。通过延长处理，木材刚度恢复到其初始值，这可能是由于细胞壁聚合物中形成了缩合键。
