State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China.
Molecules. 2022 Jun 29;27(13):4167. doi: 10.3390/molecules27134167.
In this study, densified wood was prepared by hot pressing after partial lignin and hemicellulose were removed through alkaline solution cooking. The tensile strength and elastic modulus of densified wood were improved up to 398.5 MPa and 22.5 GPa as compared with the original wood, and the characterization of its supramolecular structures showed that the crystal plane spacing of the densified wood decreased, the crystallite size increased, and the maximum crystallinity (CI) of cellulose increased by 15.05%; outstandingly, the content of O(6)H⋯O(3′) intermolecular H-bonds increased by approximately one-fold at most. It was found that the intermolecular H-bond content was significantly positively correlated with the tensile strength and elastic modulus, and accordingly, their Pearson correlation coefficients were 0.952 (p < 0.01) and 0.822 (p < 0.05), respectively. This work provides a supramolecular explanation for the enhancement of tensile strength of densified wood.
在这项研究中，通过碱性溶液蒸煮去除部分木质素和半纤维素后，用热压法制备了压缩木材。与原木材相比，压缩木材的拉伸强度和弹性模量提高至 398.5 MPa 和 22.5 GPa，其超分子结构的表征表明，压缩木材的晶面间距减小，结晶尺寸增大，纤维素的最大结晶度（CI）增加了 15.05%；更显著的是，O(6)H⋯O(3′)分子间氢键的含量最多增加了近一倍。研究发现，分子间氢键含量与拉伸强度和弹性模量呈显著正相关，其 Pearson 相关系数分别为 0.952（p < 0.01）和 0.822（p < 0.05）。这项工作为压缩木材拉伸强度增强提供了超分子解释。
