Wood is an attractive and inherently sustainable alternative to many conventional materials. Recent research on improving wood mechanical strength emphasizes wood densifcation through the partial removal of lignin and hemicelluloses, therefore the chemical and physical properties of delignifed and densifed wood require further investigation. In this study, poplar wood samples were subjected to alkali and maleic acid hydrotropic delignifcation with varying degrees of lignin and hemicellulose removal followed by hot pressing, and the microstructure, chemical properties, and dimensional stability of densifed wood through delignifcation were evaluated. The results showed that the complete wood cell collapse was observed near the surface of all the delignifed wood blocks, as well as some micro-cracks in the cell walls. The chemical analysis indicated that delignifcation occurred mainly near the surface of the wood blocks and enhanced hydrogen bonding among the aligned cellulose fibers. For dimensional stability, the set recovery decreased with the increase in alkali dosage, and the considerable fixation of compressive deformation was obtained by a post-densification hydrothermal treatment at 180 ◦C. These results have demonstrated that the densified wood with delignification can be easily fabricated using the proposed method, and the densified wood exhibited great potential to be used as a sustainable material.
Wang, Jiajun; Liu, Junliang; Li, Jianzhang; Zhu, J. Y. 2021. Characterization of Microstructure, Chemical, and Physical Properties of Delignified and Densified Poplar Wood. Materials. 14(19): 5709. https://doi.org/10.3390/ma14195709.