Abstract
Lignin-free wood has been successfully developed via a two-step chemical treatment while maintaining its inherent hierarchical structure. The first step was alcoholysis which was conducted using ethylene glycol, and whose condition was optimized by monitoring the removal of lignin using infrared spectroscopy. The second step was bleaching wherein the delignification proceeded from the surface to the core of the wood block, and finally resulted in complete decolorization. Although the wood block was free from lignin and hemicellulose as approximately confirmed by the chemical composition analysis, the 3-dimensional colorless wood block was almost unaltered, even after freeze–drying. Then, multidirectional observation was performed to investigate whether the natural hierarchical structure from anatomical- to nano-level was maintained. Optical microscopy, X-ray microcomputed tomography, X-ray diffractometry, and transmission electron microscopy demonstrated that all the stages of hierarchical structure were maintained. The lignin-free wood block has great potential for novel materials that are supported by a 3-dimensional wooden architecture. The derived lignin-free wood is also a suitable specimen that can be used to understand the formation and functionality of the anatomical structure and lignified cell wall.
Highlights
Trees produce organic compounds through photosynthesis and accumulate them in the body
The alcoholysis samples were evaluated by IR spectroscopy and their lignin contents were estimated from IR spectra using a reported calibration model [21]
The value obtained from the colorless wood is smaller than that of the untreated wood, which was consistent with the values of the crystalline index. These analyses suggested that the removal of matrix components improves the orientation of the cellulose microfibril; thereby increasing the relative crystallinity
Summary
Trees produce organic compounds through photosynthesis and accumulate them in the body. An example is wood, which consists of different cell types that aid in mechanical support, water transportation, storage of nutrient sources and the synthesis of physiological active substances. The cell wall of wood is based on multi-layers that are constructed from the oriented cellulose microfibrils, which directly interact with hemicellulose and indirectly with lignin. The highly controlled hierarchical structure signifies the remarkable mechanical properties, which facilitate the support of the huge bodies. The preparation method used for the fabrication of nanofibers has been established via three approaches, namely mechanical processing using a grinder [1], aqueous counter collision [2] and a combination of chemical and mechanical treatments using 2,2,6,6-tetramethylpiperidine-1-oxyl free radical (TEMPO)-mediated oxidation [3]. Only the molecules localized on the surface of the crystal were oxidized, which resulted in the formation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
