Preparing the reinforced wood via embedding cellulose nanocrystals (CNC) into delignified fast-growing wood followed by densification

• Published in: Cellulose (London) 2022-09, Vol.29 (13), p.7377-7396
• Main Authors: Luo, Honggang, Si, Rongrong, Liu, Jiaxuan, Li, Peng, Tao, Yubo, Zhao, Xin, Chen, Honglei
• Format: Article
• Language: English
• Subjects: Bioorganic Chemistry; Cellulose; Ceramics; Chemistry; Chemistry and Materials Science; Composites; Densification; Diamond pyramid hardness; Dimensional stability; Embedding; Flexural strength; Formic acid; Glass; Mechanical properties; Modulus of elasticity; Nanocrystals; Natural Materials; Organic Chemistry; Original Research; Physical Chemistry; Polymer Sciences; Poplar; Sustainable Development; Tensile strength
• ISSN: 0969-0239; 1572-882X
• DOI: 10.1007/s10570-022-04727-y

Delignified wood (DW) was prepared from fast-growing poplar wood by delignification with a formic acid–water azeotropic system. Compressed wood (CW) was then obtained through a mechanical hot-pressing process. The effects of the delignification degree on the physical strength of the CW were studied. To further promote the strength of the wood, a new approach was proposed by embedding cellulose nanocrystals (CNCs) into DW followed by densification and producing the reinforced wood (RW). Here, CNCs were embedded in the wood, leading to reduced water uptake and remarkably enhanced dimensional stability, as well as generally improved mechanical properties. The test on the mechanical properties exhibited a significant improvement for the RW in contrast with the CW with maximum vickers hardness value (HV), flexural strength, tensile strength, and tensile elastic modulus of 800, 211 MPa, 183 MPa, and 14 GPa, which were increased by 12%, 22%, 11%, and 16%, respectively, compared to the CW. These results demonstrate that CNC is a promising enhancer to intensify the strength of wood. This work not only provides an effective and green approach to producing high-performance materials from fast-growing wood, but also improves the mechanical properties of wood without the introduction of heterocomponents. Graphical abstract The delignified wood (DW) was prepared using formic acid–water azeotropic system, and the degradation degrees of wood cellulose were further investigated by controlling the degree of delignification. Based on the preparation method of the compress wood (CW), the reinforced wood (RW) was obtained by combining delignification, embedding CNC and followed by densification.