Wu Yan, Zhou Jichun, Huang Qiongtao, Yang Feng, Wang Yajing, Wang Jing
College of Furnishings and Industrial Design, Nanjing Forestry University, Nanjing 210037, China.
Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China.
Polymers (Basel). 2020 Mar 15;12(3):661. doi: 10.3390/polym12030661.
Two common tree species of Betula alnoides () and New Zealand pine () were selected as the raw materials to prepare for the partially transparent wood (TW) in this study. Although the sample is transparent in a broad sense, it has color and pattern, so it is not absolutely colorless and transparent, and is therefore called partially transparent. For ease of interpretation, the following "partially transparent wood" is referred to as "transparent wood (TW)". The wood template (FW) was prepared by removing part of the lignin with the acid delignification method, and then the transparent wood was obtained by impregnating the wood template with a refractive-index-matched resin. The goal of this study is to achieve transparency of the wood (the light transmittance of the prepared transparent wood should be improved as much as possible) by exploring the partial delignification process of different tree species on the basis of retaining the aesthetics, texture and mechanical strength of the original wood. Therefore, in the process of removing partial lignin by the acid delignification method, the orthogonal test method was used to explore the better process conditions for the preparation of transparent wood. The tests of color difference, light transmittance, porosity, microstructure, chemical groups, mechanical strength were carried out on the wood templates and transparent wood under different experimental conditions. In addition, through the three major elements (lignin, cellulose, hemicellulose) test and orthogonal range analysis method, the influence of each process factor on the lignin removal of each tree species was obtained. It was finally obtained that the two tree species acquired the highest light transmittance at the experimental level 9 (process parameters: NaClO concentration 1wt%, 90 °C, 1.5 h); and the transparent wood retained most of the color and texture of the original wood under partial delignification up to 4.84-11.07%, while the mechanical strength with 57.76% improved and light transmittance with 14.14% higher than these properties of the original wood at most. In addition, the wood template and resin have a good synergy effect from multifaceted analysis, which showed that this kind of transparent wood has the potential to become the functional decorative material.
本研究选择了两种常见树种，即西南桦（Betula alnoides）和新西兰松，作为制备部分透明木材（TW）的原材料。虽然该样品在广义上是透明的，但它具有颜色和图案，并非绝对无色透明，因此被称为部分透明。为便于阐述，以下将“部分透明木材”简称为“透明木材（TW）”。通过酸脱木质素法去除部分木质素制备木材模板（FW），然后用折射率匹配的树脂浸渍木材模板得到透明木材。本研究的目标是在保留原木美观、纹理和机械强度的基础上，通过探索不同树种的部分脱木质素过程，实现木材的透明化（制备的透明木材透光率应尽可能提高）。因此，在采用酸脱木质素法去除部分木质素的过程中，运用正交试验法探索制备透明木材的较佳工艺条件。对不同实验条件下的木材模板和透明木材进行了色差、透光率、孔隙率、微观结构、化学基团、机械强度等测试。此外，通过三大元素（木质素、纤维素、半纤维素）测试和正交极差分析法，得出各工艺因素对各树种木质素去除率的影响。最终得出，两种树种在实验水平9（工艺参数：NaClO浓度1wt%，90℃，1.5h）时获得最高透光率；在部分脱木质素率高达4.84 - 11.07%的情况下，透明木材保留了大部分原木的颜色和纹理，同时机械强度提高了57.76%，透光率比原木最高提高了14.14%。此外，从多方面分析可知木材模板和树脂具有良好的协同效应，表明这种透明木材有潜力成为功能性装饰材料。
