Increased wood density is obtained by compressing the wood porous structure under suitable moisture and temperature conditions to improve its physical, mechanical and color properties. A recently proposed wood densification method based on partial removal of lignin and hemicellulose in hot water solution of sodium hydroxide and sodium sulphite has shown promising results on solid wood. However, its applicability and effect on thin wood veneers have not been tested yet. In this study, the timing of the method has been adapted to estimate the densification treatment intensity dependence of wood properties (wood density and modulus of elasticity) and color change of softwood (Norway spruce) and hardwood (beech) veneers. Compared to control, density and rigidity increased, with improved wood properties peaking after only 90 s of treatment intensity. Furthermore, the color became darker after treatment compared to control, with no significant color difference between treatment intensities. In conclusion, densification of veneers, according to the presented adapted method, provides a significant improvement of veneers physical and mechanical properties, and produces color changes perceptible by the human eye. Our results can be further implemented and adapted to application in industrial plants, calling for new application of densified veneers.

中文翻译：

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创新的致密化工艺对山毛榉和挪威云杉单板的机械和物理性能的影响

通过在合适的湿度和温度条件下压缩木材多孔结构以改善其物理，机械和颜色特性，可以提高木材密度。最近提出的一种基于在氢氧化钠和亚硫酸钠的热水溶液中部分除去木质素和半纤维素的木材致密化方法在实木上显示出令人鼓舞的结果。但是，其在薄木单板上的适用性和效果尚未经过测试。在这项研究中，该方法的时机已经过调整，以估计木材特性（木材密度和弹性模量）的致密化处理强度依赖性以及软木（挪威云杉）和硬木（山毛榉）贴面的颜色变化。与对照组相比，仅经过90 s的处理强度，密度和刚度增加，木材性能达到峰值。此外，与对照相比，处理后颜色变深，处理强度之间没有明显的颜色差异。总之，根据提出的改进方法，单板的致​​密化可显着改善单板的物理和机械性能，并产生人眼可察觉的颜色变化。我们的结果可以得到进一步实施，并适合在工业工厂中使用，从而要求重新使用致密单板。并产生人眼可察觉的颜色变化。我们的结果可以得到进一步实施，并适合在工业工厂中使用，从而要求重新使用致密单板。并产生人眼可察觉的颜色变化。我们的结果可以得到进一步实施，并适合在工业工厂中使用，从而要求重新使用致密单板。