Study on the Smart Dyeing and Performance of Poplar Veneers Modified by Deep Eutectic Solvents

Imitation precious wood materials have become a research focus due to their good quality, high safety level, excellent performance, rich color, varied textures, and high utilization rates. However, their uneven dyeing, poor color stability, and lack of durability limit their further application. This study utilized a neural network model optimized with the Gray Wolf Algorithm (GWA) for color matching, using acidic dyes as raw materials and deep eutectic solvents (DESs) for modification. Functional reagents like nano tungsten trioxide (WO3) and titanium dioxide (TiO2) were introduced alongside polyvinyl alcohol (PVA) as a modifier. A dyeing-enhancement modification process was employed to create a poplar veneer that exhibited uniform and stable color performance with a smooth surface, mimicking that of precious wood. Computerized color matching was used to adjust the dye formulation for staining, ensuring stable colorimetric values on the veneer surface, which closely resembled natural precious wood. The average mean squared error in dye concentration prediction, after processing with the Gray Wolf Algorithm and a basic neural network algorithm, decreased from 0.13 to 0.006, ensuring repeatability and consistency in wood dyeing. Analysis and characterization using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and permeability testing revealed that nano TiO2 and WO3 particles were uniformly distributed within the wood cell lumens and firmly bonded. Mechanical testing on PVA-glued veneers showed that compared to untreated poplar veneers, the tensile strength of the imitation wood increased by approximately 62.5%, and the bending strength reached 809.09 MPa, significantly improving the flexibility and tensile properties of the poplar veneer. This study is the first to adopt a DES-modified dyeing-enhancement modification process to improve the dyeing performance, uniformity, durability, and structural stability of wood, showcasing its great potential in architectural decoration, high-end furniture, and artisanal crafts.