To expand the application range of fast-growing poplar, a modification method of poplar impregnated with nano-SiO2 and urea-formaldehyde resin was proposed in this study. Taking the mass ratio of nano-SiO2 mass to the solid content of urea-formaldehyde resin impregnation solution (W), high-temperature (H), and high-temperature time (T) as influencing factors, the effects of impregnation high-temperature heat treatment modification on the physical and mechanical properties of fast-growing poplar were explored. At the same time, the weight loss rate, oven-dry density, dry shrinkage properties, swelling properties, modulus of rupture (MOR), and modulus of elasticity (MOE) of the modified poplar were measured. The research results show that both the weight loss rate and the coefficient of variation of the oven-dry density have a high correlation with the temperature; the high-temperature immersion heat treatment can reduce the dry shrinkage and swelling of poplar, improve the dimensional stability, MOR, and MOE. W is 0–1%, H is 160 °C, and T is 2–4 h. The impregnated heat-treated wood has good MOR and MOE. Therefore, the combination of nano-SiO2 and urea-formaldehyde resin impregnation and heat treatment to modify poplar can improve some physical and mechanical properties of fast-growing poplar, expand the use of poplar, increase its added value, and realize high-value utilization.

To promote the performance of fast-growing poplar wood for furniture applications, this study proposes and investigates the feasibility of modifying fast-growing poplar wood with a urea-formaldehyde resin impregnating agent by adding nano-SiO2 as a way to improve its physical and mechanical properties. By observing the solubility of nano-SiO2 addition in urea-formaldehyde resin, determine the optimal ratio of nano-SiO2 addition to the solid content of the urea-formaldehyde resin solution. After the fast-growing poplar specimens were treated with nano-SiO2/UF resin, the water absorption, wet swelling, dry shrinkage, nail grip, flexural strength, and modulus of flexural elasticity of the fast-growing poplar specimens were compared and analyzed to determine the effect of impregnation modification and the optimal impregnation ratio. The results showed that the physical and mechanical properties of fast-growing poplar wood were significantly improved by impregnating the fast-growing poplar wood with urea-formaldehyde resin with SiO2, and the impregnation modification was beneficial to reducing the wet swelling and dry shrinkage of poplar wood, increasing its dimensional stability, improve the grip nail strength, and increase the flexural strength and flexural modulus of elasticity with the increase in nano-SiO2 concentration.

Plywood has poor sound insulation due to its insufficient areal density, which cannot satisfy the demands of an indoor acoustic environment. This report proposed to use furfuryl alcohol to impregnate poplar veneer as a raw material for plywood and explored the sound insulation potential of furfuryl alcohol-modified poplar veneer. The effect of different formulations on the sound insulation performance of modified veneers was discussed, such as furfuryl alcohol concentrations, catalyst categories, and solvent categories. The weight percent gain (WPG) and areal density (AD) were used to evaluate the impregnation effectiveness of furfuryl alcohol modification. The sound insulation was measured by the impedance tube method. The results showed that the WPG of the furfuryl alcohol-modified veneers was evident, and the AD was effectively improved. Furthermore, the average sound insulation of furfuryl alcohol-modified poplar veneer was 25.68~40.10 dB, which increased by 10.8~19.1% compared with that of unmodified veneer. The modified veneer with 50% furfuryl alcohol concentration, taking isopropanol as a solvent, and maleic anhydride as a catalyst, had the optimal sound insulation performance. At the same time, the cell microstructure and chemical components were characterized by scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) theory to explain the sound insulation mechanism further. The results showed that the distortion of cell walls was improved, suggesting a change in the mechanical properties of the cell wall. At the same time, more micropores formed since the filling of furfuryl alcohol resin, yielding a tortuous propagation pathway, so the sound insulation performance improved. Finally, it demonstrated the potential of furfuryl alcohol-modified poplar veneer as raw material to prepare plywood with excellent sound insulation.

The withdrawal and lateral holding properties of three types of plywood with one stapled as well as one-row multi-stapled joints were studied and compared. The results show that variations in plywood density have a significant effect on withdrawal strength and a relatively small effect on lateral holding strength. At four staples, the withdrawal strength of the eucalyptus plywood with a density of 0.59 g/cm3 is 1821 N, which is 21% higher than that of poplar plywood with a density of 0.51 g/cm3 at 1498 N and 32% higher than that of eucalyptus/poplar composite plywood with a density of 0.53 g/cm3 at 1275 N. In terms of lateral holding strength, eucalyptus plywood has a lateral holding strength of 1603 N 12% lower than the 1807 N of eucalyptus/poplar composite plywood and 10% lower than the 1761 N of poplar plywood. As the number of staples increased from 1 to 4 in increments of 1, the withdrawal strength of eucalyptus plywood continued to increase, while the nodal strengths of the poplar plywood as well as eucalyptus/poplar composite plywood did not differ significantly between 3 and 4 staples, and there is a significant increase in the lateral holding strength for all three plywood nodes. Equations for predicting the withdrawal and lateral holding strengths of one-row multi-stapled joints were derived separately.