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Recent studies have shown the advantage of wood impregnation on increasing the dowel-bearing strength of black spruce wood by almost 50%. The aim of the present study was to improve the mechanical performance of a dowel-type connection through an impregnation method for black spruce wood. The results showed that wood treatments improved the mechanical performance of dowel-type connections. The dowel-bearing strength increased up to 25%, while the stiffness increased up to 52%. The increase obtained was lower in comparison with the previous studies, however. A lower polymer quantity, resulted in a shorter vacuum time, and a lower temperature polymerization used in wood treatment brought the process closer to an industrial application.

Urea–formaldehyde (UF) resin is the main commercial adhesive used for medium-density fiberboard (MDF) manufacturing. UF resin is used to produce MDF of high quality. However, this production process of MDF releases formaldehyde in the environment. In this scenario, a mix of crude glycerol, citric acid, and tannin was used as a binder to replace UF resin in MDF manufacturing. A bio-based adhesive content of 14%, and two pressing times (420 s and 630 s) for MDF manufacturing in the laboratory were used. The effect of bio-based adhesive and pressing time on the physical and mechanical properties of MDF were investigated. According to results obtained, modulus of elasticity (2382 MPa and 2439 MPa), modulus of rupture (14.38 MPa and 14.43 MPa), and internal bonding strength (0.79 MPa and 0.90 MPa) of MDF panels are meeting requirements of the A208.2-2016 standard of the American National Standard Institute. Thermogravimetric analysis indicated that polymer cured at 630 s showed a higher thermal stability in comparison to polymer cured at 420 s. The Fourier transform infrared spectroscopy analysis shows the spectra of polymer with the peak at 1714 cm−1 and 1716 cm−1. The results showed the potential of the mix of crude glycerol and citric acid to replace UF resin in MDF manufacturing.

The benefits of aluminum lamination in improving the physical and mechanical properties of wood-based composites is now well documented. This paper shows the contribution of life cycle assessment (LCA) as a tool to assess and compare the environmental footprint in the development of laminated panels. SimaPro 9.0 software, using Ecoinvent database was used to analyze the environmental impacts associated with the manufacturing of wood aluminum-laminated (WAL) panels and aluminum honeycomb panel (AHP). The impact 2002+ method was used to estimate environmental impacts. The LCA results show that the WAL panels manufacturing had a lower environmental impact than AHP manufacturing. In term of product, wood-based composites were the best choice as a core in laminated panel manufacturing. Wood-based composite manufacturing showed environmental advantages in all damage categories except in ecosystem quality. Aluminum alloy sheets manufacturing played an important role in the generation of environmental impacts for laminated panel development.

Collapse and drying stresses are currently induced during the drying of Eucalyptus nitens in solid wood products. The purpose of this study was to investigate these drying stresses by measuring hygromechanical strains during the drying of Eucalyptus nitens boards. Small samples of Eucalyptus nitens wood were oriented in the radial and tangential directions and tested to determine the hygromechanical strains during the drying process. This experimental work consisted of cantilevered bending tests conducted under variable relative humidity conditions. Tests were performed in a conditioning chamber at 30 °C with an equilibrium moisture content ranging from 22 to 12% under four levels of stress: 0, 10, 20 and 30% of the rupture load. The strains were determined using strain gauges, and the total deflection was measured with a linear variable differential transformer. The results show that in hygromechanical strains during the drying of Eucalyptus nitens, both the surface deformation and mechano-sorption strain were found to be proportional to the applied stress and reached their maximum values in the tangential direction. The total deflection increased 0,18 mm/mm with a surface deformation of 0,20 mm/mm, and the mechano-sorptive strain provides a greater contribution with a value of 0,11 mm/mm, thus corresponding to 59% of the total deformation. In attempts to improve the drying schedules of Eucalyptus nitens to develop solid wood products, mechano-sorptive behavior may be applied to relieve collapse and drying stress.

The mechanical behaviour of wood over time depends on temperature, relative humidity, applied load and the direction of the applied load, among other factors. In the present study, the mechanical behaviour of sugar maple (Acer saccharum Marsh.) wood was determined using creep tests in cantilever bending. These tests were carried out at different load levels, in a controlled environment chamber at a constant temperature of 30± 0·5°C and a relative humidity of 37, 67 and 83% for constant conditions and a relative humidity ranging from 37 to 83% for variable conditions. The specimens were oriented in a radial pattern and cut to 110 mm in length, 25 mm in width and 7 mm in thickness. The results show the impact of load levels and moisture content. Under constant conditions, the results show a linear behaviour of viscoelastic creep. Under variable relative humidity conditions, changing moisture contents resulted in significantly higher creep (mechanosorptive) compared to constant conditions.

The purpose of this paper was to determine the mechano-sorptive strains produced during desorption of moisture from Eucalyptus nitens specimens, from a perspective of modeling wood drying stresses. Eucalyptus nitens samples were tested in the radial and tangential directions. The mechano-sorptive strain was measured by cantilever bending during desorption. The runs were performed in a conditioning chamber at constant low temperature and variable equilibrium moisture content. Four load levels were considered for testing. The results showed that the mechano-sorptive strain during desorption of moisture was proportional to applied stress and reached the maximum value in the tangential direction. Also, the mechano-sorption coefficient depended on wood orientation and reached the maximum value of 5.46 × 10-2 in the tangential direction.