Investigation of a new natural adhesive composed of citric acid and sucrose for particleboard II: effects of board density and pressing temperature

A natural adhesive composed of only citric acid and sucrose was recently proposed, and its detailed bonding performance has been researched in some wood-based materials. In this study, the effects of board density and press temperature on the physical properties of particleboard were investigated. As physical properties, the bending properties, internal bond strength and thickness swelling of the boards were evaluated. When the density was changed from 0.4 to 1.0 g/cm3 under a press temperature of 200 °C and a press time of 10 min, the board with a density of 0.8 g/cm3 had the best physical properties. When the board was manufactured at press temperatures ranging from 140 to 240 °C for a press time of 10 min and a target density of 0.8 g/cm3, the board manufactured at 200 °C had the best physical properties. The physical properties of the board with a density of 0.8 g/cm3 manufactured at 200 °C met the type 18 requirements of the Japanese industrial standard for particleboard (JIS A 5908). The results obtained from Fourier transform infrared spectra suggested that the ester linkages resulting from the reaction between citric acid and wood and/or sucrose were the main adhesion mechanism and resulted in particleboard with excellent physical properties.