High-performance wood scrimber prepared by a roller-pressing impregnation method

Wood scrimber is a wood-based composite material with high mechanical strength and large size, which can potentially replace the use of steel and cement in various fields. However, its poor dimensional stability and low flame retardancy limit its use in outdoor construction projects and fire-prone areas. To solve this, here we report a roller-pressing impregnation method to realize the deep penetration of resin using mechanical compression and low-pressure adsorption. Microstructural imaging by SEM and 3D ultra-deep field microscopy shows the phenol formaldehyde(PF) resin distribution of the roller-pressed wood scrimber (R-WS) is deeper and more uniform, which increases the flatness and crystallinity. The R-WS showed greatly improved dimensional stability, with 63 % and 35 % lower thickness swelling rate (TSR) and width swelling rate (WSR) compared with the traditional wood scrimber (T-WS). In terms of flame retardancy, the smoke production rate (SPR) and heat release rate (HRR) of R-WS decreased by 32.7 % and 52 %, respectively. The R-WS at 800 °C formed a dense char that content increased by 20 %, helping to inhibits combustion. The mechanical properties of R-WS were also improved, and the modulus of rupture (MOR), modulus of elasticity (MOE) and short-beam strength (SS) of R-WS increased by 31.2 %, 7.4 %and 26.7 %, respectively. The R-WS suffer toughness failure and wood-to-wood failure under bending and shear scenarios, respectively, indicating that the roller-pressing impregnation treatment enhanced toughness and bonding strength. In addition, the use of a rotating roller is expected to realize the continuous production of the dipping link, saving drying energy consumption and improving production efficiency. These properties are expected to promote the outdoor utilization and continuous production of wood scrimber.