Effects of Density, Cellulose Nanofibrils Addition Ratio, Pressing Method, and Particle Size on the Bending Properties of Wet-formed Particleboard.

Wet-formed particleboard bonded with cellulose nanofibrils (CNF) was prepared in this work. The effects of density, CNF addition ratio, pressing method, and particle size on the bending strength were evaluated. The results showed that density had the most important effect on the modulus of elasticity (MOE), while the CNF addition ratio had the most important effect on the modulus of rupture (MOR). For panels with low density (< 640 kg/m3), the MOE and MOR did not change much with the configuration changes between particle size and pressing method. This was due to the synergistic effect of incomplete compression and poor bonding in the core area using a constant thickness (CT) pressing method, and lower face density and higher core density using a constant pressure (CP) pressing method. For panels with medium density (640 kg/m3 to 800 kg/m3), the combination of larger particles, higher CNF addition ratio, and CT pressing method contributed to the highest bending strength. Further increase to high density (> 800 kg/m3), the pressing method's effect was more important, compared to panels with low and medium densities. With increased density and CNF addition ratio, panels were able to meet lowdensity and some medium-density standard MOE and MOR requirements. [ABSTRACT FROM AUTHOR]