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

Abstract

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/m 3 ), 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/m 3 to 800 kg/m 3 ), 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/m 3 ), 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.

Effect of Cellulose Nanofibrils on the Bond Strength of Polyvinyl Acetate and Starch Adhesives for Wood

“…The addition improved the board strength due to the more even adhesive distribution and increasing adhesive toughness. Leng et al (2017) investigated the effects of density, CNF addition ratio, pressing method and particle size on the bending properties of wet-formed particleboard.…”

The Effect of Cellulose Nanocrystals in Sugarcane Bagasse Particleboards of Pith and Fibers

“…The composites using particle fibers had shown better mechanical (MOE and MOR) and physical properties (WA) than those made with pith particles. Leng et al (2017a) found higher MOE and MOR in particleboard with CNF addition, however they used wood to produce the particleboard and this variable (CNF) interacted with others, such as density and particle size. ANSI A208.1 (ANS, 1993) stipulates the average minimum values of 1764 MPa for MOE and 11.3 for MOR, for particleboards/chipboards made with urea formaldehyde (class M1).…”

“…Better mechanical properties performance (internal bond and modulus of rupture) of particleboards reinforced with nanocellulose (CNF) and microfibrillated cellulose (MFC) were found by (Mahrdt et al, 2016;Veigel et al, 2012), and also better performance in physical properties (thickness swelling) by (Veigel et al, 2012). Leng et al (2017a) got higher bending strength in particleboard with CNF addition and Leng et al (2017b) better performance for water absorption using at least 15% of CNF in particleboard produced with large particles.…”

Laminated Wallboard Panels Made with Cellulose Nanofibrils as a Binder: Production and Properties

“…In addition, the drying of cellulose nanomaterials often leads to the loss of nanoscale size, diminishing the effectiveness of the particles in its target applications [13]. Recent developments in the dewatering of nanocellulose highlighted the possibility to remove the water at no energy inputs [3,[14][15][16]. These developments showed that water can be removed easily from nanocellulose when mixed with wood particles by applying pressure at room temperature, and several products have been produced using this methodology.…”

“…The laminate system showed no severe delamination within the laminates, and the novel system met (or exceeded) the properties of the currently used, reinforced polymer composite materials. In different studies conducted by Leng et al (2017Leng et al ( , 2016 and Amini et al (2017), CNF was applied as the sole binder to produce medium-and low-density particleboard [3,14,15]. On average, the low-density grades met the industrial requirement for particleboard manufacturing.…”