Surface characterization, mechanical and abrasion resistance of nanocellulose-reinforced wood panels

Cellulose nanocrystals (CNCs) are promising particles in the production of wood fibre nanocomposites, due to their high stiffness, mechanical strength and low density. Wood fibres are the main source of cellulose, thus allowing the direct extraction of CNCs. As an attempt to improve the quality of wood fibre panels, this work performed topographical, tribological and mechanical characterization of medium density fibreboard (MDF) reinforced with CNCs at different concentrations, by substituting from 2 to 6% of the urea formaldehyde resin by acidic CNCs. The results showed no significant differences in the topographic characteristics and abrasion wear rates due to the incorporation of CNCs, although a tendency to obtain rougher panels was observed. The addition of CNCs at low proportions affected negatively the adhesion between the resin and the fibres, compromising the mechanical properties of the panels. On the other hand, some properties such as the modulus of rupture and hardness showed a tendency to recover when the amount of CNCs increased from 2 to 6%. The analysis of the microstructure of the worn samples showed more severe wear in the regions of poor adhesion between the fibres and the resin. (paper)