Evaluation of the incorporation of lignocellulose nanofibrils as sustainable adhesive replacement in medium density fiberboards

Lignocellulose nanofibrils (LCNF) were used as a resin adhesive replacement in fiberboards. The physico-mechanical properties of the panels were affected by the LCNF content and the press temperature. At any given temperature, modulus of rupture (MOR) and internal bond strength (IB) showed a linear relationship with increasing LCNF. A temperature of 180 °C and 20% LCNF content were the optimum processing conditions giving MOR value of 12.1 MPa, close to the minimal recommended for commercial fiberboards. The IB, the thickness swelling, and modulus of elasticity met the standard values. The boards containing thermomechanical pulp (TMP), LCNF and borate minerals showed densities varying between 550 and 610 kg/m3. However, the differential density between the core and surface was reduced as LCNF content increased. The three-dimensional LCNF network with an average particle diameter of 12 ± 3 nm promoted fibers bonding and allowed inter-fiber voids filling, as observed in SEM images. Press-temperatures greater than 180 °C could cause material degradation that lowered the mechanical properties of the fiberboards. LCNF displayed a good bonding ability and showed a promising perspective for adhesive replacement in fiberboards.