The reduction of adhesive application in plywood manufacturing by using nanocellulose-reinforced urea-formaldehyde resin

The aim of the study was to investigate the effect of nanocellulose (cellulose nanocrystals [NCC]) addition to urea-formaldehyde (UF) resin on the properties of plywood and the possibility of reducing resin spread rate in plywood production. The studies have shown the increase in viscosity of experimental adhesive mixture in comparison with reference one. On the basis of the bonding quality results, it was concluded that the NCC-reinforcement led to significant improvement in bonding quality of plywood. Moreover, values of bending strength (modulus of rupture) and modulus of elasticity also increased because of the cellulosic nanoparticles introduction. The positive effect of NCC addition on the properties of plywood allowed the reduction of resin spread rate by 50 g/m(2)and maintaining equally good strength as reference panels. The modification with nanocellulose itself did not lead to a decrease of free formaldehyde content. However, allowing the reduction of adhesive application led to a slight decrease in the amount of emitted formaldehyde.