Using Na+MMT nanoclay as a secondary filler in plywood manufacturing

Abstract

Eight adhesive formulations were developed using two types of resin by urea–formaldehyde (UF) and melamine-urea formaldehyde (MUF) resins and four levels of sodium montmorillonite (Na+MMT) nanoclay by 0, 2.5, 5, and 7.5% as a secondary filler for interior beech plywood adhesives. Mechanical strength from experimental panels bounded with these formulations demonstrated that resin type and different levels of nanoclay have not any significant differences on modulus of rupture face grain parallel to span, modulus of elasticity face grain parallel and perpendicular to span, and glueline shear strength. But, for modulus of rupture face grain perpendicular to span, the highest value was calculated for MUF along with 5% nanoclay formulation. Furthermore, the results of physical properties showed that Water absorption and thickness swelling after 2 and 24-hour immersion in cold water for MUF resin was less than that of UF resin. In addition, the least amounts for thickness swelling after 24-hour immersion in cold water were attained for UF resin, along with MUF resin both treated by 5% nanoclay as a secondary filler.