Elaboration of carboxylated cellulose nanocrystals filled starch-based adhesives for the manufacturing of eco-friendly particleboards

Abstract

• Carboxylated cellulose nanocrystals (C-CNCs) were prepared from alfa fibers. • The potential of C-CNCs as nano-reinforcement for starch adhesives was assessed. • Formulated resins containing up to 2% of C-CNCs were used in particleboards. • Panels containing 1% of C-CNCs exhibited the best mechanical properties. • 1% of C-CNCs improved the physical and the water resistance properties of panels. The current work aims to assess the nano-reinforcing effect of carboxylated cellulose nanocrystals (C-CNCs) from alfa fibers in the development of corn starch-mimosa tannin bio-adhesives for the manufacturing of eco-friendly particleboards. C-CNCs were prepared through a hydrolysis process using mixed acid system of citric acid and hydrochloric acid and displayed an aspect ratio of 67.8, a crystallinity of 85 %, a zeta potential value of −38 mV and a carboxylate groups content of 976.5 mmol /Kg. The effect of fibers content (0.5, 1, 1.5 %, and 2 %) on the mechanical properties of the prepared composites was assessed. The water resistance behaviour of glued panels with the optimal amount of C-CNCs was evaluated through the study of their physical properties and the contact angle measurement. It was found that 1 % of C-CNCs led to a significant strength and water resistance behaviour relative to starch adhesive alone. The present work showed, for the first time, a new pathway for C-CNCs evaluation as a binder in starch based-adhesive for the development of woody composites.