Synthesis and characterization of cellulose nanofibers from waste paper and their utilization in wood adhesion.

Nanocellulose extraction from lignocellulosic materials is a highly chemical and energy‐intensive process as it requires the removal of lignin and hemicellulose. Writing paper is one of the processed materials that could be used as a raw material for the extraction of nanocellulose. In this work, cellulose nanofibers (CNFs) were synthesized from paper waste using TEMPO‐oxidation followed by high‐shear microfluidization. Scanning electron microscopy and atomic force microscopy confirmed the diameter of fibers in the nano‐range and a consistent zeta potential confirmed the stability of CNF suspension in water over a long time frame. Characterization of the CNFs using Fourier transform infrared spectroscopy indicated the presence of a carbonyl group due to the oxidation process. Thermogravimetric analysis and x‐ray diffraction revealed lower thermal stability and reduction in the crystallinity index of CNFs, as compared to pulp fibers. The obtained CNFs were used successfully as the sole binding agent in the preparation of fiberboards and also utilized as a reinforcing agent for polyvinyl acetate (PVAc) adhesive in the preparation of laminated veneer lumber (LVLs). The addition of CNFs in PVAc improved the glue shear strength indicating superior bonding characteristics and also increased the water resistance of the LVLs. Highlights: This work focused on cellulose nanofibers (CNFs) extraction from waste paperObtained CNFs form stable water suspension and have a diameter of less than 15 nmThermal stability and crystallinity index reduced after conversion to nanofibersCNFs form a complex network and act as a sole binder to make fiberboardsCNFs were utilized as a reinforcing agent for PVAc in preparation of LVLs [ABSTRACT FROM AUTHOR]