Understanding the physicochemical properties of olive kernel to be used as a potential tool in the development of phenol-formaldehyde wood adhesive

During olive oil production process, a great number of by-products are generated, including olive kernel. These by-products can be used for the development of new products for use in many different industrial applications. The evaluation of the physicochemical properties of these by-products constitutes a key factor in evaluating the potential reutilization of olive oil by-products. In the present study, the physicochemical properties of olive kernel were analyzed. Fourier transform infrared spectroscopy (FT-IR), cross-polarization magic angle spinning 13 C nuclear magnetic resonance (CP/MAS 13 C NMR), Brunauer, Emmett and Teller (BET), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) techniques were used. FT-IR and CP/MAS 13 C NMR analysis showed that olive kernel contained typical functions of cellulose , hemicelluloses and lignin. Morphological studies revealed different sizes and arrangements of cells, showing that olive kernel had an irregular structure . TGA showed that thermal stability was observed up to approximately 180 °C. In the present work it was found that olive kernel has the potential to act as a replacement material for up to 15% of base resin in a PF-based adhesive, whilst exhibiting similar or better adhesive properties than a commercial PF resin.