Thermosetting composites prepared using husk of pine nuts from Araucaria angustifolia

Abstract

The high consumption of pine nuts as food leads to high amounts of husk dispensed as waste. The incorporation of the husk from pine nut into composites appears as a strategic route to explore the commercialization of the Araucaria angustifolia. The present study aims to prepare and characterize thermosetting composites of urea and phenol formaldehyde and husk of pine nuts. For this, husk particles, paraffin emulsion, ammonium sulfate, and resins, were mixed with a high‐shear mixer and then cured by flat‐pressing at 4 MPa, 120°C, for 5 min. SEM and optical images revealed good homogenization between resin and husk. DTG and DSC results showed chemical affinity between filler and matrix—tracked by shifts in the DTG peaks of the husk. The UF composites showed higher wettability and water absorption; therefore higher thickness swelling. The UF and PF composites with 30% of resin provided the greatest repellency to water, and the highest mechanical properties. It was possible to prepare composites of UF and PF resins loaded with 70% and 80% of husk from pine nuts. POLYM. COMPOS., 39:476–483, 2018. © 2016 Society of Plastics Engineers