Manufacturing of oriented strand board from olive tree pruning residues

Abstract

This study investigated the feasibility of manufacturing eco-friendly flakeboard from olive tree pruning residues using three concentrations of a tannin-formaldehyde adhesive, where the condensed tannin was extracted from pomegranate peels. The research evaluated the effects of adhesive concentration (11%, 12%, and 13%) on the physical and mechanical properties of panels to verify their compliance with European standards. Panels were tested for moisture content, density, water absorption, thickness swelling, modulus of rupture (MOR), internal bond (IB) strength, and screw withdrawal resistance. While moisture content and density were not significantly affected by adhesive ratio, water absorption and thickness swelling after 24 h decreased significantly with higher resin content. Mechanically, the 13% adhesive sample exhibited superior performance, achieving the highest values for MOR (18.8 MPa), IB strength (0.61 MPa), and screw withdrawal resistance (680 N), representing improvements of 7%–10%, 16%, and 10%, respectively, over panels with the lower resin content. All produced panels met the relevant European standard specifications. The results showed that olive tree pruning waste can be successfully valorized to produce sustainable oriented strand board (OSB) panels using a bio-based tannin-formaldehyde adhesive. The panels, which also feature an attractive natural appearance, are suitable for applications in furniture manufacturing, interior cladding, and structural uses, offering a promising solution to reduce reliance on synthetic adhesives and minimizing agricultural waste.