Selected physical and mechanical properties of particleboards manufactured with addition of Betula bark post-extraction residues

As awareness grows regarding the necessity for sustainable technologies across various industries, including wood-based composites, there’s a heightened demand for ecological solutions. One of the proposed solutions is the partial replacement of wood raw materials in composites with forestry and agricultural waste, thus contributing to the circular economy. Suberin, which is a natural polyester present in tree bark, after depolymerization can be converted into suberinic acids, and after this process, post-extraction solid residues (SAR suberinic acid residues) remain, which include suberin monomers, lignin, cellulose and esters. In this study, it was decided to use this waste in the form of a powder with dimensions of 0.250 mesh as a filler for particleboards. Three-layer boards were prepared in four variants of SAR share in all layers (0%, 5%, 10%, 15%). The physical and mechanical properties of the manufactured boards were tested—modulus of rupture, modulus of elasticity, internal bond strength, screw withdrawal resistance, thickness swelling, water absorption, density profile, contact angle. The formaldehyde and total volatile compounds emissions of the boards were also determined. As a result of the research, it was shown that the addition of SAR has a positive effect on the properties of the panels, but only up to the level of 10%, whereas for boards with a SAR content of 15%, a statistically significant decrease in mechanical and physical properties was noted. The values ​obtained, however, were still within the required assumptions of the European Standards. Only the IB value obtained for the SAR 15% variant did not meet the requirements of the EU Standards. As shown, SAR addition significantly minimizes the emissions from boards, however, it decreases also the hydrophobicity. This study shows a great potential in applying post-extraction residues from bark as a filler material for wood-based panels.