LAUSR

Abstract Maritime pine (Pinus pinaster, Ait.) is one of the most important trees in the Iberian Peninsula forest. Its wood is mainly used in the wood-based panels production and for pulp and paper factories. The aim of this work was the valorisation of the main forest by-products of the P. Pinaster: bark, pinecones and needles. These organic by-products were widely used in small rural farms, but nowadays are mostly left in the forest, contributing to the forest fires problem. P. pinaster by-products were evaluated bearing in mind its wettability and chemical composition (evaluated by FTIR-ATR). Extracts were obtained from the bark, pinecones, and needles using a steam pressure extraction method (2% NaOH)”, a simple extraction method used for the first time in the valorisation of biomass for its application in biomaterials. The structures of resorcinol, catechin and phloroglucinol appear in pine needles, pinecones and bark extracts, respectively. Extracts self-condensation curing process was evaluated by differential scanning calorimetry, and an automatic bonding evaluation system. For the first time particleboards were manufactured at a specific pressure of 4 MPa and 190 °C of press temperature for 3 min, with different percentages of the three maritime pine by-products, using a melamine-urea-formaldehyde resin and citric acid as particle binder. Due to the fast reactivity between polyphenols and formaldehyde, the influence of each by-product on the formaldehyde emission was also studied. The results show that it is possible to improve water resistance and internal bonding strength, and to control formaldehyde emission of particleboards, by using underutilized Maritime pine-based by-products in particleboards, replacing wood particles up to 20 % by weight.