33 LEACHING OF NEW ENVIRONMENTAL FRIENDLY WOOD PROTECTION AGENTS Andreas Treu 1 , Erik Larnøy 2 & Holger Militz 3 ABSTRACT New environmental benign wood protection agents often come from natural resources, and are sometimes a waste product. Chitosan, a derivative from chitin which is among other sources a by-product from the shellfish industry, is tested as well as known wood protection agents and their synergetic effect with chitosan. The objective of the research presented in this paper, is to describe the leaching properties of the following compounds: Chitosan, chitosan/copper, chitosan/boron and chitosan/ScanImp (a commercial wood preservative). A leaching procedure was performed on treated Scots pine sapwood samples. The four solutions have also been tested with and without post treatment. A new effective fire preservative has been included in the test. Common wood preservatives have been tested as references. The combination with chitosan did improve the fixation of the wood protection agent ScanImp. Furthermore, the post treatment of the chitosan treated samples did significantly reduce the leaching of glucosamine and to some extend also the leaching of boron. Key words: Leaching, boron, chitosan, copper, Scots pine sapwood. INTRODUCTION One of the challenges in wood material sciences is the topic of natural durability and protection of wood. One of the greatest problems in the utilization of most types of wood as construction material is the low resistance against biotic factors. Most European and northern American softwoods in outdoor or humid conditioned applications need to be protected against wood-deteriorating microorganisms such as fungi or bacteria, for example by pressure-impregnating with chemicals or by modifying the wooden matrix. The wood protecting agents developed since the restriction of CCA are copper-organic mixtures, such as ammonium copper quat (ACQ), copper azole mixtures, with or without boron and copper systems (Green III and Schultz, 2003; Schultz and Nicholas, 2003). Copper is the primary active agent and the lack of chromium and arsenic requires higher concentrations. Since copper itself diluted in water is toxic to aquatic organisms, the new 1 Norwegian Forest and Landscape Institute, Section Wood Technology, Ås, Norway. Email: andreas.treu@skogoglandskap.no 2 Norwegian Forest and Landscape Institute, Section Wood Technology, Ås, Norway. Email: erik.larnoy@skogoglandskap.no 3 Georg-August-University, Büsgenweg 4, DE-37077 Göttingen, Germany. Email: hmilitz@gwdg.de