Chemically modified wood - a review with consideration of the opportunities for application to Irish timber.

Abstract

Chemical modification offers the opportunity to improve the dimensional stability and biological durability of wood. In the modification process, reagents are introduced which react permanently with the structural polymers cellulose and lignin, reducing their hygroscopicity and attractiveness as a fungal food source. Acetylation, in which the wood is reacted with acetic anhydride, was one of the earliest approaches used, and remains the most promising technique, with at least one European project now at the pilot plant stage. Although the reactive materials and the process require careful handling, the treated material presents none of the toxicity hazards associated with wood preserved by conventional means. Acetylation may give sufficient property improvement to allow fast grown softwoods to be used in higher value joinery applications, thus increasing the scope for utilisation of native materials.