Study of the best conditions for the acetylation of Uruguay-grown Pinus taeda.

In order to protect wood, several preservation methods have been developed, and chemical modification is an environmentally friendly alternative. The chemical modification of wood improves its performance and dimensional stability, increases its resistance to deterioration, and ensures safe disposal once the wood is out of service. The acetylation of wood, which involves the esterification of accessible hydroxyl groups in the cell wall with acetic anhydride, reduces the hygroscopicity of wood. Acetic acid is obtained as a byproduct of the reaction. The aim of this work is to study the best reaction conditions for the acetylation of Pinus taeda wood with acetic anhydride. The experimental design used was a factorial design 2² with 3 repetitions in the midpoints. The independent variables were reaction temperature and reaction time, both at two levels. Wood's weight gain percentage (WPG) and its chemical changes were used as response variables. The acetylated wood acetylated under the best conditions, as determined by the trials, was subjected to a durability test against decay fungi (Gloeophyllum separium and Trametes versicolor). Results showed that temperature was most impactful in the reaction process, being decisive for WPG results. Higher WPG was obtained at temperatures above 100°C. The acetylated wood exhibited high resistance to fungal attack, with very low mass loss.