Resistance of acetylated Jacaranda copaia wood to termites and decaying fungi attack

ABSTRACT The natural durability of the wood is essential for the definition of its use, and this property can be enhanced with the proper chemical treatment of the wood. Thus, the objective of this study was to evaluate the resistance to termites and decay fungi of Jacaranda copaia wood chemically modified through acetylation. Five experimental treatments were assessed: acetylation for 2, 4, 6 and 8 hours and a control (non-acetylated). The acetylation was carried out by immersing wood samples in acetic anhydride at 90 °C. Acetylated and control samples were subjected to the action of xylophagous termites (Nasutitermes sp.) and decaying fungi (Gloeophyllum trabeum and Trametes versicolor). The acetylation process significantly increased the resistance of Jacaranda copaia wood to the attack of the xylophagous organisms. There was no mass loss after exposure to termites of the wood in any of the acetylation treatments, while in the control wood, mass loss was 9.5%. Regarding the decaying fungi, mass loss occurred in all treatments. Acetylation for 6 and 8 hours were the most efficient chemical treatments, increasing the resistance class of the Jacaranda copaia wood to highly resistant.

摘要 木材的天然耐久性是决定其应用场景的核心属性，通过合理的化学处理可有效提升该性能。本研究以经乙酰化改性的阔荚蓝花楹（Jacaranda copaia）木材为对象，旨在评估其对白蚁及腐朽真菌的抵抗能力。实验共设置5组处理：乙酰化处理时长分别为2、4、6、8小时，另设未乙酰化的对照组。乙酰化过程采用将木材试样置于90℃乙酸酐溶液中浸渍的方式完成。将乙酰化试样与对照组试样分别暴露于食木白蚁（象白蚁属Nasutitermes sp.）以及腐朽真菌（密粘褶菌Gloeophyllum trabeum、彩绒革盖菌Trametes versicolor）的侵蚀作用下。结果显示，乙酰化处理可显著提升阔荚蓝花楹木材对食木生物的抵抗能力：经白蚁侵蚀试验后，所有乙酰化处理组的木材均未出现质量损失，而对照组木材的质量损失率达9.5%；针对腐朽真菌试验，所有处理组均出现质量损失，其中乙酰化处理6小时与8小时为最优方案，可将阔荚蓝花楹木材的抗侵蚀等级提升至高抗级别。