Transforming inferior short-rotation teak: unleashing superior durability and stability with lactic acid-based bio-treatments

Abstract This study focused on enhancing the properties of inferior short-rotation teak (SRT) wood through impregnation with lactic acid (LA)-based treatments, aiming to improve its dimensional stability, biological durability, and thermal stability. Using a vacuum-pressure process at 12.2 bar for two hours, followed by curing at 150 oC and 180 oC, the research found that wood treated at 180°C with a 10% LA and 10% citric acid (CA) composition demonstrated superior performance. Specifically, the treated wood exhibited higher anti-swelling efficiency (ASE), reduced water uptake (WU), swelling value (Sv), and water leaching (Wlc), as well as increased resistance to white-rot fungi, subterranean termites, and improved thermal stability. The best results were achieved with a 69% ASE, 27% WU, 3% Sv, and 1% Wlc, with wood resistance classified as Class I. Microscopic analysis revealed that the impregnants effectively filled the wood pores. Chemical analysis demonstrated a decrease in hemicellulose content and an increase in α-cellulose and lignin of the modified wood. FTIR analysis further confirmed strong chemical bonds formed between the LA + CA impregnants and wood cellulose and lignin. These findings highlight the potential of LA + CA-impregnated SRT wood cured at 180 oC for high-quality interior and exterior wood applications.