Improvement on dimensional stability and mold resistance of wood modified by tannin acid and tung oil

Abstract In this study, two plant derived compounds, namely tannin acid (TA) and tung oil (TO) were used to modify southern yellow pine wood ( Pinus spp.) to enhance its durability. Wood samples were firstly impregnated with aqueous TA solutions at 5, 10 and 15%, respectively, and then impregnated with TO. Samples treated by TA or TO alone were also prepared. The dimensional stability, hydrophobicity, mold resistance, and thermal stability of both treated and untreated wood were evaluated. The results showed that the dimensional stability and hydrophobicity of wood treated with 10% TA and TO (T10+TO group) improved significantly. Compared with control group, the water absorption of T10+TO group decreased by 80.0% after 192 h immersion, and the antiswelling efficiency reached up to 90.7%, with the contact angle of 118° at 50 s. The mold resistance of wood after 5% TA and TO treatment presented an effectiveness of 87.5%. Meanwhile, T10+TO group presented better thermal stability. Overall, this study revealed that wood impregnated by TA and TO exhibited excellent dimensional stability and anti-mold properties, which could be applicable to indoor environment.