Effect of chemical modification on dimensional stability of Pinus radiata D. Don using acetic anhydride

Abstract

Chemical modification is used to efficiently improve some properties of wood to make it suitable for specific end uses. Modification using acetic anhydride (AA) is found suitable to make the wood more stable dimensionally. Pinus radiata wood samples treated with pyridine catalyzed AA were exposed to four different treatment methods comprising vacuum dipping and full cell method (cured with and without chemical). Physical properties like weight percentage gain (WPG), bulking coefficient, swelling coefficient (S) due to the chemical, water absorption and anti-swelling efficiency (ASE) were assessed for a comparative analysis. Results indicated a significant reduction in water absorption of acetylated wood. The swelling coefficients of all the treatments were found in the range of 3.86–4.96, which was twice to three times less than in the control (11.72) attributing 55–64% improvement in dimensional stability. Samples treated with full cell method and cured in the chemical mixture showed minimum swelling coefficient and best anti-swelling efficiency. All the four treatment methods chosen for the study returned significantly better dimensional stability as compared to untreated wood.

Effect of chemical modification and heat treatment on biological durability and dimensional stability of Pinus roxburghii Sarg.

“…The swelling for non-modified samples ranged between 4.18-13.36 while the swelling observed for T3 was between 4.67-12.93, which was significantly higher than T1 and T2 with swelling values ranging between 3.75-9.76 and 3.68-10.32. The swelling obtained due to CM was similar to values reported for radiata pine (Pinus radiata D.Don) modified using acetic anhydride (Hom et al 2020b).…”

“…The molecular volume of the substituted group along with a degree of substitution of the hydroxyl groups influences MEE of modified wood thus reducing de-aspiration by CM as compared to HT (Chang & Chang 2002). This hinders water to create a hydrogen bond with -OH groups of wood hence increasing WEE as observed (Hom et al 2020b;Lehringer et al 2009). ML after HT depends on wood species, temperature of modification, treatment time and heating medium (Esteves & Pereira 2009).…”

“…Through a better understanding of the mode of action, cost-effective treatment methods can be explored (Singh and Singh, 2012). Chemical modification (CM) was reported to stabilise wood, improve its moisture performance, photodegradation and biodeterioration and make its performance more desirable in service (Rowell 1983;Donath et al 2004;Hansmann et al 2005;Hom et al 2020b). CM implies etherification, esterification or acetylation between some chemical and hydroxyl (-OH) group of wood.…”

Effects of Different Energy Intensities of Microwave Treatment on Heartwood and Sapwood Microstructures in Norway Spruce

“…Therefore, recent research in the niche sector of wood science and technology has focused on various wood modification processes to overcome the shortcomings associated with processing and use in service [4]. Thermal and chemical modifications of wood are the most common in practice today and have found commercial applications after satisfactory performances in terms of improved biological resistance and dimensional stability [5][6][7][8][9][10][11][12][13][14] but are often associated with high energy consumption and the use of chemicals that are not environmentally friendly.…”

Quantitative evaluation of microwave irradiation on short-rotation plantation wood species

“…This may result in early and frequent replacement of the wood in use which may not be economically and ecologically feasible (Samani et al 2019). Hence, research on wood modification nowadays in India primarily focuses on several imported and indigenous species of lower durability and enhancing their performance in service (Ganguly and Tripathi 2018, Hom et al 2020a, Samani et al 2020, Hom et al 2020b, Saha et al 2020.…”