The species Melia composita has come to prominence only during the last decade and has been found suitable for several applications and end uses. However, being non-durable and difficult to treat some pre-treatment is required to improve preservative uptake. Hence the effect of microwave (MW) pre-treatment was studied on the samples of Melia composita wood in order to ameliorate its retention, depth of penetration and treatability class to ensure its sustainable use for a longer duration. The samples were exposed to MW radiation of different intensities and treated with 6% solutions of CCA, ZiBOC, CCB and Borax boric acid (BBA) preservatives by a dip diffusion method for 24 hours. Results showed a significant improvement in preservative uptake after dipping for 24 hours, in comparison with the controls. The highest retention was found in the samples treated with ZiBOC preservative after their MW exposure to 840 MJ·m–3. Wood anatomical analysis after MW modification was also performed in order to assess the changes taking place within the wood microstructure. The cross-sectional analyses of the controls and the treated specimens were briefed accordingly. Results of the anatomical study exhibited a significant improvement in the effective vessel diameters of the microwave irradiated specimens due to the clearance of the occlusions blocking the vessels with respect to the control samples, which aids in increasing wood permeability and results in higher retention and penetration.
microwave modification; permeability; Melia composita
Dashti H., Tarmian A., Faezipour M., Hedjazi S., Shahverdi M. (2012): Effect of microwave radiation and pre-steaming treatments on the conventional drying characteristics of fir wood (Abies alba L.). Lignocellulose, 1: 166–173.
EN 350 (2016): Durability of wood and wood-based products – Testing and classification of the durability to biological agents of wood and wood-based materials.
He S., Lin L., Fu F., Zhou Y., Fan M. (2014): Microwave treatment for enhancing the liquid permeability of Chinese fir. BioResources, 9: 1924–1938.
IS 11215 (1991): Moisture Content of Timber and Timber Products-Methods for Determination. Bureau of Indian Standards, Manak Bhawan, New Delhi, India.
IS 2753 (1991): Methods for estimation of preservatives in treated timber and in treating solutions. Manak Bhawan, New Delhi, India.
IS 401 (2001): Preservation of timber code of practice. Bureau of Indian Standards, Manak Bhawan, New Delhi, India.
Liu H.H., Wang Q.W., Yang L., Jiang T., Cai Y.C. (2005): Modification of larch wood by intensive microwave irradiation, Journal of Forestry Research, 16: 237–240. https://doi.org/10.1007/BF02856823
Parthiban K.T., Bharathi A.K., Seenivasan R., Kamala K., Rao M.G. (2009): Integrating Melia dubia in agro-forestry farms as an alternate pulpwood species. Asia-Pacific Agroforestry Network (APAN), 34: 3–4.
Sharma S.K., Shukla S.R., Sujatha M., Shashikala S., Kumar P. (2012): Assessment of certain wood quality parameters of selected genotypes of Melia dubia cav. grown in a seedling seed orchard. Journal of the Indian Academy of Wood Science, 9: 165–169. https://doi.org/10.1007/s13196-012-0083-2
Smith W.B., Schneider P.F., Resch H. (1996): Rapid fixation of CCA wood preservative with electromagnetic energy. Forest Product Journal, 46: 47–51.
Torgovnikov G., Vinden P. (2010): Microwave wood modification technology and its applications. Forest Products Journal, 60: 173–182. https://doi.org/10.13073/0015-7473-60.2.173
Torgovnikov G., Vinden P. (2009): High intensity microwave wood modification for increasing permeability. Forest Products Journal, 59: 84–92.
Treu A., Gjolsjo S. (2008): Spruce impregnation, finally a breakthrough by means of microwave radiation. In: Proceedings of the “4th Meeting of the Nordic Baltic Network in Wood Material Science & Engineering (WSE)”. Riga (Latvia) 13–14 Nov 2008. Horsholm, SNS-Nordic Forest Research Co-operation Committee, Copenhagen University: 42–48.
Tripathi S. (2012): Treatability evaluation of meranti with ZiBOC and CCA. International Wood Products Journal, 3: 70–76. https://doi.org/10.1179/2042645311Y.0000000021
Tripathi S. (2013): Indian Patent 2,57,393.
Vinden P., Torgovnikov G., Hann J. (2011): Microwave modification of Radiata pine railway sleepers for preservative treatment. European Journal of Wood and Wood Products, 69: 271–279. https://doi.org/10.1007/s00107-010-0428-8
Xu K., Wang Y., Lv J., Li X., Wu Y. (2015): Microwaves & wood impregnation. BioResources, 10: 282–289.