Quality of Oleoresinous Wood Varnish Prepared using Resin Synthesized from Tannin Extracted from Stem Bark of Khaya senegalensis


  • Osei Akoto Kwame Nkrumah University of Science and Technology
  • Anthony Osei-Brefoh


Khaya senegalensis, Oleoresinous varnish, Phenol-formaldehyde resin, Tannin extract


Phenol is used as a starting material in the preparation of wood varnish. In this work efforts were made to substitute phenol from tannins extracted from the stem bark of Khaya senegalensis to produce wood vanish and assessed its quality. An extract with a Stiasny Number of 87.88 % and extractable phenols of 2.82 mg/kg was used to synthesize a phenol-formaldehyde called tannin-formaldeyde. Properties of this resin were compared with that of phenol-formaldehyde resin synthesized using a commercially available phenol following the same procedure. A yield of 89.82% for phenol-formaldehyde resins showed a good and efficient method of synthesizing the resins. The study indicated that tannin-formaldehyde resins had better solubility in linseed oil than phenol-formaldehyde resin. A dark-brown viscous resole-type phenolic resin was produced from tannin extract as against a yellow viscous resin for commercial phenol. the colour of the Subsequently, unfortified oleoresinous wood varnish (solutions of one or more natural or synthetic resins in a during oil and volatile solvent) of high gloss, good chemical resistance and good drying time paralleling each other were readily prepared from both resins. Varnish made from phenol-formaldehyde and tannin-formaldehyde resins had acid numbers of 9.9 mg KOH/g and 8.6 mg KOH/g varnish respectively: both falling within the 0.2-10.5 range for most satisfactorily commercial varnishes, this implies that tannin-formaldehyde resin is advantageous over phenol-formaldehyde resin since the source of tannins is cheaper and renewable as well as contributes to reduction in land pollution hence its production should be considered.

Author Biography

Osei Akoto, Kwame Nkrumah University of Science and Technology

Chemistry Department Senior Lecturer


Papadopoulou, K. and Chrissafis, K.,.â€Thermal study of phenol–formaldehyde resin modified with cashew nut shell liquidâ€, Thermochimica Acta, vol. 512, pp. 105-109, 2010.

Fechtal M., and Riedl B., “Use of Eucalyptus and Acacia mollossim bark extract-formaldehyde adhesives in particleboard manufactureâ€, Holzforschung, vol. 47, no.4, pp. 349-357, 1993.

Atuahene, S. K. N., The forest resource of Ghana and research on Hypsipyla robusta (Moore) (Lepidoptera: Pyralidae): Control in mahogany plantations in Ghana. In: Floyd, R.B. & Hauxwell, C. (eds), Hypsipyla shoot borers in Meliaceae. Proceedings of an International Workshop, Kandy, Sri Lanka, 20-23 August 1996. Australian Centre for International Agricultural Research, Canberra, pp. 58-62, 2001.

Brunck, F., and Mallet, B., “Problems relating to pests attacking Mahogany in Coˆte d’Ivoireâ€. Bois et Foreˆts des Tropiques, vol. 237, pp. 9-29, 1993.

Dupuy, B., “Mixed plantations in Coˆte d’Ivoire rain forestsâ€. Bois et Foreˆts des Tropiques, vol. 24, pp. 33-34, 1995.

Hawthorne, W. D., Forest Regeneration after Logging: Findings of a Study in the Bia South Game Production Reserve, Ghana. ODA Forestry Series No. 3, Natural Resources Institute, Chatham Maritime, London. 1993.

Alder, D., Natural forest increment, growth and yield. In: Wong, J.L.G. (Ed.), Ghana forest inventory project seminar proceedings. Ghana forestry Commission/Overseas Development Administration, Accra, Ghana, pp. 47-52, 1989.

Wang, M., Leitch, M., and Xu, C., “Synthesis of phenol–formaldehyde resol resins using organosolv pine ligninsâ€, European Polymer Journal, vol. 45, pp. 3380-3388, 2009.

Kumar K.P., and Vinod, Sethuraman M. G., “Studies on oleoresinous varnishes and their natural precursorsâ€. Proress in Organic Coatings, vol. 49, pp. 244-251, 2003.

Food and Agriculture Orgnization (FAO)/ IAEA, Working document (lab manual), quantification of tannins in tree foliage, IAEA, Vienna, pp.1-3, 2000.

Porter, L .J., Hrstich, L. N. and Chan, B. G., The conversion of procyanidins and prodelphinidins to cyanidin and delphinidin, phytochemistry, vol. 25, pp. 223-230, 1986.

Gardner, H. A. and Sward, G. G., Physical and chemical examination of paints, varnishes, lacquers and colours, Gardner Laboratory Incoporated, Maryland, 1978.

Hernes, P. J., Hemingway, R. W. and Karchesy, J. J., Chemistry and significance of condensed tannins. In: Proceedings of the first North American tannin conference. Plenum Press, New York, p. 62, 1989.

Hedges, J. I., Determination of condensed tannin monomers in environmental samples by Capillary Gas Chromatography of acid depolymerization extracts, Analytical Chemistry, vol. 72, pp. 5115-5124, 2000.

Simonnet C., Vincent, G., and Jean-Louis, H., Physical and chemical properties of varnishes and their vibrational consequences. PACS REFERENCE: 43 75 DE, 2004.

Marie-Pierre, L., Investigation of the wood/phenol-formaldehyde interphase morphology, PhD Thesis, Blacksburg, Virginia, 2002.

Akaranta O., and Aloko A.O., “Bituminous coating: effects of cashew nut shell on Liquid-Tannin resinsâ€, Pigment & Resin Technology, vol. 28. no.6, pp. 336-340, 1999.




How to Cite

Akoto, O., & Osei-Brefoh, A. (2014). Quality of Oleoresinous Wood Varnish Prepared using Resin Synthesized from Tannin Extracted from Stem Bark of Khaya senegalensis. Asian Journal of Applied Sciences, 2(1). Retrieved from https://ajouronline.com/index.php/AJAS/article/view/849