This work reports the extraction and application of tannins as wood-adhesives from Anogeissus leiocarpus plant using water, acetone or a mixture of these as solvent. In terms of the quantity of extracts from polyphenolic extract of Anogeissus leiocarpus bark, water was the most effective solvent, followed sequentially by acetone and solvent mixture (90% acetone and 10% water). The use of solvent mixture in tannin extraction yielded high tannin content. The poly condensation reaction of Anogeissus leiocarpus bark extract is influenced significantly by amount of formaldehyde (9.0 ml), tannin (2.5 g), glycerol (0.6 ml), cure temperature 80 O C, types and pH 7.5 of the adhesive medium. Adhesive joint of significant bond strength were obtained from Anogeissus leiocarpus tannin adhesive. Prolonged cure periods particularly at elevated temperature have adverse effect on the strength properties of these joints, especially with wood-panels as substrates. Joint prepared with adhesive derived from these extracts were tested for strength properties.

This work reports the application of tannin obtained from Anogeissus leiocarpus plant and its use in formulation of a thermosetting material for domestic and industrial use. The ploy condensation of tannin with formaldehyde produced a thermosetting resin with useful properties; formaldehyde (10.5 ml), tannin (2.5 g), glycerol (0.6 ml), hexamine (5.5 g), pH 7.5 and temperature 60 °C. Gel viscosity and effect of temperature on gel time were determined. Absorption behaviour of the films from the thermosetting material formulated under aqueous, acid and basic conditions were investigated. Water absorption up to 90% was obtained between 1 to 3 hrs. Perhaps due to differences in chain topology of the material formulated related to the molecular size holes in the polymer structure which depends on the morphology and crosslink density of the material. No acid absorption was observed after 12 hrs indicating that cross-linking reaction was still taking place in the solution.