Reactivity, characterization and mechanical performance of particleboards bonded with tannin resins and bio hardeners from African trees

ABSTRACT Gilbertiodendron dewevrei tannin extract was characterized using MALDI–ToF and CP MAS 13C NMR methods. These two characterization methods have proven that catechin gallate is the dominant constituent. Subsequently, the G. dewevrei tannin bio-resins hardened with the exudates of Vachellia nilotica, Vachellia seyal, Senegalia senegal, Acacia siebteriana and the fruit powder of V. nilotica from the extreme north of Cameroon were studied using gel time analysis and thermomechanical analysis. Analysis indicated that the cross-linking species in these hardeners was 2,5-dihydroxymethyl furan linked to carbohydrate chains. The extracts obtained in comparison to paraformaldehyde cured adhesives in equal proportions (10%) show that the ‘biohardener’ had properties for adhesive and eco-friendly applications. The internal bond (IB) strength of G. dewevrei resin-bonded panels using biohardeners ranged from 0.46 MPa to 0.61 MPa, the MOE and MOR values were from 1880.23 to 2226,52 MPa and 14,17 to 16,41 MPa. All particleboards prepared presented exterior grade capabilities.