RHEOLOGICAL ANALYSIS OF BIO-ADHESIVES BASED CASSAVA STARCH AND MILICIA EXCELSA'S TANNIN

This work investigated the rheology of two news adhesives using Vachelia nilotica exudate as a hardener. The first was developed with cassava starch (C1) and the second with Milicia excelsa tannin (C2). The Milicia excelsa species are very rapid growing and have a high percentage of tannin. Their behavior was studied by using Dynamic Mechanical Analysis (DMA) and the evaluation of viscosity and activation energy. Their activation energies calculated at the gel times were respectively 949.25 KJ.mol-1 and 105.565 KJ.mol-1. Their dynamic viscosity decreases with temperature, The C2 adhesive had better damping properties than the first C1. The storage mechanical energy of C2 adhesive was higher than that of the C1 one. Thus, at their transition temperature, their respective stiffness was of 11540 and 11550 MPa respectively. Their glass transition temperatures are 132°C and 150°C respectively. The gel times of C2 at the temperatures studied were shorter than those of C1. The mechanical properties (IB, MOE and MOR) of particleboards PBC2 using bio adhesive C2 are better than of particleboards PBC1 using bio adhesive C1. The average values of IB, MOE and MOR of PBC2 are respectively recorded o are respectively 0.41, 2008.35, 16.74 MPa.