Desorption Behavior and Thermogravimetric Analysis of Bio-Hardeners

In this work, the thermal degradation and drying of bio-hardeners are investigated. Four bio-hardeners based on exudates of Senegalia senegal, Vachellia nilotica, Vachellia seyal, and Acacia Siebteriana were analyzed by FTIR and thermogravimetric analysis, and a desorption study was also conducted. The analysis by infrared spectroscopy indicates the existence of oligomers of different types all giving 5-hydroxy-2-hydroxymethylfuran and 2, 5-dihydroxymethylfuran which are then the real hardening molecules. The pyrolysis of these extracts reveals three main regions of mass loss, a first region is located between 25 degrees C and 110 degrees C reflecting the loss of water from the adhesive and the formation of some traces of volatile organic compounds such as CO2 and CO, a second zone characterized by the release of CO, CO2 and CH4 gases with peaks between 110 degrees and 798.8 degrees C. At the end of the analysis, about 22% of the initial mass remains undecomposed, this mass corresponds to the rigid segments of the bio-hardener which are not completely decomposed.