Abstract
The objective of this work is to investigate the physico-chemical properties of agro-industrial by-products in order to determine some potential valorization applications in composites materials. Four different by-products have been studied: coconut nucifera shells, canarium schweinfurthii fruit cores, palm kernels shells and raffia vinifera fruit cores. The chemical composition of the materials was studied by Fourier transform infrared spectroscopy (FTIR). It made it possible to identify the presence of chemical compounds characteristic of biosourced materials such as cellulose, hemicellulose and lignin. The thermal properties were determined by thermogravimetric analysis (TGA), in order to determine the moisture content, the thermal degradation temperatures and the ash content of the biosourced materials. The results show a first phase with a loss of mass corresponding to the evaporation of water, with humidity contents varying between 7 and 10%. The second phase corresponds to the decomposition of cellulose and hemicellulose, starting between 185°C and 225°C. After the third phase of degradation, corresponding to the decomposition of lignin, the ash content is determined. The surface properties of the materials were also studied by wettability measurements. The contact angles of water (polar liquid) and diiodomethane (non-polar liquid) were measured. The surface energies could then be calculated, and vary between 54 and 65 mN/m. A correlation between the wettability and TGA results has been evidenced, the higher content of lignin inducing a lower surface energy, and potentially a better compatibility with polymer matrix. The targeted applications concern the use of these biosourced products as abrasive composite materials (associated with a polymer matrix), for example in the shoe industry (for the machining of soles), and also in mechanical stripping of surfaces.
