Extraction et caractérisation de la cellulose par délignification par voie douce du bois d'Eteng pour la modification des biofilms d'amidon

Abstract

This work focused on analyzing the potential of cellulose obtained through an eco-process and acacia gum used as a hardener in the formulation of cassava starch-based biofilms. The biofilms were prepared by casting using acid-hydrolyzed cellulose (AHC), bentonite as a reinforcing filler, and gum as a natural additive. Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), mechanical stress-strain tests, soil biodegradation, and moisture absorption tests were used to characterize the obtained biofilms. FTIR and XRD analyses highlighted the presence of oxidized cellulose, acacia gum, and bentonite additives in the starch-derived thermoplastic. Thermal analysis indicated an increase in the glass transition temperature (Tg) and the melting temperature (Tm) when acacia gum and/or bentonite were added to the reference plastic of acid hydrolyzed starch-cellulose (AN). Moreover, moisture adsorption is reduced by 10% and 18% respectively after the addition of gum arabic and bentonite combined with ACH in the reference biofilms. A biodegradation test conducted in a lateritic soil of Mbalmayo at pH 5.1 showed a low degradation of all composite films compared to AN. All these observations are consistent with the hardening of the composite attributed to gum arabic and mineral bentonite layers. This hardening is associated with the additive interaction with the starch matrix, which increases the H bonds. In the absence of gum arabic, the stress reaches 2 MPa; the plasticity modulus is 40 MPa, and more with gum arabic, whose values reach 7 MPa for a modulus stress of 150 MPa. Gum arabic proves to be a hardener that improves mechanical strength, thermal and crystalline properties, moisture adsorption, and biodegradation of cassava starch-based biocomposite plastics.