A preliminary survey of the interfacial bonding of some tropical hardwoods towards succinic anhydride and 2-octen-1-yl succinic anhydride molecules: Impact of lignin and carbohydrate polymers structure on the chemical reactivity

From the perspective of the utilization of the wood waste from African timber industry in the field of wood/polymer composites, the reactivity of four tropical hardwood species from Gabon, Tesula gabonensis Pellegr (T. gabonensis), Holoptelea grandis Hutch (H. grandis), Aucoumea klaineana Pierre (A. klaineana Pierre) and Tieghemella africanaPierre (T. africana) towards succinic anhydride (SA) and 2-octen-1-yl succinic anhydride (OSA) was studied on the basis of their carbohydrate complex and lignin polymers structure and composition as well as on the basis of the capability of their wood cell walls to absorb the dimethylformamide (DMF) and pyridine (Py) solution. T. gabonensis, H. grandis and T. africana wood sawdust are more reactive with SA than A. klaineana. However, T. gabonensis is the most reactive with SA as well as with OSA. The better reactivity of T. gabonensis should be connected to the abundance of the reactive hydroxyl functions in its native lignin. Furthermore, T. gabonensis, H. grandis and T. africana are rich in long polysaccharide fibers; their cell walls displayed a strong capability for swelling after DMF/Py absorption than A. klaineana. The latter displays short polysaccharide fibers assumed to agglomerate within the cell walls, limiting like this the contribution of the polysaccharide chains located within A. klaineana cell walls on its chemical reactivity; protecting thereby its cellulose matrix from a decrystallization as pointed out by X-ray diffraction (XRD) analysis. The crystalline lattice of T. gabonensis, H. grandis and T. africana for which the cell walls are more accessible to DMF/Py exhibit the most important decrease of the crystallinity index (CrI) and the crystallite sizes (D0 0 2).