Mechanism of fiber/matrix bond and properties of wood polymer composites produced from alkaline-treated Daniella oliveri wood flour

The effects of sodium hydroxide (NaOH) concentration and time of treatment on the mechanism of fiber/matrix bond and functional properties of Daniella oliveri reinforced wood polymer composites (WPCs) were investigated. The WPCs were evaluated using Fourier transform infrared spectroscopy, mechanical testing, scanning electron microscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry. The fiber/matrix adhesion mechanism could be attributed to the disruption of hydrogen bonding in the D. oliveri wood fiber network structure and the removal of lignin, wax and oils covering the external surface of the fiber cell wall. This leads to an increase in desirable functional properties as alkaline concentrations reached 4 wt%, but subsequently reduced at higher concentrations, while they increased with treatment time. Analysis of the fractographs of the WPCs suggests optimization of interfacial fiber–matrix adhesion and functional properties when D. oliveri wood fiber was treated with a 4 wt% solution of NaOH for 150 min. POLYM. COMPOS., 37:2657–2672, 2016.