Crystalline structure of cellulose in wood after chemical modification using cyclic acid anhydrides (maleic and succinic)

Abstract

The chemical modification of wood can be directed to improve various properties, e.g., the dimensional stability, hardness properties, and/or durability properties, against weathering. In this study, a Romanian softwood species Abies alba Mill. was treated and chemically modified using two cyclic acid anhydrides, i.e., maleic and succinic, to improve its interfacial properties relative to unmodified wood. Structural changes, with focus on the evolution of crystalline part in wood after chemical modification, the water absorption, and the water repellent efficiency, were determined. Maleic anhydride exhibited a lower reactivity towards wood substrate than succinic anhydride, presumably because of their different chemical structure (maleic anhydride is very sensitive to the presence of water). It was found that the percentage of water absorption was diminished, primarily after the succinic anhydride treatment. The chemically modified wood was characterized via Fourier transform-infrared spectroscopy and wide-angle X-ray diffraction methods. The crystalline part from wood structure was evidenced in relation to the employed anhydride in chemical modification approach.