Epoxy and succinic anhydride functionalized soybean oil for wood protection against UV light action

Abstract

Wood is a versatile composite material consisting of natural macromolecules, including carbohydrates (cellulose, hemicelluloses) and lignin. As a natural biological material, wood undergoes photooxidation phenomena under environmental factors action. Colour modification of wood surface is a primary consequence of the photooxidation phenomena. One way to prevent wood photodegradation consists in coating it with protective layers by chemical modification of the surface. The aim of this study is related to the photostability evaluation of chemically modified softwood by successive treatment stages with succinic anhydride and epoxidized soybean oil, respectively, during exposure to UV radiation with wavelength above 280 nm. Wood and wood coated materials photooxidation was monitored in terms of colour and structural modification as functions of irradiation time and dose. Chromatic coordinates values exhibited a slow increase with irradiation time and dose compared to the values of unmodified wood. Lignin exhibited stronger photodegradation tendencies, leading mainly to an increase of redness feature of wood samples surface. The coating layer consisting of epoxidized soybean oil protected the modified wood surface against photooxidation reactions by a screening effect.