Characterization of Ailanthus altissima Veneer Modified by Urea-formaldehyde Pre-polymer with Compression Drying

Abstract

Recently, Ailanthus altissima wood has received increased attention in China. Although Ailanthus altissima has a number of advantages, such as fast-growing character and high density, the low dimensional stability is a restraining factor. Chemical modification could be a feasible way to overcome such drawbacks. The aim of this research was to study the physical and chemical properties of Ailanthus altissima veneers treated by urea-formaldehyde pre-polymer impregnation and compression drying. The results showed that this approach not only significantly increased the dimensional stability of wood, but also enhanced the bending strength and compressive strength parallel to the grain. The FT-IR analysis showed that the intensity of hydroxyl (-OH) and carbonyl (C=O) absorption peaks decreased, which indicated that the NH-CH2-OH of the pre-polymer reacted with the wood’s carboxyl and hydroxyl groups. The positions of the XRD peaks did not change, which indicated that the structure of cellulose crystallinity was not noticeably affected by the chemical modification. The TGA showed that the thermal stability of modified wood was improved, while FESEM showed that the wood cell wall and vessels were impregnated with chemicals.