WOOD MODIFICATION USING A UREA-FORMALDEHYDE PREPOLYMER

Urea-formaldehyde prepolymer and heat treatment were used to improve the properties of fast-growing wood. Results showed that the chemical modification not only decreased moisture absorption, but also increased bending strength and compressive strength parallel to grain. Fourier transform infrared spectroscopy analysis showed that the intensity of the hydroxyl and carbonyl absorption peak decreased, which indicated that the NH-CH2-OH of urea formaldehyde prepolymer reacted with the wood carboxyl (C=O) and hydroxyl (-OH). The position of the X-ray diffraction peaks of modified wood did not change, indicating that the structure of cellulose did not change. The thermogravimetric analysis showed that the thermostability of fast-growing wood was improved. Scanning electron microscopy revealed that the cell wall and vessels were filled with impregnated chemicals.