Through impregnation with UF and PF resin, the modification technology of Poplar was experimented and studied. The study results showed that WPG(weight percent gain) of the test-pieces impregnated with UF and PF resin had less difference. The wood vessels were scarcely filled by resin especially UF resin. Regardless of impregnating with UF or PF resin, the cell lumens near the veneer junctions are basically filled by the resin. But the most of the cell lumens depart farther from the veneer junctions were only filled by PF resin instead of UF resin.

Aimed to improve the properties of Poplar, this study, taking phenol-formaldehyde resin (PF) and urea-formaldehyde resin (UF) as impregnation resin, probed the effect of the technology factors-vacuum time, solid content of resin, impregnation temperature and time on the impregnation results of Poplar, and the relationship between the resin and the wood was researched through infrared spectrum. The weight percent gain (WPG) of test-pieces increased with vacuum time extending, and WPG of the test-pieces were greatest when the solid content of resin was 30%, and the impregnation temperature was 25-30°C. when the impregnation time extended from 3 h to 9 h, WPG of the test-pieces presented increase trend which wasnt obvious. In this wood impregnated resin, the reaction between the resin and the hydroxy in wood formed ether bond binding, which proved that the resin and the wood occurred the chemical reaction.

Through impregnating with UF resin, the modification technology of Poplar was experimented and studied. The study results proved that the laminated veneer lumber (LVL), impregnated with UF resin, reached fine quality when the bumping vacuum time, the solid content of UF resin, the impregnation temperature and time were respectively 40min, 30%, 25-30°C and 3 hours. The picture of electron microscope showed that in LVL impregnated with UF resin, the wood vessels and cells near the veneer junction sections occurred mostly deformation, but the wood cells depart farther from the veneer junction sections occurred rarely deformation. The cell lumens and middle lamella near the veneer junction sections were almost filled by the resin，but the scarcely any resin filled in the wood cell lumens depart farther from the veneer junction sections.