Abstract:

The impregnation and distribution of phenol resin in Chinese Fir and its improvement methods by extracted and vacuum treated were studied. ERL(effectiveness of resin loading)of phenol resin aqueous solution was 10% under soaking condition at atmosphere, but it increased to 90% under the vacuum condition whether or not the specimens were extracted. The weight of impregnated resin in the wood with vacuum treatment was remarkably higher than that at atmosphere soaking. The distribution of resin at longitudinal direction of the wood was analyzed by soft X-ray densitometry. The results showed that the resin was mainly distributed on the end of the specimens that were treated at atmosphere soaking whether or not the specimens were extracted. The resin by vacuum impregnation can be impregnated more deeply than by atmosphere soaking for the specimens without extracting, and even reach the center of the specimens if the specimens were extracted. The variation of the resin distribution in the wood was small by test for homogeneity of variance and welch test after the specimens were extracted. It means that the impregnation and distribution of resin in the wood were improved by the vacuum and extraction treatment. Meanwhile, in the longitudinal direction and radial direction of the specimens, the resin distribution were analyzed by the microscope to observe the resin loading condition in lumen. In the longitudinal direction, the loading rate decreased from end to the center of the specimens. But the loading rates of extracted specimens were higher than that of un-extracted specimens at the same location in the longitudinal direction.

Key words: Wood modification, Phenol-formaldehyde resin, Soft X-ray densitometry, Impregnation, distribution, Chinese Fir plantation