Dielectric relaxation based on adsorbed water in wood cell wall under non-equilibrium state. 1

In order to make clear the molecular mechanism of the dielectric relaxation based on adsorbed water in wood cell wall during moisture changing process , the temperature and frequency spectrums of dielectric processes of Sikkim spruce (Picea spinulosa Griff.) were measured in three different adsorptio n processes. Three levels of relative humidity used were 40, 80 and 100 %, respectively, and the temperature was kept at 20 degrees C. In oven-dry sta te, relaxation process I based on the reorientation of CH2OH groups in amor phous region of wood cell wall was observed. While in moist state, relaxati on process II based on ionic conductivity and relaxation process III based on the additive reorientation of CH2OH groups and adsorbed water molecules occurred. Within higher humidity region, relaxation process IV concerned wi th adsorbed water in lignin was observed in the initial adsorption period, but it vanished with further adsorption.