摘要
This study investigated the effect of weight percent gain （WPG） and compression set on the crystallity of compressed poplar wood. Tests were conducted to determine the mechanism of compressed wood set. The samples of 1-72 Poplar were treated with a PF resin of water-solubility and low molecular weight. Then the air-dried samples were hot-pressed to a certain thickness. Finally the specimens were obtained from the compressed samples and scanned with an X-ray diffractometer. Results show that before press the crystallity of the inner layer is lower than that of the outer layer, and at press the difference of the crystallity between the outer layer and the inner layer will slowly disappear and finally the crystallity of the inner layer exceeds that of the outer layer; with the increasing compression set the crystallity decreases, and there is a big decrease; the crystallity difference between two layers happens because of compression set gradient, WPG difference or the joint effect.
This study investigated the effect of weight percent gain (WPG) and compression set on thecrystallity of compressed poplar wood. Tests were conducted to determine the mechanism of compressedwood set. The samples of I-72 Poplar were treated with a PF resin of water-solubility and low molecularweight. Then the air-dried samples were hot-pressed to a certain thickness. Finally the specimens wereobtained from the compressed samples and scanned with an X-ray diffractometer. Results show that beforepress the crystallity of the inner layer is lower than that of the outer layer, and at press the difference of thecrystallity between the outer layer and the inner layer will slowly disappear and finally the crystallity of theinner layer exceeds that of the outer layer; with the increasing compression set the crystallity decreases, andthere is a big decrease; the crystallity difference between two layers happens because of compression setgradient, WPG difference or the joint effect.
