不同因素对竹柳枝桠材重组木性能的影响

Properties of Salix discolor scrimber

竹柳Salix discolor枝桠材的直径小,是重组木的好原材料。试验结果表明:在竹柳重组木为密度0.9 g·cm^(-3),脲醛树脂(UF)施胶量15%,枝桠材直径5~10 mm,木束长度150和450 mm,热压温度140℃,加压时间20 min,木束含水率6%条件下制得的竹柳重组木静曲强度为102.04 MPa,内结合强度1.99 MPa,2 h吸水厚度膨胀率3.78%,其值均达到或超过LY/T 1984-2011《重组木地板》行业标准的要求;扫描电子显微镜(SEM)图像表明:用脲醛树脂压制的竹柳重组木的管孔被压缩成椭圆形,但细胞壁本身并没有被压溃,仍然保持了其完整性,木束表面附着的胶黏剂均匀;X射线能谱(EDAX)表明枝桠材直径≥10 mm制得的重组木的碳氧比为0.55,枝桠材直径5~10mm为0.60,枝桠材直径为≤5 mm为0.62。说明枝桠材直径对碳氧比有影响;且枝桠材制成的重组木的碳氧比高于枝桠材本身的碳氧比(0.41)。

This study was conducted to determine if small diameter Salix discolor branches were a favorable raw material for scrimber. To test, urea-formaldehyde resin(UF) was used indoors. Results showed that when the density was 0.90 g·cm^(-3), glue consumption was 15%; the optimum treatment parameters of plates manufactured with UF were an initial moisture content of 6%, hot-pressing temperature of 140 ℃, and hot-pressing time of 20 min. Also, the modulus of static bending strength was 102.04 MPa, internal bonding was 1.99 MPa, and the thickness swelling rate after 2 h of water soaking was 3.8%, which were up to industry standards [Scrimber Floor](LY/T 1984-2011). SEM images also showed that the UF was compressed into an oval hole, but the cell wall itself maintained its integrity and was not crushed. EDAX also showed that the C/O for wooden sticks with diameters ≥ 10 mm was 0.55, 5-10 mm was 0.60, and ≤ 5 mm was 0.62. Thus, C/O of S. discolor branches made of scrimber were higher(> 0.55) than C/O of S. discolor branches alone(0.41).