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Production and properties of high performance wood-based panels.

高性能人造板的生产和性能。

基本信息

批准号：
08660210
负责人：
KAJITA Hiromu
金额：
$ 1.54万
依托单位：
KYOTO PREFECTURAL UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

Sodium hydroxide was used with a molar ratio of phenol to formaldehyde in the range of 1 : 2. After the reaction, two kinds of low molecular-eight (number average molecular-weight, Mn=300) Phenol-formaldehyde (PF) resin were prepared : alkaline PF resin (pH : 10.3) and neutral PF resin (pH : 6.0). In the latter, organic acid was added to reduce the pH to 6.7. The neutral resin is more stable under ambient storage condition than the alkaline resin and color of the neutral resin treated wood was yellow. On the other hand, color of the alkaline resin treated wood was blackish-brown. Dimensional stabilization and biological resistance of the PF resin-treated wood were not significantly different between neutral and alkaline resin.The penetration of PF resin into cell walls on sub-and ultramicro levels was investigated by means of light microscopy, electron probe X-ray microanalysis (EPMA), and X-ray photo-electron spectroscopy (XPS). Three kinds of m-bromophenol-formaldehyde resin having Mn of 290,470, and 820 were synthesized to detect the presence of resin as a signal of bromine (Br). In the specimens impregnated with small molecular-weight resins at concentrations of 1 and 15%, light microscopic observation revealed that the PF resins were hardly located in tracheid lumina at lower concentrations. Even at a concentration of 15%, the number of tracheids filling the resin in their lumina was very small. Judging from both light microscopy and EPMA,the PF resin with small and middle molecular-weights proved to penetrate mostly into cell walls, contributing to the enhancement of dimensional stability in resin-treated wood. Also, for PF resin with larger molecular-weight, the resin components with smaller molecular-weight was suggested to be present in the walls.

使用氢氧化钠，苯酚与甲醛的摩尔比在1：2的范围内。反应后制得了两种低分子量（Mn=300）酚醛树脂：碱性酚醛树脂（pH：10.3）和中性酚醛树脂（pH：6.0）。在后者中，加入有机酸以将pH降低至6.7。中性树脂在常温下比碱性树脂更稳定，中性树脂处理的木材颜色为黄色。另一方面，碱性树脂处理的木材的颜色是黑褐色。采用光学显微镜、电子探针、X射线光电子能谱等方法，研究了酚醛树脂对木材细胞壁的渗透作用。合成了Mn分别为290、470和820的三种间溴苯酚甲醛树脂，以检测树脂的存在作为溴（Br）的信号。在浸渍与小分子量树脂的浓度为1%和15%的标本，光学显微镜观察显示，PF树脂几乎不位于管胞腔在较低的浓度。即使在15%的浓度下，填充在其管腔中的树脂的管胞的数量也非常少。光学显微镜和电子探针分析结果表明，中、小分子量的酚醛树脂主要渗透到细胞壁中，有助于提高树脂处理木材的尺寸稳定性。对于分子量较大的酚醛树脂，建议在壁中存在分子量较小的树脂组分。