PF预聚物处理固定木材压缩变形的机理

Study on the Fixation Mechanism of Compressive Deformation of Wood by PF Resin Treatment

利用Ｘ射线衍射法测得ＰＦ预聚物处理材的晶区大小和相对结晶度，结果表明，ＰＦ预聚物的引入没有改变纤维素的结构。解析ＦＴＩＲ光谱图得知．经ＰＦ预聚物处理后的压密材酯化羰基 （１７３６ ｃｍ－１）峰强度增加、半纤维素异头碳（８９７ｃｍ－１）峰强度增加，纤维素、半纤维素醚键（１０５６ ｃｍ－１）峰强度减少、说明半纤维素聚木糖经ＰＦ预聚物处理后发生改变木材细胞壁物质中的纤维素、半纤维素、木质素分子中的某些基团发生交联．形成了新的基团。从ＥＳＲ和ＥＳＣＡ测试结果可知．由于ＰＦ预聚物处理木材的机械自由基（Ｍｅｃｈａｎｏｒａｉｄｃａｌ）的浓度明显降低，可以推断出木材自由基与ＰＦ预聚物之间发生了化学作用，导致ＥＳＲ信号绝大部分丧失、ＥＳＣＡ能谱分析表明ＰＦ预聚物处理后的压密材，随着ＰＦ预聚物浓度的增加。ＣＩ态含量逐渐减少．而ＣⅡ态、 ＣⅢ态却逐渐增加、 ＣⅣ态变化不大。结果表明， ＰＦ预聚物处理能够稳定木材尺寸、固定木材横纹压缩变形的主要原因是由于ＰＦ预聚物填充于木材细胞壁空隙中和细胞腔的内表面。活性很高的羟甲基等基团与木材细胞壁物质发生反应，形成共价键和其它键型，部分取代了羟基（－ＯＨ）以及其它基因形成交联化作用。

The size of crystalline region and relative crystallinity were measured by X-ray on the timber which was treated by PF resin. The measurement results show that the crystalline structure of cellulose baldly changed compared with untreated wood. Analysis FTIR spectra of timber treated by PF resin show that esterified carbonyl peak intensity (1736 cm-1) and the end carbon degree of semicellulose (897 cm-1) increase. The free radicals of wood activate the molecular of PF resin and produce -C=O, cross linking reactions take place in cell wall materials. The results of ESCA and ESR spectra prove that with the increase of PF resin concentration. the relative content of CⅠ decreases, the relative contents of CⅡ and CⅢ increase. CⅣ hardly change. The concentrations of flee radical of wood surface reduce obviously. The wood treated by PF resin could stabilize size. fix compressive deformation.