麦草蒸汽爆破处理的研究──Ⅱ.麦草蒸汽爆破处理作用机制分析

Studies on the Steam Explosion of Wheat Straw──Ⅱ. Mechanisms of Steam Explosion of Wheat Straw

对汽爆麦草进行了电镜观察及差热、红外光谱和纤维表面特征的X-射线光电子能港分析（XPS）。汽爆麦草显微形态表明，在汽爆过程中木质素部分被抽提出之后，又重新分布沉聚于纤维的表面。汽爆麦草的差热性质分析说明了汽爆使麦草的半纤维素和部分木质素降解为低分子物质，并且使纤维疏松，形成多孔性，易于燃烧。汽爆麦草红外光谱分析表明，添加了碱性物质，半纤维素降解得很少。因此，汽相蒸煮的酸碱度是半纤维素溶出的的关键性因素。汽爆麦草纤维表面特征的XPS分析结果也说明汽馒处理使纤维比表面积增加，余水性基团更多。

Wheat straw after steam explosion treatment was investigated by SEM, DTA, IR andXPS, respectively. Micromorphologic observation indicated that lignin was deposited on the surface of fiber after it was extracted during the steam explosion. Differential thermal analysis demonstrated that steam explosion resulted in the degradation of hemicellulose and part of lignin in the wheat straw. The fiber became loose, porous and inflammable. IR spectra shotm that the degradation of hendcellulose was reduced in case of adding alkali into the reaction system .Thus, the pH value of the cooking system is the key factor in the dissolution of hendcellulose. XPS results also demonstrated that the steam explosion could lead to the increase in the special surface area and the hydrophilic groups of the fiber.