XRD与NMR的热处理竹材结晶性能研究

木质纤维素的结晶度研究方法较多,但目前观点不一。采用三种不同的热处理方法(稀酸,碱及甘油高温处理)并基于X射线衍射(XRD)和固体核磁共振技术(CP/MAS 13 NMR),综合研究竹材结晶度变化规律,通过X射线衍射参数及高斯函数曲线分析结晶纤维素C-4区域的信号面积分析,获得不同的化学热处理介入下竹材化学成分及结晶度变化机理。结果表明:经过化学热处理后,竹材的结晶度指数总体增加,碱处理002峰尖锐程度增大,并向大角度方向偏移明显,002晶面宽度变大,结晶区层间距尺度变小。CP/MAS 13 NMR与XRD结果基本一致,但是计算值偏小。未处理竹材在84.6ppm信号处分裂成两个峰顶,88.7和83.1ppm,,表明C-4在热处理过程中发生了从纤维素Ⅰ~Ⅱ的化学转换,从化学结构变化的角度证明了碱处理可以有效破坏竹子纤维之间的内结合阻力,并产生高度活性纤维素,对于实现木质纤维素原料的高效生物转化利用提供指导。

Study of Crystallinity Performance of Pretreated Bamboo Fibers Based on X-Ray Diffraction and NMR

At present there are many methods to discuss the crystallinity of lignocellulose but scholars experts have different opinions about them.This study,with bamboo under the different pretreatment conditions,and with help of acid,alkali and glycerol uses X-ray diffraction and CP/MAS 13 NMR in order to make clear of the crystallinity of bamboo change characteristics, and measured the area length,spacing,crystal plane diffraction peak position,the crystallinity index and parameters and com-plete the comparison of crystalline cellulose and Gaussian function curve C-4 area signal area.Results showed that crystalline o-verall increased significantly after pretreatment,002 peak become sharp and offset to the direction of large angle for alkali pre-treatment,002 crystal width increases,crystalline spacing is smaller.CP/MAS 13 NMR is consisting with XRD,but calculated value is smaller.It proved that effective processing can effectively disrupted the recalcitrance of bamboo,and produce highly ac-tive cellulose in lignocelluloses’biomass ethanol production,that provide guidance to realize the lignocellulose bioconversion and effective utilization.