天然纤维素结晶结构的表征

摘要

A kind of bacterial cellulose was prepared by using Gluconacetobacter xylinum 1.1812 as the strain through static culture at 30 ℃or shake culture at 12℃( shake rate 150 r/min) for 5 d.The crystalline structure of the bacterial cellulose was analyzed by X-ray diffraction ( XRD) , Fourier transform infrared spectrometry ( FTIR) and solid-state 13 C nuclear magnetic reso-nance spectroscopy ( CP/MAS 13 C-NMR) .The results showed that bacterial cellulose microspheres composed of twisted flat rib -bons formed from Gluconacetobacter xylinum 1.1812 strain after shake culture at 12℃, which is completely amorphous structure comprising the ordered para-crystalline structure with the crystal index of 9.7％;the bacterial cellulose membrane formed by the accumulation of fiber layers with the diameter of 40-100 nm after static culture at 30℃, which exhibited the cellulose I crystal structure with the crystal index of 90.3％, 4.75 and 86.7％observed by XRD,FTIR and CP/MAS 13C-NMR, respectively.%以木醋杆菌1.1812菌株为菌种,分别在30℃静态培养和12℃下振荡(振荡速率150 r/min)培养5 d,制得细菌纤维素,通过X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和固体13C核磁共振(CP/MAS 13 C-NMR)分析了细菌纤维素的结晶结构.结果表明:木醋杆菌1.1812菌株在12℃恒温振荡培养得到细菌纤维素微球,由扭曲的扁平状带子交织而成,XRD分析表明其为完全无定形结构,而CP/MAS 13 C-NMR分析其结晶指数为9.7％,表明这种完全无定形结构中包含了有序的次晶结构;30℃静态培养得到细菌纤维素膜,由直径40～100 nm纤维层层堆积而成,为纤维素Ⅰ晶型结构,XRD分析其结晶指数高达90.3％,FTIR法得到的结晶指数为4.75,CP/MAS 13 C-NMR分析其结晶指数为86.7％.