土状与鳞片状石墨氧化过程中结构变化研究

Structural Properties Change Comparison between Amorphous and Crystalline Flake Graphite in the Oxidation Process

以天然土状与鳞片状石墨为原料,采用改进Hummers法在不同氧化剂(KMnO4)用量下制得石墨的系列氧化产物,利用扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶变换红外(FT-IR)光谱、拉曼(Raman)光谱、紫外-可见(UV-vis)光谱及四探针测试仪对石墨原料及其氧化产物的结构属性与电阻率进行表征。结果表明,经氧化后土状与鳞片状石墨结构层上均接有羟基(C-OH)、环氧(C-O-C)、羧基(COOH)或羰基(C=O)等含氧官能团,但在相同KMnO4用量下土状石墨的氧化产物结构中含有更少的C-O-C和更多的COOH和C-OH。在KMnO4用量较低时,鳞片状石墨更易被氧化;在KMnO4用量较高时,土状石墨则更易被氧化。随着KMnO4用量的增加,土状与鳞片状石墨的结构有序程度与导电性均逐渐降低,但在相同的KMnO4用量下土状石墨氧化产物的结构有序程度更低,导电性更弱。

The nature amorphous and crystalline lfake graphite were oxidized by improved Hummers method, Scanning electron microscope （SEM）, X-ray diffraction （XRD）, Fourier transform infrared （FT-IR） spectroscopy, Raman spectroscopy and Ultraviolet-visible（UV-vis） spectroscopy etc. testing methods were used to study the structure and electrical properties of graphite samples and their oxidation products. The results showed that the hydroxyl group （C-OH）, ethylene （C-O-C） and carboxyl group （COOH） or carbonyl group （C=O） were connected to the graphite layer structure across the oxidation process, but the amorphous graphite structure contains more C-O-C or less COOH and C-OH than that of the crystalline lfake graphite at the same oxidation conditions. The crystalline lfake graphite could be easily oxidized with lower dosage of KMnO4, on the contrary, the amorphous graphite could be easily oxidized with higher dosage of KMnO4. The structure order degree and the conductivity of the oxidation products reduced with the dosage increase of KMnO4, but the structure order degree and the conductivity of the amorphous graphite is lower than that of the crystalline lfake graphite.