高膨胀体积无硫可膨胀石墨的制备与表征

Preparation and characterization of sulfur-free expandable graphite with high expansion volume

以天然鳞片石墨为原料,高氯酸为插层剂,高锰酸钾为氧化剂,采用化学氧化法制备无硫可膨胀石墨,利用正交试验方法优化出最佳工艺条件为C∶KMnO_4∶HClO_4(g∶g∶m L)=1∶0.4∶7,反应温度为30℃,反应时间为70 min,在此条件下制备得到的可膨胀石墨的膨胀体积达390 m L/g。相关影响因素的大小依次为反应温度、高锰酸钾用量、反应时间、高氯酸用量。对制备样品进行SEM表征可知,可膨胀石墨的层间距明显大于天然鳞片石墨的层间距,膨胀石墨具有蠕虫状结构,表面具有很多孔隙,以大、中孔为主。FTIR测试表明,高氯酸插入到了石墨层间。

Natural flake graphite was used as raw material, potassium permanganate as oxidizing agent and perchloric acid as inser- ting reagent in preparation process,An orthogonal test method was adopted for optimizing of preparing parameters.The experimental results show that the optimum conditions are as follows： natural flake graphite ： KMnO4 ： perchloric acid（g ： g ： mL） = 1 ： 0.4 ： 7, the reaction temperature and time are 30℃ and 70 min respectively. Under this condition the expandable graphite has a quite high expansion volume of 390 mL/g. The reaction temperature influences the reaction system most, followed by the amount of KMnO4, the reaction time and the amount of HC104. Meanwhile, the prepared samples were characterized by scanning electron microscope （SEM） and fourier transform infrared spectroscopy （FFIR）.SEM results show that the expandable graphite has a wider space between layers than natural flake graphite.Expanded graphite shows worm-like structure and many large and medium pores are observed on the surface of expanded graphite with numerous holes. FTIR results show that the HClO4 had been successfully entered into the space between layers.