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本文由氧化石墨烯通过水热法制备直接获得石墨烯。采用热重-差热分析方法检测了石墨烯受热过程中的质量变化和氧化温度。利用热分析-质谱联用技术在400-650°C温度区间得到了水和二氧化碳正离子质谱峰,这说明石墨烯氧化过程中的质量损失是由羟基水和二氧化碳脱除造成的。同时,还采用非等温热分析动力学方法,利用5、10、15°C?min~(-1)三种不同升温速率获得了石墨烯材料在空气气氛下的热分析动力学参数。通过Kissinger方法计算出石墨烯氧化过程中的活化能(Ea)和指前因子的对数(lg(A/s-1))分别为155.11 k J?mol~(-1)和6.90。利用Ozawa-Flynn-Wall(FWO)方法还建立了活化能和指前因子与反应转化率之间的关系。基于以上研究结果,本工作将对石墨烯在热界面、导热和先进复合材料等领域的应用提供参考价值。
In this paper, graphene is obtained directly from graphene oxide by hydrothermal method. The gravimetric change and oxidation temperature of graphene were measured by TG-DTA. Mass spectra of water and carbon dioxide were obtained at 400-650 ° C using thermal analysis-mass spectrometry, indicating that the mass loss during graphene oxidation is due to the removal of hydroxyl water and carbon dioxide. At the same time, the kinetic parameters of thermal analysis of graphene in air atmosphere were obtained by non-isothermal analysis kinetics at 5,10,15 ° C? Min ~ (-1). The activation energy (Ea) and the logarithm of the pre-exponential factor (lg (A / s-1)) of graphene were calculated by Kissinger method to be 155.11 kJ? Mol -1 and 6.90, respectively. The relationship between activation energy and pre-exponential factor and reaction conversion was also established using the Ozawa-Flynn-Wall (FWO) method. Based on the above research results, this work will provide reference value for the application of graphene in thermal interface, thermal conductivity and advanced composite materials.