Zhang Bin, Chen Tijun
State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.
Materials (Basel). 2019 May 30;12(11):1757. doi: 10.3390/ma12111757.
Graphene has outstanding mechanical properties due to its unique structure, and is regarded as an ideal reinforcement of metal matrix composites. However, it is always in an agglomerate form due to its large specific surface area, and thus, it must be first dispersed prior to combining with a matrix, and ultrasonic treatment is considered to be the most effective way. In this work, the effects of parameters of tip ultrasonic treatment, such as ultrasonic time, ultrasonic power, solvent kind, and its temperature, on dispersion and structure of graphene nanoplatelets (GNPs) were studied. The results show that increasing ultrasonic time or ultrasonic power can enhance the dispersion and exfoliation effects of GNPs, but also increase fragmentation degree and disorder degree of C-atom distribution simultaneously. Solvents with low temperature, low viscosity, or high surface tension have similar effects to those of increasing ultrasonic time or power. However, for tap water, a high-surface-tension solvent, it has relatively low fragmentation degree, and good dispersion and exfoliation effects due to the hydrophilicity of GNPs. However, ethyl alcohol is a more suitable solvent because it has excellent volatility and inert reaction characteristics with GNPs and matrix alloys besides a good dispersion effect. The GNPs can achieve the expected status when they are ultrasonically treated for 4 h under a power of 960 W in EA solvent at 35 °C.
由于其独特的结构，石墨烯具有出色的机械性能，被视为金属基复合材料的理想增强材料。然而，由于其比表面积大，它总是以团聚形式存在，因此，在与基体结合之前必须先进行分散，而超声处理被认为是最有效的方法。在这项工作中，研究了尖端超声处理参数，如超声时间、超声功率、溶剂种类及其温度，对石墨烯纳米片（GNPs）分散性和结构的影响。结果表明，增加超声时间或超声功率可以增强GNPs的分散和剥离效果，但同时也会增加C原子分布的破碎程度和无序程度。低温、低粘度或高表面张力的溶剂与增加超声时间或功率具有相似的效果。然而，对于自来水这种高表面张力的溶剂，由于GNPs的亲水性，其破碎程度相对较低，具有良好的分散和剥离效果。然而，乙醇是一种更合适的溶剂，因为除了具有良好的分散效果外，它还具有出色的挥发性以及与GNPs和基体合金的惰性反应特性。当GNPs在35℃的EA溶剂中于960W功率下超声处理4小时时，可达到预期状态。
