摘要:
在挤出过程加入超声振动作用，研究超声振动对高石墨烯微片（GNP）含量的聚丙烯基（GNP/PP）复合材料微观形态、结晶、导电性和导热性的影响。结果表明：由于超声振动提供强烈的冲击波与微射流，挤出过程中加入超声振动可有效地减薄GNP片层厚度，减少GNP团聚，增强GNP在PP中的分散均匀性，有利于构建导电导热网络，从而提高GNP/PP纳米复合材料的导电导热性能。相较于无超声振动，加入100 W超声振动后，GNP含量越高，GNP/PP电导率和热导率提升幅度越大，在GNP含量为15wt%时，电导率升幅为85%，热导率升幅为9.7%。而在GNP含量同为12wt%时，随着超声振动功率的增加，电导率和热导率呈现先增大后减少的规律。当超声功率为200 W时，电导率升幅为214%，热导率升幅为17.2%。而超声功率达到300 W时，较高功率的超声振动使部分石墨烯微片的片径减少，导致片层间更难以搭建完整的导电导热网络，使GNP/PP性能均略有下降。
Abstract:
The ultrasonic vibration was added to extrusion process, and the influences of ultrasonic vibration on the morphology, crystallization, electrical and thermal properties of nano graphene nanoplatelet (GNP)/polypropylene(PP) composites with high GNP contents were investigated. The results show that the ultrasonic vibration provides powerful shock wave and micro jet which can reduce the thickness of GNP effectively, reduce the agglomeration of GNP and enhance the uniform dispersion of GNP in PP matrix. The morphology is benefit for the building of electrical and thermal network, therefore the electrical conductivity and thermal conductivity of GNP/PP composites are increased. Compared to non-ultrasonic vibration, after the addition of 100 W ultrasonic vibration, with the increase of the GNP content, the amplitude of electrical and thermal conductivity improvement increase continuously, when the GNP content is 15wt%, the increase of electrical conductivity is 85%, and thermal conductivity is 9.7%. When the GNP content is 12wt%, with increasing the ultrasonic power, the electrical and thermal conductivity increase first and then decrease. When the ultrasonic power is 200 W, the increasement of electrical and thermal conductivity is 214% and 17.2%, respectively. While the results of 300 W ultrasonic treatment show that the higher power of the ultrasonic vibration makes the flake sizes of GNP decreased, which lets it more difficult to build a complete electrical and thermal network, so that the performance is slightly decreased.
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