Marra Fabrizio, D'Aloia Alessandro Giuseppe, Tamburrano Alessio, Ochando Isabel Maria, De Bellis Giovanni, Ellis Gary, Sarto Maria Sabrina
Department of Astronautics, Electrical and Energy Engineering, Sapienza University of Rome, 00184 Rome, Italy.
Research Center for Nanotechnology applied to Engineering, Sapienza University of Rome, 00184 Rome, Italy.
Polymers (Basel). 2016 Jul 28;8(8):272. doi: 10.3390/polym8080272.
Development of epoxy or epoxy-based vinyl ester composites with improved mechanical and electromagnetic properties, filled with carbon-based nanomaterials, is of crucial interest for use in aerospace applications as radar absorbing materials at radio frequency. Numerous studies have highlighted the fact that the effective functional properties of this class of polymer composites are strongly dependent on the production process, which affects the dispersion of the nanofiller in the polymer matrix and the formation of micro-sized aggregations, degrading the final properties of the composite. The assessment of the presence of nanofiller aggregation in a composite through microscopy investigations is quite inefficient in the case of large scale applications, and in general provides local information about the aggregation state of the nanofiller rather than an effective representation of the degradation of the functional properties of the composite due to the presence of the aggregates. In this paper, we investigate the mechanical, electrical, and electromagnetic properties of thermosetting polymer composites filled with graphene nanoplatelets (GNPs). Moreover, we propose a novel approach based on measurements of the dielectric permittivity of the composite in the 8⁻12 GHz range in order to assess the presence of nanofiller aggregates and to estimate their average size and dimensions.
开发具有改进的机械和电磁性能的环氧树脂或环氧基乙烯基酯复合材料，并填充碳基纳米材料，对于在航空航天应用中用作射频雷达吸收材料至关重要。大量研究强调了这样一个事实，即这类聚合物复合材料的有效功能特性强烈依赖于生产过程，该过程会影响纳米填料在聚合物基体中的分散以及微米级聚集体的形成，从而降低复合材料的最终性能。在大规模应用的情况下，通过显微镜研究评估复合材料中纳米填料聚集体的存在效率相当低，并且一般只能提供关于纳米填料聚集状态的局部信息，而不是由于聚集体的存在导致复合材料功能性能退化的有效表征。在本文中，我们研究了填充有石墨烯纳米片（GNP）的热固性聚合物复合材料的机械、电学和电磁性能。此外，我们提出了一种基于测量复合材料在8⁻12 GHz范围内介电常数的新方法，以评估纳米填料聚集体的存在，并估计它们的平均尺寸和维度。
