Ahmad Ahmad Fahad, Ab Aziz Sidek, Abbas Zulkifly, Obaiys Suzan Jabbar, Khamis Ahmad Mamoun, Hussain Intesar Razaq, Zaid Mohd Hafiz Mohd
Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Malaysia.
School of Mathematical & Computer Sciences, Heriot-Watt University Malaysia, Putrajaya 62200, Malaysia.
Polymers (Basel). 2018 Oct 23;10(11):1180. doi: 10.3390/polym10111180.
The preparation of chemically reduced graphene oxide (rGO) and the optimization of epoxy resins' properties using micro or nanofillers are now common practices. rGO nanoparticles (60 nm) based on an epoxy resin polymer were prepared at the concentrations of 0, 1, 2, 3, 4, and 5% weight percentage with fixed 6-mm thicknesses. The dielectric properties of the composites were measured by the reflection/transmission technique in connection with a vector network analyser (VNA) at a frequency range of 8⁻12 GHz. The microwave absorption and shielding effectiveness properties were calculated by using the reflection S and transmission S results. The microstructure and morphology of the polymer and the rGO/cured epoxy composites were studied by field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared (FT-IR) spectroscopy, and the X-ray Diffraction (X-RD) technique for characterizing crystalline materials. The dielectric and other properties of the rGO/cured epoxy composites were investigated based on the filler load and frequency. It was found that the applied frequency and the filler concentrations affected the dielectric properties of the rGO/cured epoxy composites. The results showed that the introduction of rGO particles to the composites increased their dielectric properties smoothly. The study of the dependence on frequency of both the dielectric constant ε' and the dielectric loss ε″ showed a decrease in both quantities with increasing frequency, indicating a normal behaviour of the dielectrics. Cole⁻Cole plots were drawn with ε' and ε″. A theoretical simulation in terms of the Cole⁻Cole dispersion law indicates that the Debye relaxation processes in the rGO/cured epoxy composites are improved due to the presence of the rGO filler. Moreover, with the addition of rGO as a filler into the Epoxy matrix, it now exhibits promise as a lightweight material for microwave absorption as well as an effective electromagnetic interference (EMI) shielding material.
化学还原氧化石墨烯（rGO）的制备以及使用微纳米填料优化环氧树脂性能如今已成为常见做法。基于环氧树脂聚合物制备了浓度为0、1、2、3、4和5重量百分比、固定厚度为6毫米的rGO纳米颗粒（60纳米）。通过反射/透射技术结合矢量网络分析仪（VNA）在8⁻12吉赫兹频率范围内测量复合材料的介电性能。利用反射S和透射S结果计算微波吸收和屏蔽效能性能。通过场发射扫描电子显微镜（FE-SEM）、傅里叶变换红外（FT-IR）光谱以及用于表征晶体材料的X射线衍射（X-RD）技术研究聚合物以及rGO/固化环氧树脂复合材料的微观结构和形态。基于填料负载和频率研究rGO/固化环氧树脂复合材料的介电和其他性能。发现施加的频率和填料浓度会影响rGO/固化环氧树脂复合材料的介电性能。结果表明，向复合材料中引入rGO颗粒会使其介电性能平稳增加。对介电常数ε'和介电损耗ε″随频率的依赖性研究表明，随着频率增加，这两个量均减小，表明电介质具有正常行为。用ε'和ε″绘制了科尔-科尔图。根据科尔-科尔色散定律进行的理论模拟表明，由于rGO填料的存在，rGO/固化环氧树脂复合材料中的德拜弛豫过程得到改善。此外，随着rGO作为填料添加到环氧树脂基体中，它现在有望成为一种用于微波吸收的轻质材料以及一种有效的电磁干扰（EMI）屏蔽材料。
