Abstract Fe3O4-reduced graphene oxide (FRGO)/waterborne polyurethane (WPU) composites with controllable structure and high microwave absorption capacity were developed. The aligned structure of FRGO in the FRGO/WPU composites was realized by a magnetic-field-induced method. WPU dispersion with nano-scaled particles could suppress the aggregation of FRGO during the drying process. The FRGO/WPU composites have much high complex permittivity, dielectric loss tangent, and microwave absorption capacity owing to the magnetic alignment. WPU with 2% FRGO achieved the minimum reflection loss value of −67.8 dB, which can be attributed to the orientation and three-dimensional structure of FRGO. The effective bandwidth wider than 14 GHz can be reached by a combination of two layers of composites with different permittivity through theoretical calculation. The aligned FRGO/WPU composites have a great future in the application of microwave absorption materials.

中文翻译：

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磁性排列的 Fe3O4 还原氧化石墨烯/水性聚氨酯复合材料，具有高微波吸收能力的可控结构

摘要 研制了结构可控、吸波能力强的Fe3O4还原氧化石墨烯(FRGO)/水性聚氨酯(WPU)复合材料。FRGO/WPU 复合材料中 FRGO 的排列结构是通过磁场诱导的方法实现的。具有纳米级颗粒的 WPU 分散体可以抑制 FRGO 在干燥过程中的聚集。由于磁性排列，FRGO/WPU 复合材料具有非常高的复介电常数、介电损耗角正切和微波吸收能力。含 2% FRGO 的 WPU 达到了 -67.8 dB 的最小反射损耗值，这可以归因于 FRGO 的取向和三维结构。通过理论计算，将两层不同介电常数的复合材料组合起来，可以达到14GHz以上的有效带宽。