Chemically reduced graphene (CR-G)/poly(ethylene oxide) (PEO) composites are prepared by a simple aqueous mixing method. Graphite oxide (GO) is prepared by a modified Hummers method and further dispersed in water to form graphene oxide (G-O). The as prepared G-O is mixed with PEO and in situ reduced by l-ascorbic acid. CR-G monolayers are ∼1 nm in thickness and ∼1.5 μm in both length and width as confirmed by AFM, indicating their large aspect ratio of about 1500. G-O is dispersed in PEO at the molecular level due to hydrogen bonding, and PEO acts as a barrier for CR-G layers to prevent agglomeration during the process of reduction. CR-G/PEO composites have high permittivity, resulting from the uniform dispersion of electrically conductive CR-G with high aspect ratio. CR-G/PEO composite (2.6 vol %) shows high microwave absorbing capacity as its minimum reflection loss is −38.8 dB. CR-G sheets form a huge number of electrical pathways which can dissipate microwave energy into heat effectively as well as dielectric relaxation and interface scattering induced by large CR-G/PEO interfaces.

中文翻译：

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绿色方法制备具有高微波吸收能力的石墨烯基复合材料

化学还原的石墨烯（CR-G）/聚环氧乙烷（PEO）复合材料是通过简单的水混合方法制备的。通过改进的Hummers方法制备氧化石墨（GO），然后将其进一步分散在水中以形成氧化石墨烯（GO）。将准备好的GO与PEO混合并原位还原l-抗坏血酸。经AFM证实，CR-G单层的厚度约为1 nm，长度和宽度约为1.5μm，表明它们的长宽比约为1500。由于氢键，GO在分子水平上分散在PEO中，PEO起作用作为CR-G层的屏障，可防止还原过程中的团聚。CR-G / PEO复合材料具有高介电常数，这是由于高纵横比的导电CR-G均匀分散所致。CR-G / PEO复合材料（2.6体积％）显示出较高的微波吸收能力，因为其最小反射损耗为-38.8 dB。CR-G片材形成大量的电气通路，可以有效地将微波能量耗散为热量，以及大型CR-G / PEO界面引起的介电弛豫和界面散射。