Facile fabrication of ultra-light and highly resilient PU/RGO foams for microwave absorption

Abstract

Using commercial polyurethane foams as templates, PU/RGO foams were prepared by a simple dip-coating method, which is economical and suitable for industrialized production. The formation of RGO was studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and scanning electron microscopy (SEM). The microwave absorption properties of the PU/RGO foams were investigated and the results show that for composites with a RGO loading of 31.3 wt%, the minimum reflection loss of the PU/RGO foam can reach −50.8 dB at 12.9 GHz, and the frequency bandwidth at less than −10 dB is from 10.75 to 15.95 GHz at a thickness of 2.5 mm. In addition, the results of cyclic compression tests and twisting experiments indicated that the PU/RGO composite was highly resilient. Moreover, the measured density of the foam material is just approximately 0.027 g cm⁻³ which is considerably smaller compared with most commercial wave-absorbing materials. The fabricated PU/RGO foams can be used as good microwave absorbing commercial cladding materials, with particularly lightweight and highly elastic properties.