Tuning the microwave absorption characteristics of r-GO toughened epoxy composites via SiC-induced phase separation

The multifunctionality of an exemplary microwave absorber is an essential part of EMW absorption for practical applications. Hence, the present work aims to enhance microwave absorption characteristics and thermomechanical properties. The role of auxiliary absorber SiC on m-CA/ER/r-GO is conducive to microwave absorption. It reduces the surface energy of the composite through phase-separated rough micro-nano structures, which in turn aid the modification of the thermomechanical properties. The XRD results affirmed the intercalation of r-GO between the polymer layers, and the defect density increases with SiC loading. SEM and AFM confirm the influential role of SiC in tuning the phase-separated microstructure and the roughness profile of the composites, which in turn increase the wetting profile of the m-CA/ER /r-GO composites from 79 to 96° with SiC loading. The storage modulus increases from 577 MPa to 1407 MPa with a corresponding damping factor of 0.65 and 0.54, respectively, for m-CA/ER /r-GO with SiC. A vector network analyzer was used to obtain the complex permittivity and permeability of the composites to study the microwave absorption performance. The composite only with r-GO showed poor RL characteristics; however, it transformed into an excellent absorber with RL of −46.5 dB (Effective absorption bandwidth of over 2 GHz) with SiC loading. Thus, it is worth mentioning that the role of SiC on the dispersion behavior of r-GO in m-CA/ER/r-GO composites has helped to achieve better RL, especially in the range of −28 to −46.5 dB at various thicknesses between 5 and 10 mm.