Impact of reduced graphene oxide on microstructure evolution in m-caproamine/imidazole toughened epoxy composites – Synergia of viscoelastic and microwave absorption properties

The present study investigates the effect of reduced graphene oxide (r-GO) on the microstructure evolution, damping, and microwave absorption performance of the caproamine (CA) toughened epoxy /imidazole (m-CA/ER/MI/r-GO) system. The X-ray diffraction analysis revealed good dispersion levels of r-GO featuring intercalation of r-GO into galleries of polymer chains. The effective role of r-GO in tuning the microstructure was confirmed from SEM, AFM and TEM analysis and the consequence of this is reflected in the dynamic mechanical characteristics. The m-CA/ER/3 wt% r-GO composites achieved an outstanding microwave absorption performance with a reflection loss of −51.6 dB (99.999% microwave absorption) at 9.51 GHz and an effective absorption bandwidth of 2.48 GHz when compared to m-CA/ER composite. The microwave performances are justified with the attenuation constant, impedance matching ratio, and the dielectric loss mechanisms operating in the composites. Hence, the developed m-CA/ER/r-GO will serve as a potential multifunctional composite with synergetic thermomechanical properties and excellent microwave absorption performance. [Display omitted] •Preferential localization of r-GO tuned the microstructure and escalated MW absorption performance credentials.•m-CA/ER/r-GO 3 wt. % composites exhibited the highest storage modulus of 471 MPa.•m-CA/ER/r-GO 3 wt. % composite experienced highest reflection loss of -51.6 dB at 9.51 GHz along with EAB of 2.48 GHz.•Synergetic thermo-mechanical properties of the microwave absorber find its potential in multi-functional applications.