Simultaneous reduction and functionalization of graphene oxide for high-performance EMI shielding polyurethane composites

This study investigates the enhancement of electromagnetic interference (EMI) shielding and the mechanical properties of polyurethane (PU) composites reinforced with reduced graphene oxide (rGO) functionalized with 2,4-diaminobenzene sulfonic acid (DBS). The primary objective was to evaluate the impact of rGO functionalization on the EMI shielding effectiveness and mechanical performance of PU composites in the X-band frequency range (8.2–12.4 GHz). A one-pot method was employed for the simultaneous reduction and functionalization of graphene oxide, achieving a percolation threshold of 1 wt% in the PU matrix. The results demonstrated that the rGO_DBS composites exhibited superior EMI shielding capabilities, with maximum average shielding effectiveness values of approximately 28.79 dB at 1.5 wt% loading, compared to 25.39 dB for chemically reduced rGO. Additionally, significant improvements in the tensile strength (263.15 %) and elastic modulus (235.69 %) were observed in the rGO_DBS composites. This suggests that the functionalization of rGO with DBS not only enhances the electrical conductivity and dielectric properties but also improves the mechanical integrity of PU composites, making them promising candidates for applications in electronic device protection and military equipment.