Novel amorphous/crystalline MnO2 sheet-reinforced rGO/surface-treated BN and epoxy composites with significantly enhanced thermal conductivity and EMI shielding effectiveness

Rapid technological advancements have significantly increased the amount of heat generated by electronic devices. In addition to heat, electronic devices can malfunction because of electromagnetic (EM) waves. Therefore, research is required on heat management materials with high electromagnetic interference shielding effectiveness (EMI SE). In this study, composites were prepared using reduced graphene oxide (rGO) and boron nitride (BN) as fillers and epoxy as the matrix. To improve dispersion, BN was surface-treated with hydroxyl groups (BN–OH). We have produced amorphous/crystalline novel MnO2 sheets that exhibited strong interactions with the hydroxyl groups, forming hydrogen bonds with the fillers and matrix. We utilized the strong hydrogen bonding within the amorphous/crystalline domains of novel MnO2 sheets. The novel MnO2 sheets significantly enhanced interfacial compatibility between rGO/BN–OH fillers and the epoxy matrix. rGO and BN-OH fillers were able to uniformly disperse on the MnO2 sheets. The uniform dispersion of fillers contributed to the formation of efficient pathways for heat and electrical conduction, resulting in high electrical conductivity (16.12 S/cm), EMI SE (83.17 dB), and through-plane thermal conductivity (5.84 W/m∙K). Owing to the strong interactions between the rGO/BN–OH, MnO2, and Epoxy, the tensile strength improved to 78.36 MPa. •The novel amorphous/crystalline MnO2 sheets enhanced the compatibility between the rGO/BN-OH filler and the epoxy matrix.•The electrical and thermal conductivity increased as rGO and BN-OH sheets formed pathways over the MnO2 sheets.•Strong hydrogen bonding was formed between the fillers and the matrix.