Enhancing silicone rubber composites with solid waste for thermal conductivity, electromagnetic shielding and electrical insulation

The rapid development of multifunctional and highly integrated electronic devices demands polymer composites with excellent thermal conductivity (TC), electrical insulation, and effective electromagnetic interference (EMI) shielding capabilities. Rubber is extensively employed in these applications for its flexibility and inherent thermal conduction. However, developing rubber-based materials that can simultaneously fulfill these stringent performance requirements remains a significant challenge. In this study, silicone rubber (SR) was utilized to integrate the benefits of magnetic minerals and carbon-based materials. Pyrrhotite (Pyr) tailings and industrial-grade carbon nanotubes (CNT) were employed as raw fillers to fabricate a flexible, moldable composite (Pyr/S@CNT/RTV-2SR), which demonstrates exceptional TC, EMI shielding and electrical insulation properties. The sulfurized carbon nanotubes (S@CNT) create strong interfacial bonding and interactions, efficiently links the filler with the polymer matrix, significantly reducing interfacial thermal resistance between Pyr and SR. This innovation allows the material to achieve superior multifunctional properties. Furthermore, the Pyr/S@CNT/RTV-2SR material demonstrates a TC of 1.52 W·m −1 ·K −1 and a resistivity of 5.3 × 10 11  Ω·m. Moreover, it consistently provides EMI shielding effectiveness of 39.6 dB across the 8.2–12.4 GHz frequency range, with absorption as the primary shielding mechanism. The sustainable fabrication process effectively repurposes major solid waste materials, enhancing both the sustainability and value of the material.