Constructing “sesame-biscuit” structured hybrids with SiC and Ag particles for enhancing thermal conductivity and dielectric constant of elastomer composites

Abstract

With the development of multifunctional and miniaturized integrated circuits, polymeric materials with large dielectric constant and high thermal conductivity have major significance in modern electronic industry. In this work, “sesame-biscuit” structured thermally conductive hybrids were prepared by polydopamine (PDA) modification and in-situ electroless silver (Ag) plating on the surface of silicon carbide (SiC), referred as SiC-P-Ag. Then, the SiC-P-Ag was incorporated into epoxidized natural rubber (ENR) matrix to yield polymeric composites (ENR/SiC-P-Ag) with excellent thermal and dielectric properties. It was found that PDA improved the interfacial compatibility and reduced the interface thermal resistance between SiC and ENR matrix. In addition, the formation of heat conduction channels and conductive Ag nanoparticles caused an increase in thermal conductivity of the 50 vol% ENR/SiC-P-Ag composite to 0.5655 W/(mK), which was 540% that of the pure ENR (0.1048 W/(mK)). Meanwhile, the 50 vol% ENR/SiC-P-Ag composite showed a low AC conductivity of 2.98 × 10−11 S/cm and a high dielectric constant of 35 at 10 Hz. It is noteworthy that this simple and efficient route for preparing ENR/SiC-P-Ag composites can also be applied in other fillers for simultaneously enhancing dielectric constant and thermal conductivity of polymeric composites.