Significant enhancement of thermal conductivity in segregated(GnPs&MWCNTs)@Polybenzoxazine/(Polyether ether ketone) -based composites with excellent electromagnetic shielding

Abstract

• Segregated structural composites assist in thermal conductivity enhancement. • Segregation provides more conductive reflective interfaces for shielding. • Polybenzoxazine modification increased polymer-filler interfacial interaction. • Hybrid fillers improve the interconnected filler transmission network. With the rapid development of integration and multi-functionality of electronic devices, polymer-based composites with thermal management and electromagnetic wave interference (EMI) are in urgent demand. Herein, a segregated structure multi-walled carbon nanotubes-graphite nanosheets/polyetheretherketone (PEEK) composite modified by polybenzoxazine (PBZ) have been fabricated via vacuum-assisted filtration and melting-point pressing methods. Different sizes of PEEK composite granules would yield different thermal conductivity (TC) and EMI performance of the resulting segregated composites. The TC of (GnPs&MWCNTs)@PBZ/PEEK with the grain of 200 meshes reach up to 3.38 (through plane) and 6.27 W/(m·K) (in plane) at 19.84 vol% filler loading, which is 1400% and 2600% higher than that of pure PEEK, respectively. The obtained composites also exhibit excellent EMI shielding effectiveness (54.4 dB), electrical conductivity, and thermal stability. Based on the Agari modeling, it is demonstrated that the more compact heat chain network is formed for segregated composites rather than fillers randomly distributed composites. This study provides a viable approach for enhancing the thermal conductivity of polymers-based composites with EMI capability.