Rapid fabrication of high strength PEEK/CNTs composites with segregated structure and weld repair through microwave sintering

Fabrication of conductive polymer composites (CPCs) with segregated structure to achieve electromagnetic interference (EMI) shielding while maintaining mechanical properties remains a challenging issue. In this work, high strength polyether-ether ketone (PEEK)/carbon nanotubes (CNTs) composites with segregated conductive networks were facilely fabricated via microwave sintering (MS). The selective heating behavior and temperature distribution during MS were investigated from both macroscopic and microscopic perspectives, revealing a unique heating mechanism. The coated CNTs layer was selectively heated under microwave irradiation, leading to welding of the PEEK matrix. This promoted molecular entanglement across interfaces, improving mechanical properties while maintaining the integrity of the segregated structure. Consequently, PEEK/5 wt% CNTs composites fabricated by MS exhibited excellent conductivity (17.3 S/m) and EMI SE (31.7 dB) in the X-band region, along with a high tensile strength of 81.2 MPa, which was 54.1 % higher than that of CM sample with comparable electrical properties. Finally, this technique was innovatively applied for weld repair of fractured samples. This study provides a novel, economical and energy saving strategy not only for the rapid fabrication of high strength PEEK/CNTs composites with segregated structure, but also for the field of rapid weld repair of polymer materials.