Crosslinked carbon nanotube/crystalline PEEK composites for high strength and electromagnetic interference shielding under harsh environments

With the rapid development of lightweight technologies and information systems, commercial polymer-based electromagnetic interference (EMI) shielding composites are increasingly inadequate for the complex structures and harsh operating conditions of aerospace electronic devices due to their corrosion sensitivity and low strength. Achieving high mechanical strength, EMI shielding effectiveness, and stable performance in harsh environments, such as high temperatures and corrosive media, remains a challenge. In this study, phenylacetylene groups were electrochemically grafted onto carbon nanotube (CNT) films to form phenylacetylene-grafted CNT (Ph-CNT), which was then combined with soluble phenylacetylene-capped ketimine polyetheretherketone (An-Ph-PEEK). Acidification of An-Ph-PEEK created crystalline phenylacetylene-capped PEEK (Ph-PEEK), and thermal crosslinking of phenylacetylene groups yielded crosslinked Ph-CNT/crystalline Ph-PEEK (cc@Ph-CNT/Ph-PEEK) composites. These composites exhibited high tensile strength (>240 MPa at 25 °C) and EMI shielding effectiveness (52–81 dB in the X-band across 25–250 °C), attributed to enhanced interfacial interactions and the stability of the crosslinked structure. The mechanical and EMI shielding properties were retained after prolonged exposure to corrosive media, thanks to the crystallinity of Ph-PEEK. Additionally, the composites exhibited photothermal antibacterial and electric de-icing capabilities. The high-performance cc@Ph-CNT/Ph-PEEK composites show promising potential for applications in harsh environments.