In-situ co-continuous conductive network induced by carbon nanotubes in epoxy composites with enhanced electromagnetic interference shielding performance

For the preparation of high-performance thermoset-based electromagnetic interference (EMI) shielding materials at low filler loading, a simple and practical method is still absent. Herein, the Epoxy/Polyether sulfone/Multiwalled Carbon Nanotubes (EP/PES/MWCNT) composites were prepared by ultrasonic treatment and dichloromethane-assisted dispersion. The selective localization of MWCNTs in EP phase prevented the interruption of phase continuity due to the increase of interfacial tension in the early stage of reaction-induced phase separation, resulting in co-continuous structure in the cured EP/PES (similar to 80w/20w) blends. Therefore, reliable mechanical properties and satisfactory EMI shielding performance can be obtained at low MWCNT loading. The EP/PES23/MWCNT2.9 delivered the tensile strength of 69.7 MPa and the average EMI SE of 23.0 dB, and which can be further improved by increasing the MWCNT content. This work is expected to provide more approaches for the preparation of high-performance thermosetting EMI shielding materials.