Vitrimer chemistry enables epoxy nanocomposites with mechanical robustness and integrated conductive segregated structure for high performance electromagnetic interference shielding

Abstract

Constructing segregated pathways in the conductive polymer composites (CPCs) is efficient to achieve satisfactory electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) with low content of nanofillers. Conventionally, most of segregated CPCs were based on thermoplastics and precisely controlled processing conditions were essential to achieve structural integrity and mechanical robustness. Herein, by taking the advantage of the associative dynamic bonding rearrangement in the epoxy vitrimer, we fabricated segregated MWCNTs/epoxy composites in a wide range of compression temperature and pressure. The segregated CPCs show a low conductive percolation threshold at 0.066 wt% and an EMI SE of 22 dB when only 2 wt% of MWCNTs were loaded. More promisingly, the mechanical robustness was achieved by the volatile ethylene glycol (EG) involved decomposition and repolymerization of β-hydroxyl ester at the interface even when numerous MWCNTs were in between. The segregated structure and macroscopic properties can be reserved after reprocessing and the nanofillers can be recovered with excessive EG at elevated temperature.