Selective dispersion of silver nanowires in epoxy/polyetherimide binary composites with enhanced electrical conductivity: a study of curing kinetics and morphology

Abstract This study reports on the preparation and characterization of epoxy/polyetherimide (EP/PEI) binary system containing low content of silver nanowires (AgNWs). The system was designed to form a co‐continuous structure during reaction‐induced phase separation of EP/PEI blend. With selective distribution of the AgNWs in continuous EP‐rich phase, a low percolation threshold at 3 wt% content of AgNWs was obtained in EP/PEI composite. The glass transition temperature, electrical conductivity, and thermal conductivity were all enhanced by the addition of low content of AgNWs. The surface resistivity of the EP/PEI blend decreased from 6.5 × 10¹⁶ Ω to 9.6 × 10⁵ Ω with the addition of 3.0 wt% AgNWs, and meanwhile thermal conductivity was improved by 38.2%. Furthermore, AgNWs showed a critical impact on the kinetics of reaction‐induced phase separation and the formation of co‐continuous network structure. The process of phase separation of the thermosetting/thermoplastic blends was characterized by optical microscopy, time‐resolved light scattering, differential scanning calorimetry, and scanning electron microscopy.