Enhancements of foamability, electromagnetic interference shielding and mechanical property of epoxy microcellular composite foam with well dispersed f-MWCNTs

Abstract In this work, the well-dispersed functionalized MWCNTs (f-MWCNTs), which was fabricated by simply decorating the polyether amine (M2070) and organosilanes (KH560) chains, has been applied as filler in preparation of the epoxy/f-MWCNTs microcellular foam through batch foaming process with supercritical carbon dioxide (scCO2). Compared with acidified MWCNT (acid-MWCNTs) without decorating the organic groups, the f-MWCNTs achieved more uniform dispersion in epoxy matrix, acted as plasticizing agent to reduce the glass transition temperature (Tg) of epoxy/f-MWCNTs composites, as well as increasing the composite CO2 adsorption ability, hence greatly enhanced the foamability of epoxy/f-MWCNTs composite. By adding 20 wt% f-MWCNTs, the average cell size reduced from 46.32 μm to 0.21 μm and cell density increased from 2.70×107 cell/cm3 to 2.74×1013 cell/cm3, respectively. In addition, the epoxy/f-MWCNTs microcellular foams presented enhanced electrical conductivity to 5.2×10-4 S/m, electromagnetic interference shielding effectiveness (EMI SE) to 22.73 dB and compressive strength to 26.46 MPa.