Sustainable, electrically-conductive bioepoxy nanocomposites

Abstract

Biobased epoxy nano-composites composed of untreated multi-wall-carbon-nanotubes (MWCNT) and diphenolic acid-derived biobased epoxy: diglycidyl ether of diphenolate n-butyl ester (DGEDP-Bu), were fabricated. Electrical, rheological, and mechanical percolation thresholds were compared between biobased and commercial bisphenol A (DGEBA) epoxy composites. For both epoxies, nanocomposites loaded with 0.05–0.2 wt % MWCNT's exhibited electrical and rheological percolation at 0.05 wt % and 0.2 wt % respectively. DMA and tensile results revealed that DGEDP-Bu composites exhibited equivalent or superior properties to DGEBA composites. With 0.2 wt % MWCNT's, DGEDP-Bu nanocomposites exhibited 68% higher electrical conductivity and a three-fold higher rheological yield stress than those made from DGEBA. Rheological characterization corroborated that continuous MWCNT networks are formed within epoxies between 0.1 and 0.2 wt % MWCNT's. Moreover, upon MWCNT loading, DGEDP-Bu demonstrates equal mechanical performance and better electrical conductivity than DGEBA.