Carbon Black Reinforced Epoxy Resin Nanocomposites as Bending Sensors

By blending electrically conducting carbon black particles and silica into poly(bisphenol A-co-epichlorohydrin) epoxy resin polymer, conductive nanocomposites were prepared by printing onto transparency films and curing. Application of a milling procedure prior to application is beneficial for the reduction of cracks in the subsequent nanocomposites. Electrical conduction of nanocomposite is CB content dependent. A percolation region (19-24% CB on mass of resin) exists where the nanocomposite exhibits a transition from an electrical insulator to conductor. Nanocomposites with 14% and 19% CB on mass of resin demonstrated greatest sensitivity to changes in bending angle, attributed to greater localized changes in the conductive paths within a semi-conducting sensor. Good reproducibility was observed as a result of molecular interactions between CB particles and the epoxy resin.