Abstract
Electric conductivity and adhesive properties of epoxy / silver filler blends were studied in relation to the phase structures of the epoxy matrix resins. Poly ether sulphone (PES) was applied as the modifi er to form the phase structures in the epoxy resin. Diglycidyl ether of bisphenol A (DGEBA) as the epoxy resin was cured with methylene dianiline (MDA). The resin blends of the DGEBA / PES / MDA made the phase structures in the curing process by the reaction-induced phase separation mechanism. Both the epoxy-rich phase and the PES-rich phase made continuous structures (co-continuous morphology) in the 15wt % PES blends. Then, the several amounts of silver fi llers with the diameters of 0.8 μm were added to the DGEBA / PES / MDA blends. Electron microscopy revealed that the silver fi llers were selectively localized in the epoxy-rich phases in the cured blends. The epoxy / PES / silver fi ller (14.6 vol%) adhesives gave more than 107 times in the electric conductivity than the corresponding epoxy / silver fi ller adhesives without the PES. It is estimated that the localized silver fi llers in the epoxy-rich phase give more chance to contact each other and make more conducting pass than the case without the PES. Synopsis
