Effects of coupling agents on the properties of epoxy-based electrically conductive adhesives

The study was carried out to investigate the effects of two different coupling agents on the properties of epoxy-based electrically conductive adhesives (ECAs). For the investigation, a novel mixture of solvent and diluted acid was designed to remove the lubricants on the surface of silver flakes fully and each of the following two commercially available coupling agents, a silane coupling agent and one titanate coupling agent, was used as an additive for the ECA. It was found that with the full removal of lubricants on the surface of silver flakes, the electrical conductivity is improved at the same weight filler loading. It was also found that the adding of coupling agents has different effects on the electrical, aging and lap shear properties of ECAs. According to this study, the use of silane coupling agent had a significant electrical conductivity improvement and lap shear strength increase before and after the aging test. But for the titanate coupling agent, the properties of the ECA have no significant change. Scanning electron microscopy studies revealed a strong adhesion/bonding between the filler and the matrix for coupling agent-added ECA.