Development of Polypyrrole/Epoxy Composites as Isotropically Conductive Adhesives

Abstract

Abstract As a possible replacement for lead bearing solders, metal filled isotropically conductive adhesives (ICAs) have shown a lot of potential recently. But still they have to come a long way and overcome their limitations like low impact strength and moisture instability. The current paper attempts to address the limitations of these ICAs by using intrinsically conducting polymer as a filler in place of metals. Conducting polymer (CP) polypyrrole (PPy) was incorporated as a filler in an epoxy/anhydride (EP) system and its application as an isotropic conductive adhesive was studied. PPy was synthesized by chemical polymerization using dodecyl-benzene sulphonic acid (DBSA) as dopant. The composites with varying PPy concentrations were studied for curing behavior and thermal degradation properties using DSC and TGA, respectively. The composites show good impact properties and conductivity at very low filler concentrations. SEM observations established that PPy particles were dispersed in the epoxy matrix uniformly. The overall characteristics of these conductive adhesives establish that they can be used as conductive adhesives in the electronics industry. Keywords: Conducting polymersEpoxy/Polypyrrole compositesIsotropically conductive adhesivesSolder replacement ACKNOWLEDGMENT The authors express their sincere gratitude to the Director, Delhi College of Engineering, Delhi University, Delhi, India, for his kind encouragement and support. One of the authors, Irfan Ahmad Mir, is thankful to Council of Scientific and Industrial Research, Govt. of India, for financial support as senior research fellowship.