The Conductivity and Mechanical Properties of Hybrid Carbon Black/Copper filled Linear Low-Density Polyethylene (LLDPE) and Liquid Silicone Rubber (LSR) Flexible Conductive Polymer Composites for Electronic Interconnect Applications

Abstract

The advancement in the electronics industry have led to the emerging trends towards miniaturization and flexible electronic devices. The ability to be stretched, twisted, and bent have made Flexible Conductive Polymer Composites (FCPCs) one of the attractive materials in electronic interconnect applications. In this work, the combination of Carbon Black/Copper (CB/Cu) as hybrid fillers within linear low-density polyethylene (LLDPE) and liquid silicone rubber (LSR) matrices were investigated to overcome the limitation of single filler addition such as poor dispersion with the aim to further enhance the electrical and mechanical properties of the FCPCs. The FCPCs prepared in this study were characterized and tested using various techniques such as 4-point probe, tensile testing, hardness test and electron microscopy. Composites of LLDPE/CB/Cu and LSR/CB/Cu were prepared with varying filler loadings such 3 wt.%, 6 wt.%, 9 wt.%, 12 wt.% and 15 wt.%. The ratio of copper to carbon black are 1:1. The LLDPE and LSR exhibit increased tensile strength with up to 15 wt.% CB and Cu loadings. LLDPE shows enhanced elongation at break (55.93%) with 15 wt.% filler, while LSR declines beyond 12 wt.%. The modulus of elasticity is inversely proportional to elongation at break for both materials. Electrical conductivity increases in LLDPE and LSR with fillers up to 9 wt.%, forming a conductive network that decreases at higher loadings. Shore hardness indicates increased hardness with greater CB and Cu content. SEM analysis reveals filler dispersion and distribution within the polymer matrices, providing insights into the composites’ microstructure.