Effect of single and hybrid multiwalled carbon nanotube and carbon black fillers on ethylene-butene copolymer composites for potential sensor applications

Polyolefin elastomers are widely used for engineering applications due to their balance of toughness, hardness, and strength. However, there is a need to enhance their mechanical and conductivity properties by adding more reinforcements. In this study, ethylene-butene copolymer (EBC) with a 14 mol% butene content was investigated for its potential application in sensors using multi-walled carbon nanotubes (MWCNT) and carbon black (CB) as reinforcements. The study explored the effect of these fillers on the mechanical characteristics and electrical conductivity of the EBC composites, which showed higher strength and modulus. Further, 0.5 wt% of CB reinforcement showed the best tensile properties started to decline with further addition of reinforcements. It was also noted that only a 10% increment was observed in the shore-A hardness of composites even with the highest loading level of fillers, which shows that there is not much compromise in hardness, making these composites suitable candidates for stretchable sensors. This study also concluded that hybrid particle morphology (mixture of MWCNT & CB) has a strong influence on augmenting electrical conductivity. Since these composites possess considerably good softness even at high filler loadings, they can be considered as potential candidates for strain or pressure sensors or in wearable electronics. Overall, the strategy used in this work can be employed to study the effect of reinforcement morphology in other polymer combinations to enhance the conductivity and mechanical properties.