Piezoresistive carbon-based composites for sensor applications: Effects of polarity and non-rubber components on shape recovery

Abstract

Natural rubber (NR) composites filled with carbon nanotubes (CNT), and carbon black (CB) were prepared. Also, other rubber matrices were tested, namely epoxidized-NR (ENR) and isoprene rubber (IR). The aim was to examine the effects of polarity and non-rubber constituents in rubber on mechanical and piezoresistive sensor properties. Thus, the relative resistances during extension were determined under static (stepwise) and dynamic (cycling) deformation of the composites. It was found that ENR-CNT/CB exhibited mechanical properties superior to NR-CNT/CB and IR-CNT/CB. This is attributed to the chemical ENR-CNT/CB linkages and physical interactions of non-rubber components with CNT/CB surfaces. This also helps the recovery of resistivity to the original value after 20 extension cycles. After 10 000 cycles, the resistivity had changed by 2 orders of magnitude before showing the constant resistivity. Thus, ENR-CNT/CB composites can serve in sensors for health monitoring, motion sensors, and other related products, being cost-effective and easy-to-process materials.

Keywords

• polymer composites
• nanocomposites
• rubber
• material testing
• mechanical properties