Preparation and characterization of isotactic polypropylene/high‐density polyethylene/carbon black conductive films with strain‐sensing behavior

Abstract

Novel conductive films with a unique strain (e)-sensing behavior and based on a blend of isotactic polypropylene (iPP), high-density polyethylene (HDPE), and carbon black (CB) were fabricated by an extrusion casting method. The morphology and e-sensing behavior of the films were investigated. Scanning electron microscope images showed that the oriented lamellae with a growing direction perpendicular to the extrusion direction were obtained in the HDPE phase and were accompanied by a cocontinuous structure of the iPP phase and HDPE/CB phase. The conductive percolation threshold (m c ) and resistivity-e behavior of the thin films are affected by the drawing ratio during the process of film preparation. The m c and electrical resistance of the iPP/HDPE/CB composite films increased with the drawing ratio. The gauge factor of the films within the elastic region decreased with increasing drawing ratio. Furthermore, the result of iPP/(HDPE/CB) 40/60 with a high drawing ratio shows that a reversible conductivity was obtained during the cyclic tensile testing (e 5 10%), but an irreversible conductivity makes the film fail during use at the applied e values of up to 15%. This makes them good piezoresistive candidates for e-sensing materials. Moreover, a simple structural model was proposed to describe the reversible and irreversible phenomena in the electrical resistance behavior of the iPP/HDPE/CB films under tensile loading.

Investigating the Electromechanical Properties of Carbon Black-Based Conductive Polymer Composites via Stochastic Modeling

“…This phenomenon is a consequence of particle motion within the CPC inducing rearrangement of conductive pathways, thus varying measured conductivity [ 43 ]. For researchers interested in the development of CPC flexible strain gauges, reversibility or recovery of the pristine resistivity when unloaded is desired, but often not realized [ 26 , 44 , 45 , 46 , 47 ]. For researchers interested in CPC SHM applications, understanding the underlying principles behind such irreversible conductivity change in fatigued CPC materials is a fundamental challenge on the cutting edge of the discipline.…”

Effect of plasticizer on the electrical, thermal, and morphological properties of carbon black filled poly(propylene)

“…Carbon‐filled polymer composites (CPCs) have superior electrical and thermal conductivity, improved physical properties, and resistance to corrosive chemicals when compared to metals and metal‐filled polymers. Different types of carbon fillers such as single‐walled and multi‐walled carbon nanotubes (SWCNTs and MWCNTs) , carbon black (CB) , carbon fiber , graphene , graphite and graphite derivatives are reported in the literature to meet the required electrical and mechanical properties. These composites find applications in antistatic and electrostatic dissipation materials, positive temperature coefficient materials, electromagnetic interference shielding, and in semiconducting layers to prevent the discharge .…”