Preparation, microstructure, and piezoresistive behavior of conductive nanocomposite foams based on poly(1-butene) and carbon black

Abstract

The pressure-sensitive nanocomposite foams based on thermoplastic poly(1-butene) (PB) and carbon black (CB) were prepared through melt blending, followed by a foaming process in supercritical carbon dioxide (CO2). The morphology and microstructure of nanocomposite foams were investigated with scanning electronic micrography, and the results indicated that the cellular structure and density of nanocomposite foams were strongly dependent on the CB content. The nanocomposite foams achieved a uniform cellular structure with a minimum cell size of 57.98 μm and a maximum cell density of 2.99 × 107 cells/cm3 at a CB content of 6 wt%. The nanocomposite foams also presented a percolation threshold at this CB content and obtained good electrical conduction when the CB content is higher than 6 wt%. The conductive sensitivity to mechanical stimulus for nanocomposite foams induced by uniaxial compression was investigated. The nanocomposite foams were found to exhibit a high stability of electrical resistance response during the multicyclic compressive loading–unloading process. The nanocomposite foams developed by this work show potential applications for strain sensors under compression deformation.