Tensile Piezoresistive Behavior of Polyethylene Terephthalate/Carbon Black Composite

Abstract

The polyethylene terephthalate/carbon black (PET/CB) composite was fabricated by twin-screw extrusion and injection molding method. The morphology, electrical conductive percolation threshold, tensile piezoresistivity, and stress-strain behavior of the composite were investigated. A scanning electron microscope showed that the carbon black was dispersed in the PET matrix homogeneously, but some little visible carbon black agglomerates can also be detected in the composite. The electrical conductive percolation threshold of composite was 15% by weight of carbon black. When the carbon black content changed from 15 to 2% by weight, the PET/CB composite had the tensile piezoresistivity. At the axial tensile strain from to .1, the composite with 2% by weight carbon black had the highest value of fractional change in resistivity, which had a linear relationship to tensile strain. After five times cyclic tensile loading and 1, cycles fatigue tensile loading, the composite showed good repeatability in tensile piezoresistivity. The yield strength and tensile strength of composite were 18 and 23.8 MPa, respectively. The results showed the potential way of using PET/CB composite as strain sensors for civil engineering.