Mechanical Properties of Polypropylene/Carbon Nanotube Composites by Indentation Technique

Abstract

The Instrumented Indentation Technique (IIT) is used to measure the local mechanical properties of different materials. The mechanical parameters (indentation hardness and modulus) of multi-walled carbon nanotubes filled polypropylene (PP/MWCNTs) nanocomposites derived from the load-displacement indentation curve are investigated by sharp indentation. The effect of the visco-elastic-plastic deformations on the mechanical properties is studied considering a 5-step indentation test. The mechanical properties calculated based on the traditional Oliver and Pharr method are compared with those extracted from the new indentation methodology. During the 5-step indentation test, the viscoelastic deformations during the reloading-holding phases are reduced due to the decrease in the indentation displacement with the increase in the concentration.