Preparation and Study of Thermal, Mechanical and Electrical Properties of Epoxy Based Composites Containing MWCNTs and PZT

Abstract

Piezoelectric materials are widely used as sensors, transducers, medical diagnosis aerospace equipment, structural health monitoring and other energy harvesting devices, but the brittle nature of piezoelectric materials limits their operational strains, cycle life and ability to be integrated into complex shapes and structures while maintaining high sensitivity and reliability. Polymer matrix composites containing multi walled carbon nanotubes have attracted much attention due to their flexibility, ease of processing and improved mechanical properties. Carbon nanotubes are also responsible for the conductive nature of the epoxy-CNT composites due to good electrical properties. Above problems can be overcome by synthesizing piezoelectric composites having polymer matrix of good properties, conductive inclusions and piezoelectric material, these composites have improved mechanical and electrical properties than the single piezoelectric crystal. In this work piezoelectric composites are prepared which contains DGEBA (Diglycidal Ether of Bisphenol-A) as matrix, and 4’4’ Oxidianiline (ODA) as a curing agent for epoxy, multiwalled carbon nanotubes as conductive inclusions and lead zirconate titanate (PZT) as piezoelectric material. This work suggests that inclusion of MWCNTs enhances the piezoelectric properties by increasing the electrical conductivity of the composites, it also improves mechanical properties by decreasing brittleness of the material. This work seeks to understand how the weight % of the fillers i.e. MWCNTs and PZT effect the mechanical properties, the glass transition temperature, electrical conductivity and other parameters. Mechanical properties are determined by using tensile testing, different parameters were calculated e.g. toughness, young’s modulus (modulus of elasticity), stress at break and ultimate tensile strength. Effect of fillers on glass transition temperature of epoxy matric was studied by using differential scanning calorimetry (DSC), thermal degradation was studied by thermogravimetric analysis (TGA) which includes determination of different parameters e.g. maximum degradation temperature (Tmax.), temperature at which 10% degradation occurs (T10) and char yield. Electrical conductivities of the composites were determined and effect of increasing the amount of fillers on the conductivities was studied.