Effect of styrene addition on thermal properties of epoxy resin doped with carbon nanotubes

Abstract

The paper concerns thermal properties of epoxy resin doped with carbon nanotubes (CNTs) used as a matrix for Carbon Fiber Reinforced Polymer (CFRP) composites. The aim of this work was to determine the influence of styrene addition on thermal properties of epoxy resin/CNT nanocomposites. CNTs, supplied by Nanocyl, were dispersed in epoxy matrix using three roll millings. In order to dilute epoxy/CNT mixture, to make it useful for hand lay‐up method of CFRP fabrication, three different weight amounts of styrene were tested. Scanning electron microscopy was used for both CNT dispersion control and epoxy/CNT laminates structure evaluation. Glass transition temperature and thermal stability were determined. Fourier transform infrared spectroscopy (FTIR) was used for chemical structure verification. Thermal diffusivity of epoxy doped with carbon nanotubes, as well as CFRP doped with carbon nanotubes, was measured at four temperatures. Rheological tests were performed, and viscosity and storage and loss modulus were measured. From a modulus crossover point, gel time was determined. Scanning electron microscopy observations proved uniform dispersion of CNTs and reduction of voids and/or air bubbles amount as an effect of styrene addition. Decrease of thermal stability in the first stage of degradation is observed, and a decrease of glass transition temperature with an increase of styrene amount is noticed. For a small amount of styrene, thermal conductivity increases, while it starts to decrease when measured for a higher temperature. Viscosity decreases and gel time increases with the increase of styrene amount. Copyright © 2015 John Wiley & Sons, Ltd.