An Investigation of Carbon Nanotube Dispersion in Vinyl Ester Resin Using Mechanical, Thermal and Statistical Techniques

The inclusion of 0.25 and 0.5 wt.% functionalized multi-walled carbon nanotubes (MWCNTs) into a vinyl ester (VE) resin has been studied. To investigate the effect of carbon nanotubes (CNTs) dispersion, the sonication process has been performed under a variety of parameters including mixing time and sonication amplitude. Differential scanning calorimetry (DSC) and 3-point flexural testing methods have been employed to explore the thermo-mechanical properties of materials. Differential scanning calorimetry results show up to 13°C increase in the glass transition temperature (T_g) of the VE polymer by introducing 0.25 wt.% CNTs with a total sonication energy of 60 KJ. It is also established that the flexural modulus of the polymer can be improved up to 24%. An array indentation technique has been used to evaluate the hardness and elastic modulus variations in the regions of nanoparticle concentration. The resulting variations along the indentation array have been statistically studied using three-parameter Weibull distribution. Based on the resulting dispersion conditions, the optimum sonication parameters and nanoparticle concentration have been determined.