Rheology, Flexure and Thermomechanical Characterization of Epoxy/CNF Nanocomposites: Effect of Dispersion Techniques

The aim of this study is to investigate the optimum technique to disperse vapour grown carbon nanofibres (VGCNFs) in SC-1 epoxy uniformly and to evaluate their effect on the performance of SC-1 epoxy. In this study, ultrasonication and Thinky mixing methods were used either in isolation or in combination with 3-roll shear mixing. To achieve better dispersion, VGCNF was tested either by mixing with SC-1 resin directly or premixed with a solvent and then mixed with SC-1 resin after evaporating the solvent. Flexural tests were performed to evaluate mechanical performances, and the results exhibited 25.60% and 8.88% improvement of flexural strength and modulus, respectively over neat epoxy with only 0.2 wt.% loading. Dynamic Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) indicated improvement in storage modulus, T-g, inflection temperature and residue content respectively over neat SC-1 epoxy. The high viscosity found by rheological analysis prevents their ubiquitous use in fibre reinforced composites. Thermal and mechanical properties at higher loading conditions were seen either to reduce or not significantly improve. These results indicate that the methods used for dispersion are suitable for low weight percent loading only.