Effect of hybrid multi-walled carbon nanotube and montmorillonite nanoclay content on mechanical properties of shape memory epoxy nanocomposite

In this study, the hybrid nanofiller of montmorillonite (MMT) and multi-walled carbon nanotube (MWCNT) were incorporated into shape memory epoxy (SMEP) at different loadings. The fillers were dispersed in the SMEP resin by sonication. Tensile and flexural properties were analyzed at room temperature (RT) and high temperature (HT). Field emission scanning electron microscopy (FE-SEM) was used to analyze the microstructure of fractured samples. The tensile results revealed that at RT, the hybrid filler nanocomposite exhibits a ductile behavior meanwhile at HT, the nanocomposite exhibits a brittle behavior. The sample with the hybrid filler loading of 3 wt% MMT and 1.0 wt% MWCNT produced maximum performance with an increase of 32.5% in the ultimate tensile strength (UTS) and 20.9% in Young’s modulus at RT. The trends of the UTS and modulus obtained in the HT tensile test were almost similar to the RT tensile test despite yielding lower value. The RT flexural test revealed an increasing flexural strength as the filler loading increased with a maximum of 176% increase for hybrid filler of 3 wt% MMT and 1.0 wt% MWCNT. This trend was also observed for the flexural strength at HT. From FE-SEM, it was observed that the SMEP nanocomposite containing 3 wt% MMT and 1.0 wt% MWCNT was well dispersed and interact with each other, producing a synergetic reinforcement towards the performance. This study demonstrates the tensile and flexural reinforcement effect of MMT and MWCNT hybrid nanofiller. Findings from this study can be utilized to select the optimum loading for mechanical requirements in various applications.