Evaluation of the tensile strength and impact property of polyamide/short glass fibre-multi-walled carbon nanotube composites: an experimental study based on response surface method

The tensile strength, impact property and thermal stability of polyamide 6 (PA6) reinforced with carboxylic acid-functionalised multi-walled carbon nanotubes (MWCNTs) with 1 and 2 wt.%, and short glass fibre (SGF) with 10 and 20 wt.%, were investigated. The morphological properties were examined by SEM. The differential scanning calorimetry (DSC) was also carried out to explore the thermal stability and crystallinity of nanocomposites. For determining the optimal weight percentage of reinforcements, the response surface methodology (RSM) was used. The effect of nanotubes and weight percentages of fibre on the tensile and impact properties was investigated by analysis of variance. The results indicated that the incorporation of MWCNTs to PA6 increased the tensile and impact strength of the matrix by 16% and 24%, respectively. Also, the addition of SGFs to polyamide improved the mechanical properties. The results also showed that the nanocomposite containing 1 wt.% MWCNTs and 20 wt.% SGFs had the highest properties (66% increase for tensile and 81% increase for impact strength compared to neat PA6). The DSC results confirmed the effect of reinforcements on thermal characteristics of nanocomposites. The validation of output models of responses implies the ability of models to predict the tensile and impact behaviour of composites.