Influence of MXene, graphene nanoplatelet and multi-walled carbon nanotube on mechanical properties, swelling and flammability behaviour of hybrid sisal/glass fibre reinforced epoxy laminate composites

The research work aims to utilize one of the cheapest and most abundantly available natural fibre, sisal fibre, to fabricate a hybrid nanocomposite possessing high performance efficiency. Glass fibre (GFC), sisal fibre (SFC) and hybrid glass/sisal fibre reinforced epoxy laminate composites (HFC) were prepared and subsequently, three of the most promising nano-fillers, MXene (HFCMXN), Graphene nanoplatelet (HFCGNP) and Multi-walled carbon nanotube (HFCCNT), were added into the hybrid composite. The fabricated composites were comprehensively assessed and analysed for their mechanical properties, swelling and flammability behaviour. It was observed that the glass fibre reinforced composite had lowest void content (6.3%) and glass/sisal fibre reinforced laminate had the highest void content (17.2%). The addition of nano-fillers did not further enhance the void content owing to the relatively uniform dispersion of the nanoparticle, which was particularly ensured during the whole fabrication process. The incorporation of nano-fillers led to a significant enhancement in the mechanical properties; tensile and flexural strength being highest for composites containing two dimensional nano-fillers. The GFC exhibited minimum weight gain (2.25%) and least swelling thickness (1.66%) upon soaking. Among hybrid composites, nano-filler reinforced composites had relatively less weight gain post in comparison to the hybrid composite without any nano-filler. HFCGNP had a weight gain of 6.69%, as opposed to 8.51% observed in case of HFC. The nano-fillers acted as an effective water barrier that reduced the tendency of water absorption. Furthermore, upon flammability test it was found that the burning rate decreased in order of GFC, HFC, HFCCNT, HFCMXN, HFCGNP and SFC. The addition of nano-fillers led to a decrease in the burning rate owing to the promising flame retardant properties of graphene which suppressed flame propagation and helped in extinguishing the flame.