Toughening epoxy resin system using nano-structured block copolymer and graphene nanoplatelets to mitigate matrix microcracks in epoxy nanocomposites: A DoE based framework

The inherent brittleness and highly cross-linked structure of epoxy resin, limits its practical applications. Herein, epoxy resin modified with nano-structured graphene nanoparticles (GNP: up to 1.5 wt%) and acrylic tri-block copolymer (Nanostrength (NS): up to 7.5 wt%) to achieve their improved tensile performance. The central composite design (CCD)-based response surface methodology (RSM) was opted to optimize the independent variables for maximum tensile strength. The study showed that the tensile strength of epoxy resin was increased by 13.4 %, 13.9 %, and 11.1 % compared to pristine epoxy when modified with 0.5 wt% GNP, 2.5 wt% NS, and their hybrid combinations (0.5 wt% GNP, 2.5 wt% NS), respectively. The CCD-based RSM determined the optimal independent variables to be 0.86 wt% GNP and 2.65 wt% NS, achieving a maximum tensile strength increase of 12 % compared to the pristine epoxy, with a desirability of 0.995. Field emission scanning electron microscopy (FESEM) was used to comprehensively elucidate the damage mechanisms such as GNP bifurcation and NS plasticization, which improved tensile performance. The developed hybrid nanocomposite system shows promising potential for high-performance structural applications, particularly in the aerospace and automotive industries, which requires an exceptional balance of strength, stiffness, and ductility. [Display omitted] •Demonstrated effect of nanofillers on tensile performance of epoxy nanocomposites.•Tensile performance was optimized using the CCD-based RSM.•Single and hybrid fillers improved tensile strength by 14 % and 11 %, respectively.•The optimal wt% of hybrid fillers improved the tensile strength by 12 %.•GNP bifurcation and NS plasticization improved tensile performance.