▎ 摘　　要

Fracture toughness (FT) and Tensile strength (TS) of epoxy reinforced amine-functionalized MWCNTs (A-MWCNTs)/graphene nanoparticles (GNPs) composites are investigated in cryogenic environment. Simplex centmid design is employed to decide the composition of samples. FT and TS of epoxy improved significantly on incorporating 0.25 wt% of either A-MWCNTs or GNPs, but increasing the content of nanofillers beyond 0.25% showed lower enhancement in the mechanical properties. Simultaneous addition of nanofillers in epoxy demonstrated synergistic effects, with the maximum FT (121%) and TS (132%) noticed for hybrid composite containing 0.17% of each nanofiller. It is attributed to the presence of well interconnected 3D network between nanofillers and epoxy, which yield uniform dispersion of nanofillers and strong adhesion between nanofillers and epoxy. Regression analysis suggested quadratic models for estimating FT and TS. Multiple response optimization yields the maximum FT (0.907 MPm1/2) and TS (20.6 MPa) for hybrid composite containing 99.67% epoxy, 0.17% A-MWCNTS and 0.16% GNPs.