Significantly enhancing fracture toughness of epoxy composite with promising γ-FeOOH@Fe2O3 hybrid nanoparticles by magnetic field assistance

Abstract

The toughening of epoxy resin (EP) and the interlaminar toughening of carbon fiber reinforced composite (CF/EP) laminates have been widely concerned. In this work, the needle-like γ-FeOOH nanoparticles were prepared by liquid phase deposition-air oxidation method, and then were calcined under different conditions to obtain γ-FeOOH and γ-Fe2O3 hybrid nanoparticles (γ[email protected]2O3). Effect of calcination condition of γ[email protected]2O3 and magnetic field assistance on fracture toughness (KIC) of EP was systematically investigated. Then the selected γ[email protected]2O3 with the best toughening effect were used to improve the mode I interlaminar fracture toughness (GIC) of CF/EP laminate. The resulting γ[email protected]2O3 have a length of around 1 ​μm, a diameter of around 100 ​nm and the Ms of 8.99–45.96 emu/g. After calcinated at 250 ​°C for 1 ​h, the γ[email protected]2O3 containing 24 ​wt% FeOOH and 76 ​wt% Fe2O3 achieved the best toughening effect. Under a magnetic field of 0.09 ​T, the KIC of the γ[email protected]2O3/EP composite (2.45 ​MPa ​m1/2) is 81.7% and 66.7% higher than that of neat epoxy and the composite without magnetic field induction, respectively. Furthermore, the GIC of the γ[email protected]2O3/CF/EP composite (0.914 ​kJ/m2) is also significantly increased by 88.8% and 51.8% compared to that of CF/EP and the corresponding composite without magnetic field induction, respectively.