Improving Mechanical Performance and Reversible Self‐Healing in Bismaleimide‐Grafted Carbon Fiber Composites via Graphene Oxide‐Enabled Diels–Alder Interfacial Networks

ABSTRACT The most common reasons for failure in fiber‐reinforced composites are interfacial defects. Such interfacial interactions can be reduced using self‐healing chemicals, thus improving interfacial bonding. The carbon fiber reinforced polymer laminate was fabricated via hand layup method supplemented with vacuum bagging process by graphene oxide (GO) modified epoxy at 0–1 wt.% concentrations in the present work. Tensile, flexural, and interlaminar shear strength tests are conducted to determine optimal GO loading. The highest tensile strength 571 MPa was found at 0.6 wt.% GO for a result 28% superior to neat epoxy. On the other hand, flexural strength and ILSS attained a maximum of 678 MPa and 52.5 MPa at 0.4 wt.% GO—improve 23% and 36% respectively over neat epoxy. The laminate fabricated with Bismaleimide grafted carbon fiber and GO based epoxy with thermoreversible reactions is tested at optimal GO loading. The resulting ILSS value was 50.4 MPa. After heat‐induced activation of Diels Alder reactions of BMI and GO, the fractures were recovered with an ILSS recovery of 38.67 MPa with self‐healing efficiency ≈77%. Successful fiber surface modification was verified using FTIR spectroscopy and FESEM showed an improved fiber–matrix interfacial interaction and matrix continuity pre‐ and post‐self‐healing. According to the rheological analysis, the viscosity increases at higher GO concentration, but shear‐thinning occurs at higher shear rates due to alignment of GO sheets as well as breakup of GO clusters in the epoxy matrix. The DA and retro‐DA adducts were further confirmed using Differential scanning calorimetry (DSC) analysis.