Effective interlaminar toughening of carbon fiber/epoxy composite laminates by extremely low loadings of monolayer graphene oxide

An interlaminar ultrafine spraying method was proposed for monolayer graphene oxide (GO) modified CFRP nanocomposite laminates. The well-dispersed monolayer GO nano-solutions were prepared by multi-level dispersion and then sprayed on carbon fiber/epoxy prepreg by the ultrafine atomizing technique. A series of GO/CFRP laminate specimens with different GO loadings were fabricated for our fracture toughness tests and SEM characterization. The test results indicated that the Mode I fracture toughness (GIC$$ {G}_{\mathrm{IC}} $$) was enhanced by 140% with quite a low fraction of monolayer GO nanosheets. The distinct toughening effect at such a low level of nano-contents was attributed to the sufficient quantity of monolayer GO nanosheets and also a uniform distribution, which was found to be more important than the volume/weight fraction as the principal structural parameter. Thus, the proposed interlaminar toughening approach owns the virtues of good effectiveness and especially low cost owing to the largely reduced weight percentage of nanographene, showing a promising potential of industrial scale-up.Highlights Proposed an interlaminar ultrafine spraying method for monolayer GO nanosheets. Found that the quantity of GO nanosheets is vital in polymer toughening. Realized significant toughening with extremely low loadings of monolayer GO. Provided a way with high toughening effect and low cost for industrial scale-up.