▎ 摘　　要

Some commercially available graphene (CG) samples, actually graphite nanoplates, are difficult to be applied in polymers due to their large thickness, even though their fabrication is more cost-effective. In this work, a CG sample with a thickness of about 25 nm is pre-treated via a facile acid soaking technique, and then the acid-treated CG is introduced into epoxy resin (EP) to improve the toughness while maintaining the high rigidity of the EP. The thickness of the acid-treated CG is dramatically decreased to about 1 nm, well-dispersing CG in the EP matrix. The tensile strength and the fracture energy of EP composite with 0.2 wt% acid-treated CG are increased to 85.2 MPa and 3.6 kJ m(-2) from 74.3 MPa and 2.3 kJ m(-2) of pure EP, respectively. In addition, the tensile-fractured surfaces of EP composites reveal that the toughening mechanism is mainly attributed to the crack deflection and crack pinning caused by the firmly-embedded CG nanosheets in the EP matrix. Besides, the glass transition temperature of EP composites is increased to 170.5 degrees C from 163.9 degrees C of pure EP. The present study provides a valuable approach for making use of the cost-effective graphite nanoplates to achieve a similar performance as graphene in EP.