The representative stress-strain curves of the control, EEG and EEA composites under tension are shown in Fig. . Both the control and EEA reinforced CFRP composites behaved linearly throughout the whole tensile procedure, while the EEG exhibited non-linear behaviour starting from ~0.65%. This can be attributed to the weak interfacial properties between the EEG flakes and matrix, and delamination occurred during the tensile procedure, leading to a 32.4% loss of tensile strength (Fig. ). The tensile modulus, which represents the elastic properties of the composites, remained unchanged with the addition of EEG flakes, as shown in Fig. . By comparison, EEA samples possess amine groups, which are capable of reacting with the epoxy resin and forming covalent bonding, similar to the reaction between the epoxy and hardener . Consequently, the interfacial properties and load transfer efficiency were largely improved, as a result, the tensile strength increased from 318.3±9.4 MPa to 374.4±14.7MPa, and modulus increased from 30.3±0.2 MPa to 32.7±0.5 MPa, indicates an improvement of 17.6% and 7.9% respectively, comparing against the control composites. In order to further understand the failure mechanism, a digital image correlation (DIC) system was applied to monitor the strain distribution on the composites during the test. Both control and EEA reinforced CFRP composites experienced uniform axial strain distribution (Fig. ) during the tensile procedure and fractured with sharp surfaces with no obvious delamination (Fig. ). While EEG showed a large variation of strain distribution over the sample (Fig. ) and failed with severe delamination which can be seen across the out-of-plane direction (Fig. ). The uniform strain distribution represents the uniform load transfer across the sample, indicating excellent interfacial properties. For the EEA samples, the interfacial properties are attributed to the strong connections between the EEA flakes and the matrix. On the contrary, without chemical bonding forming, EEG flakes act as points of stress concentration ,