Study on interlaminar performance of CNTs/epoxy film enhanced GFRP under low-temperature cycle

The laminates of unidirectional (UD) Glass Fiber Reinforced Plastic (GFRP) were prepared by inserting Toner/ epoxy film (as a comparison) and CNTs/epoxy film between layers to optimize the interlaminar performance. The effect of temperature variation on the interlaminar properties of materials has yet to be identified in practical applications. To explore the impact of low-temperature cycle (21 cycles between -58 degrees C and RT) on the specimens and the strengthening mechanism of the two epoxy films, interlaminar shear strength (ILSS) test, end notch flexure (ENF) test and double cantilever beam (DCB) test were prepared and carried out. The results showed that the interlaminar fracture toughness of GFRP embedded with the CNTs/epoxy film was superior to that of GFRP without film and embedded with the Toner/epoxy film in modes I (based on DCB) and II (based on ENF). The interlaminar shear strength was greatly enhanced by the interlaminar integration of CNTs/epoxy film. The impact of low-temperature cycle on the interlaminar performance of CNTs/epoxy enhanced GFRP was not significant, and the effect on the interlaminar properties of CNTs/epoxy enhanced GFRP was minimal compared with the other two kinds of specimens. The microstructure of the interlaminar strengthening interface was further studied by scanning electron microscopy (SEM).