Effect of graphene-based nanofillers addition on the interlaminar performance of CFRP composites: An assessment of cryo-conditioning

Abstract

Carbon fiber reinforced polymer (CFRP) composites are extensively being used as materials in aerospace and aircraft applications. For cryogenic applications, which require materials having high dimensional stability and low thermal conductivity, CFRP composites are an exquisite alternative to metals. These materials have to sustain and retain their promising mechanical properties which include high strength to weight ratio and stiffness at extremely low temperatures. This work involves the decoration of carbon fiber (CF) surface of carbon fiber epoxy (CF/E) composites with two types of graphene-based nanofillers. Graphene oxide (GO) and Graphene hydroxyl (GOH) were implemented onto the CF by electrophoretic deposition (EPD) technique. A comparative study of the effect of nanofillers on the interlaminar behavior of 3 CFRP composites (neat, GO-CF/E, GOH-CF/E) for different times of cryogenic conditioning was carried out. Modified CFRP laminates have shown an improvement of 15.6% and 11.42% with GO and G-OH respectively in interlaminar shear strength (ILSS) in the unconditioned state with respect to neat. The effect of fiber modification becomes less prominent with increasing time of cryo conditioning. GO was proposed to be a better modifying nanofiller than GOH. A dip in ILSS at 1 h of aging may be attributed to thermal shock and development of internal stresses. Recovery of ILSS values at higher times of aging was observed. Scanning electron microscopy was carried out to identify various modes of failure.