Enhancement of performance in flax/epoxy composites by developing interfacial adhesion using graphene oxide
Abdolmajid Alipour, Richard J. Lin, Krishnan Jayaraman
Abstract
Graphene oxide (GO) at different contents, ranging from 0 to 0.5 wt%, was exploited to develop the interfacial \nadhesion between matrix and fiber in flax/epoxy composites. A proposed mechanism, which was substantiated by Fourier \ntransform infrared spectroscopy, demonstrated that GO, thanks to possessing oxygen-containing functional groups, acted as \na coupling agent between epoxy matrix and flax fiber. As a result of the developed interfacial bonding between composite \nconstituents, significant improvements in tensile strength (68%) and flexural strength (65%) of composites up to 0.3 wt% \nwere recorded. According to X-ray diffraction (XRD) and transmission electron microscopy (TEM) observations, all \nnanocomposites formed an exfoliated structure. Microscopic observations depicted a substantial decline in the total crack \nlengths of composites and also the rate of cracks formed at the interface of fiber and matrix. It was also found that thanks to \nthe developed interfacial adhesion between epoxy matrix and flax fiber, major defects responsible for composite premature \nfailure did substantially reduce. In low-velocity impact test, resultant nanocomposites showed enhanced peak loads and \ndamage tolerance owing to a strong interfacial adhesion developed by GO presence. Scanning electron microscopy (SEM) \nimages of the impact-fractured surface of nanocomposites showed the risk mitigation of catastrophic damages, with the inclusion of GO, due to the efficient fiber adherence to the matrix.