Study on the interface toughening of particle/fibre reinforced epoxy composites with molecularly designed core–shell particles and various interface 3D models
Naveen Thirunavukkarasu, Harini Bhuvaneswari Gunasekaran, Shuqiang Peng, Abdelatif Laroui, Lixin Wu, Zixiang Weng
Abstract
Poor interface toughening reduces the utilisation of particle/fibre-reinforced thermoset polymer composites in many engineering applications. Numerous studies have been performed on polymer and fibre component modifications, yet utilising fillers in epoxy is a promising way to improve interface toughness. Here, a molecularly designed core–shell particle (CSP) is introduced into the epoxy polymer to generate a strong interface through an epoxy coupling agent acrylate shell and styrene-butadiene rubber core. The nanocomposite material, in particular, has an excellent tensile strength of 166% and exceptional elongation of 245%; these properties further improve the interlaminar shear strength of 225% in carbon fibre-reinforced polymer composite. Moreover, CSP gives better shear effects and stress transferability to the fibre–matrix interface region. It was clarified systematically by developing a 3D micro- and macro-mechanical model from field emission scanning electron microscopy (FESEM) and surface fracture analysis. Meanwhile, results suggest that effective toughness is achieved by well-dispersed and void growth, filler-epoxy interaction and strong matrix-fibre interfaces. With these features, this study emphasises a way to analyse composite structures and fibre laminates which can help engineering design strategies for various applications.