Enhancing mechanical properties of biaxial E-glass fabric/epoxy composite using cellulose nanocrystals: Impact of mixing medium

Abstract

Epoxy, a thermoset resin with myriad applications, suffers from drawbacks such as brittleness and lack of fracture toughness. A breakthrough in reinforcing epoxy-based composites can be achieved by developing cost-effective and environment-friendly nanoparticles with high elastic modulus and low density such as cellulose nanocrystals (CNCs). In this research work, CNCs were used to reinforce biaxial E-glass fabric/epoxy composite. The impact of CNCs mixing medium, i.e. hardener or a mixture of epoxy and hardener, was highlighted, as also illustrated in the graphical abstract. Biaxial E-glass fabric/CNCs/epoxy (BE2CE) nanocomposite containing optimum content of CNCs exhibited significantly enhanced mechanical properties, i.e. tensile strength and modulus, fracture toughness and Charpy impact strength. This was discussed considering synergistic contribution of CNCs and E-glass fibers to reinforce epoxy-based composite, which was manifested by increased E-glass fiber-epoxy interfacial shear strength (IFSS) at the presence of CNCs. The IFSS was measured using single fiber micro-droplet pull-out test. Additionally, regardless of CNC content, considering hardener as the mixing medium yielded superior results in manufacturing BE2CE nanocomposite.