Experimental and analysis of the mechanical behaviors of multi-walled nanotubes/polyurethane nanoweb-reinforced epoxy composites

Thermoplastic polyurethan-based nanowebs with various strengths and moduli were electrospun by adding multi-walled nanotubes. The obtained webs were impregnated with epoxy resin to form a reinforced composite. The tensile properties of the nanoweb-reinforced composites were determined to demonstrate the effect of the nanowebs on the properties of the epoxy resin. A significant increase in the mechanical response is observed, up to 29% in tensile strength, 4% in elastic modulus and 19% in tensile strain, compared with neat epoxy, when the weight fraction of multi-walled nanotubes is 3 wt% within the webs. To further understand the mechanical behavior of the nanoweb-reinforced composites, a micromechanical theory, bridging model, is employed and the in situ properties of the epoxy matrix and nanofibers is studied. The effect of incorporation of nanofibers and multi-walled nanotubes is indicated in the micromechanical analysis, which is helpful for the optimization design of nanofibers-reinforced epoxy composites.