Experimental evaluations and modeling of the tensile behavior of polypropylene/single-walled carbon nanotubes fibers

Polypropylene fibers containing up to 0.2 vol% of single-wall carbon nanotubes, prepared by meltspinning, are analyzed in terms of both experimental mechanical properties and numerical nonlocal models. In particular, fibers of a commercial polypropylene (PP) resin are compared with composite fibers, based on the same matrix, reinforced with 0.1 and 0.2 vol% of carbon nanotubes (CNT). Experimental findings shows that, although the applied processing conditions are such that the inclusion of carbon nanotubes does not alter the crystalline structure and the degree of crystallinity of the hosting matrix, tensile properties of nanocomposite fibers vary significantly with the filler content. Specifically, Young modulus, yield strength and ductility show a linear dependence upon the nanotube content over the range of compositions explored; in particular with respect to neat PP fibers filaments containing 0.2 vol% of single wall carbon nanotubes show increases of approximately 16% and 6% in the modulus and the yield strength, respectively, while the ductility decreases of about 65%.