LAUSR

In this paper, the surface properties and morphologies of the concentrated nitric acid (HNO3)-modified carbon fiber (CF) were characterized by XPS, SEM, and contact angle goniometer, respectively. The results showed that both the oxygen-containing functional groups content and the surface roughness of concentrated HNO3-modified CF significantly increased. The contact angle of concentrated HNO3-modified CF was obviously lower than that of unmodified CF. Studies on the mechanical properties of carbon-fiber-reinforced ultrahigh-molecular-weight polyethylene (CF/UHMWPE) composite revealed that the stress–strain behavior gradually changed from nonlinear to linear relationship with the rise of CF content in UHMWPE matrix. Both the tensile strength and modulus increased with the rise of CF content. Conversely, as the CF content in UHMWPE matrix is increasing, the flexural strength and modulus increased first and then decreased. The flexural strength and modulus of CF/UHMWPE composite with 30 wt.% CF content reached the maximum value of 157.61 MPa and 9.82 GPa, respectively. Moreover, the CF surface modification and CF content have a synergistic effect on the tensile and flexural mechanical properties of the CF/UHMWPE composite. The influence of CF modification on the tensile and flexural mechanical properties of the composite became more and more obvious with the rise of CF content.