Tensile mechanical characteristics of CF/PEEK biocomposites with different surface modifications

Abstract

Carbon fibre reinforced polyetheretherketone (CF/PEEK) biocomposites were prepared by the method of hot casting under pressure. The influences of CF surface treatment methods on the tensile strength and modulus of CF/PEEK biocomposites were investigated. The results indicated that the CF modified with concentrated nitric acid was beneficial to improve the tensile strength of CF/PEEK composites. On the contrary, the surface of CF treated by KH-560 silane couple agent has a little or unfavourable influence on the tensile mechanical properties of CF/PEEK composite. Furthermore, the CF surface treatment methods and CF content have a synergistic effect on the mechanical properties of the biocomposites. With the CF content rising, the difference of the effect of different treatment methods on the tensile mechanical properties of CF/PEEK composites is more and more significant. Meanwhile, the tensile stress-strain relationship of the composites showed linear variation and the break strain of the CF/PEEK composites decreased with increasing CF content. The fracture mechanism of the biocomposites gradually changed from ductile to brittle fracture with the increase of CF content. The tensile strength of the biocomposites first increased and then decreased with the increasing CF content. However, the tensile modulus increased monotonically with CF content rising.