Interfacial and mechanical performance of chemically modified high content MWCNT/PEEK thermoplastic composites

Abstract

It is difficult to increase the content of carbon nanotubes in carbon nanotubes/polyether ether ketone (CNTs/PEEK) thermoplastic composites prepared by doping carbon nanotubes into highly viscous PEEK resin using conventional methods. In this paper, a multi-walled carbon nanotubes/PEEK (MWCNT/PEEK) thermoplastic composite film with high MWCNTs content is prepared by vacuum suction filtered and hot-pressing methods. The microstructure and interfacial bonding performance of chemically modified and unmodified composites in the form of films are analyzed by molecular dynamics simulation and experiment. The results show that MWCNT can significantly improve the crystallinity of PEEK resin. Compared with the MWCNT/PEEK composites without chemical modification, the MWCNT-COOH/PEEK-OH composite film has a denser structure, and the tensile strength and elastic modulus are increased by 94.5% and 15%, respectively. The MWCNT-COOH/PEEK-OH composite films are expected to be used for interlaminar mechanical performance enhancement of CF/PEEK high-performance thermoplastic composites, which are widely used in aerospace.

A Review of Delamination Damage of Composite Materials

“…The fractographic analysis of the crack tip vicinity and delamination surfaces in a unidirectional composite shows the following. In cases of Mode I dominance, the fractures are predominantly adhesive in coal/epoxy and mixed adhesive-cohesive in coal/PEEK composites (PEEK is a polyether ketone thermoplastic matrix), with the involvement of layers in the fiber fracture process [57]. In cases of Mode II (transverse shear) dominance, the crack surfaces of delamination in relatively brittle matrices (epoxy) are comb-like, which indicates multiple turns of the crack front in the interlayer [58].…”

“…In this review, we will focus on the general characterization of approaches, and some of the stability problems and critical behavior that are characteristic of composites. As in traditional problems, the issues of delamination stability are reduced to eigenvalue problems [11,40,49] or energy methods [14,15,23,50,56,57,63,77]. At the same time, nonlinear technical theories of plates [15,77] and shells [11,50,63] are used, as well as the FEM [91,94].…”

“…Analytical approaches are usually limited to one-member approximations, taking into account the conditions of rigid clamping on the contour of the bulging delamination [11,27,32,50,56,57,63,68,77]. In a momentless undisturbed state (compression), bulging delamination is the only option when the load increases.…”

“…In a momentless undisturbed state (compression), bulging delamination is the only option when the load increases. If the subcritical state is momentary, As in traditional problems, the issues of delamination stability are reduced to eigenvalue problems [11,40,49] or energy methods [14,15,23,50,56,57,63,77]. At the same time, nonlinear technical theories of plates [15,77] and shells [11,50,63] are used, as well as the FEM [91,94].…”

“…The quasi-static critical growth problem of one-dimensional and two-dimensional delamination in plates has been discussed in [63,68], while in shells, it is covered in [11,56,57]. The delamination state is described using geometrically nonlinear approximations, as per the Karman and Mindlin theories [11,56,57,68], or through the Finite Element Method (FEM) [91][92][93][94].…”