Multiscale enhancement behavior of nano‐silica modified CF/PEEK composites prepared by wet powder impregnation

Abstract

The mechanical performance of modified multiscale carbon fiber (CF) reinforced poly(ether-ether-ketone) (PEEK) composites is improved through wet powder impregnation. The complex PEEK suspension is prepared by mixing nano-silica and PEEK powders in water homogeneously. The CFs are pulled through the complex PEEK suspension, and the modified multiscale PEEK prepregs and composites are prepared by a series of drying and consolidation process. The increasing energy storage, decreasing tan d max and the area under the tan d curve in the dynamic mechanical tests indicate strong interface interactions of modified multiscale CF/PEEK composites. The interlaminar shear strength increases by 15.6% from 72.2 to 83.5 MPa for 2.5 wt% nano-silica addition, showing significant improvement in resisting the delamination damage. Besides, the same addition makes the flexural strength and modulus increase by 13.9 and 8.6%, respectively. The modified multiscale CF/PEEK composites exhibit higher flexural strength and modulus at elevated temperature than the pristine composites. Furthermore, the enhancement mechanisms for the modified multiscale CF/PEEK composites are proposed and illustrated, which contributes to future research on multiscale enhancement for conventional composites. POLYM. COMPOS., 00:000-000, 2018. FIG. 5. The tensile fracture surfaces of PEEK nanocomposites. (a) Without nano-silica, (b) 1 wt% nanosilica, (c) 5 wt% nano-silica, (d)10 wt% nano-silica. FIG. 6. The dynamic mechanical performance. (a) Storage modulus, (b) Loss modulus, (c) The damping term-tan d. [Color figure can be viewed at wileyonlinelibrary.com]

Improved interlaminar crack resistance of glass fiber/poly (phenylene sulfide) thermoplastic composites modified with multiwalled carbon nanotubes

“…Su et al’ method need second fabrication for prepreg to introduce nanoparticles, which also expands the work. To meet the continuous manufacturing requirement of commercial application, aqueous suspension prepregging, an efficient and environmental friendly way for CFRTP manufacture, is employed to prepare nanoparticles‐modified CFRTP by dispersing the nanoparticles in the suspension during processing, which was confirmed feasible by our previous work …”

“…However, compared to pristine specimen, the image of the specimen modified with 1 wt% MWNTs revealed fewer and smaller cracks, demonstrating the strong interlaminar interactions. Load–Displacement curve showed the initiation of the cracks in 1 wt% MWNTs load specimen occurred on larger strain indicating the presence of MWNTS in the PPS matrix increased the resistance to cracks initiation. However, excessive addition of the MWNTs caused undesirable results.…”

The synergistic steric hindrance effect in the preparation of polyether ether ketone composites by powder slurry method

“…Chen et al added a small amount of surfactant (Triton) to deionized water to achieve the dispersion of PEEK in water. The suspension can remain stable for a certain period of time 27 . However, it was found that settlement stratification appeared soon after suspension was standing.…”

“…Relevant studies have shown that by selecting appropriate surfactant formulations and processes, the suspension stability can be improved. 28 Surfactants can be divided into non-ionic surfactants, cationic surfactants and anionic surfactants. Different surfactants have different mechanisms to stabilize the suspension.…”

Improvement of interfacial interactions in CF/PEEK composites by an s‐PSF/graphene oxide compound sizing agent

“…As a result, the ILSS, flexural strength and modulus of the resulting CF/PEEK composites increased by 70%, 37%, and 48%, respectively. Chen et al 17 evenly mixed nano‐SiO2 and PEEK powder in water to prepare a PEEK composite suspension. A modified multi‐scale PEEK prepreg and its composites were then prepared via a series of curing processes.…”