The 3D hollow hierarchical architectures tend to be designed for inhibiting stack of MXene flakes to obtain satisfactory lightweight, high-efficient and broadband absorbers. Herein, the hollow NiCo compound@MXene networks were prepared by etching the ZIF 67 template and subsequently anchoring the Ti3C2Tx nanosheets through electrostatic self-assembly. The electromagnetic parameters and microwave absorption property can be distinctly or slightly regulated by adjusting the filler loading and decoration of Ti3C2Tx nanoflakes. Based on the synergistic effects of multi-components and special well-constructed structure, NiCo layered double hydroxides@Ti3C2Tx (LDHT-9) absorber remarkably achieves unexpected effective absorption bandwidth (EAB) of 6.72 GHz with a thickness of 2.10 mm, covering the entire Ku-band. After calcination, transition metal oxide@Ti3C2Tx (TMOT-21) absorber near the percolation threshold possesses minimum reflection loss (RLmin) value of − 67.22 dB at 1.70 mm within a filler loading of only 5 wt%. This work enlightens a simple strategy for constructing MXene-based composites to achieve high-efficient microwave absorbents with lightweight and tunable EAB."Image missing"

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Abstract.To investigate the influence of carbon fiber (CF) surface treatment on the flexural strength and tribological properties of the short-cut CF/polyimide (PI) composites, pitch-based short-cut CF were treated by rare earth. The CF before and after treatment was examined by X-ray photoelectron spectroscopy (XPS) and by scanning electron microscopy (SEM). The flexural strength of the specimens was determined in a three-point test machine. The friction and wear behaviors of PI composites sliding against GCr15 steel rings were evaluated on an M-2000 model ring-on-block test rig. The results show that the surface of the treated CF became rougher and there formed lots of active groups after rare earth treatment. The flexural strength of PI composites with rare earth treated CF was improved. The friction coefficient and wear rate of PI composites with rare earth treated CF were lower than that with untreated CF.

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