Joint Exfoliation of MXene by Dimensional Mismatched SiC/ZIF-67 Toward Multifunctional Flame Retardant Thermoplastic Polyurethane.

The single-layer MXene fully demonstrates the advantages of 2D materials, especially catalytic, conductive, and mechanical properties. However, the high energy consumption and low efficiency faced by MXene in the divestiture process are still challenges that need to be solved urgently. In this article, dimension mismatch and collaborative stripping strategies are skillfully combined to easily realize the transformation from multi-layer MXene to single layer. In addition, the functionalized MXene@SiC@polyaniline (MXene@SiC@PANI) nano-hybrid materials are used as fillers to improve the thermal conductivity, flame retardant, and antibacterial properties of thermoplastic polyurethane (TPU). The surface temperature of TPU/MXene@SiC@PANI composites increased from 33.4 °C to 59.8 °C within 10 s. In addition, the antibacterial efficiency of TPU composites against Escherichia coli and Staphylococcus aureus is 69.6% and 88.9%, respectively. Compared with pure TPU, the peak heat release rate and total heat release are reduced by 71.4% and 34.6%, respectively. The flame-retardant mechanism of MXene hybrid materials is systematically discussed. It is worth noting that the introduction of PANI enhances the compatibility between the filler and the polymer, effectively maintaining the mechanical properties of the TPU itself. This work provides a convenient method for the multi-functional practical application of TPU.

Association between sarcopenia and hearing impairment in middle-aged and elderly people in China: a prospective cohort study.

This study used longitudinal data from CHARLS 2011-2018 for cross-sectional and longitudinal analyses to investigate the relationship between sarcopenia and hearing impairment in middle-aged and elderly adults in China. The study selected 9723 participants aged 45 years and older from CHARLS 2011 and followed up in 2015 and 2018. Binary logistic regression and cox proportional risk regression models were used for testing. The results of the study showed that in the cross-sectional analysis, probable sarcopenia was significantly associated with hearing impairment compared with the group without sarcopenia [OR (95% CI) 0.342 (1.187, 1.669), p < 0.001], but sarcopenia was not significantly associated with hearing impairment. In the longitudinal analysis, middle-aged and elderly adults with sarcopenia [HR (95% CI) 0.354 (1.043, 1.945), p < 0.01] were more likely to have hearing impairment than those with probable sarcopenia and without sarcopenia. Probable sarcopenia was strongly associated with hearing impairment in middle-aged and elderly adults, whereas sarcopenia was a strong predictor of hearing impairment over the next 7 years. The results of this study emphasize the urgent need for measures to address sarcopenia in order to prevent and delay the decline in hearing function.

Wedging crystals to fabricate crystalline framework nanosheets via mechanochemistry.

Mechanochemistry studies the effect of mechanical force on chemical bonds, bringing opportunities for synthesizing alloys, ceramics, organics, polymers, and biomaterials. A vital issue of applying macro-scale mechanical force to manipulate crystal structures is finding ways to precisely adjust the force directions to break micro-scale target chemical bonds. Inspired by a common technique of driving a wedge into the wood to make wood chopping much easier, a wedging strategy of splitting three-dimensional structured crystalline frameworks and then converting them to nanosheets was proposed, where specific molecules were wedged into crystalline frameworks to drive the directional transmission of mechanical force to break chemical bonds. As a result, various crystalline framework nanosheets including metal-organic framework nanosheets, covalent organic framework nanosheets, and coordination polymer nanosheets were fabricated. This wedging crystal strategy exhibits advantages of operability, flexibility and designability, and furthermore, it is expected to expand mechanochemistry applications in material preparation.