Yuhang Xu,Senlin Rao,Yi Wendi,Yi Junchao,Feng Liu,Gary J. Cheng
The incorporation of shear thickening fluid (STF) into aramid fabric has emerged as a compelling strategy to augment the protective attributes of aramid-based soft body armor. The peak viscosity of STF assumes a pivotal role in shaping the efficacy of this enhancement. In this study, we present an innovation in the design and synthesis of an ultrahigh peak viscosity STF using metal-organic framework (MOF)/SiO 2 nanoparticles as the core constituents. The remarkable enhancement in peak viscosity of MOFs/SiO 2 -based STF, taking ZIF-8 as an exemplary MOFs material, is attributed to the pronounced interparticle contact friction facilitated by the rugged surface morphology of the ZIF-8/SiO 2 nanoparticles. Therefore, ZIF-8/SiO 2 -based STF (62.5 wt.%) demonstrates a peak viscosity approximately 3938 times greater than that of conventional SiO 2 -based STF (62.5 wt.%). This extraordinary STF formulation has been successfully employed in aramid fabric-based soft body armor, resulting in a significantly advancement in protective performance. Compared to Kevlar fabric impregnated with SiO 2 -based STF (62.5 wt.%), the utilization of ZIF-8/SiO 2 -based STF (62.5 wt.%) results in substantial and scientifically significant improvements in key mechanical parameters. These include a notable 15.4 % increase in maximum stabbing force, a remarkable 29.5 % augmentation in maximum yarn pull-out force, a 24.3 % boost in maximum yarn tensile strength, and a 204.5 % enhancement in maximum fabric tensile strength. This research underscores the profound impact of synergizing ZIF-8 and SiO 2 within the STF matrix, and significantly improves the protective abilities of SiO 2 -based STF-impregnated Kevlar fabrics, which provides a new route to design STF-impregnated ballistic fabric with high protective performance.
In this paper, complexes of corn starch (CS) with p-coumaric acid (p-CA) and caffeic acid (CA) were prepared using ball milling for various durations. The complexes' multiscale structure, digestibility, and intermolecular interaction were explored. The ball milling treatment disrupts the orderliness of the starch double helix. Increased milling time exposes more active sites, resulting in the formation of surface-coarse complexes. The physicochemical properties and structures of the complexes varied significantly depending on the functional group and milling duration. p-CA and CA interacted with CS through non-covalent bonding to form non-inclusion complexes. Hydrogen bonding is the main driving force, and -OH and -COOH are the active sites. Phenolic acid intercalated between starch chains while wrapping the residual granules, improving the short-range ordering, thermal stability, and peak viscosity of ball-milled starch. Regarding digestibility, both phenolic acids inhibited CS digestion. However, the complexes prepared with CA, having more hydroxyl groups and longer milling times, were more effective. This study provides a basis for developing low-digestibility foods.
Yuxue Zheng,Weixuan Sun,Wenhan Yang,Shiguo Chen,Donghong Liu,Jinhu Tian,Xingqian Ye
The study describes the effects of xanthan gum (0.5–2.0%) on the in vitro digestibility and rheological and pasting properties of kudzu ( Pueraria lobata ) starch pastes. The flow behavior index ( n ) shows a decrease in trends (from 0.43 to 0.31) as the xanthan gum concentration increases, indicating pseudoplastic behavior. Dynamic viscoelasticity analysis indicate that the elastic ( G ′) and viscous ( G ″) moduli increase in the presence of xanthan gum, suggesting a strong interaction between xanthan gum and kudzu starch in the composite system. All concentrations of xanthan gum result in increased elasticity ( G ′ > G ″). Pasting properties reveal that the peak and final viscosity of the xanthan gum–kudzu starch dispersion decreases with the increasing concentration of xanthan gum, highlighting the importance of xanthan gum in controlling overall viscosity. The addition of xanthan gum also decreases the hydrolysis of kudzu starch during in vitro digestion.
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