Applied Clay Science最新文献

In this study, a silane coupling agent and kaolin, a natural mineral resource, were introduced into the wet mixing process of natural rubber latex, the high wear-resistant and low-generation heat natural rubber composites were prepared. The sputtering, collision, and deposition of coupling agent/fillers/natural rubber latex mixed emulsion onto the roller effectively could break up the filler aggregates, enable fillers to be better infiltrated, distributed, and dispersed in the rubber. The effects of dry/wet mixing processes and the ratio of kaolin to silica on the crosslinking density, filler dispersion, extrusion rheological properties, gas barrier properties, dynamic mechanical properties and thermal stability of NR composites were investigated, and the silanization mechanism was summarized by FTIR and XRD. The experimental results showed that kaolin improved the crosslinking density and failure temperature, reduced the Payne effect, extrusion swell, and rolling resistance. Compared with 60 phr silica-filled natural rubber, the gas barrier property and wear resistance of 60 phr kaolin-filled natural rubber were improved by 64 % and 27 %, respectively, and the rolling resistance was reduced by 57 %. When the ratios of silica to kaolin were both 20:40, the crosslinking density, gas barrier property, and wear resistance of wet mixing were improved by 24 %, 45 %, and 9 %, respectively, compared with dry mixing. This study provided a new method for the high-value application of kaolin in wet mixing and green tires.

The friction behavior of widespread clay minerals is a major concern in many geo-engineering problems, such as the stability of soft soil foundations and the induction of seismic fault zones. The present work aimed to study the friction behaviors of kaolinite at the particle level using the molecular dynamics method. The effects of normal force (F_n), shear velocity (v), and interfacial water film on nanofriction were discussed. The “stick-slip” phenomenon and periodic evolution of friction forces (F_f) were observed in dry friction and became less pronounced with water lubrication. The dry F_f of kaolinite was found to be insensitive to F_n. However, wet F_f exhibited a linear increase with F_n and then transitioned to a non-linear relationship as slip displacement increases due to the continuous loss of water molecules from the interface during friction. Notably, at high loads (F_n ≥ 30 nN), the peak friction of wet kaolinite showed characteristics similar to dry friction. A velocity-strengthening behavior of kaolinite at high velocities was observed in both dry and wet conditions. The macroscale friction coefficients of kaolinite were predicted from nanofriction data and results showed good agreement with experimental values. This study lays the foundation for bridging micro- and macro-mechanical behaviors, suggesting a new pathway for acquiring precise macroscopic friction of minerals through cross-scale studies.

This study comprehensively characterized LAPONITE® and evaluated its cytotoxic and genotoxic effects on rat adipose-derived stem cells (ADSCs). Chemical analyses included Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. Cytotoxic screening using the Artemia salina lethality test indicated low toxicity. ADSCs exhibited mesenchymal stem cell chracteristics. LAPONITE® demonstrated osteogenic induction capability. MTT assays revealed increased cell viability across concentrations and exposure times. The comet assay for genotoxicity showed no significant differences in damage index between experimental groups, except for a distinction in the frequency of damage between LAPONITE® concentrations at the longest exposure time. This comprehensive assessment provides valuable insights into the safety and potential applications of LAPONITE® in regenerative medicine.

Secondary batteries have received extensive attention due to the increasing demand for electric vehicles, portable electronics, and energy storage systems. A separator, a critical component of a battery, prevents short circuits by physically blocking the anode and cathode while allowing ion transport for electrochemical reactions. Although often underestimated, the separator significantly impacts the electrochemical performance and stable operation of batteries. Halloysite nanotubes (HNTs), a naturally occurring clay material, offer unique structures, surface chemistry, and abundant availability, making them ideal for improving battery separators. This review explores recent studies on HNTs in battery separators, covering preparation and coating methods, and detailed characterizations in both Li-based and non-Li-based secondary batteries. The integration of HNTs in separators offers multiple benefits such as improved thermal stability, enhanced heat conduction, better electrolyte wettability and uptake, and reinforced mechanical strength. Additionally, HNTs effectively mitigate the shuttle effect in Li‑S batteries, suppress organic intermediate migration in Zn-organic batteries, and enhance long-term cycle stability across various battery systems. This comprehensive review demonstrates the significant impact of HNTs on battery technology and paves the way for potential future advancements in energy storage devices.

The dissolution of silicate minerals plays a crucial role in many natural geological processes. In order to better comprehend the reaction mechanisms and dissolution characteristics of montmorillonite in different acidic systems, the effects of interfacial reactions of montmorillonite with oxalic and sulfuric acid solutions at various pH levels on the ionic dissolution, crystal structure, and micro-morphology were studied, and the morphology of aluminum and saturation index of secondary mineral were simulated. It was shown that the dissolution amounts of Mg²⁺, Al³⁺ and Si⁴⁺ in montmorillonite structure decreased with the increase of pH value, which reflected the dependence of montmorillonite dissolution on the pH value of solution. The dissolution percentages of Mg²⁺, Al³⁺ and Si⁴⁺ after the reaction of montmorillonite with oxalic acid solution were greater than those in sulfuric acid solution, and the highest dissolution rate of Al³⁺, indicated that both ligands and protons attacked the surface sites of montmorillonite and accelerated the dissolution of ions. Moreover, oxalate ligands exerted specific binding effects on Al³⁺ ions. While reacting with oxalate and sulfate, the tetrahedral, octahedral and interlayer cations of montmorillonite exhibited the non-stoichiometric and inconsistent dissolution. The oxalate ligands have a strong complexation effect on Al³⁺, so that Al³⁺ in oxalate solution exists in the form of aluminum oxalate complex, which reduces the effective concentration of Al³⁺ in solution and promotes the dissolution of Al³⁺ in montmorillonite structure. The Mg²⁺ ions settled at octahedral substitution sites possessed weak stability, while those from the interlayer featured strong interlayer interchangeability, demonstrating the dissolution percentage up to 10.85 % and 8.62 % even in oxalic and sulfuric acid solutions at pH of 6.5. All secondary mineral phases in the solution were undersaturated, making the montmorillonite dissolution difficult to balance. Montmorillonite has a high cation exchange capacity, which makes it have a strong buffer capacity to exogenous acids. This study helps to explain the dissolution process of montmorillonite in inorganic and organic acid solutions at different pH value.