High Mechanical Strength Research Articles

Study of anti-corrosion epoxy resin coatings with high corrosion resistance and mechanical performance based on quantum dots

The corrosion of steel construction in marine environments faces severe corrosion threats, and coatings based on nanofillers are an effective strategy for steel corrosion protection. However, the related studies of the anti-corrosion coatings based on quantum dots are still poor. In this work, CuS and ZnS quantum dots (QD) were initially synthesized, and epoxy resin (EP) coatings containing QD with ratios of 0.05 wt%, 0.1 wt%, 0.2 wt%, and 0.5 wt% were successfully prepared subsequently. Surface analysis, electrochemical measurements, salt spray tests, and mechanical tensile tests were performed to characterize the prepared quantum dots and study the anti-corrosion behavior and mechanism of the prepared coatings. Results indicated that the prepared CuS and ZnS quantum dots have small sizes with values of 13.8 and 8.9 nm, respectively. Compared to the pure EP coating, QD-EP coatings have a higher mechanical strength and toughness which is conducive to improving the coatings’ corrosion resistance and service life. The impedance values of all the QD-EP coatings increase by more than three orders of magnitude in contrast to pure EP coating after 60 d of testing. Furthermore, the prepared QD-EP coatings possess a long-term anti-corrosion property.

Experimental study of picosecond laser-assisted grinding of GH4169 nickel-based superalloy

The nickel-based superalloy GH4169 exhibits excellent thermal stability and fatigue resistance, making it widely utilized in the aerospace and marine manufacturing industries. However, the high mechanical strength of the nickel-based superalloy GH4169 leads to issues such as high grinding forces during grinding and poor surface morphology of the material after grinding. To improve the processing quality of GH4169, this study employs ultrafast pulse laser texturing to create two distinct biomimetic structures on its surface. The study explores the impact of laser parameters on both the recast layer and surface hardness. Subsequently, grinding experiments are conducted on both structured and non-structured workpieces. The grinding forces and surface roughness during grinding are analyzed, and the surface morphology of the workpiece after grinding and the corrosion resistance of the material are also tested. According to the test results, the grinding forces of the fishbone-like and nacre-like structure workpieces are reduced compared with those of the non-structured workpieces, and the maximum tangential grinding forces are reduced by 38.54 % and 35.98 %, and the maximum normal grinding forces are reduced by 30.24 % and 29.6 %, respectively. In addition, the corrosion resistance of the surface of the structured workpieces after grinding is better compared to the non-structured workpieces, and the best corrosion resistance is obtained for the fishbone-like structure.

Nanofibrous Membranes with High Mechanical Strength for the Separation and Purification of Lysozyme

Nanofibrous Membranes with High Mechanical Strength for the Separation and Purification of Lysozyme

Molecular Insights into Adhesion at Interface of Geopolymer Binder and Cement Mortar.

The degradation of concrete and reinforced concrete structures is a significant technical and economic challenge, requiring continuous repair and rehabilitation throughout their service life. Geopolymers (GPs), known for their high mechanical strength, low shrinkage, and durability, are being increasingly considered as alternatives to traditional repair materials. However, there is currently a lack of understanding regarding the interface bond properties between new geopolymer layers and old concrete substrates. In this paper, using advanced computational techniques, including quantum mechanical calculations and stochastic modeling, we explored the adsorption behavior and interaction mechanism of aluminosilicate oligomers with different Si/Al ratios forming the geopolymer gel structure and calcium silicate hydrate as the substrate at the interface bond region. We analyzed the electron density distributions of the highest occupied and lowest unoccupied molecular orbitals, examined the reactivity indices based on electron density functional theory, performed Mulliken charge population analysis, and evaluated global reactivity descriptors for the considered oligomers. The results elucidate the mechanisms of local and global reactivity of the oligomers, the equilibrium low-energy configurations of the oligomer structures adsorbed on the surface of C-(A)-S-H(I) (100), and their adsorption energies. These findings contribute to a better understanding of the adhesion properties of geopolymers and their potential as effective repair materials.

Enhancing therapeutic effects alginate microencapsulation of thyme and calendula oils using ionic gelation for controlled drug delivery

This study focuses on encapsulating and characterizing essential oils such as thyme and calendula oils, which are known for their therapeutic properties but are limited in pharmaceutical formulations due to their low water solubility and instability, with alginate microspheres. Alginate presents an excellent option for microencapsulation due to its biocompatibility and biological degradability. The ionic gelation (IG) technique, based on the ionic binding between alginate and divalent cations, allows the formation of hydrogel materials with high water content, mechanical strength, and biocompatibility. The microspheres were characterized using FT-IR, SEM, and swelling analyses. After determining the encapsulation efficiency and drug loading capacity, the microspheres were subjected to dissolution studies under simulated digestion conditions. It was observed that the swelling percentage of the microspheres in simulated gastric fluid (SGF) ranged from ∼15% to 100%, while in simulated intestinal fluid (SIF) it ranged from ∼150% to 325%. Thyme oil, with low viscosity, exhibited higher encapsulation efficiency than marigold oil. The highest encapsulation efficiency was observed in A-TO-2 microspheres, while the highest drug loading capacity was observed in A-TO-5 microspheres. During the examination of the dissolution profiles of the microspheres, dissolution rates ranging from 10.98% to 23.56% in SGF and from 52.44% to 63.20% in SIF were observed.

Organic montmorillonite modified polyethylene oxide based polymer electrolyte for dendrite-free flexible solid-state lithium metal batteries

Polyethylene oxide (PEO) based solid-state electrolytes are known for the low manufacturing cost and excellent processability, but their practical application is paved with thorns including the inferior ionic conductivity, low Li+ transfer number and insufficient Li dendrite blocking ability. Herein, we propose organic montmorillonite (OMMT) with expanded layer spacing (1.97 nm) as versatile fillers to construct PEO-OMMT electrolyte, in which OMMT not only increases Li+ transfer number (0.56) and ionic conductivity (7.15 × 10−4 S cm−1), providing fast ionic transport channels, but also endows PEO with high mechanical strength, resulting remarkable Li dendrite blocking ability (>2100 h). Additionally, the high dielectric constant and Lewis-rich polar sites of OMMT facilitate the dissociation of lithium salts and the rapid formation of LiF and Li3N-rich solid electrolyte interface layers. Impressively, the LiFePO4|PEO-OMMT|Li cell shows a high initial capacity (154.4 mAh g−1 at 0.5C) with ultralong cycling lifespan (>1200 cycles). Similarly, the LiNi0.83Mn0.05Co0.12O2|PEO-OMMT|Li cell retains a high discharge capacity of 151.5 mAh g−1 after 100 cycles at 0.2C. This work highlights the indelible contributions of OMMT functionalized fillers in improving the interfacial stability of PEO based solid-state electrolytes, paving a feasible avenue for the practical application of solid-state lithium metal batteries.

Enhancing the Mechanical Strength and Thermal Stability of Polylactic Acid (PLA) with the Addition of Epoxidized Waste Cooking Oil (EWCO)

Polylactic Acid (PLA) comes from renewable resources, has a reasonable biodegradability rate, and is used in biomedical, food packaging, textiles, and agricultural applications. PLA offers high mechanical strength and the ability to compost, similar to polyethylene terephthalate (PET) and nylon. However, the brittleness of PLA has always limited its usage. Therefore, bio-based plasticizers in the biopolymer matrices can increase flexibility (elasticity), durability, and workability. This study aims to determine the optimal blending ratio for the PLA blended with epoxidized waste cooking oil (EWCO) to enhance the mechanical and thermal properties of PLA/EWCO. The mechanical strength test consists of the hardness test (N/mm<sup>2</sup>), flexural strength (MPa), and impact energy (kJ/m<sup></sup>) adopted to evaluate the plasticizing characteristics. The thermal stability analysis involves glass transition temperature (T<sub>g</sub>) (°C), cold-crystallization temperature (T<sub>cc</sub>) (°C) and melting temperature (T<sub>m</sub>) (°C). The blending ratio is 97.5PLA/2.5EWCO, 95PLA/5EWCO, 92.5PLA/7.5EWCO and 90PLA/10EWCO. As a result, 97.5:2.5 of PLA/EWCO reduces intermolecular interactions by stimulating more free volume in biopolymer chains’ mobility and enhancing the flexibility and elasticity of the PLA blends. Ultimately, the brittleness of PLA decreased with increasing EWCO bio-based plasticizer.

Macrocyclic Supramolecular Glass: New Type of Supramolecular Transparent Materials.

Transparent materials are widely used in industries, everyday life, and scientific activities. The development of new, lightweight, and durable artificial transparent materials is a challenge in synthetic chemistry. In this study, a supramolecular approach is conceived to construct transparent glass. Cyclodextrins are selected as the building blocks for the fabrication of supramolecular glass via noncovalent polymerization. The newly formed glass displays several attractive advantages, including good thermal processability, high mechanical strength and dielectric constant, excellent visible light transparency, and good adhesion performance. Importantly, the structural characteristics of long-range disorder and short-range order are observed in cyclodextrin glass. Here a new strategy is presented for the preparation and functionalization of low-molecular-weight transparent materials.

Modulating Electrochemical Energy Storage and Multi-Spectra Defense of MXenes by Interfacial Dual-Filler Engineering.

MXenes have attracted growing interest in electrochemical energy storage owing to their high electronic conductivity and editable surface chemistry. Besides, rendering MXenes with spectrum defense properties further broadens their versatile applications. However, the development of MXenes suffers from weak van der Waal interaction-driven self-restacking that leads to random alignment and inferior interface microenvironments. Herein, a nacre-inspired MXene film is tailored by dual-filling of 2-ureido-4[1H]-pyrimidinone (UPy)-modified polyvinyl alcohol (PVA-UPy) and carbon nanotubes (CNTs). The dual-nanofillers engineering endows the nanocomposite film with a highly ordered structure (a Herman's order value of 0.838), a high mechanical strength (139.5MPa), and continuous conductive pathways of both the ab plane and c-axis. As a proof-of-concept, the tailored nanocomposite film achieves a considerable capacitance of 508.2 F cm-3 and long-term cycling stability without performance degradation for 10000 cycles. It is efficient for spectra defense in radar and infrared bands, displaying a high electromagnetic shielding capacity (19186dB cm2 g-1) and a super-low infrared (IR) emissivity (0.16), with negligible performance decay after saving in the air for 1 year, responsible for the applications in specific and complex conditions. This interfacial dual-filler engineering concept showcases effective nanotechnology toward sustainable energy applications with a long lifetime and safety.

On the feasibility to obtain CuCrZr alloys with outstanding thermal and mechanical properties by additive manufacturing

The CuCrZr alloy combines high thermal conductivity and mechanical strength with stability at high-medium temperatures, making it a promising heat sink material for the EU-DEMO divertor and limiters. Additive Manufacturing (AM) technologies have proven effective in developing complex-shaped components with almost no constraints on geometry and minimal machining and welding requirements. This makes them particularly suitable for the production of heat exchangers featuring complex cooling channels with intricate inner structures.This study demonstrates the feasibility to obtain dense CuCrZr via Electron Beam Powder Bed Fusion (EB-PBF) with high thermal conductivity and enhanced mechanical strength compared to conventional routes. Gas atomization was used to produce spherical powders with a composition close to ITER specifications. By optimising the EB-PBF process parameters, relative density values of 99.7 % were achieved after HIP treatment, that removes the eventual residual porosity. The results underscore the importance of meticulous powder manufacturing to mitigate oxidation and microstructural defects in the final components. Achieving high relative densities in the EB-PBF process requires a focus on adopting high-energy absorption rates in the powders. This strategy can be accomplished by reducing the scanning speed and consequently the building rate of the process. The microstructural characterization revealed a complex hierarchical microstructure composed of grains and grain boundaries, solidification-enabled cellular-like subgrains elongated along the building direction and an ultra-fine precipitate state (already present in the as-built condition) mainly consisting of Cr-rich nanoprecipitates, although Zr-rich precipitates were also found at the melt pool boundaries. The thermal conductivity, hardness, mechanical strength at room temperature and high-medium temperatures were measured and correlated with the EB-PBF process parameters and the microstructure obtained after HIP treatment. The results indicate that it is possible to obtain CuCrZr with improved mechanical behaviour compared to conventional manufacturing technologies, while maintaining the thermal conductivity requirements for EU-DEMO.

A bioinspired hard-soft composites with strong interfacial bonding, high load-bearing and low friction for osteochondral repair

The development of osteochondral composites that simultaneously exhibit superior load-bearing performance and lubrication properties remains a significant challenge. In this investigation, a novel hard-soft composite material, which utilizes porous Si3N4 ceramics as a structural support and PVA-CBA (synthesis by condensation of polyvinyl alcohol and 4-formylbenzoic acid) hydrogels as a lubrication, was fabricated via impregnating the hydrogel into porous ceramics, namely Si3N4/PVA-CBA composites. It demonstrates strong interfacial bonding, comprising macro-micro scale mechanical interlocking and molecular scale chemical crosslinking. The developed material exhibits high mechanical strength (∼ 103.2 MPa and ∼ 1500 % larger than the corresponding value of porous Si3N4 ceramics), low friction and wear (∼ 0.21 under 10 N load and 10 Hz frequency), and favorable cell adhesion and proliferation. This provides an effective strategy for designing hard-soft composite material in the osteochondral repair field.

Environmental-friendly and fast production of ultra-strong phenolic aerogel composite with superior thermal insulation and ablative-resistance

There is an urgent need for developing “low-carbon” synthesis technology to prepare aerogel composites with both high mechanical strength and efficient thermal insulation for applications of modern aerospace and energy saving. Herein, we propose a strategy for fabricating lightweight phenolic aerogel composites with thick-united connected nano-structure and good aerogel-fiber interfacial compatibility. The specific micro-nano structure and optimized material synergism endow the aerogel composites with an ultrahigh tensile strength (12.84 ± 0.64 MPa), bending strength (24.69 ± 1.96 MPa) and compressive strength (1.7 ± 0.053 MPa under 5 % strain), as well as low thermal conductivity (0.0541 ± 0.0003 W/(m·K)). The aerogel composites behave excellent ablation-resistance under the flame of 1200 °C within 30 min and maintain a cold-side temperature of 56.07 °C without any shape change. The rigid-flexible comminated aerogel composites open up a new technical track for developing lightweight thermal protective composites with high strength, toughness, and efficient thermal insulation demanded in extreme environments.

Excellent Antibacterial Properties of Silver/Silica-Chitosan/Polyvinyl Alcohol Transparent Film.

Transparent films with excellent antibacterial properties and strong mechanical properties are highly sought after in packaging applications. In this study, Ag/SiO2 nanoparticles were introduced into a mixed solution of chitosan (CS) and polyvinyl alcohol (PVA) and a Ag/SiO2-CS-PVA transparent film was developed. The excellent properties of the film were confirmed by light transmittance, water contact angle tests and tensile tests. In addition, for the antibacterial test, the antibacterial properties of the sample against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) were explored, and the average size of the bacteriostatic circle was measured by the cross method. The final results show that Ag/SiO2-CS-PVA transparent film has the advantages of good antibacterial properties, high transparency and high mechanical strength.

Robust and resilient piezoresistive sensor made of MWCNT-embedded aerogel prepared with elongated amyloid fibrils of α-synuclein

Pressure sensors are widely employed in various fields from biomedical to aerospace engineering. Each field requires pressure sensors with specific sensitivity, response time, recovery time, durability, and detection limit. However, developing pressure sensors that meet the increasing demands of high mechanical strength and sensitive electrical responsiveness influencing reliability and accuracy still remains challenging. Herein, a highly robust and resilient piezoresistive sensor was developed by combining elongated amyloid fibrils (eAFs) aerogel made of a self-assembly protein of α-synuclein, which provided stable porous 3D interconnected network and thus increased surface area, and multi-walled carbon nanotube (MWCNT) as a reinforcement material for improved mechanical and electrical properties. Owing to the integration between eAFs aerogel and MWCNT, the MWCNT-embedded eAFs aerogel exhibited augmentation in mechanical strength and resiliency depending on the amount of MWCNT introduced. Additionally, the MWCNT-embedded eAFs aerogel showed piezoresistive properties with stable pressure sensing capability toward human motions, airflow, and underwater pressure. It is, therefore, suggested that the pressure sensor fabricated with the eAFs aerogel containing MWCNT could be utilized in diverse areas including wearable device and artificial skin development.

Engineering the nanozyme hydrogel beads by polyvinyl alcohol/chitosan encapsulation with recyclable and sustainable catalytic activity for visual analysis of hydrogen peroxide

BackgroundHydrogen peroxide (H2O2) plays a vital role in human health and have been regarded as a crucial analyte in metabolic processes, redox transformations, foods research and medical fields. Especially, the long-time and excessive digestion of H2O2 may even cause severe diseases. Although conventional instrumental methods and nanozymes-based colorimetric methods have been developed to accomplish the quantitative analysis of H2O2, the drawbacks of instrument dependence, cost-effectiveness, short lifespan, non-portable and unsustainable detection efficacies will limit their applications in different detection scenarios. ResultsHerein, to address these challenges, we have proposed a novel strategy for nanozyme (RuO2) hydrogel preparation by the solid support from cross-linked polyvinyl alcohol (PVA) and chitosan (CS) to both inherit the dominant peroxidase-like (POD) activity and protect the RuO2 from losing efficacies. Taking advantages from the hydrogel, the encapsulated RuO2 were further prepared as the regularly spherical beads (PCRO) to exhibit the sustainable, recyclable, and robust catalysis. Moreover, the intrinsic color interferences which originated from RuO2 can be avoided by the encapsulation strategy to promote the detection accuracy. Meanwhile, the high mechanical strength of PCRO shows the high stability, reproducibility, and cyclic catalysis to achieve the recyclable detection performance and long lifetime storage (40 days), which enables the sensitively detection of H2O2 with the detection limit as lower to 15 μM and the wide detection linear range from 0.025 to 1.0 mM. SignificanceOn the basis of the unique properties, PCRO has been further adopted to construct a smartphone detection platform to realize the instrument-free and visual analysis of H2O2 in multi-types of milk and real water samples through capturing, processing, and analyzing the RGB values from the colorimetric photographs. Therefore, PCRO with the advanced detection efficacies holds the great potential in achieving the portable and on-site analysis of targets-of-interest.

Amorphous High‐Entropy Alloy Interphase for Stable Lithium Metal Batteries

AbstractThe unstable anode/electrolyte interphase induces severe lithium dendrite growth hindering the practical application of lithium metal batteries. The lithium alloy interphase presents a promising strategy for regulating Li+ plating/stripping behavior. However, binary or ternary alloys are insufficient to address various challenges in lithium metal batteries and the high temperature required for alloy preparation hampers their direct applications on lithium metal surfaces. In this study, a high‐entropy alloy (HEA) interphase is developed on lithium metal surfaces via room‐temperature magnetron sputtering, showcasing multifunctional advantages in regulating Li+ plating/stripping behavior. The cocktail effect of the (HEA) facilitated the formation of a homogeneous amorphous interphase with abundant lithiophilic sites and magnetic properties, promoting uniform Li+ nucleation and deposition. Furthermore, the high mechanical strength and corrosion resistance of HEA provided physicochemical stability for the lithium anode interphase, consistently suppressing dendrite growth. Consequently, lithium metal anodes with HEA interphases exhibited robust cycling performance lasting over 4000 h at 2 mA cm−2. The LFP full battery demonstrated high‐capacity retention of 90% with an average Coulombic efficiency of 99.7%. Thus, the HEA interphases on lithium metal surfaces offer controllable regulation of Li+ deposition behavior through high‐entropy manipulation, opening novel strategies for stable lithium metal batteries.

Interpenetrated Multinetwork Hybrid Aerogels by Layered Montmorillonite and One-Dimensional Hydroxyapatite Fibers for Heat and Fire Insulation.

It is of practical significance to develop aerogels with effective thermal insulation characteristics together with fireproof properties as well as high mechanical strength. Here, an interpenetrated multinetwork hybrid aerogel realizing thermal insulation, flame retardancy, and high compression modulus is demonstrated. Specifically, one-dimensional hydroxyapatite nanowires (HAP) played dual roles as the aerogel support skeleton to entangle with layered montmorillonite (MMT) each other to form a three-dimensional interpenetrated multinetwork structure and to optimize the thermal conductivity by adjusting the pore space in current HAP/MMT/PVA hybrid aerogels. Therefore, the interpenetrated multinetwork hybrid aerogels exhibit superior thermal insulation performance in room temperature (0.033 W m-1 K-1, 298 K, air conditions) and largely enhanced ultrahigh compression modulus (80 MPa). Moreover, the obtained hybrid aerogels also exhibit excellent flame retardancy and self-extinguishing smoke suppression properties (peak heat release rate and total smoke production as low as 92.44 kW m-2 and 0.1 m2, respectively), which is the outstanding interpenetrated multinetwork hybrid aerogel that has achieved synergistic improvement in heat and fire insulation and mechanical performance. Therefore, the interpenetrated multinetwork hybrid aerogels are promising candidates for efficient heat insulation, fire prevention, and mechanically robust applications.

Rationally Designed Li-Ag Alloy with In-Situ-Formed Solid Electrolyte Interphase for All-Solid-State Lithium Batteries.

All-solid-state lithium batteries (ASSLBs) with sulfide-based solid electrolytes have attracted significant attention as promising energy storage devices, owing to their high energy density and enhanced safety. However, the combination of a lithium metal anode and a sulfide solid electrolyte results in performance degradation, owing to lithium dendrite growth and the side reactions of lithium metal with the solid electrolyte. To address these issues, a Ag-based Li alloy with a favorable solid electrolyte interphase (SEI) was prepared using electrodeposition and applied to the ASSLB as an anode. The electrochemically formed SEI layer on the Li-Ag alloy primarily comprised LiF and Li2O with high mechanical strength and Li3N with high ionic conductivity, which suppressed the formation of lithium dendrites and short-circuiting of the cell. The symmetric cell with the Li-Ag alloy achieved a critical current density of 1.6 mA cm-2 and maintained stable cycling for over 2000 h at a current density of 0.6 mA cm-2. Consequently, the all-solid-state lithium cell assembled with the Li-Ag alloy anode with SEI, Li6PS5Cl solid electrolyte, and LiNi0.78Co0.10Mn0.12O2 cathode delivered a high discharge capacity of 185 mAh g-1 and exhibited good cycling performance in terms of cycling stability and rate capability at 25 °C.

Comparative study on the behavior of ordinary and lightweight concrete using natural pozzolan aggregates

This study is part of a comprehensive research project focused on exploring the integration of natural pozzolans into concrete production. It investigates how these materials enhance the physical properties and mechanical behavior of concrete, with a specific emphasis on improving economy, strength, and overall performance. Key objectives include evaluating workability and compressive strength through comparative tests across various concrete formulations. Special attention is given to analyzing the influence of the water-to-cement ratio and concrete age on compressive strength, particularly in comparing ordinary and lightweight concrete mixes. The findings indicate significant enhancements in concrete characteristics with the inclusion of natural pozzolans, particularly beneficial for applications prioritizing thermal insulation over high mechanical strength. This study provides valuable insights into optimizing concrete mix designs tailored to specific construction needs. Furthermore, the research underscores the potential environmental and economic benefits of incorporating natural pozzolans, promoting sustainable construction practices. By demonstrating the feasibility and advantages of these materials in concrete applications, this study contributes to advancing materials science and engineering solutions for resilient and efficient built environments.

Preparation and Properties of High Sound-Absorbing Porous Ceramics Reinforced by In Situ Mullite Whisker from Construction Waste.

Porous sound absorption ceramic is one of the most promising materials for effectively eliminating noise pollution. However, its high production cost and low mechanical strength limit its practical applications. In this work, low-cost and in situ mullite whisker-reinforced porous sound-absorbing ceramics were prepared using recyclable construction waste and Al2O3 powder as the main raw materials, and AlF3 and CeO2 as the additives, respectively. The effects of CeO2 content, AlF3 content, and sintering temperature on the microstructure and properties of the porous ceramics were systematically investigated. The results showed that a small amount of CeO2 significantly promoted the growth of elongated mullite crystals in the resultant porous ceramics, decreased the growth temperature of the mullite whiskers, and significantly increased the biaxial flexural strength. When 2 wt.% CeO2 and 12 wt.% AlF3 were added to the system, mullite whiskers were successfully obtained at a sintering temperature of 1300 °C for 1 h, which exhibited excellent properties, including an open porosity of 56.4 ± 0.6%, an average pore size of 1.32-2.54 μm, a biaxial flexural strength of 23.7 ± 0.9 MPa, and a sound absorption coefficient of >0.8 at 800-4000 Hz.