Stability Properties Research Articles

Dual-Factor-Controlled Dynamic Precursors Enable On-Demand Thermoset Degradation and Recycling.

Thermosets are well known for their advantages such as high stability and chemical resistance. However, developing sustainable thermosets with degradability and recyclability faces several principal challenges, including reconciling the desired characteristics during service with the recycling and reprocessing properties required at the end of life, establishing efficient methods for large-scale synthesis, and aligning with current manufacturing process. Here a general strategy is presented for the on-demand degradation and recycling of thermosets under mild conditions utilizing dynamic precursors with dual-factor-controlled reversibility. Specifically, dynamic triazine crosslinkers are introduced through dynamic nucleophilic aromatic substitution (SNAr) into the precursor polyols used in polyurethane (PU) synthesis. Upon removal of the catalyst and alcohol, the reversibility of SNAr is deactivated, allowing for the use of standard PU polymerization techniques such as injection molding, casting, and foaming. The resulting cyanurate-crosslinked PUs maintain high stability and diverse mechanical properties of traditional crosslinked PUs, yet offer the advantage of easy on-demand depolymerization for recycling by activating the reversibility of SNAr under specific but mild conditions-a combination of base, alcohol, and mild heat. It is envisioned that this approach, involving the pre-installation of dual-factor-controlled dynamic crosslinkers, can be broadly applied to current thermosetting plastic manufacturing processes, introducing enhancedsustainability.

High Milling Time Influence on the Phase Stability and Electrical Properties of Fe50Mn35Sn15 Heusler Alloy Obtained by Mechanical Alloying

Fe50Mn35Sn15 Heusler alloy, obtained by mechanical alloying, was subjected to larger milling times in the range of 30–50 h to study the phase stability and morphology. X-ray diffraction studies have shown that the milled samples crystallise in a disordered A2 structure. The A2 structure was found to be stable in the milling range studied, contrary to the computation studies performed on this composition. Using Rietveld refinements, the lattice parameter, mean crystallite size, and lattice strain were computed. The nature of the obtained phases by milling was found to be nanocrystalline with values below 50 nm. A linear increase rate of 0.00713 (h−1) was computed for lattice strain as the milling time increased. As the milling time increases, the lattice parameter of the cubic Heusler was found to have a decreasing behaviour, reaching 2.9517 Å at 50 h of milling. The morphological and elemental distribution—characterised by scanning electron microscopy and energy-dispersive X-ray spectroscopy—evidenced Mn and Sn phase clustering. As the milling time increased, the morphology of the sample was found to change. The Mn and Sn cluster size was quantified by elemental line profile. Electrical resistivity evolution with milling time was analysed, showing a peak for 40 h of milling time.

Metal Halide Perovskite Nanocrystals-Intermediated Hydrogel for Boosting the Biosensing Performance.

Metal-halide perovskites have become attractive nanomaterials for advanced biosensors, yet the structural design remains challenging due to the trade-off between environmental stability and sensing sensitivity. Herein, a trinity strategy is proposed to address this issue by integrating Mn (II) substitution with CsPb2Cl5 inert shell and NH2-PEG-COOH coating for designing Mn2+-doped CsPbCl3/CsPb2Cl5 core/shell hetero perovskite nanocrystals (PMCP PNCs). The trinity strategy isolates the emissive Mn2+-doped CsPbCl3 core from water and the Mn2+ d-d transition generates photoluminescence with a long lifetime, endowing the NH2-PEG-COOH capped Mn2+-doped CsPbCl3/CsPb2Cl5 PNCs with robust water stability and oxygen-sensitive property. Given the structural integration, photoluminescent hydrogel biosensors are designed by embedding the PMCP PNCs into the hydrogel system to deliver on-site pesticide information on food products. Impressively, benefiting from the dual enzyme triggered-responsive property of PMCP PNCs, the hydrogel biosensor is endowed with ultra-high sensitivity toward chlorpyrifos pesticide at the nanogram per milliliter level. Such a robust PMCP PNCs-based hydrogel sensor can provide accurate pesticide information while guiding the construction of photoluminescent biosensors for upcoming on-site applications.

Key Factors Influencing Gelation in Plant vs. Animal Proteins: A Comparative Mini-Review

This review presents a comparative analysis of gelation properties in plant-based versus animal-based proteins, emphasizing key factors such as pH, ionic environment, temperature, and anti-nutritional factors. Gelation, a crucial process in food texture formation, is influenced by these factors in varying ways for plant and animal proteins. Animal proteins, like casein, whey, meat, and egg, generally show stable gelation properties, responding predictably to pH, temperature, and ionic changes. In contrast, plant proteins such as soy, pea, wheat, and oilseed show more variable gelation, often requiring specific conditions, like the presence of NaCl or optimal pH, to form effective gels. Animal proteins tend to gel more reliably, while plant proteins require precise environmental adjustments for similar results. Understanding these factors is crucial for selecting and processing proteins to achieve desired textures and functionalities in food products. This review highlights how changing these key factors can optimize gel properties in both plant- and animal-based proteins.

Family of 2:1 resonant quasi-periodic distant retrograde orbits in cislunar space

Given the current enthusiasm for lunar exploration, the 2:1 resonant distant retrograde orbit (DRO) in Earth-Moon space is of interest. To gain an in-depth understanding of the complex dynamic environment in cislunar space and provide more options for parking orbits, this paper investigates the existence of quasi-periodic orbits near the 2:1 resonant DRO in the circular restricted three-body problem (CR3BP). Firstly, the numerical computation approach, continuation strategy, and stability analysis method of quasi-periodic orbits are introduced. Then, addressing the primary challenges in the continuation progress, we have developed an adaptive continuation algorithm with automatic adjustment of the step size and the number of discrete points that characterize the invariant torus. Finally, two types of 2D quasi-DROs and their linear stability properties are explored. Using Poincaré sections, we investigated the boundaries of the maximum extent attainable by both 2D quasi-DRO families in the CR3BP at a specific Jacobi energy, confirming that both types of quasi-periodic families have reached their respective boundaries. The algorithm described in this paper is beneficial for facilitating the computation of quasi-periodic families and aids in discovering additional potential dynamical structures.

Recent Advances in Trifluoromethylation of Olefins, Aldehydes, and Ketones

Abstract: Due to the robust electrophilic properties of the trifluoromethyl group (-CF3), its incorporation into organic compounds can markedly alter their ester affinity, stability, bioavailability, and other properties. The trifluoromethylation reaction is currently experiencing rapid advancement, with an expanding array of substrates and the emergence of novel methodologies. Consequently, compounds containing the -CF3 moiety find extensive utility across diverse fields. This article aims to comprehensively review the latest advancements in trifluoromethylation reaction of olefins, aldehydes, and ketones, encompassing nucleophilic trifluoromethylation, electrophilic trifluoromethylation, and radical trifluoromethylation. The discussion includes an exploration of the types and broadening scope of applicable substrates. Furthermore, this article addresses the associated challenges and delineates prospective directions for future developments in trifluoromethyl reaction.

Effect of zirconium addition on microstructural characteristics and nano-mechanical properties of P9 steel

Micro-alloying in steels has significant effects on microstructure and its properties. The main objective of the work is to understand the influence of zirconium (Zr) addition to P9 ferritic/martensitic (F/M) steel on phase stability, microstructure, and nanomechanical properties. The alloy compositions in this study were designed using thermodynamic calculations, based on which steels with Zr concentration in the range of 0.05–2 wt% were synthesized using vacuum arc melting. The cast alloy was subjected to thermo-mechanical treatments followed by austenitization and tempering treatments. Zr concentration of the steel was found to influence the nature of secondary phases formed, which were quantified through detailed synchrotron X-ray diffraction (XRD) analysis and also characterised extensively using electron microscopy techniques. Detailed structural analysis of the Fe23Zr6 phase using aberration corrected transmission electron microscopy is reported for the first time. The nano-mechanical properties of the heat-treated steels were evaluated using instrumented indentation (IIT) tests at room temperature with a sphero-conical indenter. A systematic variation in hardness and yield strength with Zr content of P9 steel was observed, which is correlated to the microstructural changes. The P9 F/M steel with optimum concentration of Zr, with better mechanical properties is proposed through this structure-property correlation study.

Evaluating sacha inchi (Plukenetia volubilis) oil stability and physicochemical properties: A comparison between conventional extraction and supercritical fluids

This study aimed to compare the effects of two extraction techniques (conventional n-hexane and supercritical CO2) on the oil extraction yields, fatty acids profile, anti-hyaluronidase activity, oxidative stability, and in vitro bioactivities of oils from Sacha Inchi (Plukenetia volubilis). Higher oil extraction yield (99 %) was achieved using the SC-CO2, although similar fatty acids profiles were depicted between both treatments (p < 0.05). The SC-CO2 oil presented higher anti-hyaluronidase (31 %) activity, but lower oxidative stability (5.05 h) compared to the solvent extraction (10 %, and 5.3 h, respectively). In vitro assays further revealed that the best human normal colon cells (FHC) cell viability (100 %), anti-inflammatory (50 % lower NO production), and antioxidant (20 % ROS reduction) activities were consistently observed in both extraction treatments at concentrations of 50 μg/mL and higher. These findings highlight the potential of supercritical CO2 extraction in yielding Sacha Inchi oil with enhanced bioactive properties without the disadvantages of the use of organic solvents extraction.

Passion fruit peel-derived low-methoxyl pectin: De-esterification methods and application as a fat substitute in set yogurt

Passion fruit pectin, originally high methoxyl pectin, undergoes substantial conversion into low methoxyl pectin (LMP) through de-esterification. This de-esterification is significance for reducing the application of sugar in food, as calcium ions can replace excessive sugar during gel formation. In this study, LMPs derived from passion fruit pectin were prepared using four methods: low-temperature alkali, room temperature alkali, enzymatic, and dielectric barrier discharge plasma (DBD)-assisted enzyme (DBDE). The de-esterification conditions were optimized, leading to the selection of LMPs with a degree of esterification for the analysis of molecular weight, monosaccharide composition, and gel properties. The results revealed significant differences in the structure and properties of LMPs depending on the de-esterification method applied. The galacturonic acid content of LMPs significantly increased, with LMP from DBDE (LMP-DBDE) exhibiting the highest increase at 47.81 %. Additionally, the molecular weights of LMPs significantly decreased, with LMP-DBDE showing the smallest decrease. LMP-DBDE demonstrated higher apparent viscosity, thermal stability, and gel properties, facilitating the formation of gels. After 21 days of storage, 0.40 % LMP-DBDE yogurt showed no whey separation, significantly extending its shelf life. Therefore, LMP-DBDE exhibits potential as a fat substitute, combining the advantages of LMP with enhanced water-holding capacity, and presenting promising applications in low-fat dairy products.

How bulk nanobubbles respond to elevated external pressures

Bulk nanobubbles, nanoscopic gaseous domains in aqueous solutions, exhibit surprising long-term stability and unique properties under varying environmental conditions. This study investigates the effects of external pressure on nanobubble stability and behavior through three experimental setups: pressurization at room temperature, pressurization at elevated temperatures, and constant pressure loading. Our findings reveal that increasing external pressure reduces nanobubble concentration and reshapes the bubble size distribution. Larger nanobubbles either disappeared or transformed into microbubbles, while smaller ones expanded, significantly narrowing the size distribution. These changes were found to be irreversible. Additionally, nanobubble stability is influenced by both the magnitude and duration of the applied pressure. Elevated temperatures further narrowed the size distribution at atmospheric pressure, and subsequent pressurization caused these nanobubbles to shrink, showing different response characteristics compared to room temperature. This research highlights the complex interplay between pressure, temperature, and nanobubble stability, offering valuable insight for practical applications in fields such as drug delivery, water treatment, and nanomaterial synthesis.

Improvement of the mechanical properties of the cement mortar by the incorporation of silica particles with low and high surface area

In recent years, nanoaprticules with different sizes have been incorporated in the cement mortar in order to improve their mechanical characteristics. The present work focuses onto the influence of the silica nanoparticles (SiO2) with low and high surface area over the stability and mechanical properties of the cement mortar. The quantities of nanosilica added into the cement mortar to ameliorate their mechanical characteristics vary from 0.5 % to 1.5 %wt. The obtained material after the incorporation of the SiO2 nanoparticles have been characterized by several techniques such as TG, DTG, DSC and their morphologies were determined by using SEM analysis. The workability, water absorption, compressive and flexural strengths of these materials have also been evaluated. The results obtained show that the introduction of the SiO2 nanoparticles into the cement mortar has been greatly improved their compressive and flexural strengths, and the specimens incorporated by nanosilica with high surface area are found more effective than those containing the silica nanoparticles with low surface area, suggesting that the specific surface play a crucial role in the improvement of their mechanical properties. The results show also that the appropriate dosage of silica nanoparticles in the cement mortar to have a maximum enhancement of their mechanical properties was found around 1.5 wt% by weight of cement for the nanosilica with high surface area.

Correlation study between structural parameters of droplets and rheological properties of O/W high internal phase Pickering emulsions above the closest packing density

The correlation between the structural parameters of droplets and rheological properties of O/W high internal phase Pickering emulsions (HIPPEs) stabilized by soy protein isolate (SPI) nanoparticles was elucidated, with a volume fraction of dispersed phase (ϕ) above the closest packing density (74%). The structural basis of SPI nanoparticles was confirmed to be spherical heat-induced protein aggregates, which had moderate wettability and excellent interfacial activity. The structural parameters of emulsion droplets (contact length L, diameter D, length d1, width d2, the number of adjacent contact droplets Z), and the stability and rheological properties of HIPPEs were characterized by the confocal laser scanning microscopy (CLSM), diffusing wave spectroscopy (DWS), and mechanical rheometer respectively. The results of CLSM indicated the transition of droplets from spherical to polyhedral shapes as increased ϕ, accompanied by an increased L and Z. The rheological and stability analysis confirmed the widened linear viscoelastic range, elevated gel point (εc), and the extended half−life of the intensity autocorrelation function of HIPPEs as ϕ increased. Moreover, the loss factor (tan δ) remained constant at 0.1 within the ϕ of 74% to 86%, revealing the solid−like nature of HIPPEs. The correlation between ϕ, structural parameters of droplets, and rheological properties of HIPPEs was further analyzed. The nonlinear regression fitting between the L/D and G' (elastic modulus) yielded a better fitting effect than d1/d2 and Z, suggesting an intrinsic correlation between emulsion structure and rheology. In summary, this study elucidated the intricate relationship between ϕ, droplet structure, and rheological properties of HIPPEs, offering a research foundation and theoretical basis for the development and application of protein particle−stabilized HIPPEs.

A novel coupled fermentation system for low-molecular-weight xanthan gum with diverse biological activities

Xanthan gum (XG) is a bacterial exopolysaccharide widely used in various industries due to its stability and rheological properties. Low-molecular-weight xanthan gum (LXG) exhibits enhanced properties and broader applications, but current degradation methods are limited. This study introduces an innovative coupled fermentation system for the efficient production of LXG. Endo-xanthanase from Microbacterium sp. XT11 was expressed in Pichia pastoris GS115, exhibiting optimal activity at pH 6.0 and 40 °C, with broad pH tolerance. The optimized coupled fermentation system used bean sprouts juice as nitrogen source, the inoculation quantity of X. campestris: P. pastoris was 1: 3, and the pH was controlled at 6.0. In the bioreactor, the total sugar concentration reached 12.12 g/L, the reducing sugar concentration reached 5.32 g/L, and the endo-xanthanase activity increased to 1150.26 U/L, which were 2.13, 2.3, and 3.71 times higher than those at the shake flask level, respectively. The prepared LXG had a molecular weight of 1093 Da and a monosaccharide ratio of 2.0:1.57:0.89 (glucose, mannose, and glucuronic acid). Bioactivity analysis revealed its antioxidant and prebiotic properties, promoting the growth of beneficial intestinal microbiota and metabolite production. This suggests the potential of LXG as a functional ingredient in intestinal health-focused foods and supplements.

Ab initio insight into the physical properties of new ferroelectric perovskite oxide materials XGeO3 (X = Sr, Ca)

The investigation of structural stability, electronic, mechanical, spontanous polarization, and thermodynamic properties of simple cubic perovskite oxides XGeO3 (X =Sr, Ca) has been performed through density functional theory as introduced in Wien2K code. The tolerence factor, Born criteria, and phonon dispersion confirm the stability and the formation of both materials in the ideal cubic structure. Additionally, the application of nmBJ approach in electronic properties shows an exceptional semiconducting aspect. The strain effect on spontaneous polarization of XGeO3 (X =Sr, Ca) perovskites presents an excellent ferroelectric behavior. The thermodynamic parameters such as volume, bulk modulus, thermal expansion coefficient, Debye temperature, Gibbs free energy, enthalpy, heat capacities, and Gruneisen, have been ¨ calculated and discussed with a wide range of pressures (0−20 GPa) and temperatures (0−1000 K). Based on the exceptional semiconducting nature and significant spontaneous polarization, the studied materials can be considered as ferroelectric materials, which make them as a suitable candidates in ferroelctric devices.

The structural, electronic, optical and photocatalytic properties of two-dimensional ZrIN monolayer: A first-principles study

This study presents a comprehensive investigation of the structural stability, electronic and optical properties of two-dimensional ZrIN using first-principles calculations. The stability of 2D ZrIN was confirmed through investigation of thermodynamic, mechanical, dynamic and thermal criteria. The 2D ZrIN is predicted to be an indirect bandgap semiconductor with a gap value of 2.28 eV. It demonstrates high transmittance in the violet segment of the visible spectrum. The photocatalytic properties of 2D ZrIN were also investigated under pH values of 0 and 7 by examining the band edge positions. Additionally, the impact of strain on the band structure and photocatalytic activity. It was found that compressive strain limits the photocatalytic working range of ZrIN monolayer, whereas tensile strain expands working range; however, a further increase in tensile strain leads to decrease in the effective catalytic working region. These findings provide valuable insights into the potential applications of 2D ZrIN in both optoelectronics and catalysis.

Polyrrole-encapsulated TiSe2 with Excellent Electrochemical Performance for Potassium-Ion Storage

TiSe2 as a potential electrode for potassium-ion batteries, has garnered significant attention owing to its stable ion storage property. Nevertheless, the inadequate electronic conductivity of TiSe2 impedes its practical implementation. In this investigation, we adopt a polymerization method to fabricate TiSe2@PPy, which boasts enhanced conductivity and exceptional performance. Once coated with polypyrrole, the TiSe2@PPy composites demonstrate the optimum electrochemical performance, providing a charge capacity of 67.4 mAh g-1 at 1C with a capacity retention of 68.4% after 170 cycles. The PPy coating enhances the conductivity of TiSe2 and enables potassium-ion batteries to exhibit outstanding electrochemical performance. Ex-situ Raman and FTIR tests are utilized to comprehend the electrochemical reaction between K+ and the TiSe2@PPy electrode during cycling. Overall, this work introduces a PPy coating on TiSe2, which presents a novel concept for the development.

Composite suture material based on polylactide accelerates the healing of surgical wounds in in vivo experiment.

In laboratory conditions, composite sutures based on polylactide (PLA) containing chitin nanofibrils modified with polyethylene glycol (CN-PEG) and poviargol (silver nanoparticles stabilized with poly(N-vinylpyrrolidone)) were obtained, studied, and used as a prototype. Surgical sutures threads with the addition of CN-PEG have stable mechanical properties both in air and in a buffer simulating the environment of a living organism. The yield strength of oriented threads decreased by an average of 15%, whereas for non-oriented threads the decrease was 3-4 times. The strength values in simple units of unfilled PLA, PLA containing 5 wt % CN-PEG, and PLA with 1 wt % Poviargol were on average 50% higher than the national standard 31620-2012. The results of in vivo experiments on albino rats (cross-linking skin and muscle tissue in the linea alba area) showed that composite sutures are best for suturing muscle tissue, whereas unfilled PLA sutures are more suitable for suturing skin. When suturing muscle tissue, suturing with composite sutures increased the number of collagen fibers of different diameters.

Preparation and characterization of oregano essential oil microcapsules by gelatin/polysaccharide composite coagulation method

Complex cohesions were formed through electrostatic interactions between gelatin (GE) and gum arabic, sodium carboxymethyl cellulose, pectin, and sodium alginate (SA). Of them, GE and SA served as an ideal wall material for encapsulating oregano essential oil (OEO). Applying the composite coalescence method, we here generated unique encapsulated OEO microcapsules (EOMs) by using GE–SA as the microcapsule wall material and OEO as the core material. At a concentration of 1% (w/v), a core-to-wall ratio of 1:2, a recoalescence reaction temperature of 45 °C, and an emulsifier concentration of 5% (w/w), EOMs exhibited excellent performance. Under the optimal conditions, the prepared EOMs (average particle size: 78.389 μm) had a homogeneous and complete spherical structure. Freeze-dried EOMs had a high encapsulation efficiency (71.20%) and payload (56.08%). Fourier transform infrared spectroscopy unveiled the presence of electrostatic interactions between GE and SA. The OEO in the EOMs had higher thermal stability and more stable antioxidant properties than the free OEO. Furthermore, in aqueous, acidic, oily, and alcoholic environments, EOMs exhibited some degree of slow-release ability. Additionally, EOMs exhibited strong antibacterial properties, with effective inhibition of Escherichia coli (E. coil), Staphylococcus aureus (S. aureus), and Curvularia lunata (C. lunata). Among them, the strongest inhibitory effect was on C. lunata. In summary, microcapsules prepared using GE–SA as a wall material had effectively improved OEO degradation-protecting, which enhanced the stability of OEO and controlled its antioxidant properties. Meanwhile, the microcapsules exhibited excellent antibacterial properties. This system exerted considerable potential in protecting the stability of essential oils and realizing slow release.

BN Fiber Aerogels with High Solar Reflectivity and Thermal Insulation for Green Buildings

There exists more than one-third of the stock of buildings that do not meet energy-saving building standards, so there is an urgent need for breakthroughs in the field of green buildings. Herein, we successfully prepared boron nitride (BN) fiber aerogels by sol-gel, freeze-drying and high-temperature pyrolysis. When the molar ratio of C3N6H6 to H3BO3 was 1:2 and the roasting temperature was 1000 °C, the BN fiber aerogel was produced with high specific surface area (257.690 m2/g) and high porosity (99 %). BN fiber aerogels, with their low thermal conductivity (0.043 W/(m·K)) and stable mechanical properties (no change after 45 cycles at 30 % strain), offered possibilities for thermal insulation in green buildings. Its hydrophobic properties protect the wall from the natural environment. In particular, it had a solar reflectivity of 98.6 %, which exceeds most reflective coating materials, enabling the cooling of green construction on hot summer days. The high-temperature resistance of BN fiber aerogels could be applied in special environments such as blast furnace plants and thermoelectric power plants.

Study on automatic anti-icing effect and rheological properties of asphalt based on SiO2 nanowires

This study addresses the issue of severe traffic disruptions caused by winter road icing by enhancing traffic disaster resilience. A primary road-surface ice-control technique, known as "anti-icing", is proposed. A nanomaterial with outstanding superhydrophobic properties was prepared and incorporated into asphalt to create hydrophobic ice-inhibiting modified asphalt. Extensive experimentation confirmed that the hydrophobic ice-inhibiting modified asphalt had desirable characteristics, achieving impressive anti-icing performance. The experimental results indicated that the synthesised material was superhydrophobic, with a contact angle exceeding 150° and its primary component being SiO2. At the microscopic level, the synthesised superhydrophobic material exhibited a complex microstructure, primarily characterised by entangled nanowires and a small quantity of nanoparticles. In addition, the material demonstrated stable thermal properties and good compatibility with asphalt. The superhydrophobic material significantly enhanced the hydrophobic properties of asphalt, and the prepared asphalt mixture effectively inhibited the formation of surface ice layers, consequently reducing the surface ice accumulation and ice formation efficiency by 69.11% and 19.01%, respectively, for the asphalt containing 15% superhydrophobic material relative to the base asphalt. In conclusion, the superhydrophobic material prepared in this study enhances the performance of asphalt while imparting de-icing functionality, making it a novel road surface "anti-icing" material that improves winter traffic resilience.