Search Results (96)

In this study glycerol-plasticized sodium caseinate/polyvinyl alcohol NaC/PVA composite films were prepared by solution casting, and the effects of incorporating caffeic acid powder at different concentrations 0% 2.5% 5% and 15% w/w on structural mechanical barrier and postharvest performance were investigated. Caffeic acid (CA) (3,4-dihydroxycinnamic acid) is a naturally occurring phenolic compound commonly found in plant tissues and food sources such as apples, blueberries, and coffee. FTIR analysis revealed that shifts and broadening in OH bands indicated hydrogen bonding interactions between caffeic acid and the polymer matrix influencing structural organization. The pure NaC/PVA film exhibited high WVTR due to glycerol while maintaining low OTR. Adding 2.5% caffeic acid reduced WVTR but increased OTR through structural disruption. At 5% a continuous hydrogen-bonded network formed, restricting chain mobility and reducing free volume, thus lowering WVTR and OTR while preserving mechanical integrity. SEM micrographs revealed that high CA concentrations, particularly at 15%, led to aggregation-induced partial phase separation and consequent performance loss. Packaging treatments mainly affected physical and color attributes rather than primary metabolites. The NaC/PVA/5CA reduced weight loss and delayed sugar accumulation compared with NaC/PVA. Sugars peaked earlier in NaC/PVA but increased continuously in NaC/PVA/5CA, reaching maximum at the final storage stage. These findings indicate concentration-dependent mechanisms and highlight the potential of caffeic acid-based active packaging to regulate metabolism and extend postharvest quality. Overall results support its application in sustainable packaging systems for improved shelf life management. Full article

The crosslinked binders formed by using glycidyl azide polymer (GAP) as the binder matrix and bis-propargyl succinate (BPS) as the curing agent have good application prospects in the field of solid propellants. Aiming at the shortcomings of traditional experimental research, such as high cost, and molecular dynamics (MD) simulation, which are time-consuming for complex combination problems, this study will realize accurate prediction of the mechanical properties of binders through machine learning (ML) based on the molecular simulation dataset. Firstly, 273 sets of GAP-BPS binder models under different conditions were formed based on 21 crosslinking degrees and 13 temperatures, and MD simulation and mechanical property simulation were carried out. Then, the initial conditions of molecular simulation (crosslinking degree, temperature) and structural parameters (free volume) were taken as features, and the bulk modulus and shear modulus were taken as labels to form the dataset. Three machine learning models were trained and evaluated based on this dataset to test their prediction performance. Based on the cross-validation results, the Tabular Prior Data Fitting Network (TabPFN) exhibits the highest average prediction values (the average R² for bulk modulus and shear modulus were 0.9684 and 0.8827, respectively). But the significance analysis reveals that TabPFN significantly outperforms the RF model only in predicting bulk modulus. In subsequent prediction tasks with smaller datasets, TabPFN achieves superior average prediction values compared with RF and XGBoost. Full article

Carbon molecular sieve membranes (CMSMs) provide a means to greatly improve gas separations. CMSMs have a pore size distribution comprising micropores and ultramicropores which provide high flux and high selectivity, enabling them to outperform polymeric membranes. CMSMs, however, suffer from physical aging that results from the collapse of the pores that severely reduces their gas permeability. Therefore, reducing physical aging of CMSMs is an important step in the development of these types of materials. In this work, a method for reducing physical aging through the incorporation of metal nanoparticles that serve as a structural scaffold for the membrane pore structure is presented. The pore structure in CMSMs is dependent upon the polymeric precursor, and thus the support system incorporated must be tailored. The copper nanoparticles were formed in situ from soluble, copper-based metal–organic polyhedra 18 (MOP-18) dispersed into Matrimid^® 5218, a low free volume polymer. The size (2 to 20 nm) and shape (sphere, rods) of the copper particles were refined by adjusting MOP-18 loading, pyrolysis temperature, and soaking time. The Cu-pillared Matrimid^® 5218 CMSMs from this work showed no decline in permeability or selectivity for methane (107 Barrer) and carbon dioxide (1785 Barrer) over a period of 21 d. The results suggest that tailored metal pillars can suppress physical aging in CMSMs, thereby enhancing their long-term stability and applicability in gas separations. Full article

In this work, a hybrid polymer electrolyte integrating single- and dual-ion conducting systems was developed for lithium-ion batteries using bio-based materials, namely oleic-acid derivatives and epoxidized soybean oil, through an in situ polymerization process. The fixed FSI anions in LiEFSOA enhance the selectivity of Li⁺ transport, while the cross-linked network formed by ESO provides mechanical stability, and the LiFSI incorporated into the polymer matrix helps maintain sufficient overall ionic conductivity. In addition, the long C18 oleic chains increase the internal free volume of the matrix, thereby improving segmental mobility within the amorphous phase. The in situ polymerization inside the cell causes intimate interfacial contact between the electrode and electrolyte, achieving an ionic conductivity of 1.05 × 10⁻⁴ S cm⁻¹ at 30 °C. Electrochemical evaluation using LiFePO₄/FSOA-2/Li cells shows an initial discharge capacity of 149.09 mAh g⁻¹ and a capacity retention of 81.09% after 100 cycles, and the average coulombic efficiency was 99.62%, demonstrating that the designed FSOA electrolyte exhibits stable cycling performance and competitive capacity. Overall, the combination of eco-friendly materials and a hybrid ion transport strategy provides a promising platform for developing sustainable and high-performance polymer electrolytes for lithium-ion batteries. Full article

Solid polymer electrolytes (SPEs) hold great potential in high-safety energy storage but face two key bottlenecks: low room-temperature ionic conductivity and insufficient mechanical strength. This study proposes a synergistic optimization strategy of “long-carbon-chain regulation of polymer microstructure combined with porous polyimide (PI) support”. A linear random copolyester, poly(1,3-propylene-co-1,4-butylene succinate-co-sebacate) (PBPSS), was synthesized via melt polycondensation using 1,3-propanediol, 1,4-butanediol, succinic acid, and sebacic acid as monomers. Subsequently, the PBPSS-75 composite electrolyte was prepared with this copolyester as the matrix and porous PI as support. Results show that long-carbon-chain sebacic acid effectively regulates polymer segment flexibility and free volume, synergistically enhancing ionic conductivity and interfacial mechanical stability with lithium metal. Experimental data indicate that PBPSS-75 composite electrolyte exhibits an ionic conductivity of up to 4.25 × 10⁻⁵ S cm⁻¹ (30 °C), a lithium-ion transference number of 0.81, and an electrochemical stability window of 4.48 V (vs. Li/Li⁺). In LiFePO₄//Li batteries, it maintains nearly 100% capacity retention after 300 cycles at 0.5 C, and achieves stable cycling for over 800 h in lithium symmetric cells. This study confirms that the combined strategy effectively addresses the conductivity-mechanical property trade-off of SPEs, providing theoretical guidance and technical reference for high-performance solid-state battery material design. Full article

Rare earth elements (REEs) are increasingly critical for advanced technologies like high-tech electronic devices, electric vehicles, catalysts, and supercapacitors. However, separating and purifying the REEs is challenging due to their similar physicochemical properties, such as ionic sizes and oxidation states. Traditional methods like solvent extraction require extensive use of organic solvents, involving multiple stages that generate large volumes of acidic liquid wastes. This article introduces membrane separation technologies as a more efficient approach that minimizes waste generation and offers higher selectivity and recovery rates in a single step. Membrane separation methods utilize free energy gradients and differences in ionic size or material affinity to selectively reject or allow ion adsorption and diffusion through the membrane pores. In this review paper, we critically evaluate recent advancements in the development and implementation of membrane-based systems and focus on exploring different membrane materials for REE separation, including polymer inclusion membranes, ion-imprinted membranes, nanofiltration membranes, electrodialysis membranes, metal-organic frameworks, and supported liquid membranes. The advantages, potential challenges, and technical issues with implementing these technologies are discussed, and possible areas for improvement and insights for further research are presented. Full article

Polytetrafluoroethylene (PTFE) is a self-lubricating material but has poor wear resistance. The wear resistance of the composites was enhanced by the incorporation of polyetheretherketone (PEEK), whereas the friction-reducing performance was compromised, thus resulting in an inherent trade-off between wear resistance and lubricity. Graphene nanosheets (GNSs) with high strength and lubricity were introduced as a reinforcement for PEEK/PTFE composites. Composite specimens with varying GNS contents were fabricated and characterized for their mechanical and tribological properties and wear morphologies. Combined with molecular dynamics (MD) simulations, the micro-mechanisms were further elucidated. The optimal GNS content was determined to be 2 wt%, which improved the tensile strength by 10.58% and reduced the wear rate by 17.88% compared to PEEK/PTFE. It achieved the synchronous enhancement of mechanical strength and wear resistance while maintaining desirable friction-reducing performance. MD simulation results demonstrated that the strong interfacial interactions between GNSx and the polymer enabled GNSs to adsorb polymer chains and form a dense rigid network with reduced free volume (FV). The mechanical properties were enhanced by efficient load transfer and the suppression of interfacial delamination enabled by this unique structure; meanwhile, wear resistance was improved due to the mitigation of friction-induced molecular chain scission. Full article

The rational design of polyimides (PIs) with targeted glass transition temperature (T_g) is crucial for advanced microelectronics applications. While data-driven approaches offer promise, there is a pressing need for models that are not only predictive but also physically interpretable, especially with limited datasets. Herein, we present a highly interpretable Quantitative Structure-Property Relationship (QSPR) model for accurate T_g prediction of PIs. Employing a Genetic Algorithm combined with Multiple Linear Regression (GA-MLR), we identified an optimal set of seven molecular descriptors from a curated dataset. The model demonstrates robust predictive performance and strong generalization ability, validated through rigorous statistical tests. Crucially, we provide a deep physicochemical interpretation of the descriptors, unifying their influence under the framework of free volume theory. We show that key descriptors govern T_g by modulating the fractional free volume through distinct mechanisms: descriptors like Chi0n increase free volume by introducing molecular branching that disrupts chain packing, while MinPartialCharge influences T_g through its effect on intermolecular interactions. This mechanistic understanding is translated into clear molecular design guidelines, distinguishing strategies for achieving high-T_g versus processable, low-T_g polymers. Our work establishes a reliable and transparent computational tool that bridges data-driven prediction with fundamental chemical insight for accelerating PIs development. Full article

Silicone rubber, primarily composed of polydimethylsiloxane (PDMS) chains, is widely used in sealing materials due to its excellent flexibility and durability. Its performance is significantly affected by environmental conditions, with humid-heat aging being a major factor of degradation. In this study, molecular dynamics simulations were conducted to systematically investigate the effects of water and temperature on PDMS at the molecular scale. The glass transition temperature (T_g) and free volume distribution were analyzed to evaluate the mobility of polymer chains under hydrated conditions. Mechanical simulations (including tensile and compressive deformation) indicate that the combined effect of elevated temperature and moisture significantly accelerates the degradation of rubber properties. Thermal decomposition simulations indicate that, under high-temperature and humid conditions, PDMS main chains gradually break into small molecules, with free radical reactions further promoting the aging process. The results elucidate the molecular mechanisms underlying silicone rubber performance deterioration under the coupled action of water and temperature, providing a theoretical basis for service-life prediction and durability design of sealing materials. Full article

This field study describes the successful implementation and evaluation of a Polymer-free Delayed Acid System, a next-generation acid retarder system that is chemically superior to traditional emulsified acid systems with an amphoteric-based surfactant. It is a polymer-free system that stimulates ultra-tight carbonate reservoirs in extreme sour and high-temperature conditions. The candidate well, located in an onshore gulf region field, for a major oil and gas company demonstrated chronically unstable production behavior for over two years, with test volumes fluctuating unpredictably between 200 and 400 barrels of oil per day. This indicated severe near-wellbore damage, high skin, and limited matrix permeability (<0.3 mD). The well was chosen for a pilot trial of the Polymer-free Delayed Acid System technology after a thorough formation study, which included mineralogical characterization and capillary diagnostics. The innovative acid retarder formulation, designed for deep matrix penetration and controlled acid–rock reaction, uses intrinsic encapsulation kinetics to significantly increase the acid’s reactivity, allowing it to bypass damaged zones, minimize acid leak-off, and initiate dominant wormhole propagation into the tight formation. The stimulation procedure began with a custom pre-flush designed to change nanoscale wettability and interfacial tension, so increasing acid displacement and assuring effective contact with the formation rock. Real-time injectivity testing and operational data collecting were performed prior to, during, and following the acid job, with pre-stimulation injectivity peaking at 1.2 bpm, indicating poor formation conductivity. Treatment with the Polymer-free Delayed Acid System resulted in a 592% increase in post-stimulation injectivity, indicating significant increases in near-wellbore permeability and successful propagation. However, a substantial operational difficulty arose: the well remained shut down for more than two months following the acid stimulation work due to surface infrastructure delays, notably the scheduling and execution of a flowline cleanup campaign. This lengthy closure slowed immediate flowback analysis and impeded direct assessment of treatment performance because production could not be tracked in real time. Despite this, once the surface system was operational and the well was open to flow, a structured production testing program was carried out over four quarterly intervals. The well regularly produced at an average stable rate of 500 bbl/day, more than doubling pre-treatment performance and demonstrating the long-term effectiveness and mechanical durability of the acid-induced wormhole network. Despite the post-job shut-in, the Polymer-free Delayed Acid System maintained the stimulating impact even under non-ideal settings, demonstrating its robustness. The Polymer-free Delayed Acid System outperforms conventional emulsified acid systems, giving better control over acid placement and reactivity, especially under severe reservoir conditions with bottomhole temperatures reaching 200 °F. This project offers a field-proven methodology that combines advanced chemical engineering, formation-specific design, and live diagnostics, as well as a scalable blueprint for unlocking hydrocarbon potential in similarly complicated, low-permeability reservoirs. Full article

Hydrofluorocarbons (HFC) are today widely used as refrigerants, solvents, or aerosols for fire protection. Due to their non-negligible environmental impact, there exists an increasing interest towards their effective separation and recovery, which still remains a major challenge. This work presents a comprehensive thermodynamic and transport modeling approach able to describe HFC sorption and transport in different amorphous polymers, including glassy, rubbery, and copolymers, as well as in supported Ionic Liquid membranes (SILMs). In particular, the literature solubility data for refrigerants such as R-32, R-125, R-134a, and R-152a is analyzed by means of the Sanchez–Lacombe Equation of State (SL-EoS), and its non-equilibrium extension (NELF), to predict gas uptake in complex polymeric materials. The Standard Transport Model (STM) is then employed to describe permeability behaviors, incorporating concentration-dependent diffusion using a mobility coefficient and thermodynamic factor. Results demonstrate that fluorinated gases exhibit strong affinity to fluorinated and high free-volume polymers, and that solubility is primarily governed by gas condensability, molecular size, and polymer structure. The combined EoS–STM approach accurately predicts both solubility and permeability across different pressures in all polymers, including SILM. The thorough study of HFC transport in polymer membranes provided both systematic insights and predictive capabilities to guide the design of next-generation materials for refrigerant recovery and low-GWP separation processes. Full article

In most commercial lithium-ion batteries, graphite remains the primary anode material. However, its theoretical specific capacity is only 372 mAh∙g⁻¹, which falls short of meeting the demands of high-performance electronic devices. Silicon anodes, despite boasting an ultra-high theoretical specific capacity of 4200 mAh∙g⁻¹, suffer from significant volume expansion (>300%) during cycling, leading to severe capacity fade and limiting their commercial viability. Currently, silicon-based polymer-derived ceramics have emerged as a highly promising next-generation anode material for lithium-ion batteries, thanks to their unique nano-cluster structure, tunable composition, and low volume expansion characteristics. The maximum capacity of the ceramics can exceed 1000 mAh∙g⁻¹, and their unique synthesis routes enable customization to align with diverse electrochemical application requirements. In this paper, we present the progress of silicon oxycarbide (SiOC), silicon carbonitride (SiCN), silicon boron carbonitride (SiBCN) and silicon oxycarbonitride (SiOCN) in the field of LIBs, including their synthesis, structural characteristics and electrochemical properties, etc. The mechanisms of lithium-ion storage in the Si-based anode materials are summarized as well, including the key role of free carbon in these materials. Full article

The development of cost-effective and scalable air/oxygen electrode materials is crucial for the advancement of Zn–air batteries (ZABs). Porous carbon materials doped with heteroatoms have attracted considerable attention in energy and environmental fields because of their tunable nanoporosity and high electrical conductivity. In this work, we report the synthesis of a three-dimensional (3D) N and P co-doped porous carbon (PA@pDC-1000), derived from a conjugated polyaniline–phytic acid polymer. The cross-linked, rigid conjugated polymeric framework plays a crucial role in maintaining the integrity of micro- and mesoporous structures and promoting graphitization during carbonization. As a result, the material exhibits a hierarchical pore structure, a high specific surface area (1045 m² g⁻¹), and a large pore volume (1.02 cm³ g⁻¹). The 3D N, P co-doped PA@pDC-1000 catalyst delivers a half-wave potential of 0.80 V (vs. RHE) and demonstrates a higher current density compared to commercial Pt/C. A primary ZAB utilizing this material achieves an open-circuit voltage of 1.51 V and a peak power density of 217 mW cm⁻². This metal-free, self-templating presents a scalable route for the generating and producing of high-performance oxygen reduction reaction catalysts for ZABs. Full article

In polymer-based lithium batteries, polymer electrolytes (PEs) exhibit limited ionic conductivity at room temperature (25 °C). To address this issue, this paper describes a hexagonal-structure-based single-ion conducting gel polymer electrolyte (h-SICGPE) framework with a robust and efficient cross-linked polymer network, applicable to polymer-based batteries even at 25 °C. The proposed cross-linked polymer network backbone of the h-SICGPE, as a semisolid-state thin film type, has the homogeneous honeycomb structure incorporating anion receptor(s) inside each of its hexagonal closed cells and is obtained by cross-linking between trimethylolpropane tris(3-mercaptopropionate) and poly(ethylene glycol) diacrylate in a newly synthesized anion–receptor solution. The excellent structural capability of the h-SICGPE incorporating Li⁺/TFSI⁻ can enhance ionic conductivity and electrochemical stability by suppressing crystallinity and expanding free volume. Further, the anion receptor in its free volume helps to effectively increase the lithium-ion transference number by immobilizing counter-anions. Experimental results demonstrate dramatically superior performance at 25 °C, such as ionic conductivity (2.46 mS cm⁻¹), oxidative stability (4.9 V vs. Li/Li⁺), coulombic efficiency (97.65%), and capacity retention (88.3%). These results confirm the developed h-SICGPE as a promising polymer electrolyte for high-performance polymer-based lithium batteries operable at 25 °C. Full article

The type of silane coupling agent (SCA) has an important influence on carbon fiber (CF) modification efficiency and the properties of the obtained CF-based polymer composites. To quantitatively reveal the effects of SCA type, three kinds of SCA (γ-aminopropyl triethoxylsilane, γ-glycidoxypropyl trimethoxylsilane, and γ-methacryloxy propyl trimethoxylsilane)-modified CF-incorporated silicon rubber (SR) composites were prepared. The microstructure (free volume characteristic and interfacial interaction) of the obtained CF/SR composites was revealed by positron annihilation lifetime spectroscopy (PALS). Based on the results of mechanical, electrical, and thermal properties, the relationship between microstructure and performance was established. This investigation provides a powerful approach to the quantitative description of polymer composite microstructures, which will benefit the construction of structure–property relationships and high-performance polymer composites. Full article