Search Results (311)

The article studies the influence of chlorosulfonated polyethylene CSM 40 as a compatibilizer on the curing characteristics of the rubber compound, dynamic mechanical analysis, morphology, physico-mechanical and performance properties of vulcanized rubber based on a compound of ethylene propylene diene monomer EPDM S 501A and nitrile butadiene NBR 2645 rubbers. DMA studies indicate that the temperature dependence of tanδ for vulcanizates with and without a compatibilizer based on EPDM S 501A/NBR 2645 at a ratio of 75/25 parts per hundred parts of rubber (phr) has a bimodal character, which indicates the incompatibility of the rubber phases. The temperature dependence for EPDM S 501A/NBR 2645 vulcanizates (25/75 phr) with and without a compatibilizer has a monomodal form, which characterizes the improved compatibility of the rubber phases. SEM showed that a clearly defined microporous structure is observed on a cleavage of vulcanizate sample EPDM/NBR (25/75 phr) without a compatibilizer; with the addition of CSM 40, this feature is retained, but becomes less pronounced. It is shown that vulcanizates containing the compatibilizer CSM 40 are characterized by increased strength properties and hardness compared to vulcanized rubber without a compatibilizer. It was established that the vulcanized rubber based on EPDM S 501A/NBR 2645/CSM 40 (25/75/5 phr) is characterized by the smallest changes in the elastic-strength properties and hardness of vulcanizates after a day of thermo-oxidative aging in air and their weight after exposure to industrial oil I-20A and standard petroleum fluid SZhR-1 at room temperature among vulcanizates based on EPDM S 501A and NBR 2645. The vulcanizate of the rubber compound, including a compound of EPDM/NBR (25/75 phr) with a compatibilizer CSM 40 in an amount of 5 phr (2.88 wt.%), is characterized by stable physico-mechanical properties and improved performance properties. This rubber compound can be used for the manufacture of rubber products operating under the influence of oils and hydrocarbon environments. Full article

This study explores the potential of pine bark—a highly accessible and underexploited by-product of forestry and food processing—as a renewable raw material for rigid polyurethane (PUR) foam production. Under optimal extraction conditions, water-soluble extractives rich in carbohydrates were isolated from biomass with a yield of 25% and subsequently condensed with propylene carbonate (PC) to produce bio-based polyols. The polyols synthesized at a PC/OH molar ratio ranging from 1 to 5 were incorporated into rigid PUR foam formulations as substitutes for commercial polyether polyols. The foams containing bio-polyols synthesized at a PC/OH ratio of 3 demonstrated the highest compressive strength and thermal insulation performance, exceeding those of the reference material by 30% and 9%, respectively, and exhibited enhanced thermo-oxidative stability. Incorporation of extracted bark up to 10 wt% as a filler in the PUR matrix led to a decrease in mechanical properties to the level of the reference foam and a 19% reduction in thermal insulation capacity, without affecting the closed-cell content. Cone calorimetry revealed that both filled and unfilled bio-polyol-based PUR foams exhibited lower degradation rate, heat release rate, and total smoke release compared with the reference material, indicating reduced flammability and a lower tendency toward fire propagation. Full article

Thunbergia laurifolia Lindl. is a plant known for its promising biological activity, including antioxidant and anti-inflammatory activities, and a rich source of rosmarinic acid (RA). The extraction of T. laurifolia for cosmetic and skincare products using conventional solvents has encountered difficulties, including safety concerns, skin irritation, undesirable odors, and inefficient extraction. In this work, 14 types of natural deep eutectic solvents (NaDESs) with varying compositions and ratios were investigated to compare their efficiency in extracting RA from T. laurifolia by HPLC analysis. The NaDES with the highest extraction efficiency was further utilized in ultrasonic-assisted extraction (UAE), and the extraction parameters were optimized using response surface methodology. The optimized RA content and DPPH scavenging activity were predicted by response surfaces methodology to be 7.52 mg/g DW and 37.6 mg TE/g DW, respectively. The optimal extraction condition was achieved using a propylene glycol-lactic acid NaDES (at an 8:1 molar ratio) with 37% (w/w) H₂O, a 30 mL/g liquid-to-solid ratio, an 80 °C extraction temperature, and a 32 min extraction time. The optimized extract was proved to suppress ROS in H₂O₂-induced keratinocytes. The extract demonstrated robust stability against basic, oxidative, and photolytic stresses, and maintained long-term chemical stability up to 90 days. This study introduces a new green solvent for the effective extraction of T. laurifolia, thereby improving the safety and quality of the extracts for skincare and cosmetic products. Full article

Nitrogen (N) uptake of managed turfgrasses in sand rootzones is of particular importance as it relates to reducing N leaching, reducing or maximizing N fertilizer applications, and optimizing overall plant quality. Two greenhouse experiments were conducted to determine if the inclusion of a one-time application of soil surfactant tank-mixed with ammonium sulfate fertilizer (FERT) improved fertilizer longevity and bermudagrass (Cynodon dactylon L. Pers. × C. transvaalensis Burtt-Davy, cv. ‘TifEagle’) quality (TQ), yield, leaf N content, N uptake (NUP), chlorophyll index (CI), and volumetric water content (VWC) under deficit irrigation. An untreated, fertilizer-only (Fert) (49 kg N·ha⁻¹), and non-ionic alkylpolyglycoside/ethylene oxide-propylene oxide (AEP) was tank-mixed with fertilizer at two rates, Fert+AEP(L) (1.17 L·ha⁻¹) or Fert+AEP(H) (1.75 L·ha⁻¹), to determine rate efficacy. In 2015, Fert and Fert+AEP(L) significantly increased TQ and CI, while in 2016, both AEP (L and H) significantly increased only TQ. VWC was significantly greater in untreated in 2015. At the end of the trials in 2015 and 2016, yield and NUP were significantly greater in Fert+AEP(H) and Fert+AEP(L), respectively, but leaf N content was not statistically significant between all fertilizer treatments. The role of surfactants in prolonging fertilizer effectiveness under deficit irrigation warrants further investigation. Full article

Propylene oxide is the first and only chiral molecule to have been observed in the interstellar medium. Given the mechanisms for forming chiral species, which are important for astrobiology in understanding the origins of life, we report here an experimental and theoretical investigation into the electronic structure of propylene oxide and its evolution from the methylation and epoxidation of ethene. Here, electron momentum spectroscopy is used as an orbital-imaging technique to probe experimental orbital momentum distributions. These are directly compared with theoretical orbital momentum distributions calculated at the equilibrium geometry, and those calculated by considering the vibrational motion of the propylene oxide target. This allows us to identify which molecular orbitals are sensitive to specific vibrational normal modes, thereby facilitating understanding and controlling chemical reactivity. By extending our investigation to include intermediate species along the evolution of ethene through methylation and epoxidation, we can develop an understanding of how the orbital electronic structure evolves through this series of important chemicals. Full article

This article explores the influence of synthesized zinc stearate (ZnSt) complexes with different molar ratios of zinc oxide (ZnO) and stearic acid (StA) on the sulfur vulcanization and properties of the ethylene–propylene–diene monomer (EPDM). The aim of study was to reduce the amount of ZnO in elastomer composites without affecting their compression set. The research involves synthesizing zinc complexes, including the addition of sulfur, and using them as activators in EPDM compounds. The synthesized products were characterized using DSC and FTIR to identify their composition and thermal properties. The results of the compression set and equilibrium swelling tests indicated that ZnO was used in excess as an activator. Zinc complexes allowed for a significant reduction in zinc content compared to ZnO. The stoichiometric salt of ZnO and StA was the most effective in terms of vulcanization parameters and the compression set. Non-stoichiometric complexes were less effective, proportionally to their content. SEM images showed that the dispersion of components was relatively homogeneous in vulcanizates with active ZnO and commercial ZnSt. However, the blooming of ZnSt from vulcanizates was observed. Thus, using synthesized materials could reduce the zinc content in EPDM composites while maintaining good properties, but a further reduction is needed to avoid blooming. Full article

A series of novel functional polycarbonates, specifically poly(solketal glycidyl ether carbonate-co-propylene carbonate)s with varying compositions, were synthesized through the ring-opening copolymerization of solketal glycidyl ether, propylene oxide, and carbon dioxide. The reaction was catalyzed by rac-(salcy)Co^IIIX complexes with bis(triphenylphosphine)iminium salts as co-catalysts, achieving high selectivity. The resulting terpolymers exhibited number-average molecular weights ranging from 2 × 10⁴ to 1 × 10⁵ and a narrow, bimodal molecular weight distribution, with dispersities of 1.02–1.07 for each mode. Interestingly, the addition of a small amount of water to the reaction mixture yielded a terpolymer with a unimodal molecular weight distribution and a dispersity of 1.11. Subsequent acidic hydrolysis of the solketal protective groups produced poly(glyceryl glycerol carbonate-co-propylene carbonate). All terpolymers were amorphous, with T_g near or below room temperature. The hydroxyl-functional polycarbonates underwent cyclodepolymerization under milder conditions compared to polycarbonates with protected hydroxyl groups. Full article

Carbon nanorods have been synthesized from acetylene and steam using europium oxide nanorods as a template. The resulting carbon exhibits a high conductivity of 4.66 × 10⁵ S/m and a surface area of 1226 m²/g. The Eu₂O₃ was partially or completely washed from the carbon, creating hollow nanorods. Hybrid supercapacitors were fabricated where the Eu₂O₃ contributes a redox pseudocapacitance. A gravimetric capacitance of 501.2 F/g for the hybrid cell and 202 F/g for the carbon-only cell was measured at 1 A/g using 1 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in propylene carbonate as an electrolyte. The hybrid supercapacitor exhibited an excellent energy density of 108 Wh/kg at 1 A/g compared to 43 Wh/g at 1 A/g for the carbon-only supercapacitor. Full article

Polyurethane foams containing heterocyclic rings are characterized by high thermal resistance, but unfortunately, they are flammable. This work examined the effect of halogen-free flame retardants such as melamine and expanded graphite: EG 096 and EG 290 on the properties of foams with a 1,3-pyrimidine ring. Oligoetherol obtained from 6-aminouracil, ethylene carbonate, and propylene oxide was foamed with polymeric diphenylmethane 4,4′-diisocyanate with the addition of flame retardants. The oxygen index was determined, and flammability tests were conducted on the resulting foams. Their apparent density, water absorption, thermal resistance, thermal conductivity coefficient, and compressive strength were also examined. Both melamine and expanded graphite significantly reduce the flammability of foams. The resulting foams are classified as V-0 flammability class, and their oxygen index is in the range of 24.9–29.5 vol.%. Expanded graphite is a better flame retardant and does not cause deterioration of other foam properties. Full article

The oxidative dehydrogenation of propane (ODHP) catalyzed by oxygen offers several advantages, including resistance to carbon deposition and low energy consumption. However, achieving high propylene selectivity at industrially relevant conversions remains challenging, as existing catalysts typically require temperatures exceeding 500 °C, promoting over-oxidation to CO_x. In this study, we developed a NiO nanoparticle-decorated graphitic carbon nitride catalyst (NiO@CN-600) via thermal polymerization–oxidation for photo-thermal synergistic ODHP. At 430 °C, thermal catalysis achieved a propane conversion of 14%. Remarkably, introducing light irradiation boosted conversion to 24%, a 10% increase. Further experimental results reveal that the photo-thermal synergistic catalysis can be described by the following mechanism: initial thermal energy provides sufficient activation energy, enabling the reaction to overcome the energy barrier and proceed smoothly. Simultaneously, the introduction of light energy enhances the activity of lattice oxygen, making it more likely to detach from the lattice and form oxygen vacancies, which in turn boosts the efficiency of the oxidation reaction on the catalyst surface. Full article

The rising popularity of ready-to-eat self-heating sauerkraut fish necessitates a meticulous production process to ensure high-quality products. This study investigated the impact of processing stages on the quality of ready-to-eat tilapia fillets. The results showed that lipid oxidation, protein degradation, pH levels, and TBA concentrations increased during processing. GC-IMS analysis revealed 56 volatile compounds in tilapia fillets, with distinct compositions at different processing stages. The flavor profiles of tilapia fillets underwent significant changes during blanching and rehydration. The levels of aldehydes and alcohols notably increased, with the blanching group exhibiting the highest concentration of aldehydes, particularly saturated linear aldehydes such as hexanal, nonanal, octanal, and benzaldehyde, which play key roles in enhancing fish flavor. Conversely, the proportion of ketones decreased following heat treatment, which is a crucial factor in mitigating undesirable fishy odors. Therefore, the optimal method for preparing ready-to-eat tilapia fillets was salting pretreatment (1.5% salt and 3% propylene glycol) at 4 °C for 1 h, blanching at 100 °C for 1 min, pre-freezing at −40 °C for 12 h, and vacuum freeze-drying at −40 °C under 20 Pa for 18 h. Finally, the dried fish fillets were vacuum-sealed for storage. Principal Component Analysis (PCA) revealed that the combined variance explained by the first two principal components post-dimensionality reduction was 95%, serving as a primary indicator of the volatile flavor profile of the fish. The dried fillets were thoroughly verified using sensory evaluation. This specific formulation garnered the highest scores in sensory evaluations, resulting in superior aroma, color, and texture attributes for the self-heating fish product. The findings of this study offer a foundational framework for developing ready-to-eat tilapia fillets and other convenient food products in the future. Full article

A series of polyether and poly(ether carbonate) polyols have been synthesized via Zn(II)-Co(III) double metal cyanide (DMC)-catalyzed ring-opening (co)polymerization of various epoxides, such as propylene oxide, 1,2-epoxybutane, epichlorohydrin, styrene oxide, and glycidol, with and without CO₂. The resulting polyether polyols exhibit linear and branched architectures (degrees of branching, DB = 0.27), high catalytic activities with turnover frequencies up to 461 min⁻¹, narrow dispersities (1.15–1.25), and low levels of unsaturation (0.004 meq g⁻¹). The DMC catalysts also enable the efficient synthesis of poly(propylene carbonate) polyol with carbonate contents up to 40% and yields reaching 63%. Additionally, branched poly(ether carbonate) polyols with tunable DB values (0.14–0.21), yields up to 70%, and carbonate contents up to 33% are synthesized via CO₂ fixation to glycidol. The synthesized polyols hold strong potential for industrial applications in polyurethanes and other advanced materials, offering versatile performance for use in coatings, adhesives, sealants, and elastomers. Overall, this study highlights the effectiveness of DMC catalysts in producing high-performance polyols, contributing to the development of sustainable materials with precise architectural control. Full article

Background/Objectives: Nicotine-free electronic cigarettes (NFECs) are becoming increasingly popular, especially among youth and non-smokers, yet their effects on the gastrointestinal tract (GIT) remain poorly understood. This systematic review synthesizes available in vitro, in vivo, and limited human evidence on NFEC-associated changes in gastrointestinal health and function. Methods: Literature searches were conducted in Medline, Web of Science, Cochrane, and Scopus in July 2025, following PRISMA guidelines. Eligible studies examined NFEC effects on any GIT segment, including the oral cavity, liver, intestines, and microbiome. Data on study design, exposure characteristics, and main outcomes were extracted and narratively synthesized. Results: Of 111 identified records, 94 full-text articles were retrieved, and 21 studies met the inclusion criteria. Most were preclinical, with only one human pilot study. Evidence from oral cell and microbial models suggests that NFEC aerosols can induce pro-inflammatory cytokine production, impair cell viability, and disrupt microbial metabolism through their base constituents (propylene glycol, vegetable glycerine, and flavourings). Animal studies indicate possible hepatic oxidative stress, altered lipid metabolism, and gut barrier dysfunction, with some data suggesting more pronounced steatosis in nicotine-free exposures compared to nicotine-containing counterparts. Microbiome studies report reduced tight junction expression and altered neutrophil function. Conclusions: Current evidence is limited and predominantly preclinical but indicates that NFEC exposure can affect multiple aspects of gastrointestinal health. Robust longitudinal and interventional human studies are urgently needed to determine the clinical relevance of these findings and to inform regulation and public health policy. Full article

Alkaline earth elements have emerged as crucial electronic modifiers for regulating active sites in catalytic systems, yet the influence of metal–support interactions (MSIs) between alkaline earth compounds and active metals remains insufficiently understood. This study systematically investigated Pt nanoparticles supported on alkaline earth carbonates (Pt/MCO₃, M = Mg, Ca, Ba) for low-temperature propylene combustion. The Pt/BaCO₃ catalyst exhibited outstanding performance, achieving complete propylene conversion at 192 °C, significantly lower than Pt/MgCO₃ (247 °C) and Pt/CaCO₃ (282 °C). The enhanced activity stemmed from distinct MSI effects among the supports, with Pt/BaCO₃ showing the poorest electron enrichment and lowest propylene adsorption energy. Through kinetic analyses, ¹⁸O₂ isotope labeling, and comprehensive characterization, the reaction was confirmed to follow the Mars–van Krevelen (MvK) mechanism. Pt/BaCO₃ achieves an optimal balance between propylene and oxygen adsorption, a critical factor underlying its superior activity. Full article

The development of non-noble metal catalysts for gas-phase propylene epoxidation with H₂/O₂ remains challenging due to their inadequate activity and stability. Herein, we report a Cs⁺-modified Ni/TS-1 catalyst (9%Ni-Cs/TS-1), which exhibits unprecedented catalytic performance, giving a state-of-the-art PO formation rate of 382.9 g_PO·kg_cat⁻¹·h⁻¹ with 87.8% selectivity at 200 °C. The catalyst stability was sustainable for 150 h, far surpassing reported Ni-based catalysts. Ni/TS-1 exhibited low catalytic activity. However, the Cs modification significantly enhanced the performance of Ni/TS-1. Furthermore, the intrinsic reason for the enhanced performance was elucidated by multiple techniques such as XPS, N₂ physisorption, TEM, ²⁹Si NMR, NH₃-TPD-MS, UV–vis, and so on. The findings indicated that the incorporation of Cs⁺ markedly boosted the reduction of Ni, enhanced Ni⁰ formation, strengthened Ni-Ti interactions, reduced acid sites to inhibit PO isomerization, improved the dispersion of Ni nanoparticles, reduced particle size, and improved the hydrophobicity of Ni/TS-1 to facilitate propylene adsorption/PO desorption. The 9%Ni-Cs/TS-1 catalyst demonstrated exceptional performance characterized by a low cost, high activity, and long-term stability, offering a viable alternative to Au-based systems. Full article