Search Results (239)

Non-isocyanate polyurethanes (NIPUs) represent a sustainable alternative to conventional isocyanate-based systems, eliminating toxic reagents while maintaining good performance. In this study, bio-based NIPU coatings were synthesized from carbonated soybean oil (CSBO) via the carbonation of epoxidized soybean oil (ESBO) using carbon dioxide (CO₂), followed by polymerization with ethylenediamine (EDA) and varying concentrations of 3-aminopropyltriethoxysilane (APTES) (0–20 wt%). The amine groups of EDA and APTES participate in the ring-opening of cyclic carbonates to form β-hydroxyurethane linkages, while the triethoxysilane moieties of APTES may undergo hydrolysis–condensation to produce Si–O–Si domains, resulting in a β-hydroxyurethane–siloxane hybrid network. The optimized formulation CEA-5 exhibited the best, including a tensile strength of 3.3 MPa, elongation at break of ~150%, glass transition temperature (T_g) of ~7 °C, and thermal stability up to ~350 °C, where major thermal degradation happens. The synthesized coating material also shows adhesion (3.6 MPa on oak for CEA-10), hydrophobic behavior (water contact angle (WCA) ~102° for CEA-5), good chemical and ultraviolet (UV) resistance, and shape memory. The synergistic effect of urethane hydrogen bonding and siloxane crosslinking imparted enhanced toughness, flexibility, and durability. These findings express a scalable, eco-friendly strategy for producing silane-modified NIPU coatings with good mechanical, thermal, and coating performance suitable for sustainable industrial coating and adhesive applications. Full article

Objective: Although the etiologies and pathogenesis of common hearing disorders—noise-induced hearing loss (NIHL), age-related hearing loss (ARHL), and idiopathic sudden sensorineural hearing loss (ISSNHL)—are diverse, accumulating evidence indicates that reactive oxygen species (ROS) contribute to hearing loss and that antioxidants may help prevent or treat it. We conducted a literature review to examine the relationship between hearing loss and ROS/free radicals in both humans and animal models. Methods: We performed a comprehensive literature search of PubMed/MEDLINE, Embase, the Cochrane Library, Scopus, and Google Scholar to evaluate the induction and role of ROS in the development and treatment of hearing loss. Results: We synthesized evidence across NIHL, ARHL, and ISSNHL. Factors and reactive species implicated in hearing loss included cytomegalovirus infection, genetic polymorphisms, NADPH oxidase 4 (NOX4), NOX transgenic models (NOX-Tg), lipid hydroperoxides (LOOH), and malondialdehyde (MDA). Antioxidant strategies examined for prevention or treatment included vitamins A, C, and E with magnesium; rebamipide; α-lipoic acid; LLY-283; edaravone; melatonin; glutathione peroxidase; superoxide dismutase; glucose; hydrogen-saturated saline; activation of nuclear factor erythroid 2-related factor 2 (Nrf2); inhaled hydrogen gas; and caffeic acid. Conclusions: Elevated ROS and free radicals appear to contribute to the pathogenesis of hearing loss. Although definitive conclusions cannot yet be drawn, current evidence suggests that antioxidant approaches may aid in prevention and treatment. Further studies are needed to elucidate underlying mechanisms, refine therapeutic targets and dosing, and validate efficacy in rigorously designed clinical trials. Full article

Scouring and bleaching processes of banana fiber fabric based on rare earth complex Lanthanum sesquioxide (La₂O₃) pretreatment were studied. The effects of rare earth content, hydrogen peroxide concentration, sodium hydroxide concentration, temperature, time, and stabilizer concentration on the weight loss ratio, whiteness, capillary effect, and breaking strength of the banana fiber fabric were analyzed. The optimized process was determined by an orthogonal test, namely, the rare earth Lanthanum sesquioxide (La₂O₃) 0.25% o.w.f., sodium hydroxide 4.5 g/L, hydrogen peroxide concentration 7.5 g/L, the stabilizer 3 g/L, processed 60 min at 75 °C. Through infrared spectroscopy (IR), Scanning electron microscopy (SEM), X-ray diffraction (XRD), Thermogravimetry (TG), and other analysis, it was proven that the rare earth pretreatment process did not change the molecular structure of the cellulose and had little effect on the fabric thermal stability. The fabric obtained by the rare earth pretreatment process has high whiteness, high breaking strength, less damage to the fiber, good fiber wettability, a high capillary effect, and good handle. Full article

Polyvinyl chloride (PVC), owing to its excellent electrical properties and low cost, is widely applied in the inner insulation and outer sheath of cables. To achieve early fault warning based on characteristic gases, this study integrates experimental testing with molecular simulations to systematically reveal the decomposition and gas generation characteristics of different PVC layers under electrical and thermal stresses. The results indicate that inner-layer PVC under electrical stress predominantly generates small-molecule olefins and halogenated hydrocarbons, while outer-layer PVC during thermal decomposition mainly produces hydrogen chloride, alkanes, and fragments of plasticizers. The surrounding atmosphere significantly regulates the gas generation pathways: air promotes the formation of CO₂ and H₂O, whereas electrical discharges accelerate the release of unsaturated hydrocarbons such as acetylene. By employing TG-FTIR, ReaxFF molecular dynamics, and DFT spectral calculations, a normalized infrared spectral library covering typical products was established and combined with the non-negative least squares method to realize quantitative deconvolution of mixed gases. Ultimately, a diagnostic system was constructed based on the concentration ratios of characteristic gases, which can effectively distinguish the failure modes of inner and outer PVC layers as well as different stress types. This provides a feasible approach for early detection of cable faults and supports intelligent maintenance strategies. Full article

Hydroxy-functional poly(propenyl ether)s are promising thermoresponsive materials; here we establish a controlled synthesis via living cationic polymerization of silyl-protected monomers. Among the silyl protecting groups examined, only tert-butyldiphenylsilyl (TBDPS) enabled living cationic polymerization. The living cationic polymerization of tert-butyldiphenylsiloxybutyl propenyl ether (TBDPSBPE) afforded a high-molecular-weight polymer (poly(TBDPSBPE)) with a narrow molecular weight distribution (M_n = 12,900; M_w/M_n = 1.22). Additionally, chain propagation continued in monomer addition experiments, and the molecular weight increased further with a narrow molecular weight distribution, confirming the success of living cationic polymerization. Poly(TBDPSBPE) was successfully desilylated to afford poly(HBPE) with a narrow molecular weight distribution. Poly(HBPE) exhibited a glass transition temperature (T_g) of 44 °C, 82 °C higher than that of the corresponding polymer without β-methyl groups, poly(HBVE). The enhanced thermal properties of poly(HBPE) were attributed to the steric hindrance of the β-methyl group, which fixes the position of the hydroxy group and allows stronger hydrogen bonding. To investigate the aqueous thermoresponse, a hydroxylated analog with a shorter side-chain spacer (poly(HPPE)) was synthesized, and poly(HPPE) exhibited lower critical solution temperature (LCST)-type phase separation in water with a cloud-point temperature (T_cp) of 6 °C, showing reversible transitions with thermal hysteresis. Full article

Polymers such as PLA, PLA reinforced with carbon fiber (PLA + CF), and PETG are widely employed in utensils, structural components, and biomedical device housings where load-bearing capability and chemical resistance are desirable. This is particularly relevant for reusable applications in which sterilization with hydrogen peroxide (HP) or ethylene oxide (EO) is often required. In this study, the impact of HP and EO sterilization processes on the mechanical, thermal, and structural properties of PLA, PLA + CF, and PETG was evaluated. The mechanical properties assessed included elongation at break, elastic modulus, and tensile strength after sterilization. The thermal properties examined comprised thermal stability and the coefficient of thermal expansion (CTE). Additionally, Fourier Transform Infrared Spectroscopy (FTIR) was performed to detect potential alterations in functional groups. For PLA, sterilization with HP and EO resulted in a 22% increase in ultimate tensile strength (UTS) and a 21% increase in elastic modulus, accompanied by a noticeable reduction in ductility and the appearance of more brittle fracture surfaces. PLA + CF exhibited greater stability under both sterilization methods due to the reinforcing effect of carbon fibers. In the case of PETG, tensile strength and stiffness remained stable; however, HP sterilization led to a remarkable increase in elongation at break (294%), whereas EO sterilization reduced it. Regarding thermal properties, glass transition temperature (Tg) showed variations: PLA presented either an increase or decrease in Tg depending on the sterilization treatment, PLA + CF displayed a Tg reduction after EO sterilization, while PETG exhibited a moderate Tg increase under HP sterilization. CTE decreased at lower temperatures but increased after EO treatment. FTIR analysis revealed only minor chemical modifications induced by sterilization. Overall, HP and EO sterilization can be safely applied to additively manufactured medical components based on these polymers, provided that the structures are not subjected to high mechanical loads and do not require strict dimensional tolerances. Full article

Background: Surgical procedures and alterations of the gastrointestinal (GI) tract increase the risk of small intestinal bacterial overgrowth (SIBO), which is associated with GI symptoms and complications that compromise postoperative recovery. However, the prevalence and clinical impact of SIBO after various upper GI surgical procedures remain poorly understood. Objective: This study aimed to evaluate the prevalence of SIBO after different types of upper GI surgery and to investigate the associated clinical factors. Methods: We conducted an observational study involving 157 patients with a history of upper GI surgery: Roux-en-Y gastric bypass (RYGB), laparoscopic single-anastomosis gastric bypass (OAGB), subtotal (STG) or total gastrectomy (TG), subtotal (SP)or total pancreatectomy (TP), cephalic duodenopancreatectomy (WR), and small bowel resection for Crohn’s disease. A glucose–hydrogen breath test was performed, and demographic, clinical, and treatment-related data were collected. Statistical analyses included t-tests, non-parametric tests, ANOVA, and correlation analyses using R software. Results: At a median follow-up of 25.7 ± 18.1 months, 31% (48/157) of patients tested positive for SIBO. The highest prevalence was observed after RYGB and OAGB (43%), followed by TG (30%), STG (29%), TP/WR (28%), and Crohn’s disease bowel resection (19%). No cases of SIBO were observed after SP. SIBO positivity was significantly associated with bloating and flatulence (p = 0.002), lactose intolerance (p = 0.047), systemic sclerosis (p = 0.042), T2D (p = 0.002), and exposure to adjuvant chemotherapy (p = 0.001) and radiotherapy (p = 0.027). In addition, the risk of SIBO increased proportionally with the duration of GI resection or exclusion (p = 0.013). Conclusions: In our study, the prevalence of SIBO after upper GI surgery was 31%, with the highest incidence (43%) observed in metabolic surgery patients. Importantly, adjuvant radio/chemotherapy was associated with an increased risk of SIBO, and extensive small bowel resection or exclusion was strongly associated with an increased risk of SIBO. Furthermore, the limitations of current diagnostic methods, which lack sufficient sensitivity and specificity, highlight the importance of early screening and standardization of diagnostic techniques to improve patient management and outcomes. Full article

Aluminum hydride (AlH₃) is a promising candidate for enhancing the combustion performance of liquid fuels due to its high energy density and exceptional hydrogen storage capacity. This study investigated the ignition and combustion characteristics of μ-AlH₃ particles in kerosene droplets using TG-DSC analysis, high-speed imaging, laser ignition, and combustion product characterization, with comparisons to micron- and nano-aluminum powders. Results showed that the exothermic combustion of hydrogen released from AlH₃ decomposition lowered the primary oxidation temperature of aluminum, leading to more intense combustion with smaller ejected particles. The particle size of kerosene droplets containing AlH₃ rapidly decreases due to the escape of hydrogen. The heat released by the combustion of hydrogen significantly accelerates the combustion of droplets, and the fastest combustion rate is observed at a concentration of 1% AlH₃. The combustion products of kerosene droplets containing AlH₃ are smaller than those of kerosene droplets containing aluminum, indicating that their combustion efficiency is higher. A combustion model for AlH₃-based kerosene droplets was developed, demonstrating less than 10% error in predicting ignition delay and burning rates. These findings provide valuable insights for the application of AlH₃ in liquid fuels. Full article

Precision and real-time detection of hydrogen peroxide (H₂O₂) are essential in pharmaceutical, industrial, and defence sectors due to its strong oxidizing nature. In this study, silver (Ag)-doped CeO₂/Ag₂O-modified glassy carbon electrode (Ag-CeO₂/Ag₂O/GCE) has been developed as a non-enzymatic electrochemical sensor for the sensitive and selective detection of H₂O₂. The synthesized Ag-doped CeO₂/Ag₂O nanocomposite was characterized using various advanced techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). Their optical, magnetic, thermal, and chemical properties were further analyzed using UV–vis spectroscopy, electron paramagnetic resonance (EPR), thermogravimetric-differential thermal analysis (TG-DTA), and X-ray photoelectron spectroscopy (XPS). Electrochemical sensing performance was evaluated using cyclic voltammetry and amperometry. The Ag-CeO₂/Ag₂O/GCE exhibited superior electrocatalytic activity for H₂O₂, attributed to the increased number of active sites and enhanced electron transfer. The sensor displayed a high sensitivity of 2.728 µA cm⁻² µM⁻¹, significantly outperforming the undoped CeO₂/GCE (0.0404 µA cm⁻² µM⁻¹). The limit of detection (LOD) and limit of quantification (LOQ) were found to be 6.34 µM and 21.1 µM, respectively, within a broad linear detection range of 1 × 10⁻⁸ to 0.5 × 10⁻³ M. The sensor also demonstrated excellent selectivity with minimal interference from common analytes, along with outstanding storage stability, reproducibility, and repeatability. Owing to these attributes, the Ag-CeO₂/Ag₂O/GCE sensor proved effective for real sample analysis, showcasing its potential as a reliable, non-enzymatic platform for H₂O₂ detection. Full article

The decomposition of high-energy materials often releases large volumes of toxic fumes, contributing to environmental pollution. To reduce these emissions, eco-friendly formulations are being developed by modifying chemical composition or adding functional additives that enhance combustion and reduce toxic byproducts. Hydrogen peroxide (H₂O₂), acting as both an oxidizer and potential fuel, shows promise in lowering NO_x emissions. However, its impact on formulation stability must be assessed. This study examines the morphological and thermal behavior of an ammonium nitrate, fuel oil, and hydrogen peroxide (ANFOHP) formulation using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermal analysis based on thermogravimetry (TG) connected with differential scanning calorimetry (DSC) techniques. SEM showed that the fuel oil–hydrogen peroxide (FOHP) blend formed a thin film on ammonium nitrate prills without structural damage. XRD patterns indicated an intact crystalline structure. Moreover, FT-IR analysis performed both for fresh and 24-h stored samples evidenced no structural changes. In turn, TG/DSC revealed altered thermal behavior, with a new endothermic peak near 80 °C corresponding to the simultaneous evaporation of water and hydrogen peroxide from the ANFO surface, and reduced intensity of the main ANFO decomposition peak, indicating a shift in the thermal behavior induced by the FOHP blend. Full article

To address the inherent challenge of poor interfacial compatibility in lignin/poly(butylene adipate-co-terephthalate) (PBAT) composites, lignin was extracted from Camellia oleifera shells and subjected to sequential solvent fractionation using ethanol, acetone, and tetrahydrofuran (THF). Two representative fractions—acetone-soluble (ACL) and THF-soluble (THFL)—were selected for composite preparation with PBAT via solvent casting. The influence of lignin fractionation on the structural and performance characteristics of the resulting composites was systematically evaluated through Fourier-transform infrared (FTIR) spectroscopy, the water contact angle (WCA), differential scanning calorimetry (DSC), tensile testing, and scanning electron microscopy (SEM). The results revealed that the abundant hydroxyl groups and benzene rings present in both ACL and THFL facilitated hydrogen bonding and conjugation interactions with the PBAT matrix, significantly improving interfacial adhesion. Notably, the ACL fraction effectively suppressed phase separation and increased the glass transition temperature (T_g) by 1.9 °C, leading to a 13.9% enhancement in tensile strength compared to neat PBAT. More strikingly, the incorporation of only 7 wt% THFL resulted in a remarkable 31% improvement in tensile strength. This substantial enhancement was primarily attributed to the favorable polarity match between THFL and PBAT, as well as the nucleating effect of THFL, which increased the crystallinity of PBAT by 25.3%. This study highlights the effectiveness of sequential lignin fractionation in tailoring the interfacial properties of biodegradable polymer composites. It also provides a promising strategy for the high-value utilization of lignin toward the development of high-performance, environmentally friendly materials. Full article

The competitive retention of pollutants in water tables determines their environmental fate and guides routes for their removal. To distinguish the fine differences in competitive binding at zeolite adsorption centers, a group of neonicotinoid pesticides is compared, relying on theoretical (energy of adsorption, orientation, charge distribution) and experimental (spectroscopic and thermogravimetric) analyses for quick, inexpensive, and reliable screening. The MOPAC/QuantumEspresso platform was used for theoretical calculation, indicating close adsorption energy values for acetamiprid and imidacloprid (−2.2 eV), with thiamethoxam having a lower binding energy of −1.7 eV. FTIR analysis confirmed hydrogen bonding, among different dipole-dipole interactions, as the dominant adsorption mechanism. Due to their comparable binding energies, when the mixture of all three pesticides is examined, comparative adsorption capacities are evident at low concentrations, owing to the excellent adsorption performance of the FAU zeotype. At higher concentrations, competition for adsorption centers occurs, with the expected thiamethoxam binding being diminished due to the lower bonding energy. The catalytic impact of zeolite on the thermal degradation of pesticides is evidenced through TG analysis, confirming the adsorption capacities found by UV/VIS and HPLC/UV measurements. Detailed analysis of spectroscopic results in conjunction with theoretical calculation, thermal profiles, and UV detection offers a comprehensive understanding of neonicotinoids’ adsorption and can help with the design of future adsorbents. Full article

Poly(lactic acid) (PLA) holds significant promise as an option in the field of packaging materials due to its biodegradability and antibacterial properties. Therefore, it is vital for developing packaging materials while improving their heat resistance, and transparency is essential for guaranteeing its application. Using a self-assembled nucleating agent with hydrogen bonding and thermodynamically compatible transparent polymethyl methacrylate (PMMA), this study fabricated PLA micro-crystals with an interface blurred grain. Furthermore, the crystalline structure-property relationship was investigated in different isothermal crystallization conditions; it was possible to achieve higher crystallinity while maintaining the transparency of PLA/10 wt% PMMA/0.3 wt% nucleating agent blends. Compared to other temperatures, the crystallization rate of PLA blends under annealing conditions at 90 °C was higher when induced by three different nucleating agents. Particularly, in the presence of the TC-328 nucleating agent, the system exhibited a crystallinity of 32%, the smallest grain size, and an increased Tg of 61.3 °C, as well as an elevated heat deformation temperature (HDT) from 54.13 °C to 63.2 °C. The smaller nucleating agents with high surface energy enhanced the interaction between the PLA and PMMA, enhancing the PLA/PMMA tensile strength and HDT. These findings may pave the way for designing novel blends for packaging or heat-resistant devices. Full article

Polyamides (PAs) are widely used as barrier materials in offshore oil and gas (O&G) equipment due to their mechanical strength and chemical resistance. However, long-term exposure to hydrogen sulfide scavengers (H₂S-SCVs) may significantly affect their physicochemical properties. Previous studies using thermal analysis and ¹H time-domain NMR (¹H TD-NMR) suggest that ethoxylated H₂S-SCVs impose molecular constraints, increasing the glass transition temperature (T_g) and reducing chain mobility above T_g. The present study builds upon these findings using a multi-technique analytical approach, including FTIR, Raman, ¹H DQ-TD-NMR, and ¹³C solid-state NMR (ssNMR), to provide a more comprehensive understanding of the molecular alterations in PA materials. The results clearly demonstrate that H₂S-SCV exposure leads to the progressive exudation of plasticizers from the PA matrix. This plasticizer loss is a key factor contributing to the observed shift in Tg and the reduction in molecular mobility. ¹H DQ-TD-NMR data confirmed an increase in the density of dynamically constrained chains over time and allowed for the characterization of heterogeneity in these constraints throughout the PA matrix. Moreover, ¹³C ssNMR spectra revealed the presence of immobilized H₂S-SCV chemical groups within the polymer matrix, strongly supporting the early statement that the mobility constraints observed in ¹H DQ-TD-NMR are associated with the formation of crosslinks induced by the H₂S-SCV: H₂S-SCV acts as a crosslinking agent. Taken together, our findings indicate that both plasticizer loss and H₂S-SCV-induced crosslinking contribute significantly to the microstructural evolution of PAs when exposed to ethoxylated H₂S-SCVs, offering important insights into their degradation mechanisms and long-term behavior in aggressive operational environments. Full article

Brine purification is an important process unit in chlor-alkali industrial plants for the production of sodium hydroxide, chlorine, and hydrogen. The membrane cell process requires ultrapure brine, which is obtained through mechanical filtration, chemical precipitation and fine polishing, and ion exchange using polymer resins. Temperature variations can lead to the degradation of the exchange properties of these resins, primarily causing a decrease in their exchange capacity, which negatively impacts the efficiency of the brine purification. After multiple ion exchange regeneration cycles, significant quantities of spent resins may be generated. These must be managed in accordance with resource efficiency and hazardous waste management to ensure the sustainability of the industrial process. In this paper, a comparative study is conducted to characterize the long-term stability of a new commercial chelating resin used in the industrial electrolysis process. The spectroscopic methods of physicochemical characterization included: scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR). The thermal behavior of the polymer resins was evaluated using the following thermogravimetric methods: thermogravimetry (TG), derivative thermogravimetry (DTG), and differential thermal analysis (DTA), while the moisture behavior was studied using dynamic vapor sorption (DVS) analysis. To assess the energy potential, the polymer resins were analyzed to determine their calorific value and overall energy content. Full article