Search Results (2,148)

Hydrogels have attracted considerable attention as biomedical materials owing to their distinctive properties; however, improvements in mechanical strength, biodegradability, and biocompatibility remain essential for advanced clinical applications. This study developed a new dual-crosslinked hydrogel based on gelatin (Gel) and dextran (Dex) via sequential aldimine condensation and photopolymerization. Natural Gel and Dex were functionalized to synthesize methacrylated Gel (GelMA) and oxidized Dex (ODex), respectively. An imine-linked network was initially formed between GelMA and ODex via aldimine condensation, followed by a second crosslinked network generated through blue-light-induced free-radical polymerization of GelMA, yielding dual-crosslinked hydrogels (GMODs). ¹H NMR and FT–IR analyses confirmed the successful functionalization and formation of dual-crosslinked structure. The dual-crosslinked network enhanced the thermal stability and water-retaining capacity of the freeze-dried hydrogels (DGMODs) while reducing the surface wettability and equilibrium swelling ratio of GMODs. The maximum compressive strength (σₘ) increased with crosslinking density; GMOD−2, with moderate crosslinking density, remained intact under 85% compressive strain and achieved σₘ of 108.0 kPa. The degradation rate of GMODs was tunable by adjusting the crosslinking density, thereby modulating their drug-release behavior. GMOD−3, possessing the highest crosslinking density, exhibited effective drug-sustained release for up to five weeks. Biological evaluations, including cytotoxicity assays, live/dead cell staining, and hemolysis tests, verified excellent cytocompatibility (cell survival rate > 92%) and minimal hemolysis ratio (<5%). Furthermore, inhibition zone tests preliminarily revealed moderate antibacterial activity for GMOD−1. The GMOD hydrogels exhibited superior compressive robustness, adjustable biodegradability, and excellent biocompatibility, holding great potential for biomedical applications such as sustained drug-delivery system. Full article

Membrane technology offers considerable potential for enhancing or partially replacing conventional separation techniques, which could eventually lead to substantial energy savings. This review focuses on recent advancements in membrane separation technologies including organic solvent pervaporation (OSPV), organic solvent reverse osmosis (OSRO), organic solvent nanofiltration (OSN), and organic solvent ultrafiltration (OSUF) that are increasingly vital in the pharmaceutical, biochemical, and petrochemical industries. Although hybrid and inorganic membranes exhibit promising performance, polymeric membranes provide advantages in scalability and processability. The development of materials capable of operating under demanding conditions that include exposure to organic solvents, high temperatures, extreme pH levels, and oxidative environments remains critical. Here, we examine recent innovations in membrane materials and their integration into organic solvent systems. Key challenges, including material swelling, fouling, and scaling, are discussed, along with recent strategies to address these issues. Finally, we identify emerging research directions that could drive further progress in membrane technology for organic media applications. Full article

There is a knowledge gap about the effect of pharmaceutical agents on the biodegradation of Mg-based resorbable implants. The present work investigates how three common antibiotics and three anti-inflammatory drugs affect the corrosion of high-purity Mg, with and without ceramic and hybrid ceramic/polymeric coatings, using electrochemical impedance spectroscopy and hydrogen evolution tests. A Ca-P-Si-based ceramic coating is developed using plasma electrolytic oxidation (PEO), after the AC voltage and frequency parameters are optimized. A hybrid coating included a PEO and a poly(ε-caprolactone) (PCL) top layer formed by dip coating. High-purity Mg exhibited an instantaneous onset of corrosion with a corrosion rate of 90 μm/year after 24 h of immersion in a modified α-MEM. A hybrid PEO/PCL coating prevents the onset of corrosion for at least 5 h and reduces the H₂ evolution during the following 90 h by two times by the precipitation of 5–40 μm thick Ca-P surface deposits. Gentamicin, naproxen, streptomycin, ciprofloxacin and paracetamol were found to be corrosion accelerators with respect to bare h.p. Mg, whereas aspirin was found to be an inhibitor. Streptomycin-functionalized PEO/PCL system exhibited an active protection mechanism, triggered upon the release of the coating and substrate cations, associated with the coating defect-blocking action of the insoluble Me(II)-streptomycin chelates. Full article

The remarkable growth of high-frequency electronic systems has raised concerns about electromagnetic interference (EMI), emphasizing the need for lightweight and efficient shielding materials. In this study, ternary composites based on polypyrrole (PPy), graphene oxide (GO), and silver nanowires (AgNWs) were synthesized through chemical oxidative polymerization of pyrrole monomer and embedded into polycaprolactone (PCL) matrices to create flexible films. Structural and morphological analyses confirmed the successful incorporation of all components, with scanning electron microscopy showing granular PPy, sheet-like GO, and fibrous AgNWs, while spectroscopic studies indicated strong interfacial interactions without damaging the PPy backbone. Thermomechanical analysis revealed that GO increased stiffness and defined the glass transition, whereas AgNWs improved toughness and energy dissipation; their combined use resulted in balanced properties. EMI shielding effectiveness (SE) was tested in the X-band (8–12 GHz). Pure PPy exhibited poor shielding ability, while the addition of GO and AgNWs significantly enhanced performance. The highest EMI SE values were observed in PPy/GO–AgNWs composites, with an average SE of 16.05 dB at 20 wt% of the composite in the PCL matrix, equivalent to about 84.4% attenuation of incident waves. These results demonstrate that the synergistic integration of GO and AgNWs into PPy matrices enables the creation of lightweight, flexible films with advanced EMI shielding properties, showing great potential for next-generation electronic and aerospace applications. Full article

Black polyimide (BPI) has shown important value in the field of optical engineering due to its excellent light shielding, high temperature stability, and mechanical strength. However, carbon materials or organic dye-doped BPI suffer from poor insulation, low mechanical strength, and poor thermal stability. Intrinsic BPI has gradually become a hot topic of research at this stage. Polyimides containing dianiline structure have unique reducing activity, and the visible light absorption range can be expanded by adding an oxidant in situ to achieve BPI preparation. In this work, a polymerizable dianiline derivative- 2,4-diaminodiphenylamine (NPDA) has been developed. The resulting diamine monomers were then polymerized with a dianhydride monomer via a conventional two-step method to prepare soluble polyimide. The diphenylamine-containing group PI was characterized by 1H NMR, FTIR and UV absorption spectroscopy. It was found that by changing the oxidant ratio, a yellow, red and even black controllable polyimide film could be obtained. When fully oxidized, the BPI cutoff wavelength red shifts to 591 nm, light transmittance reaches as low as 5.9% (full visible light 300–700 nm mean), and BPI can maintain the electrical insulation and heat resistance of polyimide. This method of oxidizing soluble polyimide in situ has advantages such as economy, universality, process consistency, ease of access and superior performance. Full article

This study aimed to evaluate the incorporation of graphene-based additives, graphene nanoplatelets (GNPs) and graphene oxide quantum dots (GOQDs), into polymeric fiber matrices used as biofilm supports in anaerobic digestion systems, determining additive specific effects by benchmarking the impregnated matrices against the same nylon carrier without additives under identical operational conditions. Modified matrices were assessed through BMP assays using the liquid fraction of fruit and vegetable waste (LF-FVW) as substrate. Intermediate GNP and GOQD loadings (FM50 and FMDOT50) achieved the highest methane yields (317.9 ± 20.2 and 348.4 ± 20.0 mL CH₄/g COD_(rem)) compared with the control fiber matrix (301.0 ± 20.1 mL CH₄/g COD_(rem)). Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) analyses confirmed nanomaterial retention on the matrix surface and interaction with microbial aggregates. Embedding the nanostructures within the fiber enhanced biofilm formation and methane yield while minimizing nanomaterial washout. Future work will focus on advanced physicochemical characterization (XRD, XPS, BET, and EDX mapping), leaching tests to assess long term stability, and scale up evaluation for full scale anaerobic digestion applications. Full article

Asphalt is a widely used polymeric material in pavement engineering. However, it is easily affected by heat and ultraviolet rays, which accelerate its molecular degradation and physicochemical aging, thereby limiting its service life. To improve the anti-aging properties of asphalt, three types of nano-zinc oxide (ZnO)-modified asphalt were prepared. The chemo-rheological behavior, structural evolution of polymeric components, molecular weight distribution, and nanoscale morphology of nano-ZnO-modified asphalt were studied via dynamic shear rheometry (DSR), Fourier transform infrared spectrometry (FTIR), gel permeation chromatography (GPC) and atomic force microscopy (AFM), and the aging resistance of nano-ZnO-modified asphalt was quantitatively analyzed using the rutting factor index, functional group index, molecular size ratio, and nanoscale parameters. The findings indicate that nano-ZnO enhances the high-temperature rheological properties of asphalt and delays the increase in the rutting factor of aged asphalt. Nano-ZnO is dispersed in the asphalt matrix in the form of a physical mixture without inducing new chemical bonds, and can reduce the nanoscale roughness of asphalt. After aging, the nanoscale roughness and the aspect ratio of the bee structure decreased, and the bee structure area increased. According to the changes in the functional group index and the proportions of molecular sizes in the asphalt, it was found that nano-ZnO can significantly improve asphalt’s aging resistance. The results of this study provide insights into the nanoscale modification and structure–property relationships of polymeric asphalt binders, providing a reference for the design and application of functional polymer nanocomposite systems with improved durability. Full article

The recovery of copper from metallurgical effluents is critical for advancing sustainable mining and circular economy practices. This study evaluated a hybrid process combining copper sulfide precipitation with clarification using polymeric polyvinylidene fluoride (PVDF) microfiltration membranes. Laboratory-scale experiments were performed under controlled cyanide conditions (100 mg/L free CN⁻, 1800 mg/L Cu²⁺), focusing on permeate flux behavior, fouling mechanisms, and cleaning strategies. Optimal performance was achieved at moderate transmembrane pressures (<2.0 bar) and higher flow rates, which provided a balance between productivity and fouling control. Flux decline was attributed to a combination of pore blocking and cake layer formation, confirming the multifactorial nature of fouling dynamics. Cleaning tests revealed that oxidizing solutions (HCl + H₂O₂) restored up to 96% of the initial permeability, while combined treatments with NaCN achieved complete recovery (>100%), albeit with potential risks of membrane aging under prolonged exposure. A techno-economic assessment comparing polymeric and ceramic membranes revealed similar capital and operational costs, with polymeric membranes offering slight reductions in CAPEX (10%) and OPEX (2.3%). Overall, the findings demonstrate the technical feasibility and economic competitiveness of polymeric membranes for copper sulfide clarification, while emphasizing the need to improve long-term chemical resistance to ensure reliable industrial-scale implementation. Full article

Rubber material with high elasticity and viscoelasticity has become the most widely used universal material, and the study of the aging failure mechanism of rubber has been meaningful research in the polymer materials field. Cis-polyisoprene was employed to analyze the mechanism of oxidative degradation under artificial UV irradiation, and the GQDs/g-C₃N₄ photocatalysis with a 2D layered structure prepared by the method of microwave-assisted polymerization enabled to accelerate the degradation procedure. The results showed that the oxidation of cis-polyisoprene occurred during the irradiation for 3 days and the structure of cis-polyisoprene changed. The α-H of the double bond was attacked by oxygen to form hydroperoxide. Then, aldehydes and ketones generated as the addition reaction of double bonds occurred. The content of the hydrogen of C=C reduced, and the oxidative degradation was dominant at the initial aging stage. The crosslinking reaction was dominant at the final aging stage and the average molecular weight decreased from 15.49 × 10⁴ to 8.78 × 10⁴. The GQDs could promote the charge transfer and the photodegradation efficiency and inhibit the electron–hole recombination. The light capture ability of GQDs was improved after compositing with g-C₃N₄. The free radicals ·O₂²⁻ generated after adding GQDs/g-C₃N₄ nanoparticles, and the molecular weight of cis-polyisoprene decreased to 5.79 × 10⁴, with the photocatalytic efficiency increasing by 20%. This work provided academic bases and reference values for the application of photocatalysts in the field of natural rubber degradation and rubber wastewater treatment. Full article

Electrical cable insulation, mainly composed of polymeric materials, progressively deteriorates under thermal, electrical, mechanical, and environmental stress factors. This degradation reduces dielectric strength, thermal stability, and mechanical integrity, thereby increasing susceptibility to failure modes such as partial discharges, arcing, and surface tracking—recognized precursors of fire ignition. This review consolidates current knowledge on the degradation pathways of cable insulation and their direct link to fire hazards. Emphasis is placed on mechanisms including thermal-oxidative aging, electrical treeing, surface tracking, and thermal conductivity decline, as well as the complex interactions introduced by flame-retardant additives. A bibliometric analysis of 217 publications reveals strong clustering around material degradation phenomena, while underlining underexplored areas such as ignition mechanisms, diagnostic monitoring, and system-level fire modeling. Comparative experimental findings further demonstrate how insulation aging modifies ignition thresholds, heat release rates, and smoke toxicity. By integrating perspectives from materials science, electrical engineering, and fire dynamics, this review establishes the nexus between aging mechanisms and fire hazards. Full article

Methacrylate photopolymer resin (MPR) is widely used in various fields, including the biomedical field. There are several problems associated with their use: the potential toxicity of monomer residues during incomplete polymerization and the possibility of bacterial expansion. Doping polymers with nanoparticles is one of the ways to increase the degree of polymerization (protection from toxicity), improve the performance characteristics of the polymer, and add antibacterial properties. We used an in situ polymerization method to obtain the composites of MPR with tellurium nanoparticles (TeNPs) with a dopant concentration of 0.001, 0.01, or 0.1% (v/v). The composite of MPR+TeNPs had a higher degree of polymerization compared to MPR without NPs, improved mechanical properties, and pronounced antibacterial activity. The effects depended on the concentration of TeNPs. All of the studied composites had no cytotoxic effect on human cells. MPR+TeNPs 0.1% had the maximum antibacterial effect, which is probably realized through Te-dependent induction of oxidative stress (increase in the generation of 9-oxoguanine and long-lived reactive forms of proteins). The results obtained deepen the knowledge about the influence of NPs of leading metals on photopolymerization and the final properties of the methacrylate matrix, and the synthesized MPR+TeNP composites may find potential biomedical applications in the future. Full article

Microalgae are considered to be a dual solution for CO₂ fixation and biogas slurry purification due to their high photosynthetic efficiency and strong environmental adaptability. However, their application is constrained by the low solubility of CO₂ in the solution environment, which restricts microalgal growth, resulting in low biomass production and poor slurry purification efficiency. In this study, we developed MgFe layered double hydroxide (LDH) that spontaneously combined with Chlorella pyrenoidosa to help it concentrate CO₂, thereby increasing biomass yield and purification capacity for food waste biogas slurry. The prepared MgFe-LDH exhibited a typical layered structure with a CO₂ adsorption capacity of 4.44 mmol/g. MgFe-LDH and C. pyrenoidosa carried opposite charges, enabling successful self-assembly via electrostatic interaction. Compared with the control, the addition of 200 ppm MgFe-LDH increased C. pyrenoidosa biomass and pigment content by 36.82% and 63.05%, respectively. The removal efficiencies of total nitrogen, total phosphorus, and ammonia nitrogen in the slurry were enhanced by 20.04%, 31.54% and 14.57%, respectively. The addition of LDH effectively alleviated oxidative stress in C. pyrenoidosa and stimulated the secretion of extracellular polymeric substances, thereby enhancing the stress resistance and pollutant adsorption capabilities. These findings provided a new strategy for the industrial application of microalgal technology in CO₂ fixation and wastewater treatment. Full article

Despite the long history of beech (Fagus sylvatica L.) red heartwood research, there has been no experimental proof on the structure of the chromophores yet. For the first time, using high-performance liquid chromatography/diode array detection/multistage electrospray ionization mass spectrometry, it was evidenced that red heartwood chromophores are water/methanol solvent extractable high molecular weight (400–2200 Da) compounds, which are polymerized, transformed, and oxidized products of (epi)catechin and taxifolin. Acid soluble non-extractable polyphenols (flavonoids, tannins) were not evidenced in the cell wall structure, while alkaline soluble compounds (ferulic acid, dehydrodiferulic acid, p-coumaric acid) have been identified for the first time from the sapwood/red heartwood boundary tissues: these supposedly play a role in the structural reinforcement of the cell wall structure and in the antioxidant protection and have a lesser role in color formation. Results on the structure of chromophores and on cell wall composition may enhance color homogenization technologies and contribute to a better utilization of red-heartwooded timber in the future. Full article

The increasing demand for reliable, sensitive, and cost-effective gas sensors drives ongoing research in this field. Ideal gas sensors must demonstrate high sensitivity and selectivity, stability, rapid response and recovery times, energy efficiency, and affordability. One-dimensional (1D) metal oxide semiconductors (MOSs) are prominent candidates due to their excellent sensing properties and straightforward fabrication processes. The sensing efficacy of 1D MOSs is heavily dependent on their surface area and porosity, which influence gas interaction and detection efficiency. Polymeric templates serve as effective tools for enhancing these properties by enabling the creation of uniform, porous nanostructures with high surface area, thereby improving gas adsorption, sensitivity, and dynamic response characteristics. This review systematically examines the role of polymeric templates in the construction of 1D MOSs for gas sensing applications. It discusses critical factors influencing polymer template selection and how this choice affects key microstructural parameters, such as grain size, pore distribution, and defect density, essential to sensor performance. The recent literature highlights the mechanisms through which polymer templates facilitate the fine-tuning of nanostructures. Future research directions include exploring novel polymer architectures, developing scalable synthesis methods, and integrating these sensors with emerging technologies. Full article

Binary metallic nickel–copper nanocatalysts were anchored onto a polyvinylidene fluoride-co-hexafluoropropylene membrane [NiCu/PVdF–HFP] using the electrospinning technique, followed by the chemical reduction of the relevant precursor salts by introducing sodium borohydride to the synthesis mixture. A series of varied Ni:Cu weight % proportions was developed in order to optimize the electroactivity of this binary nanocomposite towards the investigated oxidation process. A number of physicochemical tools were used to ascertain the morphology and chemical structure of the formed metallic species on polymeric films. Cyclic voltammetric studies revealed a satisfactory performance of altered NiCu/PVdF–HFP membranes in alkaline solution. Ethylene glycol molecules were successfully electro-oxidized at their surfaces, showing the highest current intensity [564.88 μA cm⁻²] at the one with Ni:Cu weight ratios of 5:5. The dependence of these metallic membranes’ behavior on the added alcohol concentration to the reaction electrolyte and the adjusted scan rate during the electrochemical measurement was carefully investigated. One hundred repeated scans did not significantly deteriorate the NiCu/PVdF–HFP nanostructures’ durability. Decay percentages of 76.90–87.95% were monitored at their surfaces, supporting the stabilized performance for prolonged periods. A much-decreased R_ct value was estimated at Ni₅Cu₅/PVdF–HFP [392.6 Ohm cm²] as a consequence of the feasibility of the electron transfer step for the electro-catalyzing oxidation process of alcohol molecules. These enhanced study results will hopefully motivate the interested workers to explore the behavior of many binary and ternary combinations of metallic nanomaterials after their deposition onto convenient polymeric films for vital electrochemical reactions. Full article