Search Results (3,766)

Poly(glycidyl methacrylate) (PGMA) is a polymer containing epoxy groups in its side chains, which makes it a suitable platform for the development of functional materials. In this study, crosslinked PGMA-based microspheres were synthesized by suspension polymerization using N,N′-methylenebisacrylamide as a crosslinker, and the effect of incorporating inorganic additives (InAds) (NaCl, CaCO_3, and MgO nanoparticles) during synthesis was evaluated. In all cases, solid microspheres were obtained, exhibiting variations in particle size, sphericity, and aggregation depending on the type and amount of InAds. Thermal stability was characteristic of crosslinked PGMA (i.e., a single broad thermal transition in ~80–110 °C), while water absorption remained within a narrow range (80–120% for t = 40 min). In addition, the number of epoxy groups per gram of sample was 4.83 ± 0.02 mmol g⁻¹. Selected microspheres were subsequently functionalized with polyethyleneimine (PEI) to obtain graft polymers (PGMA–PEI) and evaluated for the adsorption of three model contaminants: Acid Red 27 (AR-27), nitrites, and acetaminophen. PGMA–PEI showed high affinity toward AR-27 and nitrites, achieving high removal efficiencies at acidic and neutral pH, with rapid adsorption kinetics consistent with a pseudo-second-order model, attributed to electrostatic interactions between protonated amine groups and anions. At pH 11, anion desorption was promoted, enabling partial material regeneration. The results highlight the potential of PGMA–PEI microspheres for the removal of AR-27 (maximum retention ~0.25 mg of dye/g of polymer) and nitrites (maximum retention ~0.023 mg of <!-- MathType@Translator@5@5@MathML2 (no namespace).tdl@MathML 2.0 (no namespace)@ --> Full article

The study presents novel photocrosslinked hydrogels based on methacrylated chitosan and methacrylated gelatin/allyl-modified gelatin and compares their properties as drug delivery systems in wound healing applications. The polymers were selected due to their biocompatible, mucoadhesive, cell-interactive properties and flexibility in adjusting their structure, making them suitable candidates for applications that require tissue repair. A range of hydrogel formulations was obtained by modulating the ratio of modified chitosan to two distinct modified gelatins, with photocrosslinking performed using Irgacure 2959 as the photoinitiator. FT-IR analysis, SEM data, and swelling and mechanical properties confirmed the 3D networking and the compatibility between the hydrogel components. Allylic gelatin-based hydrogels present larger pores and a stronger pH-responsive swelling behaviour compared to methacrylated gelatin-based samples, reflecting the higher flexibility of allylic gelatin networks. The hydrogels release bacitracin during the first six hours, with a release profile that follows a non-Fickian diffusion mechanism. Cytocompatibility and wound healing potential were tested in the presence of human and mouse fibroblasts, cells with a pivotal role in the wound healing process. All formulated hydrogels exhibit antioxidant capacity and protein stabilization properties, which are attributed to the presence of chitosan in their composition. The cytocompatibility, in vitro wound healing, and biological properties of the obtained hydrogels, as well as the drug release results, confirm their suitability in wound healing applications. Full article

To address the limited selectivity of conventional membrane materials toward sulfonamide antibiotics, this study employed a DFT calculation approach to optimize the design of a molecularly imprinted system for sulfadiazine (SDZ). A hierarchical set of template molecules—aniline (ANL), sulfanilamide (SNM), and SDZ—was introduced to systematically elucidate structure-dependent template–monomer matching mechanisms in sulfonamide imprinting systems. Through rational screening, trifluoroethyl methacrylate (TFEMAA) was identified as the optimal functional monomer, with an optimal imprinting molar ratio of 1:4 (SDZ to TFEMAA). Guided by the simulation results, SDZ molecularly imprinted polymers (MIPs) were synthesized via precipitation polymerization and systematically characterized for their morphology and recognition properties. The MIPs exhibited a well-defined spherical morphology with abundant imprinted cavities, achieving adsorption equilibrium within 1.5 h. The adsorption kinetics followed a pseudo-second-order model, indicating a chemisorption-dominated process. Scatchard analysis revealed the presence of both high- and low-affinity binding sites in the MIPs. Selectivity experiments, quantified by distribution coefficients (K_d) and selectivity coefficients (k), demonstrated a significantly higher adsorption capacity for SDZ than for structural analogs and non-analogs. In real water samples, the MIPs outperformed conventional HLB sorbents and showed strong anti-interference capability (RSD < 3%). This work provides a material foundation for developing highly selective SDZ-imprinted membranes and advances the application of molecular imprinting technology in membrane separation systems. Full article

A photo-curable silicone-modified resin system based on polydimethylsiloxane (PDMS) was developed and systematically evaluated for stereolithography (SLA)-based 3D printing applications. The resin formulation consisted of bisphenol A ethoxylate dimethacrylate (Bis-EMA) and trimethylolpropane triacrylate (TMPTMA) as reactive monomers, with methacrylate-terminated PDMS (PDMS-MMA) incorporated at concentrations ranging from 0 to 15 wt%. The influence of PDMS-MMA content on key physicochemical properties relevant to SLA processing, including viscosity, mechanical performance, thermal stability, optical transmittance, and curing shrinkage, was systematically investigated. Moderate incorporation of PDMS-MMA improved the mechanical flexibility of the resin, with the tensile strength reaching a maximum value of 5.95 MPa at 5 wt% PDMS-MMA. However, further increases in PDMS-MMA content resulted in a gradual decrease in tensile strength and optical transmittance, indicating the importance of optimizing the formulation composition. Thermogravimetric analysis (TGA) indicated improved thermal stability with increasing PDMS-MMA content, while curing shrinkage decreased progressively as the PDMS fraction increased. Structural printing tests confirmed that the developed resin system exhibited stable layer adhesion and shape fidelity during SLA fabrication, enabling the successful printing of complex three-dimensional structures. These results demonstrate that PDMS-modified acrylate resins provide a promising strategy for balancing mechanical flexibility, dimensional stability, and printability in SLA-based additive manufacturing. Full article

In this work, a flexible and sustainable radar-absorbing material (RAM) based on porous carbon derived from raw Kraft black liquor was developed. The porous carbon filler was synthesized through a simple, eco-friendly one-pot polymerization route, thereby avoiding lignin extraction, purification, and chemical activation steps. Macroporosity was introduced by using poly(methyl methacrylate) microspheres as a hard template, yielding a lightweight carbon material with a foam-like morphology, low density, and high porosity. The carbon filler was incorporated into a silicone rubber matrix at different loadings (5–25 wt.%) to produce flexible composites. The structural, morphological, and textural properties of porous carbon were investigated by SEM, EDX, Raman spectroscopy, nitrogen adsorption, and mercury porosimetry. The electromagnetic properties of composites were measured in the X-band (8.2–12.4 GHz) using a vector network analyzer. The mechanical behavior was evaluated through Young’s modulus. The results show that increasing filler content enhances dielectric losses and attenuation capability. Among all composites, the sample containing 20 wt.% of porous carbon exhibited the best electromagnetic performance, achieving a reflection loss of −42.3 dB at 10.97 GHz with a thickness of 2.43 mm, corresponding to an absorption efficiency of 99.99%. This performance is attributed to a favorable combination of impedance matching and quarter-wavelength cancellation effects. The developed sustainable, lightweight, and flexible composites demonstrate potential as low-cost RAM for aerospace and electromagnetic interference mitigation applications. Full article

Silicone hydrogels offer high oxygen permeability but suffer from poor wettability. This study integrates a TRISS-based system (0–2.0 wt%) with a fixed PVP/NVP matrix (1.0/0.5 wt%) to enhance hydration-induced dimensional stability and surface properties. Fabricated via cast-molding, the lenses demonstrated that TRISS incorporation significantly enhances oxygen transport. Specifically, the 2.0 wt% TRISS formulation (S2.0) achieved an ~1.9-fold increase in oxygen-induced current (from 0.97 μA in pure-HEMA to 1.86 μA) while strongly suppressing hydration-induced swelling. To counter TRISS’s inherent hydrophobicity, the PVP/NVP matrix acted as a vital compensatory mechanism, driving the equilibrium contact angle down to 56.04° and avoiding the severe hydrophobic plateau (93.79°) of the additive-free comparator. S2.0 maintained a robust oxygen response alongside improved wettability. In conclusion, this system defines a workable low-silicone design window accommodating up to 2.0 wt% TRISS without wettability loss or optical degradation (>97%). Crucially, by leveraging TRISS to mitigate swelling-induced mechanical stress and PVP/NVP to ensure stable wettability, this structurally robust hydrogel provides a highly viable foundational matrix for future smart contact lenses equipped with diagnostic micro-components. Full article

Self-curing poly(methyl methacrylate) (PMMA) remains widely used for provisional restorations and denture bases; however, its limited mechanical strength and susceptibility to water-related degradation restrict long-term performance. This study investigated the concentration-dependent reinforcement of self-curing PMMA with polyetheretherketone (PEEK) particles and evaluated mechanical properties and physicochemical stability. PMMA specimens containing different PEEK concentrations were fabricated and tested for flexural strength, compressive strength, surface hardness, water sorption, and water solubility according to standardized protocols. Mechanical performance demonstrated a concentration-dependent enhancement, with moderate PEEK incorporation significantly improving strength parameters compared to the control group. Excessive filler loading, however, did not yield proportional improvements. Water sorption and solubility values remained within clinically acceptable and ISO-recommended limits. These findings suggest that controlled PEEK reinforcement provides a feasible approach to enhancing the mechanical durability of self-curing PMMA without compromising physicochemical stability. The study offers a practical material modification strategy for improving interim prosthetic materials in clinical dentistry. Full article

Fe₂O₃-reinforced PMMA nanocomposites were prepared by melt blending using a twin-screw micro-extruder. Fixed Fe₂O₃ loading of 2.5 wt.% was employed, and mixing times of 6 and 12 min were used to obtain nanocomposites with different dispersion characteristics. The structural and morphological properties of the samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), while their thermal degradation behavior was evaluated by differential thermal and thermogravimetric analyses (DTA/TG). The activation energies of thermal degradation were calculated using the Kissinger, Takhor, and Augis–Bennett methods. Increasing the mixing time improved nanoparticle dispersion and reduced agglomeration. The addition of Fe₂O₃ slightly decreased the characteristic degradation temperatures of PMMA, while the activation energy increased for the better-dispersed sample. The results indicate that interfacial interactions and particle dispersion play important roles in the thermal degradation behavior of PMMA/Fe₂O₃ nanocomposites. Full article

Cartilage regeneration remains an unmet clinical challenge. Despite the great advances in the production of hydrogels as support matrices for cartilage regeneration, the resulting mechanical properties remain low. Granular composite hydrogels appear as ideal candidates due to their injectability and modularity in design. Here, we report on the fabrication and characterization of heterogeneous composite granular hydrogels based on methacrylated chitosan (CHIMA) and gelatin (GelMA) microparticles supported by an interstitial methacrylated alginate (ALMA) matrix. Microparticles were prepared by an oil-emulsion method and their size and morphology optimized, resulting in CHIMA and GelMA microparticles of 10.8 µm (95% CI 9.2, 13.1) and 115.8 µm (95% CI 107.5, 137.6) in diameter, respectively. The microparticles were mixed with ALMA and crosslinked to form granular hydrogels that demonstrated reduced swelling and weight loss. The storage modulus increased from 33 to 66.4 kPa for CHIMA/ALMA hydrogels and from 11.5 to 19.5 kPa for GelMA/ALMA hydrogels when the particle concentration increased from 10 to 50%, and was higher than traditional ALMA hydrogels. Hydrogels of 50:50 CHIMA:GelMA permitted a 6.6-fold increase in cell number after 28 days of culture, and promoted the chondrogenic differentiation of embedded mouse mesenchymal stem cells with a glycosaminoglycan deposition of over 15 µg and the expression of chondrogenic markers. Full article

Methacrylate-POSS (M-POSS) is a novel organic–inorganic additive shown to reinforce dental composites and reduce polymerization shrinkage. This study aimed to evaluate the influence of M-POSS addition (0.5, 2, 10, or 15 wt.%) on the mechanical properties of an experimental polymer matrix (bis-GMA/UDMA/TEGDMA/HEMA = 35/35/20/10 wt.%) and a dental resin composite (45 wt.% silanized silica as filler). Vickers hardness (HV), three-point bending strength (FS), diametral tensile strength (DTS), and shrinkage stress generated during polymerization were studied. The results show HV values between 16 and 18 compared to 15 ± 1 in the control group. Hardness in the control composite was 34 ± 4, and after modification, it showed similar or slightly lower values between 32 and 35. FS increased from 90 ± 4 MPa before modification to 100 ± 5 MPa for 2 wt.% M-POSS, and then decreased to 78 ± 5 MPa for materials containing 15 wt.% M-POSS. FS of composites were within the range of 61–77 MPa, with a similar tendency in variation to that of matrices. DTS values decreased after M-POSS addition, from 37 ± 4 MPa before modification to 31–33 MPa after modification. Flexural modulus decreases after modification, both for matrices and composites. The morphology of composites with >10 wt. % M-POSS showed visible surface irregularities. In conclusion, M-POSS affects matrix hardness, resulting in an increase in HV. The addition of M-POSS also increases FS values of the matrix, but only up to a certain concentration. However, the introduction of M-POSS does not significantly affect the HV or bending strength of the composites. Although DTS values decreased, this change was not statistically significant. Finally, contraction stress was significantly reduced for groups containing 2 wt.% and 10 wt.% M-POSS, representing an anticipated and promising improvement. Full article

Hydrogels are widely investigated as drug carriers for cancer therapy due to their ability to provide sustained release and reduce systemic side effects. In this study, MeBSA–PNIPAm hydrogels were developed as dual-temperature and pH-responsive systems for gastrointestinal delivery of 5-FU. MeBSA was successfully synthesized using glycidyl methacrylate and confirmed by FTIR and ¹H-NMR analyses. Hydrogels with varying MeBSA/NIPA ratios were prepared via redox polymerization. DSC results showed that increasing MeBSA content shifted the phase transition temperature of hydrogels, while TGA analysis revealed enhanced thermal stability with higher MeBSA incorporation. Temperature-dependent swelling experiments further demonstrated that the VPTT slightly shifted depending on the surrounding pH, indicating that the thermoresponsive behavior of the hybrid network is influenced by the pH-dependent charge state of the protein component. Swelling studies performed at 30, 37, and 40 °C and at pH 1.2 and 7.4 confirmed dual-responsive behavior. Drug loading efficiencies above 70% were achieved for all formulations. In vitro release studies at 37 °C demonstrated distinct composition-dependent release profiles. During the first 2 h, all hydrogels exhibited controlled and limited release without burst behavior under acidic conditions. Following the transition to pH 7.4, a composition-dependent increase in drug release was observed. GEL 4 achieved the fastest and highest cumulative release (91%), whereas GEL 1 provided the most sustained release over 72 h (32%). Kinetic analysis indicated diffusion-controlled release, best described by the Weibull and Korsmeyer–Peppas models. Cytocompatibility tests showed that fibroblast viability improved with increasing MeBSA content. Overall, protein-modulated dual-responsive hydrogels offer tunable and biocompatible platforms for stimuli-responsive gastrointestinal drug delivery applications. Full article

This study investigates the key performance-related fuel properties of emulsifier–diesel solutions and ethanol-in-diesel microemulsions. This work begins with the in situ polymerization of long alkyl chain-substituted glycidyl methacrylate (R-GMA) in diesel and the optional presence of a second methacrylate monomer. The resulting diesel-soluble oligomer functions as a nonionic emulsifier. Controlled amounts of ethanol are subsequently incorporated into the emulsifier–diesel solution to form a stable microemulsion, referred to as E-Diesel. This study examines how the structure of the emulsifier influences key fuel properties, including (i) ethanol–diesel miscibility, (ii) gross calorific value, (iii) Ramsbottom carbon residue (% of fuel), (iv) entrapped polycyclic aromatic hydrocarbons (PAHs), and (v) fuel lubricity. Both the hydrophilic–hydrophobic balance and the structure of the emulsifier side chains are found to significantly affect these properties. Compared with neat diesel, oligomeric emulsifiers enable the substantial dispersion of ethanol in diesel (up to 18 wt.%). The resulting fuel exhibits a gross calorific value exceeding the theoretical sum of diesel and ethanol at the same composition (a synergistic effect) and achieves an enhancement in lubricity up to 49.5% relative to neat diesel at a 5% emulsifier loading. Although the presence of emulsifiers leads to an increase in the carbon residue by up to 54.7% compared to neat diesel during controlled pyrolysis, it simultaneously reduces the PAH content in the exhaust. Overall, this study establishes fundamental correlations among microemulsion stability, combustion synergy, carbon residue formulation, and fuel lubricity, which are governed by the structure of the emulsifier. Full article

Organic field-effect transistors (OFETs) incorporating a triple insulating layer of polymethyl methacrylate (PMMA), silicon dioxide (SiO₂), and zinc oxide (ZnO) were successfully fabricated on glass and on flexible PET substrates. The insulating layers significantly enhanced device performance, with the OFETs achieving field-effect mobility (µ) values more than twice as high as those reported in the literature. Specifically, mobility values of ~6.75 cm²/V·s were recorded on glass, ~7.14 cm²/V·s on flexible substrates before bending, and ~6.88 cm²/V·s on flexible substrates after bending. Threshold voltages (V_th) of −7 V and −9 V were estimated for the flexible OFETs before and after bending, respectively, along with a high on/off current ratio, exceeding 10³ for all devices. Minimal hysteresis in the transfer and output characteristics indicated excellent, trap-free interaction between the insulating layers and the pentacene. The high dielectric constant of the PMMA/SiO₂/ZnO triple insulating layers was identified as a critical factor driving the exceptional performance, stability, and low hysteresis of the OFETs. These results underscore the pivotal role of advanced insulating layers in optimizing OFET performance and durability. Full article

Semiconductor quantum dots (QDs) are attractive materials for light-emitting devices, and the photoluminescence (PL) from QDs can be enhanced near a metal surface due to surface plasmon (SP) resonance. To integrate QDs into metal structures, QD/poly(methyl methacrylate) (PMMA) composite thin films are generally used. However, it has been reported that QDs tend to aggregate in the PMMA matrix. In this study, we fabricated two types of QD/polymer composite thin films with different degrees of QD aggregation by additionally using poly(methyl methacrylate-co-methacrylic acid) (PMMA-co-MA), which is known to prevent QD aggregation. Furthermore, these two types of films were fabricated on Ag films, with the distance between the Ag films and the QDs controlled by Al₂O₃ spacer layers, and the PL enhancement was compared between the two film types. Finally, we reveal that QD aggregation in the polymer matrix significantly affects the PL enhancement. Although the aggregation trends differed between PMMA and PMMA-co-MA, the results suggest a possible increase in the internal quantum efficiency (IQE) in both film types. Full article

The plugging of fractured gas reservoirs with severe lost circulation during oil and gas drilling and production has long been challenged by technical issues such as low plugging strength and short effective duration. This paper reports the preparation of a high-strength supramolecular gel plugging agent via micellar copolymerization based on the synergistic effects of hydrophobic association and hydrogen bonding. Systematic optimization determined the optimal synthesis formula: acrylamide (AM) 12%, 2-acrylamido-2-methylpropanesulfonic acid (AMPS) 2%, stearyl methacrylate (SMA) 0.4%, sodium dodecyl sulfate (SDS) 1.5%, and potassium persulfate 0.3%, with a reaction temperature of 60 °C. Performance evaluations revealed that the gel possesses a controllable gelation time (120 min) and excellent viscoelastic recovery properties. At a compressive strain of 87%, the compressive stress reached 1.43 MPa while maintaining structural integrity. Swelling behavior analysis indicated that the gel follows a non-Fickian diffusion mechanism, with its swelling process governed by the synergistic interplay of water molecule diffusion and polymer network relaxation. Core plugging experiments demonstrated that the gel achieved plugging efficiencies exceeding 95% for cores with permeabilities ranging from 0.18 to 0.90 μm², with a maximum breakthrough pressure gradient of up to 11.48 MPa/m. These results highlight the gel’s efficient and broad-spectrum plugging capability for fractured lost circulation zones. This preliminary study provides experimental foundations for the material design and performance optimization of supramolecular gel-based long-lasting plugging agents for severe lost circulation gas reservoirs, and further field-scale validation is required for engineering application. Full article