Search Results (1,459)

High-temperature temporary sealing operations require liquid plug materials that can be placed as low-viscosity precursors, converted into mechanically stable networks under reservoir temperature, and subsequently removed after service. Existing epoxy-based sealing systems generally provide high post-curing strength, but the coordination among pumpability, thermally triggered curing, and post-service degradability remains insufficiently addressed. In this work, an epoxidized soybean oil (ESO)-modified epoxy–anhydride liquid plug was designed to regulate these sequential stages within a single material system. The precursor formulation, rheological transition, curing kinetics, mechanical response, network structure, and degradation behavior were evaluated using viscosity monitoring, curing-time tests, DSC, compression testing, DMA, gel fraction and swelling measurements, FTIR, and high-temperature degradation experiments. The optimized precursor exhibited an initial viscosity of 65.4 ± 2.1 mPa·s, remaining below the pumpability threshold of 100 mPa·s before curing. Its curing time was adjustable within 1–10 h at 120–140 °C through temperature and initiator regulation. ESO incorporation produced a non-monotonic mechanical response, with the optimized network reaching a compressive strength of 112.5 ± 3.5 MPa and an elastic modulus of 142.50 ± 5.26 MPa. FTIR and thermal–mechanical analyses supported the formation of an ester-rich epoxy–anhydride network containing both rigid epoxy-derived segments and ESO-derived flexible chains. In the post-service stage, degradation was strongly temperature dependent, with the characteristic unsealing time decreasing from 84 h at 120 °C to 24 h at 130 °C and 18 h at 140 °C. The combined results define a coupled curing–degradation window in which pumpable placement, thermal network formation, load-bearing sealing, and controlled unsealing are temporally separated but structurally connected. Full article

This study evaluated the effectiveness of maleic anhydride polypropylene (MAPP) in improving the mechanical performance and interfacial adhesion of lignocellulosic fiber-reinforced polypropylene (PP) composites. Based on Scanning Electron Microscopy (SEM) investigations, the relationship between fiber fraction, MAPP content, mechanical characteristics, and fracture morphology was the main focus. The test results showed that the stiffness and tensile strength of the composites increased with the addition of MAPP. The esterification reaction between the anhydride groups of MAPP and the hydroxyl groups of the fibers strengthened the interphase covalent bond, with the 46:50:4 composition producing the highest elastic modulus of 79.67 MPa and maximum tensile stress of 11.01 MPa. The dense interphase zone, few gaps, and no dominant fiber tension were all confirmed by SEM morphology, and also indicated effective stress transfer from the PP matrix to the fibers. However, the toughness of the material decreased significantly with increasing stiffness. Due to strong plastic deformation in the PP matrix that is not tightly attached to the fibers, the composition without MAPP (30:70:0) shows high impact energy and breaking strain, reaching 25.39 kJ/m² and 121.26%, respectively. The increase in chemical bonding at 4% MAPP content limits the mobility of the polymer chains, making it more brittle. In addition, even though MAPP is still present in the system, increasing the fiber fraction above 60% causes agglomeration, decreased homogeneity, and increased voids due to limited matrix wetting, ultimately deteriorating the mechanical properties. Tensile stress and elastic modulus have a very strong positive correlation (R² = 0.93), while impact energy and strain have a good correlation (R² = 0.89). The results overall showed that the ideal MAPP dosage is in the range of 4% before interface saturation occurs and confirmed that MAPP efficiency is determined by the balance between fiber composition, MAPP quantity, and dispersion homogeneity. Full article

Chronic wounds, particularly those complicated by infection, present significant challenges in clinical management. The microenvironment of these wounds is typically characterized by the accumulation of reactive oxygen species (ROS) and abnormal local pH levels, both of which impede the healing process. Baicalin (BA), a natural flavonoid, exhibits anti-inflammatory activity, ROS-scavenging capability, and pro-healing effects. In this study, hydrogels were synthesized through photoinitiated radical polymerization of methacrylic anhydride (MAA) and dopamine (DA)-modified chondroitin sulfate (ChSMA-DA), grafting degrees of MA and DA were 58%, 23%, MPDA@MnO₂ nanoparticles (NPs), and methacrylated gelatin (GelMA). The gelation time, microtopography, swelling behavior, and water retention of the hydrogels were investigated, along with their degradation, rheological properties, and photothermal effects. The results indicate that swelling ratio (SR) and water retention (WR) of optimal HG-MPDA@MnO₂-M sample were 5.7, 82.42%, exhibited responsive behavior upon weakly acidic environment with pH 6.5 and elevated ROS levels, and exhibited a stable photothermal effect (photothermal conversion efficiency was 22.7%) under 808 nm near-infrared (NIR) light. Following the incorporation of the drug model BA, the cumulative release percentage over 24 h under the combined stimulation of pH 6.5, 1 mmol·L⁻¹ H₂O₂, and 808 nm NIR was 81.1%, significantly higher than either factor alone. These hydrogels show promise as an injectable dressing for chronic wounds, effectively integrating the internal microenvironment of the wound tissue with external NIR to modulate drug release. Full article

This study investigated the optimization of the physicochemical properties of normal maize starch (NMS) by esterification with octenyl succinic anhydride (OSA). The synergistic effects of OSA addition time, temperature, and total reaction time on the degree of substitution (DS) and the physicochemical properties of starch were evaluated using a combination of single-factor experiments and Response Surface Methodology (RSM). FT-IR spectroscopy confirmed the successful incorporation of OSA groups into starch molecules, with the appearance of two characteristic absorption peaks at 1724 and 1572 cm⁻¹. Single-factor experiments revealed that a temperature of 40 °C, an OSA addition time of 2 h, and a total reaction time of 6 h effectively maximized the DS. These conditions balanced efficient esterification with the suppression of OSA hydrolysis and droplet aggregation. The resulting optimized OSA starch displayed lower gelatinization temperature and enthalpy, higher viscosity, more pronounced shear-thinning behavior, and greater resistance to retrogradation. Pearson correlation and simple linear regression analyses demonstrated that DS was negatively correlated with both ΔH and G′_max. The RSM model accurately predicted the optimal synthesis parameters (41.96 °C, 2.25 h OSA addition time, 6.9 h total reaction time), achieving a validated DS of 0.0258. This study provides valuable insights for producing starch-based additives in complex food systems. Full article

ASP flooding wastewater contains crude oil, suspended solids, anionic polymers and surfactants, with high viscosity, high zeta potential, difficult demulsification, flocculation and slow separation and sedimentation. In order to solve the problem of wastewater treatment of ASP flooding in oil fields, a magnetic branched core was prepared from ethyl silicate (TEOS), nano Fe₃O₄ and aminopropyl triethoxysilane (APTES), and then reacted with polyamine and methyl acrylate to synthesize the magnetic hyperbranched molecule FSNMN with demulsification ability. Using acrylamide (AM), acryloxyethyl trimethylammonium chloride (DAC) and maleic anhydride (MA) as raw materials, cationic polymer long chain (CAMHA) with flocculating properties was synthesized and grafted with hyperbranched molecules. The demulsification flocculation ability of the product regarding ASP flooding wastewater was evaluated, and the demulsification flocculation mechanism was summarized. The results showed that the average molecular weight of 3-FSNMN₄-C was 4.7 million, the cationic degree was 20.5%, and the saturation magnetization was 20 EMU/g. The removal rate of oil and suspended solids was 93.82% and 91.95% respectively when the simulated sewage was treated by magnetic field for 30 min. Magnetic hyperbranched star chain polymer provides a solution to the serious ecological environment problems caused by ASP flooding. Full article

Single-use polypropylene (PP) food containers represent a rapidly growing waste stream characterized by compositional heterogeneity and microstructural defects. Conventional reactive compatibilization using isotactic maleic anhydride-grafted PP (iPP-g-MA) provides rigid crystalline anchoring but lacks the interfacial flexibility to accommodate complex micro-defects. Herein, we propose a defect-tolerant compatibilization strategy by developing a binary iPP-g-MA/aPP-g-MA masterbatch for real post-consumer rPP derived from food-service containers. The amorphous aPP-g-MA component is proposed to provide a compliant interfacial environment that accommodates stress concentrations associated with microscale defects, whereas the iPP-g-MA component contributes crystalline anchoring with the recycled PP matrix. This soft/hard interfacial architecture is supported by grafting-degree analysis, GPC, XRD, DSC crystallization behavior, and SEM fracture morphology. The 1:1 mass-ratio binary formulation shows a marked improvement in elongation at break to 200%, representing a 203% increase relative to the single-component iMA system. The notched Charpy impact strength is enhanced to 8.98 kJ m⁻², while tensile strength is retained at 20.9 MPa within the typical strength–ductility trade-off of polymer toughening. TGA shows no premature degradation within the melt-processing window, indicating adequate thermal stability for melt reprocessing. This study provides a compositionally tunable, data-supported route for high-value upcycling of heterogeneous post-consumer polyolefins. From an application viewpoint, the improved ductility-impact balance makes the material relevant to injection-moulded semi-structural products such as storage crates, appliance housings, and automotive interior panels. Full article

Gelatin methacrylate (GelMA) hydrogels are promising carriers for bioactive agents like curcumin (Cur) and adenosine diphosphate (ADP) in wound healing. However, existing GelMA-based systems fail to achieve both rapid hemostasis and sustained anti-inflammatory effects. In this study, we developed a Cur/ADP GelMA hydrogel, and evaluated its anti-inflammatory, regenerative, hemostatic, and biocompatible properties. Proton nuclear magnetic resonance (¹H-NMR) analysis showed that a 65% degree of substitution of GelMA is optimal for wound dressings. Scanning electron microscopy revealed a uniform pore size, aiding inflammatory exudate removal. The Cur/ADP GelMA hydrogel exhibited strong adhesion, stability, and antibacterial activity, reducing E. coli and S. aureus proliferation by 85% and 72%, respectively. Hemostatic effects were observed, with blood loss reduced to 238 ± 23 mg compared to 559 ± 18 mg in the untreated group. The ELISA results showed reduced pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and increased IL-10. In vivo studies demonstrated 98% wound closure by day 14, enhanced granulation tissue formation, and a 70% thicker epidermis compared to controls. Mechanistically, ADP accelerates platelet activation and clot formation, while Cur modulates the inflammatory microenvironment, enabling synergistic hemostasis and immune regulation, thus promoting accelerated wound healing. Full article

A novel macromolecular photoinitiator (MPI) was synthesized from a copolymer of maleic anhydride and methyl methacrylate and subsequently functionalized with 3-hydroxy-2-methoxy-1,2-diphenylpropan-1-one moieties via a polymer-analogous acylation reaction. The structure and physicochemical properties of the MPI were characterized by IR, UV–Vis, NMR, DSC, and TGA analyses. TiO₂ nanoparticles were successfully functionalized with the MPI, yielding materials with enhanced surface activity and photoinitiating efficiency. The MPI-modified TiO₂ facilitated efficient UV-induced polymerization of methyl methacrylate, as confirmed by DLS and SEM analyses. Compared with unmodified fillers, the resulting composites exhibited improved dispersion, accelerated polymerization rates, and enhanced mechanical properties. This hybrid strategy offers a promising approach for the development of high-performance polymer nanocomposites through the integration of surface-engineered inorganic fillers and photoreactive polymers. Full article

Pour point depressants (PPDs) based on functionalized polyolefins were obtained and evaluated for their efficiency in pour point reducing of Kumkol waxy crude oil (Kazakhstan), which contains 15.2 wt.% paraffin and has a pour point of +17 °C. An ethylene–propylene copolymer (EPR-505A) was treated through grafting of maleic anhydride (MA-g-PO) and then converted into three different derivatives that had an identical polymer backbone: an ester-functionalized, an amide-functionalized, and a combined ester–amide additive. The obtained products were tested at 500 g/t through kinematic viscosity measurements, equilibrium and kinetic interfacial tension analysis, pour point determination, cooling curve analysis, and optical microscopy. The ester derivative reduced the pour point by 7 °C, the amide derivative did so by 5 °C, and the combined additive achieved a 10 °C pour point reduction and a more than twofold decrease in kinematic viscosity at 0 °C. Interfacial tension measurements and adsorption kinetics allowed us to assume that ester groups govern macromolecular solubility and diffusion mobility, while amide groups enhance adsorption affinity at paraffin crystal surfaces. Their combined action shifts crystallization from a collective to a dispersed regime. These findings establish structure–activity relationships between polar group architecture and PPD efficiency. Full article

Volatile organic compounds can aggravate the atmospheric pollution and health risks due to their high toxicity and photochemical reactivity. Herein, a series of cobalt aluminate spinel catalysts with high efficiency was fabricated via a cost-efficient solvothermal method. Plentiful oxygen vacancies with negative charge were introduced adjacent to the octahedrally coordinated Co³⁺ species in CoAl₂O₄ catalysts, thereby generating the synergetic Co³⁺-oxygen vacancy (Ov) sites, which facilitated the rapid activation and migration of oxygen species. Accordingly, the superior catalytic activity was observed for 1Al-1Co even with lower cobalt due to the presence of abundant Co³⁺-Ov sites, revealing the predominant roles of synergetic sites in the toluene oxidation. Moreover, the 1Al-1Co catalyst exhibited the optimal intrinsic catalytic performance with the lowest activation energy of 161.2 kJ·mol⁻¹ and the highest specific toluene reaction rate of 3.18 × 10⁻⁵ mmol·h⁻¹·m⁻². In situ DRIFTS results further verified that oxygen vacancies and active Co³⁺ species could synergistically boost highly reactive oxygen species, which rapidly oxidize benzoate into maleic anhydride, achieving the efficient complete oxidation of toluene. Full article

Tissue engineering represents a central strategy in regenerative medicine to restore damaged or missing tissue through structural and functional replacement. In this study, a two-component bioink platform was developed based on amine–anhydride conjugation as a mild crosslinking reaction between synthetic anhydride-containing oligomers (oSMoMA-x) and natural biopolymers. The compatibility of the oligomers with different amine-containing biopolymers, including chitosan, gelatin, and hydrolyzed collagen peptides, was systematically evaluated. To improve cytocompatibility and enable controlled network formation, oSMoMA oligomers with varying anhydride contents were synthesized and characterized, allowing targeted tuning of material properties through comonomer composition. The resulting hydrogels were comparatively assessed with respect to their rheological and physicochemical properties. While hydrogel formation was achieved with all investigated biopolymers, gelatin-based systems exhibited the most favorable characteristics for bioink development. Two gelatin/oSMoMA bioink formulations with distinct gelation behavior were obtained by employing different base catalysts, enabling control over crosslinking kinetics and material properties. Cytocompatibility was comprehensively evaluated using viability assays, demonstrating enhanced metabolic activity of cells encapsulated in gelatin/oSMoMA-3.5 hydrogels compared to established reference systems, with sustained compatibility for up to seven days. Extrusion-based 3D bioprinting was performed using a modified printhead with integrated temperature control to maintain physiological conditions. The bioinks were successfully printed with embedded murine 3T3 fibroblasts, and post-printing analyses confirmed cell proliferation within the hydrogel constructs. Overall, the results demonstrate the broad compatibility of amin–anhydride-crosslinked oSMoMA systems with different biopolymers and highlight gelatin/oSMoMA bioinks as promising cytocompatible materials for stable 3D bioprinting applications in tissue engineering. Full article

This study developed high-performance, biodegradable nanocomposites from polyvinyl alcohol (PVA) reinforced with nanocellulose derived from the invasive Nile rose plant (NR). Cellulose nanofibrils (CNFs) were successfully extracted using maleic anhydride treatment, yielding nanofibers with an average diameter of 20.81 nm and a high negative surface charge of −40.7 mV, indicating effective functionalization. The synergistic effect of incorporating 7.5% CNF and applying 50 kGy gamma irradiation dramatically enhanced the composite properties, resulting in a 64.01% improvement in tensile strength compared to neat PVA. The crosslinked network significantly increased hydrophobicity, with the water contact angle rising from 60.95° to 106.40°, and reduced moisture absorption. Optical characterization demonstrated excellent UV-shielding capabilities, maintaining a visible light transmittance of 66.6% at 800 nm, while thermal analysis confirmed enhanced stability against high-temperature degradation. These findings suggest that the developed nanocomposites are promising candidates for advanced protective packaging applications where UV shielding and moisture resistance are critical. Full article

The synthesis of hydroxamic acids from sterically hindered substrates, such as abietane-type resin acids, remains a synthetic challenge due to the congestion of the tricyclic skeleton. This study reports an efficient one-pot protocol for the direct conversion of abietic and dehydroabietic acids into their corresponding hydroxamic derivatives, achieving 65% and 74% isolated yields, respectively. Systematic screening of activating agents identified diethyl chlorophosphate (DCP) as the reagent for the hydroxyamidation. A critical finding of this work is that the optimization of the isolation process specifically minimizing the water amount during aqueous work-up was key to recovering these polar products and preventing important yield loss. The reaction proceeds through diethyl phosphate mixed anhydride intermediate, which was successfully isolated, providing direct experimental evidence of the activation pathway. The reaction mechanism was further elucidated using Density Functional Theory (DFT) calculations at the M062X/6-31G** level, identifying a concerted transition state for the simultaneous addition of hydroxylamine and expulsion of the phosphate group. Furthermore, the study rationalizes the observed chemoselectivity; although the ester is the more stable thermodynamic product, the formation of the N-hydroxy amide is kinetically favored through a substantially lower activation barrier. This combined experimental and theoretical approach establishes a practical and scalable methodology for the functionalization of abundant similar natural terpenoids. Full article

Thyroxine (T4) is a key hormone regulating metabolic, cardiovascular, and neurodevelopmental processes, yet its clinical quantification still relies on centralized immunoassays that limit rapid or point-of-care monitoring. Here, we present a label-free biosensing platform based on silicon nanowire field-effect transistors (SiNW-FETs) functionalized with a T4-selective DNA aptamer via a 3-Triethoxysilyl propylsuccinic Anhydride (TESPSA)-mediated silanization approach, enabling a streamlined two-step modification for oriented immobilization. The biosensor achieves robust real-time detection of T4 across the physiological concentration range (5–30 pM), with a limit of detection of ~5 pM and a strong linear correlation between drain current and analyte concentration (R² = 0.9931). Specificity is confirmed using non-functionalized devices and estradiol as a non-target control. All measurements were performed in undiluted phosphate-buffered saline, representing a physiologically relevant ionic environment and demonstrating stable sensor performance under realistic buffer conditions. The dose–response behavior follows a Hill model, allowing extraction of binding parameters and confirming that the electrical signal originates from specific aptamer–target interactions. These results demonstrate that aptamer-functionalized SiNW-FETs provide a highly sensitive, selective, and miniaturizable platform for quantitative thyroid hormone monitoring, with strong potential for future point-of-care applications. Full article

This study investigated the comparative effects of various maleic anhydride-grafted polymeric compatibilizers such as polyethylene-graft-maleic anhydride, polypropylene-graft-maleic anhydride, polyethylene(alt)-graft-maleic anhydride and poly(styrene-ethylene/butylene-styrene)-graft-maleic anhydride on the final properties of polypropylene (PP) carbon nanotube (CNT) composites. Polypropylene nanocomposites (PP-CNT) were prepared by melt mixing using a laboratory scale twin-screw extruder. The mechanical test results showed that the incorporation of CNTs along with various compatibilizers increased the tensile strength (10.3%) and tensile modulus (24.2%). The tensile modulus and yield stress of the PP-CNT nanocomposites were significantly higher than those of the pristine PP. Differential Scanning Calorimetry (DSC) analysis revealed that the addition of CNTs slightly increased the melting temperature of the crystallization peaks. In the compatibilized PP-CNT composites, the CNTs were well dispersed to enhance the onset of degradation and maximum decomposition temperatures. The frequency-dependent rheological behaviors of PP-CNT nanocomposites indicated that the storage modulus (G′), loss modulus (G″), and complex viscosity (η*) PP increased for the compatibilized system. The XRD results indicated that the addition of CNTs and compatibilizers slightly affected the crystalline nature of PP. Scanning electron microscopic images of the fractured surfaces presented in the micrographs showed the brittle nature of the surface morphology of PP-CNT nanocomposites. Full article