Search Results (639)

A high-temperature-resistant plugging–inhibitor (DS) was synthesized via emulsion polymerization using styrene (St), butyl acrylate (BA), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), and N-vinylformamide (NVF), with divinylbenzene (DVB) as crosslinker and ammonium persulfate (APS) as the initiator. The structure and properties were characterized by FTIR, TG, SEM, and contact angle analysis. Plugging and inhibition performances were evaluated through filtration, high-temperature high-pressure (HTHP) plugging, linear swelling, and shale recovery tests. DS exhibits spherical morphology with particle sizes of 50–100 nm and a decomposition temperature of ~297 °C, indicating good thermal stability. The addition of DS significantly reduces filtration loss; at 1.5 wt%, the API filtration loss decreases to 6 mL. Under 180 °C conditions, 1 wt% DS reduces HTHP filtration loss from 12 to 6 mL, demonstrating excellent high-temperature plugging performance. DS also effectively suppresses shale hydration, with linear swelling reduced to 1.48 mm and shale recovery increased to 64.68% at 3 wt%. These results indicate that DS possesses excellent thermal stability, plugging efficiency, and inhibition performance, offering a promising solution for wellbore stability in shale gas drilling. Full article

With the continuous growth in global energy consumption and the increase in the proportion of energy use attributed to buildings, the development of highly efficient and energy-saving building materials has become necessary for reducing energy demands and greenhouse gas emissions. Phase change materials (PCMs) exhibit great potential for enhancing the thermal inertia of buildings owing to their ability to efficiently absorb and release latent heat during phase transitions. In this study n-hexadecane@ polymethyl methacrylate (16-MMWS-K) microcapsules (where “@” denotes the core-shell encapsulation structure) with a crosslinked structure were successfully prepared via emulsion polymerization, using n-hexadecane as the core material and polymethyl methacrylate as the shell. The prepared microcapsules were incorporated into a cement matrix to fabricate a phase-change energy-storage composite material. The morphology, structure, and thermal properties of the microcapsules, as well as their effects on the thermal and mechanical performance of the cement composites, were systematically investigated. The prepared 16-MMWS-K microcapsules exhibited a well-defined core–shell structure, excellent thermal stability, and a suitable phase-change temperature. Increasing the microcapsule content significantly enhanced the thermal energy storage capacity of the cement composites, reduced thermal conductivity, improved hydrophobicity, and demonstrated effective temperature regulation in building simulation experiments. This study provides both theoretical insight and experimental evidence supporting the practical application of 16-MMWS-K microcapsules in cement composites. The 28-day compressive strength (51.7 MPa) remains acceptable despite higher porosity and slight strength reduction. Full article

Maintaining wellbore stability in deep and ultra-deep formations demands plugging agents capable of sealing nano- to micro-scale pores under high-temperature conditions. A core–shell nano-plugging agent (CSP) was synthesized via emulsion polymerization using KH-570-modified nano-SiO₂ as the rigid core and a poly(styrene-co-butyl acrylate-co-methyl methacrylate) terpolymer as the deformable shell. CSP particles had a mean diameter of 196.5 nm (polydispersity index, PDI = 0.183) and an onset decomposition temperature of 342 °C. Compatibility tests at 180 °C confirmed that 3 wt% CSP caused no adverse changes in the rheology or emulsion stability of the oil-based drilling fluid (OBM). At 180 °C, CSP reduced the high-temperature high-pressure (HTHP) filtrate loss by 64.4% and the permeability plugging apparatus (PPA) filtrate loss by 66.1%. Sand-disk tests elevated the breakthrough pressure from 1.5 to 9.2 MPa. Core displacement on sandstone cores achieved a plugging rate of 98.30%, and pressure transmission tests on natural shale cores extended the 50% equalization time by 7.8-fold. Comparative evaluation confirmed that the core–shell architecture consistently outperformed nano-SiO₂ alone, polymer alone, and their physical blend. Low-temperature N₂ adsorption provided direct evidence of pore sealing, with the treated-shale Brunauer–Emmett–Teller (BET) surface area and total pore volume reduced by about 62% (12.6 to 4.8 m²/g and 0.0325 to 0.0121 cm³/g, respectively). Scanning electron microscopy of the shale surface before and after treatment further provided direct visual evidence of pore sealing, showing the open, porous matrix being converted into a dense, compacted filter cake. Filter-cake thickness measurements are consistent with a proposed three-stage plugging mechanism—bridging, deformation filling, and thermal compaction—driven by the complementary roles of the rigid core and the deformable shell. These findings indicate that CSP merits further evaluation as a high-temperature plugging agent for wellbore stabilization in deep shale formations. Full article

Traditional research was mostly focused on the effects of emulsions on the mechanical properties and durability of cement mortar, while studies on the regulation mechanism of emulsions on the rheological properties of cement-based materials and the coupling mechanism with the hydration process were rarely conducted. In this paper, a novel core–shell structured emulsion was prepared by free radical polymerization. The regulation of cement mortar yield stress, creep recovery, dynamic viscosity, and thixotropy by different dosages (0–10%) of the emulsion admixture was systematically investigated, and combined with characterization by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR), the microscopic action mechanism of the emulsion was elucidated. It was demonstrated that the Bingham fluid behavior of cement mortar was not altered by the core–shell emulsion, whereas a significant dosage-dependent regulatory effect on its rheological parameters was observed, and a critical regulation interval of 4–6% was identified. At an emulsion dosage of 10%, the yield stress of the mortar was increased by 937.0% compared to that of the control group. At dosages of 2–4%, the static structural stability and construction flowability of the mortar were synergistically optimized, and the weakest thixotropy and the best structural stability were exhibited at an emulsion dosage of 4%. A more pronounced shear-thinning behavior was shown by all modified mortars, and their high-shear flowability was not affected. Microstructural analysis confirmed that no chemical reaction occurred between the emulsion and the cement hydration products. Through the triple effects of “hydration retardation by physical coating, pore filling and densification, and composite network enhancement”, a film was formed on the surface of cement particles by the emulsion, which hindered the diffusion of water and ions, thereby regulating the cement hydration process and microstructural evolution. Full article

Natural lacquer, a bio-based polymer derived from Toxicodendron vernicifluum, has attracted renewed scientific interest as a sustainable coating material with exceptional mechanical durability, chemical resistance, and aesthetic qualities. This review synthesizes current knowledge on the chemical composition, enzymatic curing mechanisms, and structure–property relationships of lacquer-based polymer systems, with particular focus on recent advances in functional modification and processing technology. Key findings indicate that laccase-catalyzed oxidative polymerization, operating optimally at pH 6.0–7.5 and 20–30 °C, governs the formation of a highly cross-linked urushiol network whose properties are fundamentally determined by side-chain unsaturation and emulsion stability. Mechanistic analysis reveals that polyurethane hybridization improves weathering resistance by introducing flexible aliphatic segments and additional hydrogen-bonding cross-links, while graphene oxide incorporation enhances anticorrosion performance through a physical barrier mechanism that prolongs ionic diffusion pathways. UV-curable LPEA derivatives achieve an 83% reduction in curing time relative to ambient-cured lacquer, enabling integration with industrial spray-coating lines. Despite these advances, several critical limitations remain inadequately resolved. Allergen reduction strategies have not yet achieved sufficient quantitative efficiency for large-scale commercial deployment, and the long-term stability of nanocomposite lacquer films under sustained UV exposure and hydrothermal conditions is not well established. Furthermore, most high-performance modification systems reported in the literature are demonstrated only on laboratory scale, with scalability, substrate compatibility, and lifecycle performance remaining largely unvalidated. The review identifies the absence of standardized performance evaluation protocols and the fragmentation of structure–property data across studies as key barriers to systematic progress, and proposes that future work prioritize the development of integrated processing–modification–performance frameworks to guide the rational design of next-generation lacquer-based functional materials. Full article

The demand for sustainable, high-performance biomaterials has driven intense research towards natural polysaccharide hydrogels. Accordingly, this study aimed to synthesize novel starch-based hydrogel materials, considering their inherent hydrogel-forming capabilities together with diverse potential applications (e.g., pharmaceuticals, medicine, and the cleaning application for the artifacts). To obtain hydrogels with enhanced mechanical and physico-chemical properties, starch was combined with other polymeric species (i.e., alginate, polyvinyl alcohol, and polyvinylpyrrolidone), and a gelling process was induced by using calcium cations or borate anions. Two distinct hydrogels (named S-Ca and S-SB, respectively) were prepared and characterized by a range of instrumental and experimental techniques. The assessed properties included water and solvent resistance, equilibrium water content, water-releasing capacity, morphology and microstructural features with their composition by SEM-EDS analysis, and mechanical properties (tensile strength, elasticity, Young’s modulus, and hardness). The results indicated that the investigated hydrogels exhibited suitable properties for a variety of applications, including surface cleaning processes in the field of cultural heritage conservation. For instance, they showed equilibrium water content (between 80 and 90%) comparable with other hydrogels commonly used as cleaning tools (e.g., agar and p(HEMA)/PVP) and quite low water-releasing capacity (between 10 and 17 mgcm⁻²). Moreover, the S-SB hydrogel displayed distinctly better tensile strength and elongation at break than hydrogel prepared in the presence of Ca²⁺ (S-Ca). Notably, S-SB experienced considerable elasticity improvement after freezing–thawing cycles, as indicated by a decrease in tensile strength (from 275 to 102 kPa) and an increase in elongation at break (from 121 to 275%). However, it should be noted that the hydrogel selection depends on the requirements of the target application, as different processes demand materials with distinct characteristics. Hence, both S-Ca and S-SB hydrogels were tested as cleaning tools for the removal of artificially aged acrylic coating (i.e., Paraloid B-72) from the surface of marble and wood specimens, respectively. The tests provided positive results, as aged coating was satisfactorily removed by applying the hydrogels loaded with a nanostructured emulsion (NSE). These novel starch-based hydrogels demonstrate significant potential as high-performance alternatives to conventional hydrogel systems currently used in conservation science as well as in other industrial applications. Full article

SiO_x anodes are highly promising for next-generation lithium-ion batteries due to their superior theoretical capacity. However, issues such as drastic volume expansion and low initial Coulombic efficiency (ICE) impede their practical use. While macroporous architectures can mitigate these challenges, traditional fabrication often depends on tedious hard templating methods and significant organic solvent consumption. In this work, we report a sustainable, emulsion-self-templated and organic solvent-free strategy to synthesize a carbon-coated 3D macroporous SiO_x/C composite (3DM-SiO_x/C@C). Our approach uniquely integrates radical polymerization with a water-in-oil emulsion and sol–gel process, followed by chemical vapor deposition (CVD). The 3D macroporous framework is generated via in-situ emulsion droplets acting as self-templates, effectively eliminating the need for external sacrificial templates and toxic etchants. Notably, this organic solvent-free process achieves an exceptional precursor to (precursor + organic solvent) mass ratio of 1.0, contrasting sharply with conventional methods (0.0044–0.17). The resulting hierarchical structure, characterized by interconnected macropores and a uniform carbon coating, significantly enhances structural integrity and electronic conductivity. Electrochemical evaluations reveal that 3DM-SiO_x/C@C exhibits an improved ICE of 74.32% and long-term cycling stability even at a high current density of 1.0 A g⁻¹ compared to non-porous and uncoated counterparts. This integrated synthesis offers a green and scalable pathway for developing high-performance silicon-based anodes for large-scale energy storage. Full article

High-energy insensitive energetic materials are currently a research focus. Octogen (HMX) is one of the best-performing nitramine explosives, but its poor crystal morphology causes high mechanical sensitivity, limiting its application. This study proposed a method combining spheroidization, nanosizing, and coating desensitization. Nano-SiO₂ and TiO₂ were used to modify methyl methacrylate (MMA), and HMX/PMMA composite energetic microspheres were successfully prepared with the assistance of an ultraviolet (UV) lamp for catalytic polymerization. Molecular dynamics simulations determined the optimal particle ratios, and the effects of modifier content on morphology, crystal form, thermal stability, mechanical properties, and static mechanical properties were experimentally investigated. The prepared HMX/PMMA/modifier microspheres exhibited uniform size, dense structure, excellent performance, and ideal coating. Thermal decomposition kinetics showed that the activation energy of HMX/PMMA/SiO₂ (0.75 wt% SiO₂) increased by 79.86 kJ/mol and 27.55 kJ/mol compared with raw HMX and HMX/PMMA, respectively. Its impact sensitivity was 3.6 times that of raw HMX, and its friction sensitivity was twice that of raw HMX. Static mechanical analysis revealed that the compressive strength of HMX/PMMA/SiO₂ (0.75 wt% SiO₂) and HMX/PMMA/TiO₂ (0.5 wt% TiO₂) microspheres increased by 7.3 MPa and 6.1 MPa, respectively, over HMX/PMMA, indicating significant improvement. Overall, HMX/PMMA/SiO₂ and HMX/PMMA/TiO₂ microspheres prepared by photoinitiated emulsion polymerization exhibited excellent thermal stability and mechanical properties. Full article

Lost circulation in oil-based drilling fluids (OBDFs) under high-temperature conditions remains a significant challenge in deep and ultra-deep drilling. In this study, a high-temperature-resistant composite lost circulation material (LCM) was developed based on a synergistic strategy combining rigid bridging–consolidation and flexible embedding–filling. Rigid self-consolidating particles were prepared by coating skeleton materials with modified thermosetting resin, while flexible oil-absorbing resin was synthesized via suspension polymerization. The materials exhibited excellent lipophilicity, thermal stability, and structural integrity at 150 °C, with oil absorption capacity up to 3.43 g/g. The optimized composite LCM showed superior plugging performance, achieving compressive strengths above 11 MPa in white oil and 5 MPa in base mud at 150 °C. Effective sealing of 1–3 mm pore structures was obtained with leakage volumes below 10 mL, and fractured formations could be successfully consolidated. Mechanistically, rigid particles provide structural bridging, flexible resin enables pore filling via swelling, and modified resin(thermosetting resin chemically modified to achieve self-consolidation) enhances consolidation and micro-pore sealing, resulting in a dense and high-strength plugging layer. This work provides a promising approach for designing high-performance LCMs for OBDFs in high-temperature drilling environments. Full article

Gel plugging agents are key drilling fluid additives for maintaining wellbore stability. However, the downhole ultra-high-temperature, high-salinity environments, and developed micro-fractures in deep and ultra-deep wells pose severe challenges to the performance of gel plugging agents. To address this problem, this paper presents the preparation of a nano-micron gel plugging agent with a core–shell structure, denoted as LMS, suitable for high-temperature and high-salinity water-based drilling fluids. LMS was synthesized via emulsion polymerization, using a styrene–sodium p-styrenesulfonate copolymer as the core and 2-acrylamido-2-methylpropanesulfonic acid and methacryloyloxyethyltrimethyl ammonium chloride as the shell-modifying monomers. LMS was characterized by infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and particle size analysis, confirming that LMS met the design expectations. Experimental results showed that after aging at 220 °C for 16 h under saturated-salt conditions, the filtration loss of the drilling fluid with 3 wt% LMS was 10.4 mL, a reduction of 57.4% compared to the base mud. Meanwhile, LMS exhibited good plugging performance in microporous membrane tests and sand bed tests. After aging at 220 °C for 16 h under saturated-salt conditions, the core plugging rate reached 95.4%. LMS can not only adsorb onto clay surfaces to increase the thickness of the hydration film, enhancing drilling fluid stability, but can also synergistically build a filter cake with clay particles to plug nano-micron pores, preventing drilling fluid infiltration into the formation. This paper provides a preparation method for a high-temperature- and high-salinity-resistant gel plugging agent with excellent plugging effects, which is expected to support safe and efficient drilling in deep and ultra-deep formations. Full article

Porous glycidyl methacrylate-based copolymers crosslinked with ethylene glycol dimethacrylate (EGDMA) and trimethylolpropane trimethacrylate (TMPTMA) were synthesized via suspension–emulsion polymerization and subsequently functionalized with triethylenetetramine. The effect of the monomer composition on the epoxy group content and porous structure was systematically investigated by varying the GMA-to-crosslinker molar ratio from 1:1 to 5:1. Increasing the GMA fraction enhanced the epoxy group content (2.8–5.0 mmol/g) but significantly reduced the specific surface area (333–23 m²/g), indicating a trade-off between functionality and porosity. ATR-FTIR and elemental analysis confirmed successful amine functionalization while preserving a considerable degree of porosity. The modified copolymers were evaluated for Cr(VI) removal, showing strong pH dependence, with maximum efficiency at pH 3 due to electrostatic interactions between protonated amine groups and HCrO₄⁻ ions. Equilibrium studies revealed saturation-type behavior, with a maximum sorption capacity of 165.47 mg/g for TMPTMA-based copolymers. Despite the higher nitrogen content in EGDMA-based materials, TMPTMA-crosslinked copolymers exhibited a superior adsorption performance, demonstrating that pore accessibility, rather than functional group density alone, governs adsorption efficiency. These findings provide insight into the rational design of amine-functionalized porous polymer sorbents for efficient chromium(VI) removal. Full article

Micro- and nano-container-based self-healing coatings have emerged as a promising strategy for the long-term conservation of cultural heritage artifacts, including metals, stone, organic matter, and construction materials. These coatings incorporate microcapsules or nanocapsules with tailored shell and core materials, enabling autonomous release of healing agents or corrosion inhibitors in response to damage. For metallic artifacts, benzotriazole@mesoporous silica nanoparticles (BTA@MSN) microcapsules achieve selective pH-responsive release, reaching 77% at pH 9.0 and 42% at pH 5.0, effectively mitigating localized corrosion. Temperature-adaptive poly(methyl methacrylate-co-methacrylic acid) (PMMA-MA)/MgO microcapsules exhibit controlled rupture rates, with a 75% reduction at elevated temperatures, enhancing crack repair efficiency by approximately 5%. Organic artifacts, such as wooden or paper manuscripts, benefit from clove oil nanocapsules, which increase tensile strength by 43.5% and fracture toughness by 101.9%, with only 2.91% weight loss over 7 days compared to 33.1% for unencapsulated oil. Advanced fabrication methods—including microfluidics, Pickering emulsions, and multi-core systems—enable high encapsulation efficiency (up to 73.5%), uniform particle size, and repeatable healing. Multi-stimuli responsiveness (pH, temperature, light, magnetic fields) and biobased, environmentally friendly materials further enhance adaptability and sustainability. In this review, “self-healing” is defined broadly to include both physical crack repair and autonomous restoration of protective functions. Overall, self-healing micro/nanocapsule coatings provide a highly controllable, efficient, and durable solution for active heritage protection, representing a shift from passive to intelligent conservation strategies. Furthermore, a systematic comparison of different capsule systems is provided to clarify their respective advantages and limitations. Overall, hybrid systems exhibit the most balanced performance, while inorganic nanocontainers offer superior stability and controlled release, and polymeric capsules enable rapid healing but limited reusability. Full article

Oil–water emulsions constitute essential components in a wide range of industries. Despite their extensive use in emulsion systems, synthetic emulsifiers are often associated with environmental concerns and high costs. In this study, lignin—a by-product of the pulping industry—was polymerized with acrylic acid and employed as an emulsifier in a xylene–water system to address this challenge. When testing two lignin–acrylic acid copolymers, the results confirmed that the one possessing a higher molecular weight (7.99 × 10⁵ g/mol) and charge density (4.7 mmol/g) (KL-AA-10) generated xylene–water emulsions with improved stability, and higher viscosity and viscoelastic moduli. These observations were consistent with the greater adsorption of this polymer, relative to the counterparts with a lower molecular weight and charge density at the xylene–water interface, as monitored using a Quartz Crystal Microbalance. The adsorption of KL-AA-10 resulted in the formation of smaller emulsion droplets (D50 = 0.6 µm) within the system, as evidenced by confocal microscopy analysis. This study underscores the potential of lignin as a renewable emulsifier for diverse applications. Full article

To address the trade-off between storage stability and curing reactivity in NCO-terminated waterborne polyurethane (WPU) systems, a solvent-free WPU emulsion with dual-curing characteristics was developed using vanillin (VAN) and 2-hydroxyethyl acrylate/pentaerythritol triacrylate (HEA/PETA). Hexamethylene diisocyanate (HDI) and 2,2-bis(hydroxymethyl)butyric acid (DMBA) were used as the isocyanate component and internal hydrophilic moiety, respectively, to prepare a self-dispersible polyurethane prepolymer. VAN was introduced as a latent isocyanate-related component, while HEA/PETA served as acrylate-bearing reactive modifiers, followed by self-emulsification to form a stable aqueous dispersion. The prepolymer structure, curing behavior, and adhesive performance on bamboo substrates were systematically investigated. The results supported the successful introduction of VAN-derived structures into the polyurethane chains and the retention of polymerizable C=C bonds from HEA/PETA. Thermal analysis suggested dual-curing behavior with two distinguishable thermal events, involving lower-temperature polymerization of unsaturated groups and a VAN-related higher-temperature reaction. The resulting WPU exhibited dry and wet shear strengths above 23 MPa and 9 MPa, respectively. These findings demonstrate a feasible strategy for integrating emulsion stability, staged curing, and adhesive performance in solvent-free WPU systems. Full article

An effective and facile emulsion polymerization method was developed for the preparation of highly antibacterial hydrogel. In this study, polyhexamethylene guanidine (PHMG) was successfully cross-linked with polyvinyl alcohol (PVA) to form hydrogel micropowders with exceptional antibacterial properties. Subsequently, to improve the mechanical properties of the hydrogel, the hydrogel micropowders cross-linked with the antibacterial agent were combined with epoxy resin and coated onto stainless steel plates to form composite coatings. FT-IR spectroscopy was used to analyze the composition of the samples, confirming the successful reaction between PVA and PHMG. Bacterial inhibition assays demonstrated that the product exhibited an inhibition rate exceeding 99.99% against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) when the PHMG content exceeded 2.0 wt%. The anti-protein adsorption and algae resistance tests confirm the good antifouling performance of the coatings. These results highlight the potential of this material for marine antifouling applications. Full article