Search Results (473)

In this study, two epoxy-functional polysiloxanes were synthesized and applied for cotton hydrophobization using two modification routes: direct reactive deposition and thiol-crosslinking on the fiber surface. PS1 contained epoxy groups, whereas PS2 contained both epoxy groups and alkyl chains. The modified fabrics were characterized by add-on measurements, FT-IR spectroscopy, SEM-EDS, SEM imaging, washing tests, and static water contact angle measurements. Both modification strategies enabled the formation of polysiloxane-based layers on cotton, as confirmed by the presence of silicon in all modified samples and sulfur in thiol-crosslinked samples. SEM images showed continuous and relatively uniform coatings without visible fiber damage. All modified fabrics became hydrophobic and retained their properties after washing. Thiol-crosslinking was more effective than direct reactive deposition, giving WCA values up to 144°. PS1 provided stable hydrophobicity regardless of thiol type or concentration, while PS2 benefited from higher modifier concentration and the use of tetrafunctional thiol. The results show that epoxy-functional polysiloxanes, especially when crosslinked with multifunctional thiols, are effective modifiers for producing washable hydrophobic cotton fabrics. Full article

Epoxy/dicyandiamide adhesive film is required for the bonding of polymethyl methacrylate (PMMA) aircraft cockpit edges. An imidazole/alkanolamine composite accelerator was developed to satisfy the requirement of maintaining a bonding temperature below 90 °C for this structure, successfully reducing the curing temperature of the adhesive film from 180 °C to 85 °C. The curing process of the low-temperature curing adhesive film and its hydrothermal aging resistance after curing were investigated using mechanical testing, Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). The results indicate that the curing process of 85 °C for 6 h enables the adhesive film to fulfill the adhesion strength requirements for aircraft cockpit edge applications. The cured adhesive film is found to exhibit limited intrinsic water resistance due to its low crosslinking density. Therefore, external edge sealing is required in practical engineering applications to isolate moisture. This work provides an application-specific one-component epoxy/dicyandiamide adhesive film for the low-temperature flexible bonding of aviation PMMA cockpit edges to PETR, and clarifies its adhesion performance and hydrothermal aging behavior under the target service scenario. Full article

Marine deck coatings suffer from premature failures such as wear thinning, flaking, and brittle cracking under repeated rolling, abrupt stopping/steering, and high shear loads of heavy equipment due to the imbalance of hardness, strength, toughness, and wear resistance. To address this issue, a rolling load-resistant coating system with an epoxy–amine/epoxy–thiol dual-crosslinked network was constructed using liquid polysulfide rubber (Lp-3) as the key crosslinking modifier, and the effect of Lp-3 content (0–2 wt%) on the comprehensive performance of the coating was systematically investigated. The results showed that the coating achieved the optimal synergy of properties at 1 wt% Lp-3 loading: Shore hardness reached 88.7 HD with the pencil hardness maintained at 8H, adhesion strength increased to 7.2 MPa, Taber abrasion loss significantly decreased to 14.8 mg, tensile strength rose from 5.5 MPa to 12.4 MPa, elongation at break nearly doubled, shear strength reached 10.2 MPa, and the failure mode transformed from brittle cleavage to ductile shear. Mechanistic analysis revealed that the terminal thiol groups of Lp-3 underwent a click reaction with epoxy groups, covalently embedding flexible polysulfide segments into the rigid epoxy network and forming Fe–S interfacial chemical bonds to enhance adhesion. The microphase separation, chain relaxation, and energy dissipation mechanisms effectively blunted crack propagation and alleviated stress concentration, while maintaining sufficient surface hardness and the continuity of the load-bearing skeleton. This work realizes the synergistic optimization of high strength, high toughness, strong adhesion, and excellent wear resistance for marine deck coatings and provides a new strategy and critical technical parameters for the design of functional coatings under heavy-duty dynamic service environments. Full article

Poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer electrolytes suffer from low ionic strength and poor mechanical performance. Meanwhile, lithium lanthanum titanate (LLTO) fillers exhibit severe agglomeration and weak interfacial compatibility with the polymer matrix. To solve these problems, 3-glycidoxypropyltrimethoxysilane (KH560) at four different concentrations (1 wt%, 2 wt%, 3 wt%, 4 wt%) was loaded onto polydopamine-modified LLTO (PDA@LLTO). The modified materials were mixed with PVDF-HFP, and composite solid electrolytes were fabricated by the solution casting method. The epoxy groups in KH560 undergo ring-opening reactions with amino and hydroxyl moieties on PDA, while its trimethoxysilane groups crosslink with the polymer matrix, forming a robust “LLTO-PDA-KH560-polymer” interfacial structure. This dual modification markedly improves the dispersion of PDA@LLTO, strengthens interfacial adhesion, and enhances the mechanical and electrochemical properties of the composite electrolyte. All KH560 loadings suppress LLTO agglomeration, and the 3 wt% grafting ratio yields the optimal performance: a uniform and dense microstructure, a room-temperature ionic conductivity of 5.92 × 10⁻⁴ S cm⁻¹, an electrochemical stability window extended to 4.88 V, and a tensile strength over 50% higher than the ungrafted sample. The modified electrolyte effectively inhibits lithium dendrite growth and enhances the cycling stability of solid-state batteries. This work demonstrates that KH560-PDA synergistic modification enables comprehensive performance optimization of composite electrolytes, offering a viable strategy for designing high-performance electrolytes for solid-state lithium-metal batteries. Full article

End-of-life thermoset composite coatings removed from fuel storage infrastructure represent a difficult waste stream because they combine a cross-linked polymer matrix, glass fibre reinforcement, functional layers and possible contamination from long-term contact with petroleum products. This study presents a preliminary assessment of an epoxy-glass laminate removed from the internal surface of a large vertical diesel fuel storage tank. The work combined a simplified numerical analysis of the technical role of the coating with thermogravimetric analysis and microscopic examination of solid residues after thermal conversion. The numerical results confirmed that the coating had a real reinforcing function, reducing the maximum equivalent stress in the corroded steel shell from 228.80 MPa to 191.85 MPa. TG/DTG analysis showed that the main mass loss of the laminate occurred below 500–600 °C, while the residual mass depended strongly on the process atmosphere. The highest residue was obtained after pyrolysis (28.75%), followed by CO₂-assisted conversion (26.17%) and combustion (20.87%). Microscopic observations showed that pyrolysis favoured morphological preservation of the fibrous/mineral fraction, but the glass fibres remained partly associated with carbonised epoxy resin and graphite-containing particles. Combustion removed the organic fraction more completely, but the remaining fibres showed signs of degradation. The results indicate that pyrolysis should be treated as a promising preliminary pretreatment route when morphological preservation of the fibrous/mineral fraction is prioritised, although the retained mechanical performance and phase composition of the fibres were not assessed. The study should be regarded as a thermogravimetric and microscopic screening of a real post-service epoxy-glass coating, supporting preliminary selection of end-of-life management pathways rather than a complete recycling or environmental assessment. By linking the thermal behaviour of a real post-service composite coating with feasible end-of-life pathways, the study contributes to sustainable waste management by supporting more informed decisions on material preservation, energy recovery, industrial co-processing and avoidance of landfilling for difficult thermoset composite wastes. Full article

Epoxy resin (EP) exhibits pronounced intrinsic brittleness arising from the highly crosslinked network formed after curing, thereby restricting its application in load-bearing structures. Although TiO₂ nanoparticles possess the potential for impact-strength improvement, they are highly prone to aggregation, which compromises stress-transfer efficiency within the composite. To overcome this challenge, a ball-milling strategy is adopted to anchor TiO₂ nanoparticles onto three-dimensional graphene oxide (3DGO), leading to the successful fabrication of a 3DGO@TiO₂ hybrid filler. At an ultralow loading of 0.03 wt%, the 3DGO@TiO₂ epoxy resin composite shows a 221.5% increase in impact strength to 19.55 kJ/m² and 33.53% and 32.34% increases in tensile and flexural strength to 64.32 MPa and 96.17 MPa, respectively, relative to neat EP. Morphological analyses indicate that the 3DGO spatial confinement reduces TiO₂ aggregate characteristic length by 55.1% from 1123 nm to 504 nm. Molecular dynamics simulations show that the hybrid filler decreases fractional free volume to 17.6%, induces denser matrix packing, and increases the calculated physical interfacial energy to 1023 kcal/mol, which is 2.2 times that of the pure TiO₂ epoxy resin system. This work confirms that 3DGO simultaneously optimizes nanofiller dispersion and physical confinement, offering a novel strategy for high-performance epoxy composites at ultralow loadings. Full article

Bisphenol A type epoxy resin has the problem of relatively high brittleness after curing. Although traditional polysiloxane toughening methods can improve toughness, they often come at the expense of strength. In this paper, methylphenyl dimethoxysilane (MPS) was used as a monomer to synthesize end-hydroxyl poly(methylphenyl)siloxane (PMPS), which was then used to modify E51 epoxy resin. The structure and reaction degree were characterized by infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry and viscosity tests. The mechanical test results show that when the PMPS content is 20 wt%, the tensile, flexural, compressive and impact strengths of the modified resin increase by 31.26%, 26.16%, 18.53% and 98.66%, respectively, compared with the unmodified resin, and the tensile and flexural elastic moduli increase by 38.36% and 32.25%, respectively. The fracture toughness increases by 60.29%, indicating that the strength, stiffness and toughness of the material have all been improved. Dynamic mechanical analysis shows that the glass transition temperature and crosslinking density of the system gradually decrease with increasing PMPS content. Thermogravimetric analysis shows that the introduction of PMPS increases the char yield and decreases the maximum thermal decomposition rate, thereby enhancing the thermal stability of the system. Microscopic morphology analysis by optical microscopy, scanning electron microscopy and atomic force microscopy shows that the system has good compatibility, and the internal different modulus phases are distributed in a network-like manner, forming a uniform co-continuous or bicontinuous phase structure. This structure effectively promotes stress transfer and energy dissipation, alleviates local stress concentration, and thus comprehensively improves the mechanical properties of the resin system. Full article

Ambient-temperature asphalt binders have emerged as a sustainable alternative to traditional hot-mix asphalt, offering significant advantages in energy conservation and emission reduction. This review systematically examines the research progress and development trends of high-performance reactive asphalt binders designed for ambient-temperature application, which achieve enhanced performance through chemical cross-linking reactions. The study focuses on three core material systems: epoxy resin, waterborne epoxy emulsified asphalt, and polyurethane. For each system, we comprehensively summarize the material composition, strength formation mechanisms, and mix design methodologies. Key evaluation methods for critical pavement performance—including strength characteristics, water stability, and high-temperature performance—are critically reviewed. Furthermore, microscopic characterization techniques including scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) are discussed to elucidate the underlying mechanisms governing performance evolution. Analysis reveals that epoxy-based binders exhibit superior strength and stiffness, rendering them suitable for heavy-traffic pavements; waterborne epoxy emulsified asphalt binders combine environmental compatibility with construction convenience for thin-layer rehabilitation, while polyurethane-based binders demonstrate exceptional elasticity and rapid curing characteristics for quick-traffic-opening scenarios. Although current research has established a preliminary performance evaluation framework, the absence of unified technical standards constrains widespread engineering implementation. Future research priorities should focus on developing water-triggered curing systems, intelligent responsive materials, and comprehensive standardization systems to fully harness the engineering potential of these sustainable binders. Full article

Polymer electrolyte membranes serving in proton exchange membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs) must possess sufficient mechanical–dimensional stability and excellent proton conducting capacity. Derived from the successful syntheses of two different sulfonated poly(aryl ether ketone)s bearing functional amine groups, two series of novel epoxy-crosslinked and silane-crosslinked sulfonated poly(aryl ether ketone) electrolyte networks are constructed for highly conductive and mechanically stable proton exchange membranes. The designed multi-component architecture, which integrates a moderate-ion-exchange-capacity sulfonated poly(aryl ether ketone) (moderate-IEC SPAEK), a high-IEC SPAEK, and a tailored crosslinker (epoxy or silane), enables a breakthrough in decoupling the traditional trade-off between conductivity and stability. The resulting membranes exhibit an outstanding combination of properties: exceptional proton conductivity exceeding 0.18 S cm⁻¹ at 100 °C, tensile strength above 28.80 MPa, and enhanced chemical resistance, thermo-oxidative stability, and competitive direct methanol fuel cell performance. This work establishes a rational design strategy for crosslinked multi-component membranes as a promising platform for next-generation high-performance fuel cells. Full article

Developing circularly polarized phosphorescence (CPP) materials integrating long-afterglow room-temperature phosphorescence (RTP) and chiral optical properties is highly attractive but challenging. Herein, we report a facile and efficient strategy to achieve enhanced CPP by doping chiral naphthyl phosphoric acid derivatives (BNP-CZ, BNP-DPA, BNP-TPA) into a thermally cured Bisphenol A Epoxy Resin (DGEBA) matrix crosslinked with 1,8-diaminooctane (DAO). The rigid crosslinked network effectively suppresses nonradiative transitions and stabilizes triplet excitons, affording a long phosphorescence lifetime of up to 973 ms and a high photoluminescence quantum yield of 26.55%. Significantly, the BNP-CZ@DAO exhibits remarkably boosted CPP signals and realizes the switch from circularly polarized fluorescence (CPF) in solution to CPP in the thermally cured resin film. Benefiting from the long afterglow and chiral optical properties, these polymers are successfully applied in multi-dimensional anticounterfeiting with high security. This work provides a universal and scalable approach for developing high-performance CPP materials. Full article

The cross-linked network structure of epoxy resins gives them excellent mechanical properties and heat resistance. However, it also makes them difficult to reprocess and recycle. This leads to environmental pollution and resource waste. Dynamic covalent bonds can make epoxy resins reprocessable. However, this involves a hard trade-off: adding flexible segments improves processing stability at the cost of mechanical strength, whereas keeping a rigid backbone retains the initial strength but leads to incomplete network reformation after multiple reprocessing cycles. As a result, performance continues to decrease. To solve this problem, this paper proposes a new strategy. It combines rigid cross-linked networks with alkyl dangling chains. The strategy does not sacrifice the rigid backbone of the epoxy. Instead, the alkyl dangling chains form physical entanglements during reprocessing. These entanglements compensate for the loss of chemical cross-linking density. Thus, the mechanical properties are retained or even enhanced. A vanillin-based Schiff base epoxy system was used. Alkyl dangling chains of different lengths were compared, and the results show that the system with longer alkyl dangling chains had higher mechanical properties after three reprocessing cycles; its tensile toughness increased by 85.7% compared to the system without dangling chains. At the same time, its thermal stability and glass transition temperature remained almost unchanged. This strategy effectively solves the conflict between strength and processing stability in reprocessable epoxy resins, as well as providing a new idea for designing green, high-performance, and closed-loop recyclable epoxy materials. 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

To qualify epoxy resin systems for use in superconducting magnets of future particle accelerators up to peak doses beyond 100 MGy, the effects of the irradiation source, the irradiation environment and the irradiation temperature have been assessed. Identical epoxy resin samples have been irradiated with ⁶⁰Co gamma rays, 24 GeV/c protons and by mixed neutron/gamma radiation in a reactor and at a spallation source up to a dose of 170 MGy. Irradiation-induced cross-linking and chain scission have been monitored by Dynamical Mechanical Analysis (DMA). When irradiations are performed with the same dose rate and in the same environment, the different radiation sources have a similar efficiency to produce radiation damage, and the total absorbed dose is a good scaling factor to compare irradiation effects in polymers. To distinguish between the influence of the irradiation temperature and of environmental oxygen, proton irradiations have been carried out in ambient air, inert gas at ambient temperature and in liquid helium. Compared to ambient air irradiation, in inert atmosphere more cross-linking is observed. Cross-linking rates are strongly reduced at 4.2 K. For some polymers the irradiation temperature has a strong influence on the chain scission rate. The most-radiation-hard epoxy resin systems maintain substantial mechanical strength up to doses beyond 100 MGy. Full article

Superhydrophobic coatings are regarded as a promising passive anti-icing strategy; however, their practical engineering application, particularly in electrical insulation, is severely hindered by the performance deterioration caused by mechanical damage and a lack of theoretical understanding of microscopic ice adhesion mechanisms. In this study, a layered polymer composite coating was designed to resolve the trade-off between abrasion resistance and low ice adhesion. The chemistry of the coating relies on a synergistic “primer–topcoat” design: the primer consists of an epoxy resin matrix chemically modified by amino silicone oil to lower its surface energy and improve toughness, while the topcoat features hierarchical SiO₂ clusters functionalized with hexamethyldisilazane (HMDS) and silane coupling agents. This architecture was fabricated via a controllable layer-by-layer spraying method. Systematic investigations revealed that the hierarchical micro/nanostructure, composed of microscale protrusions and nanoscale SiO₂ clusters, provides excellent superhydrophobicity (contact angle of 155.2°, sliding angle of 2°). Crucially, the crosslinked polymer network and stable siloxane (Si-O-Si) covalent bonding ensure that the coating maintains its functionality after a cumulative sand impact of 3 kg, demonstrating superior mechanical durability. Furthermore, differentiated theoretical models for ice adhesion in Cassie–Baxter and Wenzel states were established based on intermolecular interactions, identifying that maintaining a stable Cassie–Baxter state is key to reducing adhesion. This study offers a robust approach to balancing functionality and durability in polymer composites through synergistic structural design, providing both a scalable fabrication strategy and a quantitative theoretical framework for understanding interfacial ice adhesion. Full article

Eucommia ulmoides gum (EUG), a sustainable plant-derived natural polymer, was functionalized via three distinct routes, including vulcanization, epoxidation, and hydroxylation to yield vulcanized (VEUG), epoxidized (EEUG), and hydroxylated EUG (HEUG), respectively. We systematically characterized the effects of modification route and degree on the chemical structure, crystallization behavior, thermal stability, hydrophilicity, and mechanical properties of functionalized EUG and further evaluated the high/low-temperature performance, microstructure, and mechanical properties of the corresponding modified asphalt binders (VEMA, EEMA, HEMA) as a function of modifier type and loading. For VEUG, C-S cross-linking networks formed during vulcanization suppress EUG crystallization, enabling a rigid-plastic to elastic transition, while high-temperature cleavage of C-S bonds reduces its initial thermal stability. For EEUG, epoxidation breaks C=C double bonds and introduces epoxy groups to strengthen intermolecular interactions; subsequent ring-opening grafting of hydroxyl groups onto EEUG yields HEUG, which forms additional cross-links via dynamic hydrogen bonds. Increasing modification degree for both EEUG and HEUG reduces their number- and weight-average molecular weights with narrower distribution, diminishes crystallinity, enhances thermal stability and hydrophilicity, and drives a rigid-plastic to elastic transition, characterized by decreased strength (0.65 MPa < σ_HEUG < σ_EEUG < 10.18 MPa) and markedly improved ductility (143.6% < ε_EEUG < 262.0%, 679.9% < ε_HEUG < 1360.3%). In asphalt binders, VEUG’s cross-linked network endows VEMA with refined more abundant bee-like microstructures, drastically boosting high- and low-temperature performance: relative to pristine EUG-modified asphalt (EUGMA), VEMA’s DMT modulus decreases by 94%, and adhesion increases by 87%. EEMA forms covalent bonds with polar asphalt components via epoxy groups, while HEMA constructs a hydrogen-bonded cross-linked network; both effectively inhibit asphaltene aggregation. With increasing modifier loading, EEMA and HEMA exhibit increased modulus, reduced adhesion, and gradually improved high- and low-temperature performance, except for the non-significant high-temperature enhancement of HEMA at higher loadings. Full article