ABSTRACT Epoxy‐based materials are widely used in protective coatings and structural composites. However, the water absorption and interface performance degradation caused by long‐term exposure to humid environments still limit the stability of their service life. This paper proposes a dual‐scale interface control strategy for silicone rubber‐derived powder (SR‐Powder) and constructs an E‐44 epoxy composite surface with superhydrophobic and freezing‐delay properties. The incorporation of SR‐Powder enhanced the tensile strength of the representative epoxy composite formulation. A hierarchical surface structure was further constructed by imprint‐assisted deposition using a 200‐mesh sieve. The water contact angle of the obtained epoxy composites reached 159.9°, and the sliding angle and contact angle hysteresis decreased to 3.9° and 3.8°, respectively. At −15°C, the freezing delay time of this surface reached 359.0 s, which was 372.4% higher than that of pure epoxy. Molecular dynamics simulations indicate that SR‐Powder weakens the interaction between water molecules and the epoxy interface, reduces the diffusion ability of interface water molecules, and provides a molecular‐scale basis for the low adhesion and water‐repellent mechanism of the composite surface. This study provides a pathway for the functional utilization of silicone rubber‐derived powder and the design of high‐performance water‐repellent epoxy materials.
ABSTRACT Low‐viscosity epoxy grout (LER) is susceptible to interference from frontal water during application, but the quantitative relationship between LER curing and frontal‐water conditions remains unclear. This study introduces the frontal water‐to‐grout ratio ( x ) as a quantitative parameter and examines LER curing under different frontal water conditions. Focused beam reflectance measurement (FBRM), isothermal microcalorimetry (TAM), rheological testing, in situ attenuated total reflectance infrared spectroscopy (ATR‐IR), and molecular simulation (MS) were employed. FBRM and TAM indicated phase separation within 3 min across the investigated x range of 0%–80%, while epoxy ring opening remained the dominant curing reaction. MS indicated that frontal water increased the curing energy barrier from 1800 to 2100 kcal mol −1 . ATR‐IR analysis identified two distinct curing stages: the induction period and the post‐induction period. At x = 80%, the apparent activation energy increased by 10.5 kJ mol −1 during induction and by 4 kJ mol −1 after induction. A novel LER curing‐kinetics model incorporating frontal water content over x = 0%–80% was established. The model provides a theoretical basis for analyzing and predicting the curing performance of organic grouting materials under water‐rich engineering conditions.
ABSTRACT Blending is a key strategy for modulating the structure of polyolefins. This study systematically investigates how the distinct chain architectures of ethylene‐octene random copolymers (ORC) and ethylene‐octene block copolymers (OBC) influence the crystallization, microstructure, and macroscopic properties of linear low‐density polyethylene (LLDPE) blends and their cast films. Through a comprehensive analysis using DSC, SAXS, SEM, and mechanical and optical testing, it was demonstrated that the block architecture of OBC was found to act as an effective nucleating agent, promoting the formation of larger, well‐ordered lamellar structures. This resulted in a synergistic enhancement of mechanical performance in the cast films, significantly increasing both tensile strength and elongation at break. Conversely, the random architecture of ORC refined the crystalline morphology by disrupting spherulitic growth. This markedly improved the films' optical properties, leading to substantially reduced haze and enhanced transparency. These findings reveal a clear structure–property relationship, establishing that OBC is an ideal modifier for mechanical reinforcement, whereas ORC is superior for enhancing optical clarity. This work provides a strategic guide for tailoring LLDPE film performance by selecting modifiers with specific chain architectures.
ABSTRACT The development of sustainable thermosetting polymers with thermo‐responsive shape memory capability has attracted increasing attention due to their potential applications in smart materials and advanced engineering systems. In this study, bio‐based citric acid was employed as an alternative curing agent for epoxy resin to fabricate thermo‐responsive shape memory epoxy composites. The thermal properties, as well as shape memory behavior of the composites were investigated by differential scanning calorimetry (DSC) analysis and bending tests, respectively. The effects of polyethylene glycol (PEG) as a plasticizing agent in addition to sepiolite and colemanite as mineral reinforcing fillers on the thermal and shape memory properties of the epoxy composites were systematically investigated. The incorporation of PEG improved the chain mobility of the epoxy network, enabling decreased T g and enhanced shape recovery behavior. The optimized composites exhibited excellent thermo‐responsive shape memory performance, achieving high shape recovery ratios with rapid recovery response under thermal stimulation. The obtained results demonstrate that citric acid‐cured epoxy composites reinforced with natural mineral fillers provide a promising sustainable platform for the development of high‐performance shape memory materials.
ABSTRACT While photocatalytic membranes have attracted significant attention for wastewater treatment, conventional electrospun membranes often display limited durability under continuous water flow. Although composite membrane structures can enhance mechanical stability, their fabrication generally involves complex, multi‐step procedures and additional bonding treatments. To overcome these challenges, a single‐step electrospinning strategy was employed to fabricate a mechanically robust, photocatalytic poly(vinylidene fluoride) (PVDF)/Fe 2 O 3 composite membrane directly integrated with cellulose filter paper (CFP). Incorporation of cellulose acetate (CA) markedly improved interfacial compatibility between the electrospun layer and the cellulose substrate, resulting in a mechanically interlocked structure without the need for secondary adhesives. The optimized composite (PFC15@CFP) exhibited superior interfacial adhesion strength and delamination resistance in T‐peel tests. Furthermore, the addition of Fe 2 O 3 nanoparticles was systematically investigated to adjust the physicochemical and photocatalytic properties of the PVDF matrix. Energy‐dispersive X‐ray spectroscopy (EDS) confirmed a homogeneous distribution of Fe 2 O 3 within the electrospun fibers. Increasing Fe 2 O 3 content reduced fiber diameter and enhanced membrane wettability, decreasing the water contact angle from 112° to 93°. Among the fabricated samples, the PF8 membrane, characterized by uniform fibrous morphology and the smallest average fiber diameter (1.72 μm), achieved the highest methylene blue degradation efficiency. These findings present a straightforward and effective method for developing mechanically stable, high‐performance photocatalytic composite membranes for practical water‐treatment applications.
