Journal of Applied Polymer Science最新文献

In this work, tetraepoxy-cyclohexaneethyl 2, 4, 6, 8-tetramethylcyclotetrasioxane (TECCTS), with a tetrafunctional epoxy group, was prepared and utilized as a toughening agent in epoxy resin. In the synthesis, vinyl epoxycyclohexane was introduced into the epoxy resin via a hydrosilylation addition reaction using D₄H, which is a cyclic structure formed by the SiOSi bond, as the main structure. A series of E51/TECCTS/D230 epoxy resins were prepared for performance testing. The successful synthesis of TECCTS was confirmed through the analysis of FT-IR and NMR. Mechanical property tests demonstrated that as the incorporation of TECCTS increased, the tensile strength of the E51/TECCTS/D230 epoxy resin gradually decreased, while the elongation at break gradually increased. The elongation at break of TECCTS-40 epoxy resin was found to be 164.56%, representing a substantial increase of 1342% in comparison to E51/D230 epoxy resin. The experimental findings demonstrated that TECCTS, due to its distinctive molecular structure and flexible chain segments, can effectively enhance the molecular chain mobility of modified resins, thereby efficiently toughening epoxy resins.

The monovalent cation exchange membrane (MCEM) plays a crucial role in strategic resource recovery fields such as lithium/magnesium separation and seawater softening. This study proposes a two-stage modification strategy of “nanoparticle deposition – quaternization cross-linking”: first, deposit the Polypyrrole -Polyethyleneimine (PPY-PEI) composite nanoparticles in situ on the commercial Cation Exchange Membrane (CEM) surface, and then undergo quaternization cross-linking to prepare a high-performance monovalent cation exchange membrane (MCEM). The rigid structure of Polypyrrole -Polyethyleneimine (PPY-PEI) nanoparticles completely avoids the traditional problem of monomer penetration, and the rate of membrane pore blockage is significantly reduced. Electrified nanoparticles form gradient nanochannels to achieve dual mechanism synergy: The surface positive charge layer repels and blocks Mg²⁺ through the Donnan effect; 2–5 nm mesoporous channels facilitate K⁺ transport through size sieving. Subsequent quaternization crosslinking strengthened the modified layer and increased the positive membrane charge density, leading to further improvement in perm-selectivity. The results show that the modified membrane achieves a breakthrough performance in the separation of K⁺/Mg²⁺: the selectivity reaches 6.9; the K⁺ flux remains at 0.14/(m²·s). Molecular dynamic simulation of the ion diffusion behavior confirmed that the presence of Polypyrrole -Polyethyleneimine (PPY-PEI) can accelerate the diffusion rate of K⁺ while limiting the transport of Mg²⁺, providing a theoretical basis for the performance prediction of selective ion exchange membranes.

Superabsorbent polymers (SAP) are emerging as promising materials for internal curing in concrete. However, the water absorption performance of most SAP in concrete is significantly affected by complex ionic environments. This study developed a novel method to fabricate SAP composites. Utilizing calcination-exfoliation and structural memory effects, we synthesized acrylic acid-intercalated layered double hydroxide (AA-LDH), which was incorporated into P(AA-co-AM) copolymer to form a composite SAP with unique physicochemical structures. The study evaluated the SAP's water absorption performance, water retention, thermal stability, and desorption behavior under various conditions. The results show that the water absorption rate of the composite SAP added 1 wt% AA-LDH in deionized water reached 618.2 g/g, which is 6.7% higher than that of the unmodified SAP. The water retention rate of the composite SAP is significantly improved, and the highest is 92.5%. The addition of AA-LDH improves the thermal stability of the SAP. Specifically, AA-LDH can effectively inhibit the thermal decomposition of the molecular chain of the SAP above 400°C. These enhanced physicochemical properties enable the SAP to better adapt to the concrete environment.

The green crosslinking strategy for ethylene-vinyl acetate-glycidyl methacrylate terpolymer elastomer (EVM-GMA) composites is helpful for the rubber development in the future. However, waste EVM-GMA products continue to present challenges related to environmental pollution and resource waste. To address this issue, rubber powders were made from crosslinked EVM-GMA sheets through physical pulverization methods and used as filler for silicone rubber to realize the green recycling and reuse of crosslinked EVM-GMA. Compared with the EVM-GMA powders prepared by using the low-temperature physical pulverization method, EVM-GMA powders prepared by using a mechano-chemical pulverization method have smaller particle sizes and higher reactivity. Scanning electron microscopy and transmission electron microscopy observations reveal the EVM-GMA powders are uniformly dispersed in silicone rubber, and there are transition layers between the two phases. EVM-GMA powders/silicone rubber (45/100) composite has a tensile strength of 7.4 MPa, and an elongation at break of 232%. Dynamic mechanical properties results show that the maximum loss factor of the EVM-GMA powders/silicone rubber composites increases significantly with increasing EVM-GMA powders content. Notably, the composite retains excellent mechanical properties even at −30°C. This simple recycling approach to obtaining silicone rubber composites with good mechanical and damping properties also provides a new method for the high-value recycling of waste EVM-GMA products.

Indium tin oxide (ITO) is widely used in optoelectronics for its excellent conductivity and high infrared reflectivity. Depositing ITO on fibers enables multifunctional wearable textiles with infrared stealth and thermal insulation properties. Here, ITO was deposited onto cotton fabrics via radio-frequency (RF) magnetron sputtering. To address the issue of ineffective bonding between ITO films and cotton substrates, amino-modified polydimethylsiloxane (AM-PDMS) was employed as a pretreatment agent to activate the cotton surface. This interfacial strategy effectively facilitated the fiber-film interaction, enabling the first fabrication of cotton textiles with low emissivity and durable infrared stealth performance under domestic washing. The approach successfully resolved the issue of poor interfacial adhesion between ITO films and cotton. The resulting ITO/AM-PDMS/cotton composite exhibited an emissivity of 0.46, significantly lower than that of untreated cotton fabric (0.85). After 12 times household laundering cycles, the ITO/AM-PDMS/cotton fabric exhibited a slight increase in emissivity while maintaining good infrared reflectivity, demonstrating enhanced durability. Moreover, the composite retained water vapor transmission, air permeability, and hand feel of cotton, with added improvements in water repellency and UV resistance. These findings demonstrate that RF magnetron sputtering, combined with interfacial modification, offers a practical route for fabricating durable, low-emissivity cotton textiles for infrared stealth wearables.

Molybdenum disulfide (MoS₂) with a sandwich-like layered structure is regarded as a highly promising nano-additive for enhancing the mechanical properties of polymer materials. However, the surface of MoS₂ is inert and lacks any active functional groups, resulting in poor compatibility with the epoxy resin (EP). In this study, MoS₂ was exfoliated by the liquid-phase exfoliation method, and its surface was functionalized with polythiol. The approach aimed to embed organic molecules into the sulfur vacancy sites on the MoS₂ nanosheet surfaces, thereby modulating the interface between MoS₂ and epoxy resin and enhancing their interfacial interaction. The modified product was characterized in terms of structure, thickness, and morphology. The functionalized MoS₂ (SH-MoS₂) was then incorporated into an epoxy resin to form an adhesive, and the bonding performance of the adhesive was investigated at different adhesive layer thicknesses. Compared with the epoxy adhesive without SH-MoS₂, the mechanical and bonding properties of the SH-MoS₂/epoxy nanocomposite adhesive were significantly improved. This method yielded an SH-MoS₂ (0.50 wt.%)/epoxy nanocomposite adhesive that exhibited superior tensile shear performance across 0.1–1 mm bondline thicknesses, with all measured values surpassing 20.7 MPa. The findings offer practical design principles for developing polymer nanocomposite adhesives applicable to wide-gap structural bonding manufacturing.

A novel triple-responsive composite hydrogel, p(NIPAM-co-MAA-co-SPMA), was designed and synthesized via free radical polymerization, incorporating N-isopropylacrylamide (NIPAM) for temperature responsiveness, methacrylic acid (MAA) for pH sensitivity, and spiropyran methacrylate (SPMA) for light responsiveness. This study aimed to develop a novel stimuli-responsive sustained release drug delivery system. The composition and structure of the hydrogel were characterized by nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Doxorubicin (DOX) was used as a model drug to evaluate loading and release behavior. The hydrogel achieved a drug loading content (DLC) of 25.7% and a drug loading efficiency (DLE) of 74.3% and enabled controlled release with approximately 89% cumulative DOX release within 6 h under combined thermal, acidic, and ultra-violet light stimuli. Cytotoxicity assays and cellular uptake studies confirmed the excellent biocompatibility of the hydrogel and its efficacy in suppressing cancer cell growth. These results highlight the potential of p(NIPAM-co-MAA-co-SPMA) as an intelligent platform for on-demand targeted anticancer therapy.

Polylactic acid (PLA) is a promising biomaterial for orthopedic implants because of its excellent biocompatibility and mechanical properties. However, its biologically inactive surface limits its clinical applicability. To address this issue, we report a 3D printed PLA scaffold modified with chitosan-based electrospun nanofibers (CH) by combining the advantages of 3D printing and electrospinning. FE-SEM analysis confirms the coating of electrospun nanofibers on PLA scaffolds. An acellular biomineralization study has been performed to evaluate the efficiency of the developed scaffolds to promote hydroxyapatite crystals deposition. The PLA scaffold coated with CH electrospun nanofibers shows significant deposition of hydroxyapatite crystals. Additionally, the antimicrobial activity of the modified scaffolds has been evaluated against Staphylococcus aureus and Escherichia coli , where CH electrospun nanofibers modified scaffolds show significant antimicrobial activity. XRD analysis confirms the hydroxyapatite crystal formation in the (121) plane. Here, NH₂ groups of chitosan on the scaffolds act as nucleation sites for calcium phosphate deposition. ATR-FTIR analysis reveals that these hydroxyapatite crystals have a carbonated nature resembling biological apatite. Flower-like morphology of deposited hydroxyapatite is confirmed by FE-SEM. This study highlights the critical role of PLA surface chemistry in imitating the biomineralization process in vitro and demonstrates the potential of these scaffolds in bone tissue regeneration.

Polyimide (PI) has been extensively employed in flexible insulation applications for electrical equipment due to its exceptional mechanical properties, thermal stability, and superior electrical insulation performance. This study employed two-dimensional (2D) tungsten disulfide (WS₂) with varying surface dimensions and thickness to modify PI for the first time, exploring the mechanism of the interfacial effect of WS₂ in the matrix on the performance enhancement of composite films. The 2D WS₂, owing to its low interlayer friction characteristics and the formation of a continuous interfacial phase within the polymer matrix, facilitates efficient stress transfer between the filler and matrix. Additionally, the high thermal conductivity of WS₂ mitigates localized overheating, which in turn increases the thermal decomposition temperature of the polyimide film. Moreover, the uniformly dispersed lamellar architecture introduces a high density of interfacial charge traps; the confinement effect of these traps on the charge effectively inhibits the development of discharge channels. The WS₂/PI composite film prepared by in situ polymerization shows excellent performance, with significant increases of 162.9% in elongation at break and 12.8% in breakdown strength. This work provides critical insights into the design and preparation of advanced flexible insulating materials for high-voltage electrical applications.

An adhesive conductive hydrogel (ACH) is developed based on a polyacrylamide–poly(ethylene glycol) diacrylate (AAm@PEGDA) matrix functionalized with polydopamine (PDA) and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS), aiming for application as a flexible electronic bio-interface (EBI). ACH features a porous structure with a swelling ratio of approximately 300% in artificial sweat and maintains breathability approximately 2.5 times longer than conventional PEDOT:PSS-based conductive hydrogels (CHs). It exhibits tunable mechanical properties (2.5–10 MPa), excellent elasticity, and strong skin adhesion (~1 mN). Electrical conductivity is significantly enhanced through post-treatment in deionized water, reaching 3.66 × 10⁻⁵ S/m—about 345 times higher than the commercial adhesive conductive hydrogel sample. This aqueous treatment provides a more biocompatible alternative to organic solvents such as dimethyl sulfoxide. Surface electromyography (sEMG) measurements demonstrate a signal amplitude of 0.2836 V and a signal-to-noise ratio (SNR) of 12.46 dB, showing comparable performance to PEDOT:PSS hydrogels (11.4 dB) despite the incorporation of PDA for enhanced adhesion. The ACH shows no cytotoxicity or sensitization responses in biological evaluations. Its high moisture retention supports ionic transport during long-term wear and offers potential for sweat-based biomarker sensing. These properties suggest ACH is well-suited for use as an EBI and holds strong potential for next-generation wearable electronics and sEMG monitoring applications.