Journal of Applied Polymer Science最新文献

Anticorrosion coatings are the primary measure for metal protection. Traditional epoxy (EP) resin anticorrosion coatings fail to provide metal protection due to defects that allow corrosive media to penetrate. Adding nanofillers that can block and consume corrosive media is an essential means of enhancing the corrosion-resistant performance of EP coatings. Montmorillonite (MMT) nanosheets possess excellent barrier properties and mechanical performance, while polyaniline (PANI) and phytic acid (PA) have excellent passivation and corrosion inhibition properties. In this work, phytic-doped polyaniline encapsulated MMT nanomaterials (PANI/MMT) are prepared as fillers for EP resins, improving the strength and corrosion resistance of the coatings. Due to the rough surface of PANI/MMT nanosheets and their excellent compatibility with EP resin, they can fill defects in the coating, enhancing its strength (3.09 MPa, compared to 1.5 MPa for pure EP). The |Z|_0.01 Hz of the PANI/MMT/EP coating after being immersed in a 3.5 wt% NaCl solution for 150 days is 6.75 × 10⁸ Ω cm². This is three orders of magnitude higher than that of the EP coating alone. Based on these findings, PANI/MMT holds significant potential for the development of long-term corrosion-resistant coatings.

This study investigates the tribological performance of graphene oxide (GO) grafted via reversible addition–fragmentation chain transfer (RAFT) polymerization with two methacrylate monomers: 2-hydroxyethyl methacrylate (HEMA) and pentyl pentanoate methacrylate (PPEMA). Extensive analyses—including Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), solid-state nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDS)—confirmed successful polymer grafting onto GO surfaces. Adding 0.5 wt% of these grafted GO additives to castor oil significantly reduced friction and wear compared to neat oil and pristine GO dispersions. Graphene oxide grafted with PPEMA (GO–PPEMA) achieved the lowest friction coefficient and more stable sliding behavior, attributed to its hydrophobic side chains forming effective boundary films and reducing shear. Meanwhile, graphene oxide grafted with HEMA (GO–PHEMA) offered slightly better wear protection due to enhanced interfacial interactions from its polar hydroxyl groups. Thermal analyses revealed increased decomposition temperatures for both composites, confirming their stability under frictional heat. Overall, RAFT-mediated polymer grafting effectively tailors the tribological properties of GO additives, offering a promising strategy for advanced and sustainable lubrication systems.

A critical challenge in self-healing asphalt is concurrently achieving repeatable healing and mechanical reinforcement. This study introduces epoxy-amine functionalized polyacrylonitrile (EA-PAN) fibers to address this gap, leveraging thermally activated chemistry at the fiber-asphalt interface. The fibers were synthesized and systematically characterized (SEM, AFM, FTIR, XPS), and their impact on asphalt composite performance was evaluated through rheological tests (DSR), damage-healing protocols, and nano-computed tomography (Nano-CT). Functionalization significantly enhanced interfacial compatibility. The surface roughness (Ra) of EA-PAN fibers increased to 272 nm, compared to 133 nm for unmodified PAN, and their formamide contact angle decreased to 36.14° from 67.57°. Consequently, the EA-PAN&SBS/MA composite exhibited superior high-temperature performance, with its dynamic shear modulus (G*) increasing by 112.5% at 82°C compared to the PAN&SBS/MA composite. Most notably, EA-PAN&SBS/MA achieved an excellent healing index of 85.11%, significantly surpassing the 61.54% of PAN&SBS/MA. Nano-CT analysis confirmed efficient microcrack repair in the EA-PAN&SBS/MA composite, with its interfacial void ratio decreasing from 83.67% to 11.33% post-healing. FTIR analysis revealed that healing is driven by new covalent bonds from residual epoxy and amine groups. This study validates that EA-PAN fibers provide an effective strategy for developing advanced asphalt composites that are both mechanically robust and highly self-healing.

The effect of reinforcement type, along with epoxy-to-hardener ratio (ER:H), on the curing quality and overall performance of epoxy composites has not yet been adequately established. To address this gap, this study employed a combined methodology of differential scanning calorimetry (DSC) and cure index (CI) analysis to quantitatively assess crosslinking efficiency alongside structural and mechanical properties. Composites were reinforced by nylon mesh, aluminum foil, polyethylene, and jute fiber at ER:H ratios of 8:2 and 7:3. DSC revealed that ER + aluminum (7:3) achieved the highest enthalpy (1049.3 J g⁻¹), representing a ~52% increase relative to unreinforced epoxy (695 J g⁻¹). CI evaluation confirmed that this formulation attained an “excellent” cure classification, while polymeric and natural reinforcements exhibited poor cure quality. Mechanical testing showed that the elastic modulus improved to 24.1 GPa for ER + aluminum (ER:H = 7:3), and hardness increased by ~22% over epoxy. Furthermore, water absorption resistance was dramatically improved by the reinforcement of aluminum and jute at ER:H = 7:3, showing negligible uptake (< 0.1%). Overall, the integration of DSC and CI provides a rigorous framework to link curing dynamics with multifunctional performance, demonstrating that optimizing the ER:H ratio and reinforcement selection, particularly with aluminum, yields highly cross-linked, mechanically robust, and moisture-resistant composites suitable for demanding structural applications.

The development of functional polymer nanocomposites for efficient dye adsorption has become increasingly important. In this study, a functional polymer nanocomposite of chitosan-vanillin Schiff base and nickel oxide nanoparticles (CS-VAN/NiO) was synthesized for acid blue 93 (AB93) dye removal from aqueous systems. The CS-VAN/NiO nanocomposite was thoroughly characterized using Brunauer–Emmett–Teller (BET) surface area analysis, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDX). The CS-VAN/NiO nanocomposite exhibited a mean pore diameter of 14.08 nm, a BET surface area of 6.91 m²/g, and a total pore volume of 0.02436 cm³/g. The adsorption process was optimized using response surface methodology (RSM) with a Box–Behnken design (BBD), considering key parameters such as CS-VAN/NiO dosage (0.01–0.07 g/L), pH (4–10), and contact time (10–40 min). The adsorption kinetics followed the pseudo-first-order model, while equilibrium data were best explained by the Freundlich model, suggesting multilayer adsorption. The CS-VAN/NiO nanocomposite achieved a maximum adsorption capacity of 278.3 mg/g for AB93 dye. The adsorption mechanism was attributed to multiple interactions, including electrostatic forces, π–π stacking, n–π interactions, and hydrogen bonding interactions. The novelty of this work lies in the fabrication of a bio-derived CS-VAN Schiff base polymeric matrix embedded with NiO nanoparticles, offering a synergistic combination of biodegradability, functional surface groups, and enhanced adsorption performance. The results indicate that the CS-VAN/NiO nanocomposite functions as an efficient adsorbent for the removal of organic dyes from aqueous solutions. The CS-VAN/NiO nanocomposite, characterized by its high adsorption capacity and advantageous physicochemical properties, demonstrates strong potential as an effective material for wastewater treatment and environmental remediation.

Hydrophobic charge-induced chromatography (HCIC) membrane adsorbers are cost-effective for IgG separation but have limited adsorption capacity. Based on the nanofiber membrane, an HCIC nanofiber membrane adsorber with a high specific surface area was prepared by gel modification of the fiber surface. The regenerated cellulose (RC) nanofiber membrane obtained by electrospinning, thermal crosslinking, and deacetylation reaction was modified via cationic ring-opening polymerization (CROP) of polyethylene glycol diglycidyl ether (PEGDE), followed by epoxy ring-opening with 2-mercaptobenzimidazole (MBI) to prepare the HCIC nanofiber membrane adsorber (HCIC-g-MBI). Successful preparation of the HCIC membrane adsorber was confirmed by SEM, FTIR, and XPS analyses. The HCIC membrane adsorber had a static adsorption capacity of 252 mg/g for human immunoglobulin G (IgG) under pH 7 and 0.8 mol/L Na₂SO₄ conditions in PBS buffer. At pH 3, the recovery of IgG reached 91%, which showed a high recovery efficiency. These results indicated that the HCIC nanofiber membrane adsorber could be used in antibody purification.

Metal materials in engineering structures face severe corrosion challenges. Waterborne polyurethane (WPU) is widely regarded as a sustainable coating alternative and holds potential in corrosion protection; nevertheless, its actual usage is constrained by inadequate mechanical characteristics, limited water resistance, and insufficient corrosion resistance. In this study, graphene oxide (GO) and nano-cerium oxide (CeO₂) were introduced as functional fillers into a WPU matrix via physical blending to prepare three composite materials (WPU-GO, WPU-Ce, and WPU-GO-Ce). The influence of nanofillers on the characteristics of WPU was comprehensively examined. The findings indicated that the addition of nanofillers substantially improves the overall properties of the composites. Specifically, CeO₂ (at 0.25 wt%) interacts with the hard segments of polyurethane through interfacial hydroxyl groups, increasing the tensile strength of WPU-Ce to 31.37 MPa. The synergistic effect of GO (at 0.125 wt%) and CeO₂ (at 0.125 wt%) in the WPU-GO-Ce system forms a dense physical barrier, achieving an impedance modulus of 8.03 × 10⁵ Ω·cm² two orders of magnitude higher than WPU, indicating optimal corrosion resistance. Additionally, nanofillers delay corrosive medium diffusion via a “maze effect,” while improving thermal stability (T₅₀ up to 404.63°C) and UV shielding performance (near-zero transmittance across the entire UV spectrum). This work reveals that the GO/CeO₂ co-modification strategy significantly enhances the multifunctional performance of WPU coatings, providing theoretical and technical support for long-term corrosion protection in complex environments.