Journal of Applied Polymer Science最新文献

We report the development of low turn-on voltage organic rectifier diodes based on a bulk-heterojunction (BHJ) film of regio-regular P3HT and Y6. Encouraged by the low open-circuit voltage observed in P3HT:Y6-based organic solar cells, we fabricated rectifier diodes with the same architecture as P3HT:Y6-based organic solar cells. The rectifier diodes achieved a turn-on voltage (V _f) of 344 mV, a low value compared to those of other solution-processed organic rectifier diodes. Although initial devices exhibited a low rectifier ratio (RR) of 1.7 × 10², substituting a laminated Au electrode for the PEDOT:PSS layer improved RR to 2.5 × 10³. Mechanistic analysis revealed that rectification originates from the p–n junction formed between P3HT and ZnO rather than the BHJ-P3HT:Y6 interface. Interestingly, Y6 plays a secondary role in enhancing forward current by modifying the molecular orientation of P3HT. AC–DC conversion simulations at 13.56 kHz yielded a 127 mV output from a 400 mV input, establishing potential for radio-frequency identification applications.

This study investigates dielectric relaxation, electrical conductivity, and charge transport mechanisms in pristine polypyrrole (PPy) and carbon black (CB)–doped polypyrrole (PPy/CB) composites synthesized via in situ polymerization. Structural and morphological characterization using XRD, FTIR, Raman spectroscopy, and SEM confirms the successful incorporation and homogeneous dispersion of CB within the PPy matrix. Broadband dielectric spectroscopy (BDS) measurements carried out over the frequency range of 10⁻¹–10⁷ Hz reveal a systematic evolution of dielectric and transport behavior with increasing CB content. The dielectric constant (ε′) decreases with CB loading, indicating a transition from polarization dominated dielectric behavior to conduction dominated electrical response. DC conductivity increases markedly from nearly insulating pristine PPy to 0.032 S cm⁻¹ for the PPy/CB composite containing 10 wt% CB. The frequency dependent AC conductivity follows Jonscher's universal power law with exponent values between 0.5 and 0.7, suggesting charge transport via localized hopping in a disordered system. Cole–Cole model analysis confirms broad, non-Debye relaxation processes across all compositions. The combined σ′–σ″ dispersion, impedance (Z′–Z″) behavior, and asymmetric relaxation parameters provide clear evidence that charge transport is governed by frequency activated hopping and strong interfacial Maxwell–Wagner–Sillars polarization at PPy–CB interfaces. These enhanced dielectric and electrical properties highlight the potential of PPy/CB nanocomposites for electronic, sensing, and energy storage applications.

Efficient hemostasis remains a major challenge in treating noncompressible bleeding wounds, thereby necessitating the development of haemostatic materials with both excellent clotting performance and antimicrobial activity. To address this need, we fabricated chitosan/poly(vinyl alcohol) (CS/PVA) hybrid aerogels with anisotropic structures via sol–gel and freeze-drying methods. The aerogel was further crosslinked through interactions between Fe³⁺, protocatechualdehyde (PA), and chitosan (CS), which imparted antimicrobial functionality. By modulating the PVA content, the aerogels exhibited a fishbone-like axial structure and a uniform radial honeycomb structure (77.8 μm pore size), with an axial elastic modulus that was nearly an order of magnitude greater than the radial elastic modulus. At 66% solid content and 80% compressive strain, the aerogel achieved a compressive stress > 2.2 MPa and toughness of 450 kJ/m³, thereby significantly surpassing those of conventional aerogels. In rat liver hemorrhage models, the CS/PVA aerogel reduced the bleeding volume by approximately 73% and the hemostasis time by approximately 50% compared with those of the blank controls and gelatine sponges. Additionally, it demonstrated strong antibacterial activity against Staphylococcus aureus and Escherichia coli, along with excellent biocompatibility (no cytotoxicity or haemolysis being observed). This multifunctional aerogel demonstrates promising potential for managing noncompressible wound hemorrhage.

In this study, we develop breathable waterproof (BW) coated textiles with network-structured polyurethane coatings on common woven fabric substrates via a simple yet useful one-step fabrication route integrating hydrophobicity by the in situ introduction of fluorinated chemicals into the coating solution. The on-demand regulation of lyophobic network architecture is enabled by tuning the incorporation depth of water droplets into the coating solutions through adjusting the concentrations of fluorinated acrylates. The impacts of fluorinated additive contents of the coating solutions on the structure–property relationships of the network-coated fabrics are investigated. Benefiting from interconnective channels (porosity of 57.1%), small apertures (mean pore size of 3.52 μm), and strong hydrophobicity (water contact angle of 138.6°), the optimal networks provide the resultant coated fabrics with outstanding breathability (water vapor transmission rate of 2834 g m⁻² d⁻¹) and good waterproofness (hydrostatic pressure of 3.71 kPa). Overall, this study not only proposes a straightforward fabrication strategy for BW network coatings but also offers a versatile platform for the development of functional polymer-coated materials for various applications, including sportswear, wound dressing, wearable electronics, and beyond.

Addressed the challenges of poor dispersion and interfacial incompatibility of alkali lignin (AL) in natural rubber (NR) matrices which is arising from AL's high polarity, an innovative wet mixing synergistic strategy was developed using silica hollow microspheres (SHM) as physical carriers for AL and epoxidized natural rubber (ENR) as an interfacial compatibilizer. The effects of different SHM:AL mass ratios on the performance of the resulting SHM/AL/NR composites were systematically investigated. Microstructural characterization revealed that AL achieved optimal dispersion in the NR composite at an SHM:AL mass ratio of 1:3. In the SHM/AL/NR composite with 50 wt% carbon black (CB) replaced by SHM/AL (1:3), the tensile strength reached 26.7 MPa. The retention rates of tensile strength and elongation at break were 97.4% and 89.9%, respectively, indicating excellent mechanical properties and anti-aging performance. Furthermore, ENR was incorporated as an interfacial compatibilizer to enhance the compatibility between SHM/AL and the rubber matrix. At an ENR content of 20 phr, the tensile strength of the SHM/AL/ENR/NR composite was further increased to 27.8 MPa. In comparison with the 20CB/20ENR/NR composite, its tensile strength retention and elongation retention rose by 12.1% and 22.6%, respectively, whereas the tensile strength remained nearly unchanged.

This work proposes an in situ hybrid fibrillation strategy to simultaneously enhance the toughness and thermal resistance of fully bio-based polylactic acid (PLA) melt-blown nonwovens (MBNs). A reactive PLA/(PA11/G-HNTs) ternary gradient blending system was designed in which polyamide 11 (PA11) serves as a ductile fibrillating phase and epoxidized halloysite nanotubes (G-HNTs) act as nanoscale skeletons of reinforcing agents. The tailored interfacial reactions and rheological tuning enable PA11 to undergo stable in situ microfibrillation during melt-blown, while G-HNTs align along the fibril axis to form a hierarchical “microfibril–nanotube” hybrid network. Structural analyses (SEM, TEM, DSC, DMA, rheology) reveal a clear transition from a droplet–matrix morphology to a fibril-reinforced architecture, accompanied by improved crystallization and melt strength. The optimized PLA/(PA11/G-HNTs) MBNs achieve more than a 150% increase in elongation-at-break, as well as exhibit 20°C–30°C higher dry-heat dimensional stability compared with neat PLA MBNs. These findings demonstrate a scalable, melt-processing-compatible route for producing super-tough and heat-resistant PLA melt-blown nonwovens.