Polymers最新文献

The industrial preparation via solid-state polymerization (SSP) of high-viscosity copolyamides 6/66 (PA6/66) addresses the challenges, including prolonged reaction times, high energy consumption, and uneven viscosity distribution. In this study, sodium hypophosphite was introduced into the PA6/66 copolymerization system as a solid-state polymerization catalyst. The effects of this catalyst on the solid-state viscosity-increasing rate and relative viscosity were systematically investigated, and the extraction process was optimized to solve the loss of catalyst and controllable extractable content. The results showed that the relative viscosity of PA6/66 increased linearly with the SSP time, and the apparent viscosity increase rate could be stably maintained at 0.14 h^-1 at 160 °C due to the catalytic action. Based on the phosphorus (P) content in the chips, the viscosity increase rate is not further large when the P content is 25 ppm at 150 °C and 30 ppm at 160 °C, which can be added as a "control concentration" as a catalyst. The extraction kinetics showed that the catalyst concentration of the chip could be kept higher than the control concentration, and the extractable content can satisfy the requirements for processing. The catalyst of sodium hypophosphite was utilized on the 4500 tons/year PA6/66 continuous polymerization test line, and the high-viscosity PA6/66 chips with uniform viscosity were stably prepared. This study provides a reliable theoretical basis and process route for the large-scale continuous preparation of high-quality and high-viscosity PA6/66 resin.

Colloidal amorphous structures comprise short-range ordered arrays of monodisperse submicrometer-sized particles. They exhibit angle-independent structural color and hence are expected to be promising candidates for advanced color materials. In particular, non-close-packed colloidal amorphous structures embedded in soft polymers can alter the angle-independent color through stimuli-induced volume changes in the polymer. Consequently, such materials should have significant potential for application in sensor devices. This paper reports the preparation of an elastomer-immobilized non-close-packed colloidal amorphous film with an angle-independent color using a hydrogel-immobilized non-close-packed colloidal amorphous film as the starting material. The swelling solvent (i.e., water) in the hydrogel film was replaced with a hydrophilic elastomer precursor solution, which was photopolymerized to immobilize the colloidal amorphous structure with the separated particles within the elastomer film. The color of the elastomer-immobilized non-close-packed colloidal amorphous film was angle-independent and was easily altered under stretching. Furthermore, hydrophilic carbon black dispersed well in the hydrophilic elastomer precursor solution, improving the saturation of the resultant elastomer-immobilized non-close-packed colloidal amorphous film. The flexible nature of the prepared film should allow it to be attached to curved surfaces, thereby promoting its application as a simple strain sensor to express invisible strains through color changes.

Grafted polypropylene (PPG) has demonstrated significant potential as a recyclable insulation material for high-voltage cables. While its fundamental electrical, mechanical and thermal properties have been widely studied, research on its long-term performance remains insufficient. This study comparatively investigates the thermo-oxidative ageing performance of PPG and traditional cross-linked polyethylene (XLPE) to evaluate the expected lifespan of cable insulation. The evolution of mechanical and electrical properties of PPG and XLPE was monitored during accelerated thermo-oxidative ageing experiments conducted at their respective maximum allowable operating temperatures, and the most sensitive ageing parameter was identified. Furthermore, the influence of thickness on the insulation ageing process was examined through experiments on samples of different thicknesses. Results indicate that the estimated thermo-oxidative ageing lifespan of XLPE at its maximum operating temperatures of 90 °C is 37.75 years, while that of PPG at 110 °C is 45.65 years. This work offers a practical methodology for polymer ageing lifespan analysis and provides valuable insights for assessing the long-term performance of PPG cables in high-voltage applications.

Two-dimensional (2D) materials open up exciting possibilities for the study of ion transport behavior for green energy. Here, a simple and effective strategy to fabricate high-conductivity nanofluidic channels based on exfoliated montmorillonite (MTM) nanosheets is proposed. The resource-rich and low-cost layered MTM was first exfoliated into monolayer nanosheets using Exolit OP 550. Subsequently, the MTM nanosheets with Exolit OP 550 were assembled into 2D nanofluidic devices by the layer-by-layer self-assembly method. The results show that Exolit OP 550 exfoliates different types of layered MTM into monolayer nanosheets with uniform contrast and integrity. The reconstructed Na-MTM nanofluidic device has the highest ionic conductance. The ionic conductivity of the Na-MTM 2D nanofluidic device was effectively improved after Li⁺ modification with a higher charge density. After further optimizing the content of Exolit OP 550, the ion conductivity of the MTM nanofluidic device reached 4.66 × 10^-4 S cm^-1, which is 55.3% higher than the highest known value among the same nanofluidic devices. Interestingly, this nanofluidic device exhibited a very high sensitivity in detecting water evaporation, which can reach 10^-12 S s^-1 in resolution. This economically viable strategy may advance the study of low-dimensional ion transport properties in new energy coatings and the design of evaporation detectors.

Ciprofloxacin, being a widely used antibiotic agent, has sparked growing interest in the field of molecularly imprinted polymers (MIP) for its selective recognition and removal. This review provides a comprehensive analysis of the recent advances in the synthesis and applications of ciprofloxacin-imprinted polymers. The examination of synthesis compositions for the preparation of these polymers includes thorough discussions on functional monomers, crosslinkers, initiators, and solid supports. Various imprinting techniques, including bulk, precipitation, co-precipitation, and surface polymerization, have been assessed for the fabrication of the imprinted polymers. Furthermore, the advancing imprinting techniques, encompassing nano-scale imprinting, multi-functional monomers, multi-template imprinting, and electrochemical imprinting, are also highlighted. Additionally, an extensive exploration of the diverse applications of these polymers is also presented. These applications encompass selective separation and removal of ciprofloxacin from environmental samples, visual and electrochemical detection in complex matrices, their use as a stationary phase for HPLC, drug release, and photocatalysis. This review offers valuable insights into the current advancements and potential future directions in the development of ciprofloxacin-imprinted polymers, emphasizing their importance in diverse analytical and environmental applications.

Granite residual soil (GRS) is highly susceptible to water-induced softening, posing significant risks of slope instability and collapse. Conventional impermeable grouting often exacerbates these hazards by blocking groundwater drainage. This study investigates the efficacy of a permeable water-reactive polyurethane (PWPU) in stabilizing GRS, aiming to resolve the conflict between mechanical reinforcement and hydraulic conductivity. Uniaxial compression tests were conducted on specimens with varying initial water contents (5%, 10%, and 15%) and PWPU contents (5%, 10%, and 15%). To reveal the multi-scale failure mechanism, synchronous acoustic emission (AE) monitoring and digital image correlation (DIC) were employed, complemented by scanning electron microscopy (SEM) for microstructural characterization. Results indicate that PWPU treatment significantly enhances soil ductility, shifting the failure mode from brittle fracturing to strain-hardening, particularly at higher moisture levels where failure strains exceeded 30%. This enhancement is attributed to the formation of a flexible polymer network that acts as a micro-reinforcement system to restrict particle sliding and dissipate strain energy. An optimal PWPU content of 10% yielded a maximum compressive strength of 4.5 MPa, while failure strain increased linearly with polymer dosage. SEM analysis confirmed the formation of a porous, reticulated polymer network that effectively bonds soil particles while preserving permeability. The synchronous monitoring quantitatively bridged the gap between internal micro-crack evolution and macroscopic strain localization, with AE analysis revealing that tensile cracking accounted for 79.17% to 96.35% of the total failure events.

Vanadium carbide (V₂C) MXene shows great potential for addressing challenging implant-associated infections in bone regeneration due to its strong photothermal conversion efficiency. However, its photothermal efficacy is restricted to the near-infrared I (NIR-I) region due to a limited absorption range. To address this, we designed platinum nanoparticle-decorated V₂C heterostructures (Pt@V₂C) via an in situ growth method, leveraging Pt's plasmonic and catalytic properties to extend the photoresponse to the NIR-II window. Subsequently, Pt@V₂C was integrated into poly-L-lactic acid (PLLA) to fabricate PLLA-Pt@V₂C scaffolds with photothermal antibacterial function by selective laser sintering. The optimized PLLA-Pt@V₂C scaffold achieves a record photothermal conversion efficiency (56.03% at 1064 nm), triggering simultaneous hyperthermia (>52 °C) and catalytic ·OH radical generation. In vitro studies demonstrate exceptional antibacterial efficacy against Staphylococcus aureus and Escherichia coli, achieving over 99% killing rates upon 1064 nm near-infrared irradiation. Furthermore, the scaffold demonstrated significant inhibition of biofilm formation, achieving over 90% reduction in biofilm biomass. Moreover, the scaffold demonstrated high cell viability, confirming its dual functionality of potent bactericidal activity and biocompatibility that supports tissue regeneration. This work provides a feasible strategy for combating implant-associated infections.

Controlled drug delivery systems (CDDSs) are increasingly attracting interest from the scientific community in order to achieve highly precise, customized, and efficient therapeutic treatment of various diseases. The challenge is to develop highly innovative devices and appropriate administration methods in order to reduce side effects and further improve patient compliance. In this context, transdermal drug delivery systems (TDDSs) represent smart tools that permit supplying therapeutically effective amounts of drugs at a fixed time using the skin as the administration route. They are non-invasive and allow for avoiding gastric side effects and first-pass metabolism occurring in the liver. TDDSs have been produced using numerous therapeutic agents and, more recently, also biological molecules. However, it must be highlighted that they are complex systems, and their formulation requires a multidisciplinary approach and expertise in polymer chemistry and materials science. A contribution in this direction is given from the integration of membrane technology with biological and pharmaceutical sciences. The present review deals with a general overview of controlled drug delivery systems. Particular attention is devoted to TDDSs and to the materials used for producing polymeric membrane-based TDDSs with a membrane engineering perspective. It also describes the passive and the most advanced active strategies for transdermal delivery. Finally, different transdermal membrane-based release systems, like patches, mixed-matrix membranes, and imprinted membranes are discussed.

The global crisis concerning multidrug-resistant microorganisms necessitates the development of innovative antimicrobial strategies that avoid conventional antibiotics and overcome the toxicity and environmental persistence associated with traditional metal-based biocides. This work aims to develop safe and sustainable antibacterial filtration materials by integrating cationic hyperbranched polymer dendrimers (HBP) into electrospun nanofibers. Cationic HBPs were successfully embedded into recycled polyamide 6 nanofibers using industrial needleless electrospinning. Filtration efficiency, assessed against a 0.3 µm paraffin oil aerosol according to EN 149:2001, consistently exceeded 99.8%, meeting and surpassing the FFP3 classification threshold while maintaining low air resistance. The HBP-functionalized nanofibers exhibited pronounced contact-active antibacterial activity against Staphylococcus aureus and Escherichia coli. Quantitative plate count assays confirmed viability reductions of up to 74.1% after 2 h of co-incubation. Crucially, the absence of inhibition zones in agar diffusion tests confirmed that the active polymer was stably embedded within the nanofiber matrix and did not leach. Comprehensive toxicological tests, including cell line and 3D human skin and airway tissue models, confirmed the material's safety for both dermal and respiratory contact. This study presents a scalable, metal-free, and environmentally responsible next-generation filtration system that combines high mechanical efficiency with active antimicrobial functionality.

Advances in modern industry largely depend on the development of high-performance materials. In this study, the influence of hexagonal boron nitride (h-BN) filler on the performance of glass fiber/epoxy laminates was systematically investigated. Composites containing h-BN with different particle sizes (65-75 nm and 790 nm) and contents (0.2 and 0.4 wt.%) were fabricated, and their mechanical (tensile, in-plane shear, hardness, impact), thermal (Differential Scanning Calorimetry, DSC), electrical (volume resistivity), and spectroscopic (Fourier Transform Infrared Spectroscopy, FTIR) properties were examined. The results demonstrated that specimens with 65-75 nm h-BN at 0.2 wt.% exhibited the highest tensile and shear strengths, whereas those with 790 nm h-BN at 0.4 wt.% showed superior impact resistance and hardness. DSC analyses revealed that h-BN addition increased the glass transition temperature (Tg), while FTIR confirmed interfacial interactions between h-BN and the epoxy matrix. Electrical measurements indicated that h-BN preserved the insulating nature of the composites, with only limited reductions in resistivity observed at higher contents of larger particles due to morphological effects. Overall, these findings highlight that h-BN filler enhances load transfer efficiency, thermal stability, and mechanical reliability, offering significant potential for applications requiring multifunctional performance, such as aerospace, marine, and electrical and electronic insulation systems.