Polymer International最新文献

Polyethylene terephthalate (PET) fabric was functionalized by carbon dioxide (CO₂) plasma treatment to introduce carboxyl (–COOH) functionality on its surface. The presence of hydrophilic groups increased the hydrophilicity and decreased the water drop absorption time as the plasma exposure time increased from 30 to 120 s. The maximum carboxyl content of 1.9 μg cm⁻² was achieved within 60 s exposure time, with 80 W discharge power and 40 cm³ min⁻¹ gas flow rate. The surface chemistry of untreated and plasma-treated PET fabrics was analyzed using attenuated total reflectance - Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The surface morphology was monitored as a function of exposure time using field emission scanning electron microscopy (FE-SEM) and atomic force spectroscopy (AFM). The colony count method was used to study the Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacterial adhesion on the surface. Polyethylene glycol (PEG) (molecular weight 1000) was used to immobilize the plasma-treated surface. The results showed a significant reduction in the bacterial adhesion to the functionalized PET fabric compared to untreated fabric. However, the immobilization of PEG on the PET surface inhibited bacterial adherence significantly and imparted antifouling behavior on the fabric surface. © 2025 Society of Chemical Industry.

Piezocomposites provide lightweight, flexible and scalable technologies for efficiently converting mechanical energy into electrical energy. For sustainable energy production, we examined a low-cost, biobased alternative to convert mechanical energy into piezoelectric energy. Hydroxyapatite (HA) having a particle size of 53.26 nm made from chicken eggshell waste was combined with polyurethane (PU) to produce piezoelectric composites. In situ polymerization was performed using aliphatic isocyanates, isophorone diisocyanate, poly(propylene glycol) and 1,4-butanediol. The piezoelectric properties of six different composite films with varying HA concentrations (0–25%) were optimized using a statistical mixture design approach. Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction analysis, dynamic mechanical analysis and scanning electron microscopy were utilized for physicochemical characterization. As the HA concentration was increased, the mechanical properties were enhanced, as a uniform dispersion of HA was observed within the PU matrix. An oscilloscope displayed an output voltage of 17.46 V at 16 Hz, with 3 N force applied to a 25% HA composite film. The dielectric constant, dielectric loss and resistivity are frequency functions, and impedance analysis showed low-frequency values with high dielectric properties. The present study has indicated that PU/HA biocomposites are cost-effective and lightweight and can be used in piezoelectric devices in biomedical and wearable electronics. © 2025 Society of Chemical Industry.

Due to the fact that the inter-turn insulation of frequency conversion motors is constantly subjected to harsh environments characterized by strong electric fields and high temperatures, higher requirements are imposed on the corona aging resistance and dielectric properties of inter-turn insulation materials. This study employed a hydrolysis–condensation method to prepare Si-B-Zr nano-oxide dispersion, which was then modified by doping with gas-phase SiO₂ to obtain Si-B-Zr/SiO₂ dispersion. Subsequently, 6FDA-type Si-B-Zr/SiO₂/FPI three-layer composite films were fabricated at different concentration gradients using in situ polymerization and dip-coating methods. The influence of Si-B-Zr/SiO₂ content on the corona resistance of the materials was systematically investigated, aiming to achieve excellent corona resistance while reducing the dielectric constant and dielectric loss. Experimental results demonstrated that compared with pure PI, the Si-B-Zr/SiO₂/FPI three-layer composite films with different doping amounts all exhibited significant improvement in corona resistance. In particular, the composite film with 10 wt% doping showed optimal performance under the test conditions of 155 °C and 80 kV mm⁻¹, with a corona resistance life reaching 8 h, which is 5.3 times that of pure PI and 3.6 times that of FPI. Meanwhile, this composite film displayed excellent dielectric properties, with a dielectric constant as low as 3.4 and a dielectric loss of only 0.0085 at operating frequency. © 2025 Society of Chemical Industry.

The present study aims to formulate and characterize novel composite materials consisting of miswak (Salvadora persica) and bioactive glass (45S5 and 54S4P) in different ratios (25%–75%, 50%–50% and 75%–25%). Miswak sticks were dried, ground into a fine powder and blended with bioactive glass powder obtained through a melt-derived technique at 1400 °C. The resulting composites, designated M25BG45, M50BG45, M75BG45, M25BG54, M50BG54 and M75BG54, were compacted into pellets 1 mm thick weighing approximately 150 mg using a manual hydraulic press and then sintered at 200 °C. Comprehensive characterization was conducted using gas chromatography–mass spectrometry, field emission SEM (FESEM), XRD, X-ray fluorescence spectroscopy and Fourier transform infrared (FTIR) spectroscopy. FESEM showed a homogeneous distribution of miswak particles within the bioactive glass matrix. XRD confirmed the amorphous nature of the bioactive glass and the distinctive peaks of miswak. FTIR spectra revealed absorption bands corresponding to both miswak and bioactive glass. The structural assessment of these composites, incorporating varying proportions of miswak with bioactive glass types 45S5 and 54S4P, provides valuable contributions towards optimizing bioactivity and biocompatibility. These findings suggest potential applications of the innovative miswak–bioactive glass composite in oral and dental healthcare. © 2025 Society of Chemical Industry.

Electrical storage continues to be a vital domain which contributes to more efficient, reliable and sustainable energy systems to meet the ever-growing demand for useable electrical energy. In recent years, the benefits of excellent mechanical and dielectric performance have led to a significant increase in interest in polymer-based composites for capacitive energy storage applications. Here, poly[(vinylidene fluoride)-co-trifluoroethylene]/0.5(BaZr_0.2Ti_0.8O)₃–0.5(Ba_0.7Ca_0.3TiO)₃/graphene oxide (PVDF-TrFE/BZT-BCT/GO) three-phase composite films were prepared via solvent casting followed by a hot-pressing method. X-ray diffraction and Fourier transform infrared and Raman spectroscopies were performed for structural confirmation of the composites. Dielectric study showed a maximum relative permittivity of 19.35 at 1 kHz, which is around 65% of that of pure PVDF-TrFE film. Static hysteresis loops were traced for all the samples, showing a maximum efficiency of 89.33% for a composite film. Positive up negative down measurements were also done to confirm the data obtained from static hysteresis analysis. Furthermore, the electromechanical coupling coefficient was analyzed using the resonance–antiresonance method, which gives an insight into the electromechanical properties in the synthesized films. The synthesized three-phase composites can therefore find application for piezoelectric purposes along with capacitive energy storage. © 2025 Society of Chemical Industry.

Improving the flame retardancy of epoxy thermosets without sacrificing mechanical properties, thermal decomposition stability and glass transition temperature (T_g) remains a challenge. In this study, a novel halogen-free flame retardant containing phosphorus/nitrogen (N₃P₃-DI) was synthesized from cyclotriphosphazene, p-hydroxybenzaldehyde, itaconic anhydride and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). Subsequently, N₃P₃-DI was used for flame-retardant modification of epoxy resin (EP). After the introduction of 10 wt% N₃P₃-DI, the EP thermoset achieved a limiting oxygen index of 29.6% and UL-94 V-0 rating. The peak heat release rate and total smoke production of the N₃P₃-DI-modified EP thermosets decreased by 48.4% and 27.5%, respectively, compared to those of the pure EP thermoset. Furthermore, the flame retardancy effect of N₃P₃-DI was confirmed by analysis of pyrolysis volatiles and the residual char of the thermoset. Compared with the pure EP thermoset, the N₃P₃-DI-modified EP thermoset also exhibited an increase of both the impact strength and flexural strength by 46.3% and 31.2%, respectively, demonstrating the effect of simultaneous toughening and strengthening. This is mainly due to the introduction of N₃P₃-DI reducing the crosslinking density of the thermoset network and increasing the free volume, while also improving the rigidity of the network chain. In addition, the modified EP thermosets still maintained high levels of T_g and thermal decomposition temperature. Therefore, this study provides an attractive strategy to simultaneously improve the flame retardancy, toughness and strength of epoxy thermosets, showing great prospects for future advanced applications in composites. © 2025 Society of Chemical Industry.

Two novel luminescent main-chain polybenzoxazine polymers, (Poly1)_main and (Poly2)^x_main, were synthesized and characterized to explore their structural, thermal, morphological and photophysical properties. Polymer (Poly1)_main was obtained via a Mannich condensation reaction without a catalyst, followed by thermal polymerization to produce the crosslinked polymer (Poly2)^x_main. Structural analyses using Fourier transform infrared spectroscopy and X-ray diffraction confirmed the successful formation of the polymers, with (Poly2)^x_main exhibiting a higher degree of crosslinking and partial ordering in an otherwise amorphous structure. Scanning electron microscopy imaging revealed that thermal polymerization significantly altered the morphology, transforming the porous structure of (Poly1)_main into a denser, layered morphology in (Poly2)^x_main. Thermogravimetric analysis and differential scanning calorimetry highlighted the improved thermal stability of (Poly2)^x_main due to extensive crosslinking. Photophysical studies showed that (Poly1)_main in solution exhibited yellow-green luminescence with a broad emission maximum at 522 nm and CIE coordinates (0.39, 0.48). In contrast, the powders of both polymers displayed sharp red luminescence with an emission peak at 658 nm and CIE coordinates (0.72, 0.27), attributed to molecular packing effects and exciton coupling in the solid state. These results underscore the interplay among structural, morphological and photophysical properties, highlighting the potential of these polymers in optoelectronics, sensing and luminescent materials. © 2025 Society of Chemical Industry.

Polymeric photocatalysts have emerged as promising alternatives to traditional metal-based catalysts due to their tunable properties, low cost and environmental friendliness. This review highlights the significant contributions of Professor Dr Kai A. I. Zhang in advancing the field of polymeric photocatalysis. By leveraging the structural versatility of polymers, Professor Zhang's work has developed innovative strategies to enhance light absorption, charge separation and catalytic activity. The review delves into the fundamental principles underlying polymeric photocatalysis, including exciton generation, charge carrier dynamics and surface reactions. It further explores the design considerations for optimizing polymer structures to achieve efficient photocatalytic performance. Key advancements in the synthesis and characterization of polymeric photocatalysts are discussed, along with their applications in various chemical transformations. Professor Zhang's pioneering work has opened up new avenues for the development of sustainable and efficient photocatalytic systems, driving the transition towards a greener future. © 2025 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Waterborne polyurethane dispersions are known as non-toxic, non-flammable, environmentally friendly products widely used in the coatings industry. We prepared a series of anionic dispersions based on the polyol from high-oleic soybean oil, isophorone diisocyanate and dimethylol propionic acid. Stable anionic dispersions were achieved when the acid content in formulations ranged from 7.7 to 10.8 wt%. All dispersions in this series had average particle sizes of 163–211 nm with unimodal size distribution. Utilization of the high-oleic oil, with three double bonds on average, and the resulting trifunctional polyol, renders crosslinked products with improved hydrophobicity and excellent chemical and physical properties. Also, it is beneficial in the control of the synthesis process since it reduces the chance of gelation during the dispersion preparation, compared to natural oils with higher unsaturation. The network formation in the systems used was analyzed by applying gelation theory to adjust optimal time for the dispersion in water. It was found that the isocyanate reaction with water always produces imperfect networks but the degree of imperfection can be controlled by the reaction time before dispersion in water. The polyurethane formulations with hard segment content of 39–46 wt% resulted in cured elastomeric films, with single glass transitions around room temperature and low phase separation, but good mechanical properties. The films exhibited enhanced hydrophobicity, low water absorption and water contact angle close to 90°, with promising applications in leather, wood, paper and plastic coatings. © 2025 Society of Chemical Industry.

With the rapid development of flexible optoelectronic devices, colorless polyimide films with excellent comprehensive performance have received widespread attention. In this work, a series of poly(amide-imide)s (PAIs) were synthesized by copolymerization of 4,4′-(hexafluoroisopropylidene)diphthalic anhydride, 1,4-cyclohexanedicarbonyl chloride (CHDC) and 2,2′-bis(trifluoromethyl)benzidine. The thermal dimensional stability and mechanical properties of the PAI films were improved due to the introduction of rigid rod-like amide bonds in the polymer chain. In addition, the PAIs with more trans-CHDC content showed higher glass transition temperature (T_g) and lower coefficient of thermal expansion (CTE). At the same time, the cooperative conformational transitions of cyclohexane rings in trans-CHDC promoted molecular chain slip and improved the film toughness. Moreover, with the introduction of the cyclohexane moiety, these PAIs had excellent optical transparency and solubility. In particular, PAI-6 exhibited high T_g of 364 °C, low CTE of 29.8 ppm K⁻¹, high transmittance of 87% at 400 nm, tensile modulus of 3.6 GPa and elongation at break of 9.7%. Therefore, the incorporation of cyclohexane structures and amide bonds into the main chain through copolymerization with CHDC provided a simple method for the synthesis of tough colorless PAIs with excellent comprehensive properties. © 2025 Society of Chemical Industry.