Polymers

13 pages, 1413 KB

Open AccessArticle

Evolution of Microplastics Released from Tea Bags into Water

by Alexander A. Yaroslavov, Anna A. Efimova, Tatyana E. Grokhovskaya, Anastasiia G. Badikova, Vasily V. Spiridonov, Denis V. Pozdyshev, Sergey V. Lyulin and Jose M. Kenny

Polymers 2025, 17(19), 2700; https://doi.org/10.3390/polym17192700 - 7 Oct 2025

Abstract

Eight different types of tea bags were investigated in this work using dynamic light scattering, electrophoretic mobility and nanoparticle tracking analysis methods to determine the concentration and size of released particles from the bag materials at different temperatures and times. Infrared spectroscopy and [...] Read more.

Eight different types of tea bags were investigated in this work using dynamic light scattering, electrophoretic mobility and nanoparticle tracking analysis methods to determine the concentration and size of released particles from the bag materials at different temperatures and times. Infrared spectroscopy and calorimetric methods confirmed that the bag material consisted of synthetic (nylon or polypropylene) or natural polymers (cellulose). The size of the released particles lies in the range of 200 nm^–1 µm with an initial bimodal distribution and with an average diameter of about 600 nm. The concentration of released particles increases with increasing temperature and brewing time. The released particles of synthetic polymers remain quite stable and are not affected by natural enzymes, while cellulose particles are easily degraded by the proteolytic complex Morikrase. When analyzing the electrophoretic mobility, it was found that the released particles have a negative surface charge, which probably determines the absence of cytotoxicity established on the epithelial cell line Caco-2 even at the maximum values of the observed particle concentrations (14 × 10⁹ particle/L for synthetic polymers and 170 × 10⁹ particle/L for cellulose). Full article

(This article belongs to the Special Issue Degradation and Stabilization of Polymer Materials 2nd Edition)

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22 pages, 4154 KB

Open AccessArticle

Evaluating the Performance of 3D-Printed Stab-Resistant Body Armor Using the Taguchi Method and Artificial Neural Networks

by Umur Cicek

Polymers 2025, 17(19), 2699; https://doi.org/10.3390/polym17192699 - 7 Oct 2025

Abstract

Additive manufacturing has promising potential for the development of 3D-printed protective structures such as stab-resistant body armor. However, no research to date has examined the impact of 3D printing parameters on the protective performance of such 3D-printed structures manufactured using fused filament fabrication [...] Read more.

Additive manufacturing has promising potential for the development of 3D-printed protective structures such as stab-resistant body armor. However, no research to date has examined the impact of 3D printing parameters on the protective performance of such 3D-printed structures manufactured using fused filament fabrication technology. This study, therefore, investigates the effects of five key printing parameters: layer thickness, print speed, print temperature, infill density (Id), and layer width, on the mechanical and protective performance of 3D-printed polycarbonate (PC) armor. A Taguchi L₂₇ matrix was employed to systematically analyze these parameters, with toughness, stab penetration depth, and armor panel weight as the primary responses. ANOVA results, along with the Taguchi approach, demonstrated that Id was the most influential factor across all print parameters. This is because a higher Id led to denser structures, reduced voids and porosities, and enhanced energy absorption, significantly increasing toughness while reducing penetration depth. Morphological analysis supported the statistical findings regarding the role of Id on the performance of such structures. With optimized printing parameters, no penetration to the armor panels was recorded, outperforming the UK body armor standard of a maximum permitted knife penetration depth of 8 mm. Moreover, an artificial neural network (ANN) utilizing the 5-14-12-3 topology was created to predict the toughness, stab penetration depth, and armor panel weight of 3D-printed armors. The ANN model demonstrated better prediction performance for stab penetration depth compared to the Taguchi method, confirming the successful application of such an approach. These findings provide a critical foundation for the development of high-performance 3D-printed protective structures. Full article

(This article belongs to the Section Polymer Analysis and Characterization)

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20 pages, 5489 KB

Open AccessArticle

Sustainable Cement Production: TEA-TIPA as Grinding Aids: Optimizing Ratios for Efficiency and Environmental Impact

by Veysel Kobya, Yahya Kaya, Fatih Eren Akgümüş, Yunus Kaya, Naz Mardani and Ali Mardani

Polymers 2025, 17(19), 2698; https://doi.org/10.3390/polym17192698 - 7 Oct 2025

Abstract

In line with sustainable construction goals, this study investigates the synergistic use of amine-based grinding aids (GAs), triethanolamine (TEA), and triisopropanolamine (TIPA) to enhance grinding performance and cement properties. GAs were physically blended at varying TEA/TIPA ratios, and their effects on grinding efficiency, [...] Read more.

In line with sustainable construction goals, this study investigates the synergistic use of amine-based grinding aids (GAs), triethanolamine (TEA), and triisopropanolamine (TIPA) to enhance grinding performance and cement properties. GAs were physically blended at varying TEA/TIPA ratios, and their effects on grinding efficiency, CO₂ emissions, and environmental footprint were assessed based on energy consumption per target Blaine fineness. The interaction of blended GAs with Ca²⁺ ions was modeled to understand adsorption behavior. Cement particle size distribution (PSD), Hausner ratio, Carr index, and angle of repose were analyzed to evaluate powder flowability. Scanning electron microscopy (SEM) was employed to examine microstructural changes. Finally, the Taguchi method statistically analyzed the effective parameters influencing system performance. Results demonstrated that the optimized blend containing 25% TEA and 75% TIPA improved grinding performance, enhanced polymer–ion interactions, refined PSD, and significantly increased powder flowability. Overall, the study underscores the potential of amine-based polymeric GAs in producing environmentally friendly, high-performance cement composites. Using a Taguchi design with the larger-is-better S/N criterion, the optimal formulation was determined to be 25% TEA and 75% TIPA at a dosage of 0.10%. ANOVA results indicated that the TEA content was the most significant factor, while the dosage had no statistically significant effect. Full article

(This article belongs to the Special Issue Polymers in Sustainable Construction Composites: Rheology, Mechanical Performance, and Durability)

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15 pages, 2336 KB

Open AccessArticle

Enhancing the Buckling Performance of Thin-Walled Plastic Structures Through Material Optimization

by Alexander Busch, Olaf Bruch and Dirk Reith

Polymers 2025, 17(19), 2697; https://doi.org/10.3390/polym17192697 - 7 Oct 2025

Abstract

Reducing material usage in plastic products is a key lever for improving resource efficiency and minimizing environmental impact. In thin-walled structures subjected to mechanical loading, material efficiency must be achieved without compromising structural performance. In particular, resistance to buckling, a critical failure mode, [...] Read more.

Reducing material usage in plastic products is a key lever for improving resource efficiency and minimizing environmental impact. In thin-walled structures subjected to mechanical loading, material efficiency must be achieved without compromising structural performance. In particular, resistance to buckling, a critical failure mode, must be taken into account during product development. Due to the large number of design and process variables, many of which are interdependent, optimization approaches are uncommon in the blow-molded packaging industry. This paper presents a sensitivity-based optimization approach to improve buckling resistance by modifying the product’s material distribution. Since the sensitivity is nonlinear and depends on the product’s deformation state, various methods are developed and tested to reduce the frame-wise sensitivity data to a single sensitivity vector suitable for optimization. These methods are then tested on common extrusion blow-molded products, achieving improvements in buckling load of up to 60%. This approach is transferable to other thin-walled structures across various engineering domains, offering a pathway toward lightweight yet load-compliant designs. Full article

(This article belongs to the Special Issue Mechanical Behaviors and Properties of Polymer Materials, 2nd Edition)

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24 pages, 3018 KB

Open AccessArticle

Kinetics of Carboxylic Acids Formation During Polypropylene Thermooxidation in Water Saturated with Pressurized Oxygen

by Vadim V. Zefirov, Polina S. Kazaryan, Andrey I. Stakhanov, Svetlana V. Stakhanova, Mikhail M. Ilyin, Ivan A. Godovikov, Elizaveta V. Shmakova, Andrey G. Terentyev, Alexander V. Dudkin, Elena P. Kharitonova, Marat O. Gallyamov and Alexei R. Khokhlov

Polymers 2025, 17(19), 2696; https://doi.org/10.3390/polym17192696 - 7 Oct 2025

Abstract

In this paper we study in detail the products formed during the process of water-assisted thermal oxidative decomposition (TOD) of polypropylene in the presence of pressurized oxygen. A set of techniques has shown that the main decomposition product in such a process is [...] Read more.

In this paper we study in detail the products formed during the process of water-assisted thermal oxidative decomposition (TOD) of polypropylene in the presence of pressurized oxygen. A set of techniques has shown that the main decomposition product in such a process is acetic acid with small amounts of other carboxylic acids (formic, propionic, succinic). The kinetics of carboxylic acid formation is studied by means of gas chromatography–mass-spectrometry as well as capillary electrophoresis, and the possible mechanisms behind the products formation are discussed. The role of water is considered based on the results obtained from substituting H₂O with D₂O in TOD. Compositions of residual oligomeric fractions as well as gas products are analyzed. Full article

(This article belongs to the Section Circular and Green Sustainable Polymer Science)

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16 pages, 1001 KB

Open AccessArticle

Production of Hydrogen-Rich Syngas via Biomass-Methane Co-Pyrolysis: Thermodynamic Analysis

by Haiyan Guo, Zhiling Wang, Kang Kang and Dongbing Li

Polymers 2025, 17(19), 2695; https://doi.org/10.3390/polym17192695 - 5 Oct 2025

Abstract

This study presents a thermodynamic equilibrium analysis of hydrogen-rich syngas production via biomass–methane co-pyrolysis, employing the Gibbs free energy minimization method. A critical temperature threshold at 700 °C is identified, below which methanation and carbon deposition are thermodynamically favored, and above which cracking [...] Read more.

This study presents a thermodynamic equilibrium analysis of hydrogen-rich syngas production via biomass–methane co-pyrolysis, employing the Gibbs free energy minimization method. A critical temperature threshold at 700 °C is identified, below which methanation and carbon deposition are thermodynamically favored, and above which cracking and reforming reactions dominate, enabling high-purity syngas generation. Methane addition shifts the reaction pathway towards increased reduction, significantly enhancing carbon and H₂ yields while limiting CO and CO₂ emissions. At 1200 °C and a 1:1 methane-to-biomass ratio, cellulose produces 50.84 mol C/kg, 119.69 mol H₂/kg, and 30.65 mol CO/kg; lignin yields 78.16 mol C/kg, 117.69 mol H₂/kg, and 19.14 mol CO/kg. The H₂/CO ratio rises to 3.90 for cellulose and 6.15 for lignin, with energy contents reaching 43.16 MJ/kg and 52.91 MJ/kg, respectively. Notably, biomass enhances methane conversion from 25% to over 53% while sustaining a 67% H₂ selectivity. These findings demonstrate that syngas composition and energy content can be precisely controlled via methane co-feeding ratio and temperature, offering a promising approach for sustainable, tunable syngas production. Full article

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13 pages, 3906 KB

Open AccessArticle

Influence of Post-Washing Time and Build Orientation on Mechanical Properties and Biocompatibility of Additively Manufactured Permanent Dental Resin Material

by Pei-Wen Peng, Jia-Syuan Chou, Le-Xin Chen, Po-En Chuang, Hidekazu Takahashi, Min-Chieh Hsieh and Wei-Fang Lee

Polymers 2025, 17(19), 2694; https://doi.org/10.3390/polym17192694 - 5 Oct 2025

Abstract

Background: Digital light processing (DLP) is widely used in permanent dental restorations for its precision and efficiency, yet the effects of build orientation and post-washing time on resin properties remain unclear. This study aims to investigate the factors that impact the performance and [...] Read more.

Background: Digital light processing (DLP) is widely used in permanent dental restorations for its precision and efficiency, yet the effects of build orientation and post-washing time on resin properties remain unclear. This study aims to investigate the factors that impact the performance and biocompatibility of DLP-printed dental resins. Methods: Specimens were additively manufactured using permanent dental resin at 0°, 15°, and 90° orientations and post-washed for 90, 120, or 150 s. Evaluated properties included dimensional accuracy, hardness, flexural strength and modulus, degree of conversion, water sorption/solubility, and cytotoxicity. Results: Build orientation and post-washing time significantly affected dimensional accuracy, with thickness showing the least deviation. Flexural strength (p < 0.001) and modulus (p < 0.01) were highest at the 0° orientation. Post-washing for 90 s led to the greatest water absorption, while solubility remained unaffected. Cell viability increased with longer post-washing times, peaking at 150 s, with significant effects observed on days 5 and 7 (p < 0.05). Conclusions: Build orientation significantly affected dimensional accuracy and flexural strength, while post-washing time had minimal impact on physical properties. Notably, extended post-washing improved cell viability and reduced cytotoxicity, indicating its potential to enhance the clinical biocompatibility of DLP-fabricated dental resin. Full article

(This article belongs to the Special Issue Applications of Polymer Biomedical Materials in Medicine and Dentistry)

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18 pages, 4920 KB

Open AccessArticle

Electrospray Beta-Glucan Particle Coated PVP/CA Electrospun Mat as a Potential Scaffold for Dental Tissue Regeneration

by Thanutham Somboonchokephisal, Pratchaya Tipduangta, Sarawut Kumphune and Tanida Srisuwan

Polymers 2025, 17(19), 2693; https://doi.org/10.3390/polym17192693 - 5 Oct 2025

Abstract

Regenerative endodontic procedures (REPs) are a promising treatment for immature teeth with pulpal necrosis. However, the outcomes remain unpredictable, partly due to scaffold limitations. Beta-glucan (BG), a bioactive polysaccharide with regenerative properties, may enhance scaffold performance. This study aimed to fabricate BG-coated polyvinylpyrrolidone/cellulose [...] Read more.

Regenerative endodontic procedures (REPs) are a promising treatment for immature teeth with pulpal necrosis. However, the outcomes remain unpredictable, partly due to scaffold limitations. Beta-glucan (BG), a bioactive polysaccharide with regenerative properties, may enhance scaffold performance. This study aimed to fabricate BG-coated polyvinylpyrrolidone/cellulose acetate (PVP/CA) electrospun scaffolds and evaluate their physicochemical properties and cell attachment. Electrospun scaffolds were fabricated by electrospinning a 10% w/v PVP/CA (70:30) solution in acetone and N,N-dimethylacetamide (2:1) (PC). BG (8% w/v in 1 M NaOH) was electrosprayed onto the scaffold at 0.1, 0.2, and 0.4 mL volumes, generating PC-BG01, PC-BG02, and PC-BG04, respectively. Scaffold characterization included SEM, FTIR, BG enzymatic assay, water absorbance, degradation, and cell adhesion assays. SEM images of the scaffolds exhibited smooth cylindrical fibers (547.3–585.9 nm diameter) with high porosity (42.37–49.91%). BG particles were confirmed by elemental analysis and BG enzymatic assay. At 28 days, the PC group showed significant fiber diameter and porosity reduction. BG particle degradation was observed at 14 and 28 days. Notably, BG-coated scaffolds significantly enhanced initial apical papilla cell adhesion at 1 and 24 h. These findings highlight the potential of BG-coated scaffolds as bioactive scaffolds for REPs. Full article

(This article belongs to the Special Issue Latest Research on Polysaccharides: Structure and Applications)

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24 pages, 4745 KB

Open AccessReview

Recent Progress on the Characterization of Polymer Crystallization by Atomic Force Microscopy

by Shen Chen, Min Chen and Hanying Li

Polymers 2025, 17(19), 2692; https://doi.org/10.3390/polym17192692 - 5 Oct 2025

Abstract

The crystallization behavior of polymers affects the structure of aggregated states, which influences the properties of materials. Atomic force microscopy (AFM) is a helpful characterization tool with high spatial resolution at the nanometer-to-micrometer scale and low-destruction imaging capabilities, making it an important means [...] Read more.

The crystallization behavior of polymers affects the structure of aggregated states, which influences the properties of materials. Atomic force microscopy (AFM) is a helpful characterization tool with high spatial resolution at the nanometer-to-micrometer scale and low-destruction imaging capabilities, making it an important means of studying polymer crystallography. This review is intended for scientists in polymer materials and physics, aiming to inspire how the rich applications of AFM can be harnessed to address fundamental scientific questions in polymer crystallization. This paper reviews recent advances in polymer crystallization characterization based on AFM, focusing on its applications in visualizing hierarchical polymer crystal structures (single crystals, spherulites, dendritic crystals, and shish kebab crystals), investigating crystallization kinetics (in situ monitoring of crystal growth), and analyzing structure–property relationships (structural changes under temperature and stress). Finally, we introduce the application of the latest AFM technology in addressing key issues in polymer crystallization, such as single-molecule force spectroscopy (SMFS) and atomic force microscopy–infrared spectroscopy (AFM-IR). As AFM technology advances toward higher precision, greater efficiency, and increased functionality, it is expected to deliver more exciting developments in the field of polymer crystallization. Full article

(This article belongs to the Section Polymer Physics and Theory)

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15 pages, 2550 KB

Open AccessArticle

Investigation of the Effects of Polymer-Based Grinding Aids on the Surface Chemistry Properties of Cement

by Kenan Çinku, Ebru Dengiz Özcan, Şenel Özdamar and Hasan Ergin

Polymers 2025, 17(19), 2691; https://doi.org/10.3390/polym17192691 - 4 Oct 2025

Abstract

Polymer-based superplasticizers represent an emerging class of additives in cement and concrete production with demonstrated effects on zeta potential, ion exchange, turbidity and rheological behavior during hydration. This study examines the influence of polymer-based grinding aids focusing on the dosage of A2 on [...] Read more.

Polymer-based superplasticizers represent an emerging class of additives in cement and concrete production with demonstrated effects on zeta potential, ion exchange, turbidity and rheological behavior during hydration. This study examines the influence of polymer-based grinding aids focusing on the dosage of A2 on the grinding performance of Portland cement. Among the tested additives, A2 exhibited superior dispersing ability and agglomeration-preventing activity, yielding a zeta potential of −8.98 mV. Correspondingly, the release of the ion concentration of Ca²⁺ decreased to 190 mg/L, while SO₄²⁻ increased to 400 mg/L, indicating enhanced ionic interaction at the optimal A2 dosage of 2.5 g. The turbidity tests further revealed that cement samples ground with 2.5 g of A2 remained homogeneously suspended for longer periods compared to other additives. Overall, the analysis of cement surface properties confirmed that polymer-based grinding aids, particularly A2, significantly improve the dispersion stability of cement particles during grinding. Full article

(This article belongs to the Special Issue Advanced Polymer Materials: Synthesis, Structure, and Properties)

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18 pages, 1472 KB

Open AccessArticle

Cassava Starch–Onion Peel Powder Biocomposite Films: Functional, Mechanical, and Barrier Properties for Biodegradable Packaging

by Assala Torche, Toufik Chouana, Soufiane Bensalem, Meyada Khaled, Fares Mohammed Laid Rekbi, Elyes Kelai, Şükran Aşgın Uzun, Furkan Türker Sarıcaoğlu, Maria D’Elia and Luca Rastrelli

Polymers 2025, 17(19), 2690; https://doi.org/10.3390/polym17192690 - 4 Oct 2025

Abstract

This study valorizes onion peel, an agro-industrial by-product rich in phenolic compounds and structural carbohydrates, for the development of cassava starch-based biodegradable films. The films were prepared using the solution casting method; a cassava starch matrix was mixed with a 2.5% glycerol solution [...] Read more.

This study valorizes onion peel, an agro-industrial by-product rich in phenolic compounds and structural carbohydrates, for the development of cassava starch-based biodegradable films. The films were prepared using the solution casting method; a cassava starch matrix was mixed with a 2.5% glycerol solution and heated to 85 °C for 30 min. A separate solution of onion peel powder (OPP) in distilled water was prepared at 25 °C. The two solutions were then combined and stirred for an additional 2 min before 25 mL of the final mixture was cast to form the films. Onion peel powder (OPP) incorporation produced darker and more opaque films, suitable for packaging light-sensitive foods. Film thickness increased with OPP content (0.138–0.218 mm), while moisture content (19.2–32.6%) and solubility (24.0–25.2%) decreased. Conversely, water vapor permeability (WVP) significantly increased (1.69 × 10⁻⁹–2.77 × 10⁻⁹ g·m⁻¹·s⁻¹·Pa⁻¹; p < 0.0001), reflecting the hydrophilic nature of OPP. Thermal analysis (TGA/DSC) indicated stability up to 245 °C, supporting applications as food coatings. Morphological analysis (SEM) revealed OPP microparticles embedded in the starch matrix, with FTIR and XRD suggesting electrostatic and hydrogen–bond interactions. Mechanically, tensile strength improved (up to 2.71 MPa) while elongation decreased (14.1%), indicating stronger but less flexible films. Biodegradability assays showed slightly reduced degradation (29.0–31.8%) compared with the control (38.4%), likely due to antimicrobial phenolics inhibiting soil microbiota. Overall, OPP and cassava starch represent low-cost, abundant raw materials for the formulation of functional biopolymer films with potential in sustainable food packaging. Full article

(This article belongs to the Special Issue Applications of Biopolymer-Based Composites in Food Technology)

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24 pages, 2320 KB

Open AccessArticle

PVA- Bentonite-Water Coatings: Experimental and Simulation Studies

by Sarojini Verma, George D. Verros and Raj Kumar Arya

Polymers 2025, 17(19), 2689; https://doi.org/10.3390/polym17192689 - 4 Oct 2025

Abstract

This study explores the drying kinetics and film formation behavior of polyvinyl alcohol (PVA)-based and PVA–bentonite composite coatings with initial thicknesses of approximately 2500 µm and 2000 µm. Four coating formulations were investigated, varying in PVA concentration and presence of bentonite as an [...] Read more.

This study explores the drying kinetics and film formation behavior of polyvinyl alcohol (PVA)-based and PVA–bentonite composite coatings with initial thicknesses of approximately 2500 µm and 2000 µm. Four coating formulations were investigated, varying in PVA concentration and presence of bentonite as an inorganic filler. The drying process was monitored through changes in solid concentration, residual solvent content, and film thickness over time. Results revealed that coatings with higher PVA content exhibit slower drying rates, due to the transition from evaporation-controlled to diffusion-limited mechanisms, attributed to polymer densification and reduced solvent diffusivity. In contrast, coatings incorporating bentonite dried more rapidly despite their similar or higher total solids content, indicating a beneficial role of bentonite in facilitating moisture transport. Thinner coatings demonstrated faster drying but retained the characteristic mechanistic transitions observed in thicker films. A simple realistic model to simulate the drying rate was also proposed. Overall, the study highlights the significant influence of formulation variables on drying behavior and final film properties, offering valuable guidance for the design and optimization of waterborne coatings in industrial applications. Full article

(This article belongs to the Section Polymer Membranes and Films)

18 pages, 2205 KB

Open AccessArticle

Design of Residual Stress-Balanced Transferable Encapsulation Platform Using Urethane-Based Polymer Superstrate for Reliable Wearable Electronics

by Sung-Hun Jo, Donghwan Kim, Chaewon Park and Eun Gyo Jeong

Polymers 2025, 17(19), 2688; https://doi.org/10.3390/polym17192688 - 4 Oct 2025

Abstract

Wearable and skin-mounted electronics demand encapsulation designs that simultaneously provide strong barrier performance, mechanical reliability, and transferability under ultrathin conditions. In this study, a residual stress-balanced transferable encapsulation platform was developed by integrating a urethane-based copolymer superstrate [p(IEM-co-HEMA)] with inorganic thin films. The [...] Read more.

Wearable and skin-mounted electronics demand encapsulation designs that simultaneously provide strong barrier performance, mechanical reliability, and transferability under ultrathin conditions. In this study, a residual stress-balanced transferable encapsulation platform was developed by integrating a urethane-based copolymer superstrate [p(IEM-co-HEMA)] with inorganic thin films. The polymer, deposited via initiated chemical vapor deposition (iCVD), offered over 90% optical transmittance, low RMS roughness (1–3 nm), and excellent solvent resistance, providing a stable base for inorganic barrier integration. An ALD Al₂O₃/ZnO nano-stratified barrier initially delivered effective moisture blocking, but tensile stress accumulation imposed a critical thickness of 30 nm, where the WVTR plateaued at ~2.5 × 10⁻⁴ g/m²/day. To overcome this limitation, a 40 nm e-beam SiO₂ capping layer was added, introducing compressive stress via atomic peening and stabilizing Al₂O₃ interfaces through Si–O–Al bonding. This stress-balanced design doubled the critical thickness to 60 nm and reduced the WVTR to 3.75 × 10⁻⁵ g/m²/day, representing an order-of-magnitude improvement. OLEDs fabricated on this ultrathin platform preserved J–V–L characteristics and efficiency (~4.5–5.0 cd/A) after water-assisted transfer and on-skin deformation, while maintaining LT80 lifetimes of 140–190 h at 400 cd/m² and stable emission for over 20 days in ambient storage. These results demonstrate that the stress-balanced encapsulation platform provides a practical route to meet the durability and reliability requirements of next-generation wearable optoelectronic devices. Full article

(This article belongs to the Section Polymer Applications)

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14 pages, 2032 KB

Open AccessArticle

Effect of Rock Crystal Addition on the Properties of Silicone Pressure-Sensitive Adhesives

by Adrian Krzysztof Antosik and Marcin Bartkowiak

Polymers 2025, 17(19), 2687; https://doi.org/10.3390/polym17192687 - 4 Oct 2025

Abstract

In the presented work, a natural mineral—rock crystal—was used as a filler to obtain new silicone adhesive tapes. It was expected that, properly crushed, this hard mineral, consisting almost entirely of silica (silicon dioxide), should enhance the thermal resistance and cohesion of the [...] Read more.

In the presented work, a natural mineral—rock crystal—was used as a filler to obtain new silicone adhesive tapes. It was expected that, properly crushed, this hard mineral, consisting almost entirely of silica (silicon dioxide), should enhance the thermal resistance and cohesion of the self-adhesive composition with no/or low reduction in the rest of performance properties of the products. For this purpose, tests were conducted on the functional properties of new self-adhesive tapes, such as adhesion, cohesion, and tack. The obtained results confirmed the scientific assumptions and the thermal resistance of adhesive layers reached over 225 °C. The material itself turned out to not agglomerate in the adhesive composition and to be compatible with it. The new self-adhesive materials have application potential and can be used as materials for special applications in the field of heating, e.g., in connecting pipes, where thermal resistance and thermal expansion are of immense importance. Full article

(This article belongs to the Section Polymer Processing and Engineering)

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31 pages, 5792 KB

Open AccessArticle

Development, Characterization, and Biological Evaluation of a Self-Healing Hydrogel Patch Loaded with Ciprofloxacin for Wound Dressings

by Wasan Al-Farhan, Osama H. Abusara, Mohammad Abu-Sini, Suhair Hikmat, Ola Tarawneh, Sameer Al-Kouz and Rania Hamed

Polymers 2025, 17(19), 2686; https://doi.org/10.3390/polym17192686 - 4 Oct 2025

Abstract

Hydrogels are crosslinked polymer chains that form a three-dimensional network, widely used for wound dressing due to their ability to absorb significant amounts of fluid. This study aimed to develop a hydrogel patch for wound dressing with self-healing properties, particularly for joints and [...] Read more.

Hydrogels are crosslinked polymer chains that form a three-dimensional network, widely used for wound dressing due to their ability to absorb significant amounts of fluid. This study aimed to develop a hydrogel patch for wound dressing with self-healing properties, particularly for joints and stretchable body parts, providing a physical barrier while maintaining an optimal environment for wound healing. Polyvinyl alcohol (PVA) and sodium carboxymethyl cellulose (Na CMC) were crosslinked with borax, which reacts with the active hydroxyl groups in both polymers to form a hydrogel. The patches were loaded with ciprofloxacin HCl (CIP), a broad-spectrum antibiotic used to prevent and treat various types of wound infections. Hydrogels were subjected to rheological, morphological, antimicrobial, self-healing, ex vivo release, swelling, cytotoxicity, wound healing, and stability studies. The hydrogels exhibited shear-thinning, thixotropic, and viscoelastic properties. Microscopic images of the CIP hydrogel patch showed a porous, crosslinked matrix. The antimicrobial activity of the patch revealed antibacterial effectiveness against five types of Gram-positive and Gram-negative bacteria, demonstrating a minimum inhibitory concentration of 0.05 μg/mL against E. coli. The swelling percentage was found to be 337.4 ± 12.7%. The cumulative CIP release percentage reached 103.7 ± 3.7% after 3 h, followed by zero-order release kinetics. The stability studies revealed that the crossover point shifted toward higher frequencies after 3 months of storage at room temperature, suggesting a relaxation in the hydrogel bonds. The cytotoxicity study revealed that the CIP hydrogel patch is non-cytotoxic. Additionally, the in vivo study demonstrated that the CIP hydrogel patch possesses wound-healing ability. Therefore, the CIP PVA/Na CMC/Borax patch could be used in wound dressing. Full article

(This article belongs to the Special Issue Biopolymers for Wound Management: Translation for Clinical Practice)

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21 pages, 25531 KB

Open AccessArticle

Effect of Processing Parameters on the Mechanical Behavior of 3D-Printed Basalt Moon Dust Reinforced Polylactic Acid Composites

by Lucian Alexander-Roy, Meelad Ranaiefar, Mrityunjay Singh and Michael Halbig

Polymers 2025, 17(19), 2685; https://doi.org/10.3390/polym17192685 - 4 Oct 2025

Abstract

Advanced composite materials and manufacturing technologies are critical to sustain human presence in space. Mechanical testing and analysis are needed to elucidate the effect of processing parameters on composites’ material properties. In this study, test specimens are 3D printed via a fused-filament fabrication [...] Read more.

Advanced composite materials and manufacturing technologies are critical to sustain human presence in space. Mechanical testing and analysis are needed to elucidate the effect of processing parameters on composites’ material properties. In this study, test specimens are 3D printed via a fused-filament fabrication (FFF) approach from a basalt moon dust-polylactic acid (BMD-PLA) composite filament and from pure PLA filament. Compression and tensile testing were conducted to determine the yield strength, ultimate strength, and Young’s modulus of specimens fabricated under several processing conditions. The maximum compressive yield strength for the BMD-reinforced samples is 27.68 MPa with print parameters of 100% infill, one shell, and 90° print orientation. The maximum compressive yield strength for the PLA samples is 63.05 MPa with print parameters of 100% infill, three shells, and 0° print orientation. The composite samples exhibit an increase in strength when layer lines are aligned with loading axis, whereas the PLA samples decreased in strength. This indicates a fundamental difference in how the composite behaves in comparison to the pure matrix material. In tension, test specimens have unpredictable failure modes and often broke outside the gauge length. A portion of the tension test data is included to help guide future work. Full article

(This article belongs to the Section Polymer Processing and Engineering)

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20 pages, 12618 KB

Open AccessArticle

Characterization of 3D-Printed Glass Fiber-Filled and Calcium Carbonate-Filled Polypropylene Components for Surgical Planning

by Núria Adell-Gómez, Irene Buj-Corral, Miquel Domingo-Espin, Jordi Llumà, J. Antonio Travieso-Rodríguez, Josep Rubio-Palau, César García-Fontecha, Alejandro Domínguez-Fernández and Arnau Valls-Esteve

Polymers 2025, 17(19), 2684; https://doi.org/10.3390/polym17192684 - 4 Oct 2025

Abstract

The purpose of this study is to characterize two different 3D-printed materials, glass fiber-filled polypropylene (GF-PP) and calcium carbonate-filled polypropylene (CaCO₃-PP), which make it possible to obtain surgical bone models at a reasonable cost. The methodology involved selecting two filaments, among [...] Read more.

The purpose of this study is to characterize two different 3D-printed materials, glass fiber-filled polypropylene (GF-PP) and calcium carbonate-filled polypropylene (CaCO₃-PP), which make it possible to obtain surgical bone models at a reasonable cost. The methodology involved selecting two filaments, among six, which showed better processability in the fused filament fabrication (FFF) process. Then, samples of the two selected materials were 3D printed, followed by characterization in terms of dimensional error, porosity, surface roughness, and mechanical strength. The results showed that both materials can be sterilized, with an increase in dimensional error and porosity after sterilization and slight changes in roughness and tensile strength. Additionally, anatomical models of mandible and femur bones were clinically validated by surgeons. Full article

(This article belongs to the Special Issue Medical Application of Polymer-Based Composites, 5th Edition)

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15 pages, 1026 KB

Open AccessArticle

Flexible, Stretchable, and Self-Healing MXene-Based Conductive Hydrogels for Human Health Monitoring

by Ruirui Li, Sijia Chang, Jiaheng Bi, Haotian Guo, Jianya Yi and Chengqun Chu

Polymers 2025, 17(19), 2683; https://doi.org/10.3390/polym17192683 - 3 Oct 2025

Abstract

Conductive hydrogels (CHs) have attracted significant attention in the fields of flexible electronics, human–machine interaction, and electronic skin (e-skin) due to their self-adhesiveness, environmental stability, and multi-stimuli responsiveness. However, integrating these diverse functionalities into a single conductive hydrogel system remains a challenge. In [...] Read more.

Conductive hydrogels (CHs) have attracted significant attention in the fields of flexible electronics, human–machine interaction, and electronic skin (e-skin) due to their self-adhesiveness, environmental stability, and multi-stimuli responsiveness. However, integrating these diverse functionalities into a single conductive hydrogel system remains a challenge. In this study, polyvinyl alcohol (PVA) and polyacrylamide (PAM) were used as the dual-network matrix, lithium chloride and MXene were added, and a simple immersion strategy was adopted to synthesize a multifunctional MXene-based conductive hydrogel in a glycerol/water (1:1) binary solvent system. A subsequent investigation was then conducted on the hydrogel. The prepared PVA/PAM/LiCl/MXene hydrogel exhibits excellent tensile properties (~1700%), high electrical conductivity (1.6 S/m), and good self-healing ability. Furthermore, it possesses multimodal sensing performance, including humidity sensitivity (sensitivity of −1.09/% RH), temperature responsiveness (heating sensitivity of 2.2 and cooling sensitivity of 1.5), and fast pressure response/recovery times (220 ms/230 ms). In addition, the hydrogel has successfully achieved real-time monitoring of human joint movements (elbow and knee bending) and physiological signals (pulse, breathing), as well as enabled monitoring of spatial pressure distribution via a 3 × 3 sensor array. The performance and versatility of this hydrogel make it a promising candidate for next-generation flexible sensors, which can be applied in the fields of human health monitoring, electronic skin, and human–machine interaction. Full article

(This article belongs to the Special Issue Semiflexible Polymers, 3rd Edition)

12 pages, 5822 KB

Open AccessArticle

Torsional Characteristics of Injection-Molded Hinges from Plastics and Glass Fiber-Reinforced Plastics

by Tran Minh The Uyen, Van-Thuc Nguyen, Xuan-Tien Vo, Pham Son Minh and Hai Nguyen Le Dang

Polymers 2025, 17(19), 2682; https://doi.org/10.3390/polym17192682 - 3 Oct 2025

Abstract

This study investigates the torsion characteristics of injection-molded flexural hinges manufactured from common polymers and plastic-based composites. The compliant mechanism provides a nearly constant torque over a specific rotational period. The flexural hinges are created via the injection molding technique, which has the [...] Read more.

This study investigates the torsion characteristics of injection-molded flexural hinges manufactured from common polymers and plastic-based composites. The compliant mechanism provides a nearly constant torque over a specific rotational period. The flexural hinges are created via the injection molding technique, which has the advantage of mass production and low price. The injection plastics are pure polypropylene (PP), acrylonitrile butadiene styrene (ABS), and polyamide 6 (PA6), and the injection composites are PA6 combined with glass fibers. The torsional moment of the ABS flexural hinge ranges from −0.2 to 0.94 N∙m. The torsional moment of the PP polymer typically ranges from −0.6 to 0.8 N∙m. The torsional moment of the PA6 polymer ranges from −0.2 to 1.0 N∙m. Interestingly, the torsional moment diagram for this polymer is comparable to that of ABS, with a stable pattern in both positive and negative ranges. Furthermore, in other words, the PP flexural range is greater than the ABS range. Both ABS and PA6 flexural hinges have a higher level of stability compared to the PP one due to the higher elastic modulus and higher strength of these polymers than the PP polymer. The PP flexural hinge has the lowest negative torsional moment (−0.6 N∙m) compared to ABS and PA hinges. PA6 flexural hinges also have the most stable torsional moment compared to pure polymer varieties. Adding 5% to 10% fiberglass (FG) significantly improves the torsional moment of composite flexural hinges. More flexural hinges from different polymer types should be investigated. Further research should conduct some statistical analysis to clarify the variations between the torques for the various materials. The findings improve our understanding of plastic flexure hinges and expand their applicability. Full article

(This article belongs to the Section Polymer Composites and Nanocomposites)

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