Next Issue
Volume 17, December-1
Previous Issue
Volume 17, November-1
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
9.7
4.9
Journals
Polymers
Volume 17
Issue 22
polymers-logo

Journal Menu

► Journal Menu

Journal Browser

► Journal Browser
share announcement

Polymers, Volume 17, Issue 22 (November-2 2025) – 124 articles

Cover Story (view full-size image): Colloidal stability and targeted delivery represent major challenges for mRNA therapeutics. Following intravenous administration, mRNA nanoparticles encounter protein adsorption and suffer from salt- and serum-induced aggregation. In this study, double-pH-responsive lipo-xenopeptides were combined with distinct PEGylated lipids to enhance colloidal stability and enable ligand-mediated targeted mRNA delivery. High transfection efficiency was maintained by pH-dependent PEG–lipid anchoring, which restored endosomal interaction. PEGylation additionally modulated the protein corona, thereby reducing protein adsorption. View this paper
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
19 pages, 27759 KB  
Article
Effects of Stoichiometric Variations in L-Arginine-Cured Epoxy Resins
by Melissa Walter, Dennis Gibhardt and Bodo Fiedler
Polymers 2025, 17(22), 3089; https://doi.org/10.3390/polym17223089 - 20 Nov 2025
Viewed by 1111
Abstract
For the purpose of reducing environmental and health risks in the production of fibre-reinforced polymers, biomolecules are increasingly examined as alternative resources. For example, amino acids can serve as curing agents for epoxy resins. However, their particular appearance and possible reactions differ from [...] Read more.
For the purpose of reducing environmental and health risks in the production of fibre-reinforced polymers, biomolecules are increasingly examined as alternative resources. For example, amino acids can serve as curing agents for epoxy resins. However, their particular appearance and possible reactions differ from those of conventional hardeners. To find a performance-optimised mixing ratio, it is relevant to know how deviations in the mixing ratio affect the reactions that take place and the resulting thermo-mechanical properties. Consequently, in this study, eleven mixing ratios of L-arginine-cured DGEBA without a catalyst or accelerator were investigated optically, thermo-mechanically, and via FTIR analysis. Based on the theoretical stoichiometric ratio, a wide range of good thermo-mechanical properties between stoichiometric ratios of R = 0.8 and R = 1.0 could be determined. However, this study led to an extension of a possible reaction mechanism for the curing of epoxides with amino acids, particularly L-arginine, postulating the thermo-induced deprotonation of α-NH3+ groups, etherification as part of successful crosslinking, and the unfavourable reactivity of the guanidium group in the case of L-arginine, shifting the optimal to slightly sub-stoichiometric configurations. Full article
(This article belongs to the Special Issue Advances in Epoxy-Based Materials)
►▼ Show Figures

Graphical abstract

18 pages, 7308 KB  
Article
Early Cell Adhesion of Periodontal Ligament Stem Cells on 3D Printed Polylactic Acid/Hydroxyapatite Scaffolds: An In Vitro Study
by Ildefonso Serrano-Belmonte, Javier Montero, Elena Guerrero-González, Alexandra Munteanu, Virginia Pérez-Fernández, Amparo Pérez-Silva and Ascensión Martínez-Cánovas
Polymers 2025, 17(22), 3088; https://doi.org/10.3390/polym17223088 - 20 Nov 2025
Viewed by 842
Abstract
Polylactic acid (PLA) and its composites with hydroxyapatite (HA) have been studied in the field of bone repair applications. The objective of this study was to evaluate the biocompatibility of PLA/HA at different concentrations and to analyze early adhesion of periodontal ligament stem [...] Read more.
Polylactic acid (PLA) and its composites with hydroxyapatite (HA) have been studied in the field of bone repair applications. The objective of this study was to evaluate the biocompatibility of PLA/HA at different concentrations and to analyze early adhesion of periodontal ligament stem cells (PDLSCs). Cells were seeded in two 24-well plates, each containing six disk-shaped samples of PLA/HA (10%, 15% and 20%) and six control samples and then examined using scanning electron microscopy. Twelve 96-well plates were prepared with different elution concentrations (1/1, 1/2, 1/4, and 1/8) to assess biocompatibility using MTT cell viability and Hoechst 33342 assays at 24, 48, and 72 h. PLA/HA 20% showed the highest early adhesion (p = 0.0057), with cells adopting a more elongated morphology. The MTT assay revealed no differences in viability between concentrations (p = 0.6196), whereas the Hoechst assay demonstrated the highest viability for PLA/HA 20% (p < 0.0001). Overall, PLA promoted cell adhesion, with the 20% formulation providing the greatest adhesion. All concentrations maintained high viability, and longer culture time enhanced both adhesion and viability. Full article
(This article belongs to the Special Issue Polymer/Ceramic Composites, 2nd Edition)
►▼ Show Figures

Figure 1

16 pages, 4244 KB  
Article
Polyethylene Terephthalate-Based Composites with Recycled Flakes and Chemically Resistant Glass Fibres for Construction
by Krzysztof Adam Ostrowski, Paulina Romańska, Radosław Piech, Tomasz M. Majka, Adam Michalik, Dariusz Bednarowski and Zuzanna Zawadzka
Polymers 2025, 17(22), 3087; https://doi.org/10.3390/polym17223087 - 20 Nov 2025
Cited by 1 | Viewed by 1337
Abstract
This study aims to evaluate the influence of glass fibre (GF) type and content on the thermal, mechanical, and morphological properties of polyethylene terephthalate (PET)-based composites containing post-consumer PET flakes, intended for mouldings exposed to cementitious environments (e.g., anchors). Two chemically resistant GFs [...] Read more.
This study aims to evaluate the influence of glass fibre (GF) type and content on the thermal, mechanical, and morphological properties of polyethylene terephthalate (PET)-based composites containing post-consumer PET flakes, intended for mouldings exposed to cementitious environments (e.g., anchors). Two chemically resistant GFs were compared: alkali-resistant (AR) fibres with soft sizing (SGFs) and electrical-/chemical-resistant (ECR) fibres with hard sizing (HGFs). Composites with fibre contents of 10–60 wt.% were prepared, with detailed analysis focused on 30 to 50 wt.%—the range typical for practical applications. AR fibres experienced greater shortening during processing, and their actual fibre content was lower than the intended value. Differential scanning calorimetry (DSC) revealed enhanced crystallisation kinetics for SGF composites, with higher crystallinity of the injection-moulded samples and elevated crystallisation temperatures (206–208 °C for SGF vs. 196–197 °C for HGF). Thermogravimetric analysis (TGA) indicated that thermal stability was primarily governed by fibre content; both SGF and HGF composites showed improved resistance compared to neat PET. Mechanical tests demonstrated that both fibre types effectively reinforced the matrix: HGF composites exhibited a higher elastic modulus (20.6 GPa for HGF-50 vs. 18.3 GPa for SGF-50), whereas SGF composites exhibited roughly 10–20% higher tensile, flexural, and impact strength, despite slightly lower fibre content. SEM analysis confirmed more uniform fibre distribution and fewer voids in SGF composites. These results highlight the importance of GF selection for PET composites in alkaline environments, taking into account the properties of the sizing film former and balancing trade-offs between mechanical performance, thermal stability, processability, and economic factors. Full article
(This article belongs to the Special Issue Fiber and Polymer Composites: Processing, Simulation, Properties and Applications, 3rd Edition)
►▼ Show Figures

Figure 1

42 pages, 17996 KB  
Article
How Method Matters: The Impact of Material Characterisation Techniques on Liquid Silicone Rubber Injection Moulding Simulations
by Maurício Azevedo, Silvester Bolka and Clemens Holzer
Polymers 2025, 17(22), 3086; https://doi.org/10.3390/polym17223086 - 20 Nov 2025
Viewed by 791
Abstract
Injection moulding of liquid silicone rubber (LSR) requires reliable computer-aided engineering simulations to support process optimisation, which in turn depend on accurate material data. In this study, thermo-physical and kinetic properties of a highly filled injection moulding (IM) grade of LSR were systematically [...] Read more.
Injection moulding of liquid silicone rubber (LSR) requires reliable computer-aided engineering simulations to support process optimisation, which in turn depend on accurate material data. In this study, thermo-physical and kinetic properties of a highly filled injection moulding (IM) grade of LSR were systematically characterised using complementary experimental approaches, and their impact on simulation fidelity was critically assessed. Specific heat capacity was measured using both modulated DSC and the standard sapphire method, revealing temperature dependence but no intrinsic change during curing, with sapphire-based data incorporating enthalpic effects more realistically for process prediction. Thermal conductivity was found to be nearly constant across the processing temperature range. Curing kinetics were investigated by calorimetry and rheology, with the former supporting an autocatalytic mechanism and the latter suggesting an nth-order model, reflecting differences in detection sensitivity and onset characterisation. When implemented into injection moulding simulations, viscosity primarily affected injection pressures, while differences in specific heat capacity and curing kinetics strongly influenced predicted curing profiles and cycle times. These results emphasise that dataset choice, particularly for curing-related parameters, is critical to achieving predictive accuracy in LSR injection moulding simulations. Unlike previous studies on LSR injection moulding, which typically adapt thermoplastic-inspired characterisation methods without systematically addressing their limitations, this work introduces an organised and comparative methodology to evaluate how different material characterisation techniques influence simulation outcomes. The proposed approach establishes a methodological framework that can guide future research and improve the reliability of process simulations for LSR and other polymeric systems. Full article
(This article belongs to the Special Issue Theoretical and Computational Polymers Science: Physics, Chemistry and Biology—2nd Edition)
►▼ Show Figures

Figure 1

25 pages, 4000 KB  
Article
Printability Metrics and Strain Rate Sensitivity of Multirole PVDF in Extrusion-Based Additive Manufacturing
by Nectarios Vidakis, Nektarios K. Nasikas, Nikolaos Michailidis, Maria Spyridaki, Nikolaos Mountakis, Apostolos Argyros, Vassilis M. Papadakis, Amalia Moutsopoulou and Markos Petousis
Polymers 2025, 17(22), 3085; https://doi.org/10.3390/polym17223085 - 20 Nov 2025
Cited by 5 | Viewed by 1063
Abstract
Recently, significant attention has been paid to the use of multirole materials in additive manufacturing (AM). Polyvinylidene fluoride (PVDF) is an ideal candidate material that has been selected for examination because of its unique characteristics. This study establishes a correlation between the macroscopic [...] Read more.
Recently, significant attention has been paid to the use of multirole materials in additive manufacturing (AM). Polyvinylidene fluoride (PVDF) is an ideal candidate material that has been selected for examination because of its unique characteristics. This study establishes a correlation between the macroscopic mechanical behavior and microscopic structural mechanisms, enabling the utilization of the deformation rate in tailoring the mechanical response of printed PVDF components. This research focuses on testing AM PVDF samples under different strain rates (10–300 mm/min), aiming to report their behavior under loading conditions compatible with the stochastic nature of real-life applications. The thermal (thermogravimetric analysis and differential scanning calorimetry) and rheological (viscosity and melt flow rate) properties were investigated along with their morphological characteristics (scanning electron microscopy). The response under combined dynamic and thermal loading was investigated through dynamic mechanical analysis, and the structural characteristics were investigated using spectroscopic techniques (Raman and energy-dispersive spectroscopy). The properties examined were the ultimate and yield strengths, modulus of elasticity, and toughness. Sensitivity index data are also provided. For completeness, the flexural strength, Charpy impact strength, and Vickers hardness were also evaluated, suggesting that the AM PVDF samples exhibit a resilient nature even when subjected to extremes regarding their strain rate versus their overall mechanical characteristics. PVDF exhibited a strain-hardening response with an increase in its strength of up to ~25% (300 mm/min) and a stiffness of ~15% (100 mm/min) as the loading speed of testing increased. Full article
(This article belongs to the Section Polymer Processing and Engineering)
►▼ Show Figures

Graphical abstract

54 pages, 2713 KB  
Review
Composite Electrolytes for Non-Lithium-Ion Batteries
by Qunting Qu, Lili Liu, Lijun Fu, Xuecheng Chen, Yuping Wu and Rudolf Holze
Polymers 2025, 17(22), 3084; https://doi.org/10.3390/polym17223084 - 20 Nov 2025
Cited by 1 | Viewed by 2472
Abstract
Composite electrolytes for applications in batteries and supercapacitors, i.e., in electrochemical energy technology, are gaining growing attention. In the absence of a commonly accepted definition, binary and ternary combinations of materials, e.g., a polymer with an electrolyte salt or electrolyte salt solution and [...] Read more.
Composite electrolytes for applications in batteries and supercapacitors, i.e., in electrochemical energy technology, are gaining growing attention. In the absence of a commonly accepted definition, binary and ternary combinations of materials, e.g., a polymer with an electrolyte salt or electrolyte salt solution and a third conductivity- and performance-enhancing constituent, are assumed as a definition of a composite electrolyte in the following review. Relevant fundamentals and reported research results, including explanations of the described effects of added ingredients and achieved improvements, are reviewed. Future perspectives and directions of further research are sketched. Full article
(This article belongs to the Special Issue Boosting Energy Storage Battery Performance and Safety with Polymers)
►▼ Show Figures

Graphical abstract

23 pages, 1548 KB  
Review
Review of Biopolymer Polyhydroxybutyrate (PHB) and Blends: Modification of Thermal and Mechanical Properties via Additive Manufacturing Processing
by Dan Li, Yunxia Yang, Ruochen Liu, Yufeng Wu and Fu Guo
Polymers 2025, 17(22), 3083; https://doi.org/10.3390/polym17223083 - 20 Nov 2025
Cited by 12 | Viewed by 4672
Abstract
The non-degradable polymers used in daily and commercial application are generally inexpensive; however, their excessive use leads to extensive environmental damage. In light of this, the demand for bio-derived, biocompatible, and biodegradable polymers increases since these materials are potential alternatives to petroleum-derived polymers. [...] Read more.
The non-degradable polymers used in daily and commercial application are generally inexpensive; however, their excessive use leads to extensive environmental damage. In light of this, the demand for bio-derived, biocompatible, and biodegradable polymers increases since these materials are potential alternatives to petroleum-derived polymers. Polyhydroxybutyrate (PHB), a class of highly crystalline thermoplastics derived from natural sources, offer significant environmental advantages over fossil fuel-based polymers due to their inherent biodegradability. This eco-friendly profile has spurred research into their commercial applications, ranging from food packaging to pharmaceuticals. However, processing challenges, particularly for polyhydroxybutyrate (PHB)—including high costs and the requirement for elevated temperatures—remain major obstacles. Additionally, PHB-based products are often brittle and exhibit inferior mechanical properties compared to conventional petroleum-based polymers such as polypropylene and polyethylene. This review comprehensively examines the state-of-the-art processing techniques for PHB and their composites. Key properties, such as mechanical performance, thermal behavior, and degradation characteristics, are scrutinized. Furthermore, the review explores mitigation strategies, such as blending and plasticization, aimed at overcoming the mechanical brittleness while upholding the principles of sustainability and maintaining a low carbon footprint. Full article
(This article belongs to the Special Issue Eco-Friendly Polymer-Based Materials: Design and Applications)
►▼ Show Figures

Figure 1

30 pages, 7520 KB  
Review
From Agricultural Residues to Sustainable Boards: Complex Network Analysis of Binderless Composites
by Lucia Rossi, Luis A. Miccio, Emiliano M. Ciannamea and Pablo M. Stefani
Polymers 2025, 17(22), 3082; https://doi.org/10.3390/polym17223082 - 20 Nov 2025
Viewed by 1736
Abstract
The transition toward sustainable panel technologies is driving intensive research on binderless boards and self-bonded lignocellulosic composites. Particleboard, an engineered wood composite made by hot pressing wood particles with synthetic adhesives, is among the most widely produced wood-based panels due to cost-effectiveness and [...] Read more.
The transition toward sustainable panel technologies is driving intensive research on binderless boards and self-bonded lignocellulosic composites. Particleboard, an engineered wood composite made by hot pressing wood particles with synthetic adhesives, is among the most widely produced wood-based panels due to cost-effectiveness and versatility. However, pressure on forest-derived raw materials and concern over formaldehyde emissions are accelerating the search for renewable resources and greener routes. Residues and underutilized materials from agro-industrial, food, and forestry sectors (such as cereal straws, sugarcane bagasse, brewer’s spent grain, and fruit-processing by-products) offer a sustainable alternative, enabling waste valorization, lowering environmental burdens, and supporting circular bioeconomy models. Binderless boards, produced without adhesives, exploit natural bonding among lignocellulosic components, including lignin softening, thermoplasticization, and covalent crosslinking during hot pressing. This review adopts a complex network approach to systematically map and analyze the scientific landscape of binderless board production. Using citation-based networks from curated seed papers and their first- and second-degree neighbors, we identify thematic clusters, with cluster “A” as the research core. The examination of this cluster, complemented by word-cloud analysis of titles and abstracts, highlights prevalent raw materials and key research lines, like raw-material sources and lignocellulosic composition, processing parameters, and pretreatment strategies. Based on these findings, brewer’s spent grain is selected as a representative case study for cost analysis. This approach synthesizes the state of the art and reveals emerging directions, research gaps, and influential works, providing a data-driven foundation for advancing self-bonded lignocellulosic composites. Full article
(This article belongs to the Special Issue Sustainable Biopolymer-Based Composites: Processing, Characterization, and Application II)
►▼ Show Figures

Figure 1

18 pages, 8198 KB  
Article
Degradation Mechanism of Perfluoroelastomer (FFKM) in the Acidic SC2 Solution of Semiconductor Radio Corporation of America (RCA) Cleaning
by Fandi Meng, Xiaolong Wen, Qishan Chen, Tao Zhang and Li Liu
Polymers 2025, 17(22), 3081; https://doi.org/10.3390/polym17223081 - 20 Nov 2025
Viewed by 1368
Abstract
The degradation behavior and mechanism of perfluoroelastomer (FFKM) in the acidic Standard Clean 2 (SC2) solutions were studied to facilitate their application in semiconductor Radio Corporation of America (RCA) cleaning processes. The results indicate significant degradation of the mechanical properties of FFKM in [...] Read more.
The degradation behavior and mechanism of perfluoroelastomer (FFKM) in the acidic Standard Clean 2 (SC2) solutions were studied to facilitate their application in semiconductor Radio Corporation of America (RCA) cleaning processes. The results indicate significant degradation of the mechanical properties of FFKM in the SC2 solution, characterized by surface pitting and particle formation, accompanied by progressive destruction of the cross-linked network. FTIR and XPS analyses revealed that degradation primarily occurs in the Trialkyl isocyanurate (TAIC) cross structure, while the main chain and side groups remain stable. HCl-induced acid hydrolysis and H2O2-induced oxidation act synergistically to break down the cross-link structures. This degradation compromised the filler matrix interface, leading to filler release and a consequent progressive deterioration of the overall properties of FFKM. This work elucidates the degradation mechanism of the FFKM in acidic environments, providing a scientific basis for the reliable design and lifetime prediction of FFKM components in semiconductor wet processes. Full article
(This article belongs to the Section Polymer Analysis and Characterization)
►▼ Show Figures

Figure 1

20 pages, 4485 KB  
Article
Innovative Carbon Black Replacement in Rubber Compound: Impact of Pyrolytic Carbon Black and Energy-Gypsum By-Products on Vulcanization and Properties
by Ivan Labaj, Juliána Vršková, Ivan Kopal, Andrej Dubec and Darina Ondrušová
Polymers 2025, 17(22), 3080; https://doi.org/10.3390/polym17223080 - 20 Nov 2025
Cited by 4 | Viewed by 1333
Abstract
This study focuses on the possibility of substituting the conventional carbon black filler N339 in a rubber compound, which also contains an energy-gypsum filler obtained as an industrial by-product, with an alternative carbon filler produced by pyrolysis of rubber waste. The proposed basic [...] Read more.
This study focuses on the possibility of substituting the conventional carbon black filler N339 in a rubber compound, which also contains an energy-gypsum filler obtained as an industrial by-product, with an alternative carbon filler produced by pyrolysis of rubber waste. The proposed basic rubber compound recipe demonstrated excellent mechanical properties, which were also verified through industrial tests. Practical application in transport systems confirmed the reliability, durability, and robustness of the compound ensuring long-term functionality even in demanding operating conditions. From an ecological point of view, the substitution of conventional fillers with pyrolytic carbon materials is being pursued to reduce the environmental burden of the material. The rheological and vulcanization characteristics of the compounds were subject to minimal changes of up to 8%. The increase in the scorch time value of the compounds can be positively assessed given that the optimal vulcanization time has decreased, which leads to a faster course of the vulcanization process. The most significant effect was a 56% reduction in tensile strength without significant effect on elongation at break. These results document the potential for complete replacement of traditional fillers in rubber systems while maintaining several functional parameters. Full article
(This article belongs to the Special Issue Novel Carbon-Based Polymer Composites: Preparation, Properties and Applications)
►▼ Show Figures

Graphical abstract

14 pages, 2022 KB  
Article
Stable and High-Performance Polyaniline/V2CTx MXene Composite Electrochromic Films Prepared by One-Pot Electrodeposition Method
by Dan Zhou, Qihuang Deng and Liping Yang
Polymers 2025, 17(22), 3079; https://doi.org/10.3390/polym17223079 - 20 Nov 2025
Cited by 1 | Viewed by 1022
Abstract
In order to improve the electrochromic performance of polyaniline (PANI), porous PANI/vanadium carbide MXene (PANI/V2CTx) composite electrochromic films were prepared via a rapid, facile, and low-cost one-pot electrodeposition method from an aqueous solution composed of aniline and V2 [...] Read more.
In order to improve the electrochromic performance of polyaniline (PANI), porous PANI/vanadium carbide MXene (PANI/V2CTx) composite electrochromic films were prepared via a rapid, facile, and low-cost one-pot electrodeposition method from an aqueous solution composed of aniline and V2CTx for the first time. The addition of V2CTx with a 2D layered structure results in the PANI/V2CTx composite films exhibiting significantly different morphologies, structures, electrochemical and electrochromic properties from the pure PANI film. The results show that compared with the pure PANI film, the composite film with optimum V2CTx content possesses superior electrochromic properties, such as higher optical contrast, switching speed, coloration efficiency, and cycling stability. The improved electrochromic properties of the composite film can be ascribed to its unique porous morphology and strong hydrogen bond and/or electrostatic interaction between PANI and V2CTx. This research demonstrates that the one-pot electrodeposition method and the prepared conductive PANI/MXene composite films have potential applications in various fields. Full article
(This article belongs to the Special Issue Material-Process-Structure Integrated Design for Advanced Polymeric Composites)
►▼ Show Figures

Graphical abstract

36 pages, 4270 KB  
Review
Advances in 3D Bioprinting and Microfluidics for Organ-on-a-Chip Platforms
by Natan Roberto de Barros, Samarah Vargas Harb, Cintia Delai da Silva Horinouchi, Larissa Bueno Tofani, Daniela Mayra dos Santos, Giovanna Blazutti Elias, Julia Carnelos Machado Velho, Ana Carolina de Aguiar, Monielle Sant’Ana and Ana Carolina Migliorini Figueira
Polymers 2025, 17(22), 3078; https://doi.org/10.3390/polym17223078 - 20 Nov 2025
Cited by 5 | Viewed by 5691
Abstract
The convergence of 3D bioprinting and microfluidics has revolutionized the development of organ-on-a-chip platforms, offering unprecedented opportunities in biomedical research and tissue engineering. This comprehensive review delves into the latest advancements in these technologies, highlighting their significance and transformative potential. The introduction provides [...] Read more.
The convergence of 3D bioprinting and microfluidics has revolutionized the development of organ-on-a-chip platforms, offering unprecedented opportunities in biomedical research and tissue engineering. This comprehensive review delves into the latest advancements in these technologies, highlighting their significance and transformative potential. The introduction provides an overview of 3D bioprinting, microfluidics, and organ-on-a-chip systems, emphasizing their critical roles in replicating physiological conditions and enhancing the precision of biomedical studies. The review aims to move beyond fundamental concepts, focusing on recent innovations and applications that have propelled these technologies to the forefront of research. In the realm of 3D bioprinting, the review explores the evolution of bioprinting techniques, including extrusion-based, inkjet, and laser-assisted methods and polymer-based biomaterials as matrices for in vitro tissue modeling. Technological breakthroughs such as high-resolution bioprinting, multi-material printing, and advanced bioink development are discussed, showcasing their impact on creating complex tissue structures. Innovations in bioinks, including printable polymer-based hydrogels and decellularized matrix bioinks, are highlighted for their ability to replicate tissue microenvironments more accurately. The review also covers microfluidic innovations, detailing advances in design and fabrication, including 3D printing and sensor integration. Key innovations in fluid dynamics and tissue integration are examined, demonstrating how these advancements enhance tissue modeling and mimic physiological perfusion. Developing multi-organ-on-a-chip systems and connecting multiple tissue types for systemic studies are also explored. Hence, integrating 3D bioprinting and microfluidics is a focal point, with discussions on how their convergence enhances organ-on-a-chip platforms. The review concludes by examining current challenges, such as scalability and regulatory hurdles, and future directions, including emerging technologies like 4D bioprinting and AI-driven tissue design. Full article
►▼ Show Figures

Figure 1

10 pages, 1977 KB  
Article
The Role of Time in the Structural Ordering of Poly-3-Hexylthiophene
by Ikemefuna Uba, Wisdom Jagoi, Brenden Forrest, Abdul-Majeed Hamidu, Kenneth Granderson, Emmanuel Baskerville, Lailah Outsey, Robert Birdow, Kamar Mann and Justice Ash
Polymers 2025, 17(22), 3077; https://doi.org/10.3390/polym17223077 - 20 Nov 2025
Viewed by 843
Abstract
An investigation into the influence of annealing time on structural ordering of Poly-3-Hexylthiophene has been performed via analyses of absorbance data, on the premise that ordering status is reflected in optoelectronic properties. Thin films heated from 0 to 100 min were examined. It [...] Read more.
An investigation into the influence of annealing time on structural ordering of Poly-3-Hexylthiophene has been performed via analyses of absorbance data, on the premise that ordering status is reflected in optoelectronic properties. Thin films heated from 0 to 100 min were examined. It was found that 20 min annealing yields a thin film with the highest structural ordering, with density of states of 6.08 ± 0.16 × 1038 m−3 kg−1 and carrier density of 5.54 ± 0.14 × 108 m−3. Samples annealed beyond 40 min exhibited optoelectronic traits midway between unannealed and 20 min annealing. The results demonstrated that during thermal treatment at a fixed temperature, the structural ordering and conformity continuously change with time, affecting the optoelectronic properties, thus emphasizing the necessity of the “time-profile” to determine the appropriate annealing time for a specific application of the polymer. Full article
(This article belongs to the Section Polymer Analysis and Characterization)
►▼ Show Figures

Figure 1

17 pages, 4246 KB  
Article
Hydrothermal Treatment to Enhance Supercritical CO2 Polycaprolactone Foaming Processes for Tissue Engineering Scaffolds
by Belén García-Jarana, Diego Valor, Ignacio García-Casas, Jezabel Sánchez-Oneto, Casimiro Mantell, Juan R. Portela and Clara Pereyra
Polymers 2025, 17(22), 3076; https://doi.org/10.3390/polym17223076 - 20 Nov 2025
Cited by 2 | Viewed by 927
Abstract
Hydrothermal treatment was investigated as a strategy to enhance the supercritical CO2 foaming process for the fabrication of polycaprolactone (PCL) scaffolds intended for tissue engineering applications. PCL samples were subjected to supercritical foaming at 300 bar and 40 °C for 60 min, [...] Read more.
Hydrothermal treatment was investigated as a strategy to enhance the supercritical CO2 foaming process for the fabrication of polycaprolactone (PCL) scaffolds intended for tissue engineering applications. PCL samples were subjected to supercritical foaming at 300 bar and 40 °C for 60 min, combined with hydrothermal treatments performed either before or after foaming at temperatures of 70–100 °C and pressures of 10–20 bar. The effects of these treatments on scaffold morphology, porosity, and mechanical behavior were evaluated using scanning electron microscopy, micro-computed tomography, and compression testing. The results showed that hydrothermal treatment prior to foaming significantly improved scaffold porosity from 16.5% (untreated PCL) up to 57.9% while increasing pore interconnectivity (up to 156.8 throats mm−3). Conversely, post-foaming hydrothermal treatment led to pore collapse and loss of structural integrity. The pre-treated scaffolds maintained compressive moduli within 2–12 MPa, consistent with values required for bone tissue engineering. In vitro degradation in PBS revealed a moderate increase in weight loss (~10% after 90 days), indicating that the hydrothermal step slightly accelerates polymer hydrolysis without compromising stability. These findings demonstrate that combining hydrothermal pre-treatment with supercritical CO2 foaming provides a solvent-free route to tailor scaffold morphology and mechanical performance, offering a sustainable alternative for the design of bioresorbable materials in regenerative medicine. Full article
(This article belongs to the Special Issue Polymer Scaffolds for Tissue Engineering, 3rd Edition)
►▼ Show Figures

Figure 1

24 pages, 2367 KB  
Review
Failure Modes and Influencing Factors of Rubber O-Ring Seals in High-Pressure Hydrogen Environments
by Zhenwei Lv, Sohail Yasin, Jianfeng Shi and Sheng Zeng
Polymers 2025, 17(22), 3075; https://doi.org/10.3390/polym17223075 - 20 Nov 2025
Cited by 3 | Viewed by 2521
Abstract
Rubber O-rings play a crucial role in ensuring the safety and reliability of high-pressure hydrogen systems. However, their degradation and failure under hydrogen exposure remain a major barrier to the long-term stability of sealing structures. This review summarizes the failure modes of rubber [...] Read more.
Rubber O-rings play a crucial role in ensuring the safety and reliability of high-pressure hydrogen systems. However, their degradation and failure under hydrogen exposure remain a major barrier to the long-term stability of sealing structures. This review summarizes the failure modes of rubber O-rings in high-pressure hydrogen environments and clarifies the interaction mechanisms among hydrogen permeation, swelling, rapid gas decompression (RGD), and mechanical fatigue. Compared with conventional high-pressure gases, hydrogen significantly accelerates the coupling of mechanical and physicochemical degradation, leading to multi-mechanism failure characterized by blistering, crack propagation, and modulus reduction. This review highlights the limitations of existing research, including insufficient long-term experimental data, simplified single-mechanism models, and the lack of multi-physics coupling analysis. Future research priorities are proposed in four aspects: (1) development of hydrogen blister-resistant elastomers, (2) collaborative optimization of sealing structures and materials, (3) in-depth investigation of tribological behavior under hydrogen cycling, and (4) establishment of predictive life models integrating multi-scale simulations and experimental validation. This work provides a state of the art of hydrogen-induced failure mechanisms and offers theoretical and engineering guidance for designing reliable sealing systems in next-generation hydrogen energy applications. Full article
(This article belongs to the Special Issue Advancements in Mechanical Properties and Material Testing in Polymer Science)
►▼ Show Figures

Figure 1

21 pages, 2517 KB  
Article
Anticancer Potential of Fisetin Against Glioblastoma: In Vitro Evaluation, Radiostability Assessment, and Preliminary PLGA Encapsulation
by Agnieszka Sobczak, Katarzyna Dominiak, Bartłomiej Sztenc, Barbara Jadach, Aneta Woźniak-Braszak, Mikołaj Baranowski, Paweł Bilski, Aleksandra Majchrzak-Celińska, Violetta Krajka-Kuźniak, Anna Jelińska, Maciej Stawny and Aleksandra Gostyńska-Stawna
Polymers 2025, 17(22), 3074; https://doi.org/10.3390/polym17223074 - 20 Nov 2025
Cited by 1 | Viewed by 1126
Abstract
(1) Background: Glioblastoma is the most common and aggressive primary brain tumor in adults, with a median survival time for patients treated with standard chemotherapy often of less than 1 year. Potential anticancer activity against glioblastoma is demonstrated by flavonoids, including fisetin (FIS). [...] Read more.
(1) Background: Glioblastoma is the most common and aggressive primary brain tumor in adults, with a median survival time for patients treated with standard chemotherapy often of less than 1 year. Potential anticancer activity against glioblastoma is demonstrated by flavonoids, including fisetin (FIS). Although, its clinical application is limited by poor solubility and chemical instability. This study aimed to conduct a preliminary evaluation of fisetin’s suitability for intravenous delivery by developing and characterizing FIS-loaded poly(lactic-co-glycolic acid) nanoparticles (FIS-PLGA-NPs) and assessing their in vitro cytotoxic potential against glioblastoma. (2) Methods: Six FIS-PLGA nanoparticle formulations were prepared via the emulsification–solvent evaporation method and evaluated for key physicochemical properties. The biological activity of fisetin was examined through cell cycle analysis and apoptosis assays, and the most promising formulation was further assessed using an MTT assay in U-138 MG glioblastoma cells. In parallel, pure fisetin was exposed to ionizing radiation, including the standard sterilization dose of 25 kGy, to evaluate its structural stability and suitability for terminal sterilization approaches. (3) Results: The selected formulation (NP4) exhibited a mean particle size of approximately 330 nm, a zeta potential of −7.2 mV, a polydispersity index of 0.25, and high encapsulation efficiency and drug loading of 83.58% and 13.93%, respectively. Despite its preliminary nature, this formulation retained cytotoxic activity in vitro. Moreover, pure fisetin maintained its structural and chemical integrity following radiation exposure, supporting the feasibility of radiation sterilization prior to nanoparticle incorporation. (4) Conclusions: These findings confirm the feasibility of combining radiosterilizable fisetin with PLGA-based nanoencapsulation and provide an initial foundation for the development of an injectable fisetin delivery system for glioblastoma treatment. Further optimization, particularly surface modification, will be required to enhance colloidal stability and systemic performance. Full article
(This article belongs to the Special Issue Recent Advances in Polymer-Based Drug Delivery Systems: 2nd Edition)
►▼ Show Figures

Figure 1

19 pages, 2242 KB  
Article
Formation and Interfacial Behavior of Chitosan–Alginate Interpolyelectrolyte Complexes: From Bulk Dispersions to Layer-by-Layer Films
by Rafael Martín-López, Ana Puente-Santamaría, Ramón G. Rubio, Francisco Ortega and Eduardo Guzmán
Polymers 2025, 17(22), 3073; https://doi.org/10.3390/polym17223073 - 20 Nov 2025
Viewed by 1343
Abstract
This study investigates the formation, physicochemical properties, and interfacial behavior of interpolyelectrolyte complexes (IPECs) composed of chitosan (CS) and sodium alginate (ALG) in aqueous media at pH 4.5. Using a combination of turbidity, ζ-potential, conductivity, and interfacial tension measurements, we explore how mixing [...] Read more.
This study investigates the formation, physicochemical properties, and interfacial behavior of interpolyelectrolyte complexes (IPECs) composed of chitosan (CS) and sodium alginate (ALG) in aqueous media at pH 4.5. Using a combination of turbidity, ζ-potential, conductivity, and interfacial tension measurements, we explore how mixing protocols and solution composition influence complex formation and stability. The results reveal that while ζ-potential remains largely unaffected by polymer concentration, turbidity and interfacial tension exhibit strong dependence, particularly near the stoichiometric charge equivalence point (Z ≈ 1). These findings suggest that neutral complexes formed at Z ≈ 1 display enhanced aggregation and surface activity, especially when ALG is in excess. Additionally, we extend the study to layer-by-layer (LbL) films assembled from CS and ALG, monitored via Quartz Crystal Microbalance with dissipation (QCM-D). The films exhibit quasi-linear growth and increasing elastic modulus with layer number, indicating uniform deposition and strong interlayer interactions. The viscoelastic properties of the multilayers further confirm the structural integrity and potential applicability of these systems in surface engineering and encapsulation technologies. Overall, this work provides a comprehensive understanding of CS–ALG complexation from bulk to interfacial assemblies. Full article
(This article belongs to the Section Polymer Physics and Theory)
►▼ Show Figures

Figure 1

16 pages, 1934 KB  
Article
Study on Performance and Structural Optimization of Concrete Bridge Deck Pavement Materials in Hot and Humid Areas
by Qinghua He, Qun Lu, Qiang Zhang, Chuan Xiong and Chengwei Xing
Polymers 2025, 17(22), 3072; https://doi.org/10.3390/polym17223072 - 20 Nov 2025
Viewed by 726
Abstract
This paper investigated the durability and structural performance of concrete bridge deck pavements under high temperature and high humidity conditions, focusing on three aspects: mix design, road performance evaluation, and structural optimization design. Through Marshall testing, the surface layer material SMA-13 and the [...] Read more.
This paper investigated the durability and structural performance of concrete bridge deck pavements under high temperature and high humidity conditions, focusing on three aspects: mix design, road performance evaluation, and structural optimization design. Through Marshall testing, the surface layer material SMA-13 and the middle layer material AC-13 were identified as suitable for hot and humid climates. The former exhibited excellent high-temperature stability and resistance to water damage, while the latter possessed good structural density and load-bearing capacity. A combination of high-temperature, low-temperature, water stability, and impermeability tests was used to systematically evaluate the adaptability of the mixture in hot and humid environments. Furthermore, the performance of different interfacial bonding materials was analyzed through interlaminar pull-out and direct shear tests. The results revealed that the incorporation of epoxy resin notably enhanced the interlayer bond strength and overall durability of the pavement system in hot and humid environments. The proposed “SMA-13 + epoxy resin + AC-13” configuration demonstrates promising potential for improving the mechanical performance and service life of concrete bridge deck pavements. Full article
(This article belongs to the Special Issue Polymer Materials for Pavement Applications)
►▼ Show Figures

Figure 1

15 pages, 1958 KB  
Article
Comparative Effects of Various Plasticizers on the Physicochemical Characteristics of Polyhydroxybutyrate (PHB) Film for Food Packaging
by Siwar Taamallah, Sabrine Douiri, Sherif M. A. S. Keshk, Rim Ben Arfi, Achraf Ghorbal, Khaled Charradi, Rached Ben Hassen, Hamadi Attia and Dorra Ghorbel
Polymers 2025, 17(22), 3071; https://doi.org/10.3390/polym17223071 - 20 Nov 2025
Cited by 2 | Viewed by 1178
Abstract
This work examined the effects of four plasticizers, glycerol (GLY), potassium phosphate (PHOS), polyethylene glycol (PEG), and soy lecithin (SL), on the structural, surface, thermal, optical, and mechanical properties of polyhydroxybutyrate (PHB) films. FTIR spectra demonstrated that these plasticizers maintained the PHB molecular [...] Read more.
This work examined the effects of four plasticizers, glycerol (GLY), potassium phosphate (PHOS), polyethylene glycol (PEG), and soy lecithin (SL), on the structural, surface, thermal, optical, and mechanical properties of polyhydroxybutyrate (PHB) films. FTIR spectra demonstrated that these plasticizers maintained the PHB molecular structure, while X-ray diffraction data proved that PHB crystallinity decreased upon adding SL, GLY, and PHOS. Under SEM, we discovered several defects in the plasticized samples, most of which were holes of distinct sizes and forms. The thermal analyses evaluated the impact of plasticization on PHB thermal processability, demonstrating that the material’s thermal stability improved, easing thermal processing due to the reduced melting peak temperatures (Tm) caused by all the additives assessed. While PEG, GLY, and PHOS reduced the hydrophilicity of the film, SL enhanced its affinity to water, as shown by the contact angle measurements. Reduced transparency resulted from adding 20% plasticizers with an increase of 345% in elongation at break and a decrease of 67% in elastic modulus compared to pristine PHB. Thus, SL proved to be the most promising of the four plasticizers used in terms of mechanical properties, crucial for PHB-based films for food packaging. Full article
(This article belongs to the Special Issue Polymer Packaging: Sustainable Innovations and Alternatives to Fossil-Based Materials)
►▼ Show Figures

Graphical abstract

14 pages, 607 KB  
Article
Shear Bond Strength of Biointeractive Restorative Materials to NeoMTA Plus and Biodentine
by Zübeyde Uçar Gündoğar, Gül Keskin and Merve Yaman Küçükersen
Polymers 2025, 17(22), 3070; https://doi.org/10.3390/polym17223070 - 20 Nov 2025
Cited by 1 | Viewed by 2888
Abstract
Background: The bonding compatibility between calcium silicate-based bioceramic cements and restorative materials is critical for long-term success in pediatric dentistry. This study compared the shear bond strength (SBS) of contemporary biointeractive restorative materials to two widely used bioceramics, NeoMTA Plus (NM) and Biodentine [...] Read more.
Background: The bonding compatibility between calcium silicate-based bioceramic cements and restorative materials is critical for long-term success in pediatric dentistry. This study compared the shear bond strength (SBS) of contemporary biointeractive restorative materials to two widely used bioceramics, NeoMTA Plus (NM) and Biodentine (BD). Methods: Eighty acrylic resin blocks with standardized cavities were filled with either NM or BD (n = 40 each) and subdivided into four restorative groups: nanohybrid composite (Filtek Ultimate), giomer (Beautifil II), bioactive restorative (Activa BioActive Restorative), and high-viscosity glass ionomer cement (Fuji IX GP Extra) (n = 10 each). All restorations followed a standardized etch-and-bond protocol. SBS was measured using a universal testing machine, and failure modes were assessed under a stereomicroscope. Data were analyzed using one-way ANOVA and Tukey’s HSD (p < 0.05). Results: BD exhibited significantly higher SBS values than NM (p < 0.001). In the BD group, Filtek Ultimate and Beautifil II achieved the highest and statistically comparable SBS, outperforming Activa BioActive Restorative and Fuji IX GP Extra (p < 0.05). In the NM group, no significant differences were found among materials. Adhesive failures predominated in NM (85%), while BD showed more cohesive failures (50%). Conclusions: Biodentine demonstrated superior bonding stability to restorative materials, with composite resin and giomer performing best. Giomer’s bioactivity and ion release make it a viable alternative to composite resin in suitable clinical contexts. Full article
(This article belongs to the Special Issue Polymers in Restorative Dentistry: 2nd Edition)
►▼ Show Figures

Graphical abstract

24 pages, 5914 KB  
Article
Impact of Printing Angle and Layer Height on the Mechanical Strength of PLA Reinforced with Chopped Carbon Fibres Using FDM 3D Printing
by Oscar Araque, Luz Adriana Sánchez-Echeverri and Ivonne X. Cerón
Polymers 2025, 17(22), 3069; https://doi.org/10.3390/polym17223069 - 19 Nov 2025
Cited by 4 | Viewed by 1664
Abstract
This research addresses the inherent limitations of low mechanical strength in FDM-printed materials by studying Carbon Fibre-reinforced Polylactic Acid (PLA-CF) composites. The low strength limitation of PLA-CF in FDM requires identifying the most suitable print angle and layer height parameters. This study maximises [...] Read more.
This research addresses the inherent limitations of low mechanical strength in FDM-printed materials by studying Carbon Fibre-reinforced Polylactic Acid (PLA-CF) composites. The low strength limitation of PLA-CF in FDM requires identifying the most suitable print angle and layer height parameters. This study maximises its structural robustness, filling a knowledge gap regarding its combined effect on tensile and flexural strength. The main objective was to find the best printing angle and layer height to improve mechanical performance, an important requirement for advancing additive manufacturing applications. A total of 210 FDM-printed specimens of the PLA-CF material were subjected to uniaxial tensile (ASTM D3039) and three-point bending (ASTM D790) tests, systematically varying the printing angles (0–90°) and layer heights of 0.1, 0.2, and 0.3 mm, following a full experimental design matrix. The ANOVA method has been used to determine the significant effect of factors on the established parameters. The findings indicated that both factors had a pronounced effect on the mechanical strength. Printing at lower angles (0° and 15°) provided, on average, greater resistance under tension (up to ~3920 N for a layer height of 0.1 mm), as well as under bending (up to 88.54 N for the same layer height), attributed to favourable fibre alignment and better load distribution. Conversely, higher angles (60° to 90°) drastically reduced strength (tensile failures due to delamination; bending forces as low as 30.02 N for a layer height of 0.3 mm, highlighting the weakness of perpendicular layer interfaces. Furthermore, lower layer height could result in better overall mechanical properties. In conclusion, FDM parameters with low print angles and reduced layer heights are essential for maximising the mechanical robustness and structural integrity of PLA-CF parts, enabling the identification of improved production processes for industrial applications and educational prototypes, among others. Full article
(This article belongs to the Section Polymer Processing and Engineering)
►▼ Show Figures

Figure 1

17 pages, 2877 KB  
Article
Modal Analysis–Based Detection of Barely Visible Impact Damage in Carbon/Epoxy Overwraps of Type-IV Polymer-Lined Pressure Vessels
by Mirosław Bocian, Mikołaj Kazimierczak, Barbara Kmiecik, Marek Kryspin and Maciej Panek
Polymers 2025, 17(22), 3068; https://doi.org/10.3390/polym17223068 - 19 Nov 2025
Viewed by 730
Abstract
A vibration-based protocol is presented for identifying barely visible impact damage (BVID) in type-IV composite-overwrapped pressure vessels (COPVs). A 1 kJ hemispherical-tip strike was applied to a fully pressurized vessel, which was subsequently depressurized and characterized by free–free experimental modal analysis over a [...] Read more.
A vibration-based protocol is presented for identifying barely visible impact damage (BVID) in type-IV composite-overwrapped pressure vessels (COPVs). A 1 kJ hemispherical-tip strike was applied to a fully pressurized vessel, which was subsequently depressurized and characterized by free–free experimental modal analysis over a 168-point grid. The frequency response functions (FRFs) at the impact meridian exhibited distinct peaks near 3.70, 4.34, and 4.90 kHz with larger amplitudes and lower coherence than at the diametrically opposite meridian, indicating local circumferential stiffness loss. A detailed finite element model of the liner, bosses, and carbon/epoxy overwrap was updated by idealizing a cylindrical sub-volume with a 90% reduction in orthotropic stiffness. The pristine and “damaged” numerical modal sets agreed closely (mean frequency error < 2%), and for most of the first 60 modes, the diagonal Modal Assurance Criterion (MAC) remained ≥ 0.90. However, in several nearly degenerate circumferential mode pairs, the diagonal MAC dropped to 0.49–0.88 because the local asymmetry rotated the eigenvectors within a common subspace, showing that classical MAC alone cannot expose such early-stage defects. Radial displacement scan-lines provided the missing spatial resolution. Modes whose antinodal regions intersect the dent showed pronounced local amplitude bulges and slight angular shifts in the peak toward the impact site, whereas modes with a nodal line across the damage were virtually unchanged. The combined use of FRF asymmetry, MAC screening, and scan-line deformation profiling localized the impact to the correct circumferential sector with centimeter-scale resolution along the scan ring, yielding predictive signatures for rapid, non-pressurized in situ assessment of impacted COPVs after depressurization. Full article
(This article belongs to the Special Issue Polymers and Polymer Composite Structures for Energy Absorption)
►▼ Show Figures

Figure 1

20 pages, 7391 KB  
Article
Thermoformability of Biopolymer Composites with Coffee Silverskin
by Ana C. Machado, Mariana Beltrão, Maria C. R. Castro, Carla I. Martins, Vasco Cruz, Pedro V. Rodrigues and Fernando M. Duarte
Polymers 2025, 17(22), 3067; https://doi.org/10.3390/polym17223067 - 19 Nov 2025
Viewed by 763
Abstract
The valorisation of agro-industrial residues in polymer composites represents a promising strategy for waste valorisation and the development of sustainable packaging materials. In this study, coffee silverskin (CSS), a lignocellulosic by-product, was added at concentrations up to 15 wt.% and processed into sheets [...] Read more.
The valorisation of agro-industrial residues in polymer composites represents a promising strategy for waste valorisation and the development of sustainable packaging materials. In this study, coffee silverskin (CSS), a lignocellulosic by-product, was added at concentrations up to 15 wt.% and processed into sheets via extrusion, followed by thermoforming using moulds with different draw ratios. Processability (MFI) and structural (FTIR), morphological (SEM, optical microscopy), thermal (TGA, DSC), and mechanical characterizations (tensile tests) were performed. Although the SEM images showed that CSS particles were well dispersed in the polymer matrix, and the mechanical behaviour was negatively affected when compared to the neat biopolymer. On the other hand, the addition of CSS increased the melt flow index, suggesting a lubricating/plasticizing effect. DSC results showed a reduction in cold crystallization temperature with CSS addition, confirming a nucleating effect, while glass transition and melting temperatures remained unchanged. Despite a narrower thermoforming temperature window with increasing CSS content, defect-free parts with adequate mould replication were successfully obtained for all formulations. Overall, the incorporation of CSS into PLA matrix provides a viable pathway for producing thermoformable as potential compostable composites, enabling waste valorisation within a circular bioeconomy framework. Full article
(This article belongs to the Special Issue Sustainable Biopolymer-Based Composites: Processing, Characterization, and Application II)
►▼ Show Figures

Graphical abstract

14 pages, 5870 KB  
Article
Recyclable Palladium-Polysiloxane Catalyst with Ultra-Low Metal Leaching for Drug Synthesis
by Ekaterina A. Golovenko, Polina P. Petrova, Dmitrii V. Pankin, Sergey V. Baykov, Vadim Yu. Kukushkin, Vadim P. Boyarskiy and Regina M. Islamova
Polymers 2025, 17(22), 3066; https://doi.org/10.3390/polym17223066 - 19 Nov 2025
Cited by 1 | Viewed by 907
Abstract
A carbon-supported palladium-containing polysiloxane macrocatalyst (Pd-PDMS) was developed for pharmaceutical-grade cross-coupling reactions. The catalyst demonstrates exceptional year-long stability at room temperature while maintaining full catalytic activity. Pd-PDMS efficiently promotes three pharmaceutically relevant reactions: Suzuki coupling (80% yield), copper-free Sonogashira coupling (90% yield at [...] Read more.
A carbon-supported palladium-containing polysiloxane macrocatalyst (Pd-PDMS) was developed for pharmaceutical-grade cross-coupling reactions. The catalyst demonstrates exceptional year-long stability at room temperature while maintaining full catalytic activity. Pd-PDMS efficiently promotes three pharmaceutically relevant reactions: Suzuki coupling (80% yield), copper-free Sonogashira coupling (90% yield at 55 °C), and Heck coupling (80% yield at 90 °C). The copper-free Sonogashira protocol eliminates toxic copper cocatalysts, phosphine ligands, and organic bases while operating under mild conditions. Most significantly, palladium contamination in products reaches ultra-low levels of 22 ppb (Sonogashira, Suzuki) and 167 ppb (Heck), representing a 60–450-fold improvement over European Medicines Agency requirements (10 ppm). The catalyst exhibits excellent recyclability without activity loss over multiple cycles, with simple washing protocols between uses. Scanning electron microscopy and X-ray photoelectron spectroscopy confirmed uniform Pd-PDMS coating on carbon fibers, while density functional theory calculations revealed specific coordination interactions between the palladium complex and carbon support at 3.26 Å distance. This convergence of pharmaceutical-grade metal contamination control, exceptional stability, and multi-reaction versatility establishes a significant advancement for sustainable cross-coupling catalysis in pharmaceutical applications. Full article
(This article belongs to the Special Issue Polymer-Based Catalytic Materials: Synthesis, Characterization, and Applications)
►▼ Show Figures

Figure 1

15 pages, 1256 KB  
Article
Performance Evaluation of HDPE-Bakelite Dual-Modified Asphalt Mixtures for Sustainable Pavements
by Muhammad Yasir, Naqeeb Ullah Khattak, Inamullah Khan and Menglim Hoy
Polymers 2025, 17(22), 3065; https://doi.org/10.3390/polym17223065 - 19 Nov 2025
Viewed by 786
Abstract
Flexible pavements using conventional bitumen are prone to suffering severe distress in hot climates, particularly rutting and moisture-induced damage. This study explores synergistic effects of waste-derived High-Density Polyethylene (HDPE) and Bakelite as dual modifiers for asphalt mixtures under Pakistan’s extreme climate, where summer [...] Read more.
Flexible pavements using conventional bitumen are prone to suffering severe distress in hot climates, particularly rutting and moisture-induced damage. This study explores synergistic effects of waste-derived High-Density Polyethylene (HDPE) and Bakelite as dual modifiers for asphalt mixtures under Pakistan’s extreme climate, where summer temperatures exceed 45 °C. Modified mixtures were prepared via wet process using HDPE (3%, 6%, 9% by weight of optimum bitumen content) combined with 6% Bakelite, evaluated against control mixtures (60/70 bitumen, NHA Class-B gradation). Performance assessment included indirect tensile strength, moisture susceptibility (TSR), resilient modulus, and Hamburg wheel tracking tests. The optimal 6%HDPE + 6%Bakelite formulation achieved remarkable improvements over control: 24.7% higher dry ITS (0.647 MPa), 48.7% higher conditioned ITS (0.617 MPa), 95.36% TSR (19% above specifications), 43.7% greater resilient modulus (4866 MPa), and 27.4% lower rutting depth (2.38 mm). These enhancements are likely associated with the development of a stiffer polymer resin network between HDPE and rigid Bakelite particles, which appears to provide a favorable balance between mixture flexibility and stiffness. At 9% HDPE, performance degradation in strength and moisture-related properties suggests possible phase separation, although rutting resistance continued improving. This dual-modification strategy provides sustainable, cost-effective enhancement of pavement durability in hot climates while addressing waste management challenges, offering significant potential for reducing maintenance costs and extending service life. Full article
(This article belongs to the Section Circular and Green Sustainable Polymer Science)
►▼ Show Figures

Figure 1

17 pages, 3299 KB  
Article
Mechanical Enhancement of Polychloroprene Adhesives via Reinforcement with Aluminum Oxide Nanofibers
by Il’ya Bril’, Anton Voronin, Yuri Fadeev, Ayraana Kuular, Marat Nureev, Fedor Ivanchenko, Mikhail Sumunin, Egor Moskvichev, Ivan Nemtsev, Sergey Dorbosmyslov, Alexandr Samoilo and Stanislav Khartov
Polymers 2025, 17(22), 3064; https://doi.org/10.3390/polym17223064 - 19 Nov 2025
Viewed by 929
Abstract
In this study, we demonstrated chloroprene rubber (CR)-based composites with the addition of synthesized alumina nanofibers (AONF) with a high aspect ratio (>1000). AONF were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). AONF were introduced by [...] Read more.
In this study, we demonstrated chloroprene rubber (CR)-based composites with the addition of synthesized alumina nanofibers (AONF) with a high aspect ratio (>1000). AONF were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). AONF were introduced by pre-dispersion. The resulting chloroprene rubber/aluminum oxide nanofiber (CR/AONF) composites were subjected to tensile and shear adhesive bonding tests. The tensile test results for the CR/AONF composites are 81% greater than those of the original CR composite (0.85 MPa and 1.54 MPa, respectively). Shear adhesive bonding tests were conducted for glass and steel. CR/AONF demonstrates a 213% (for steel) and 262% (for glass) increase in shear strength. The main strengthening mechanisms are reinforcement, CR adsorption on the AONF surface, and crack arrest. These results may expand our understanding of the potential of sealant strengthening using AONF. Full article
(This article belongs to the Special Issue Mechanical and Durability Properties of Polymer Materials)
►▼ Show Figures

Figure 1

19 pages, 1928 KB  
Article
Coupled Mechanical/Dielectric Behavior of Bio-Modified PP/PBS Nanocomposites Reinforced with Organically Modified Montmorillonite
by Sirine Taktak, Nouha Ghorbel, Sébastien Rondot, Omar Jbara and Ahmed Tara
Polymers 2025, 17(22), 3063; https://doi.org/10.3390/polym17223063 - 19 Nov 2025
Viewed by 878
Abstract
The performance of heterogeneous polymer-based materials is largely governed by the efficiency of interfacial adhesion and the strength of interactions between their constituent phases. This work mainly focuses on correlating the properties of dielectrically active interfaces, identified through broadband dielectric spectroscopy (BDS), with [...] Read more.
The performance of heterogeneous polymer-based materials is largely governed by the efficiency of interfacial adhesion and the strength of interactions between their constituent phases. This work mainly focuses on correlating the properties of dielectrically active interfaces, identified through broadband dielectric spectroscopy (BDS), with the mechanical behavior of heterogeneous polymer-based materials. Blends of polypropylene (PP) and biodegradable poly (butylene succinate) (PBS) were investigated across a wide composition range (100/0, 80/20, 70/30, 50/50, 20/80, and 0/100 PP/PBS). The interface between the immiscible PP and PBS phases induces a Maxwell–Wagner–Sillars (MWS) interfacial polarization in the permittivity spectrum. For the 80PP/20PBS formulation, the high activation energy of this polarization is well correlated with the material’s elevated tensile strength measured under uniaxial tension. A series of nanocomposites based on the 80PP/20PBS blend and reinforced with organically modified montmorillonite (Cloisite 20A) were thoroughly investigated. A strong correlation was established between their mechanical performance and the additional interfacial polarization arising from charge accumulation at the clay–matrix interface. The 80PP*/20PBS–3%C20 nanocomposite demonstrated superior matrix–filler adhesion, reflected by the highest activation energy of interfacial polarization and a marked increase in Young’s modulus (~22%) and zero-shear viscosity η0 (~44%). Complementary rheological measurements confirmed a substantial increase in viscosity and relaxation time for the 80PP/20PBS–3%C20 nanocomposites, indicating restricted chain mobility and the formation of a percolated network. Morphological analysis by SEM provided insights into the overall microstructure of the polymer blends and nanocomposites. These results demonstrate a direct correlation between interfacial structure, chain dynamics, and macroscopic performance in immiscible polymer blends and nanocomposites. Full article
(This article belongs to the Special Issue Polymer-Based Nanoparticles: Synthesis, Characterization and Applications)
►▼ Show Figures

Figure 1

11 pages, 1808 KB  
Article
Hierarchically Porous Polyaniline Exhibiting Enhanced Pseudocapacitive Property from Copolymerization of Aniline and Tetrakis(4-aminophenyl)methane
by Jinsoon Choi, Kyeong Eun Yeo and Ji-Woong Park
Polymers 2025, 17(22), 3062; https://doi.org/10.3390/polym17223062 - 19 Nov 2025
Viewed by 771
Abstract
Hierarchically porous polyaniline (PANI) was synthesized by oxidative copolymerization of tetrakis(4-aminophenyl)methane (TA) and aniline. Mixing TA with ammonium persulfate (APS) followed by aniline addition generated both tetra-arm star-shaped and linear PANIs; their insolubility in the reaction medium led to aggregation into solid precipitates. [...] Read more.
Hierarchically porous polyaniline (PANI) was synthesized by oxidative copolymerization of tetrakis(4-aminophenyl)methane (TA) and aniline. Mixing TA with ammonium persulfate (APS) followed by aniline addition generated both tetra-arm star-shaped and linear PANIs; their insolubility in the reaction medium led to aggregation into solid precipitates. During assembly, linear PANI formed nanofibers, while star-shaped PANI created short branches on the nanofiber surfaces. The TA molar fraction in the feed governed morphology and properties: higher TA increased specific surface area and the mesopore fraction but decreased electrical conductivity. Balancing this porosity–conductivity trade-off identified PANI (TA 3%) as optimal, exhibiting the highest CV current response with pseudocapacitive profiles, with a specific capacitance of 556 F g−1 versus 380 F g−1 for pristine PANI. Device-level galvanostatic charge–discharge yielded 239 F g−1 at 0.1 A g−1 (vs. 199 F g−1), while high-rate performance was limited by conductivity. These results show that introducing a small comonomer fraction to promote star-chain growth can produce hierarchical porosity and enhance pseudocapacitive behavior; further conductivity enhancement is expected to improve high-rate capacitance. Full article
(This article belongs to the Section Smart and Functional Polymers)
►▼ Show Figures

Figure 1

22 pages, 563 KB  
Review
Challenges of Alginate-Based Cast Films in Plastic-Free Food Packaging Applications: An Overview
by Sophie Schenk, Matthias Bucher, Michael Herrenbauer, Daniela Schmid and Markus Schmid
Polymers 2025, 17(22), 3061; https://doi.org/10.3390/polym17223061 - 19 Nov 2025
Cited by 6 | Viewed by 2560
Abstract
This review investigates the potential of sodium alginate, a biobased polysaccharide from brown algae, for food packaging applications. It analyzes the main challenges of cast films, including water vapor permeability, mechanical performance, and processability, and evaluates strategies to enhance these properties without chemical [...] Read more.
This review investigates the potential of sodium alginate, a biobased polysaccharide from brown algae, for food packaging applications. It analyzes the main challenges of cast films, including water vapor permeability, mechanical performance, and processability, and evaluates strategies to enhance these properties without chemical modification. Chemical modification is excluded because it would classify alginate as a plastic under EU regulations (PPWR, SUPD), conflicting with plastic-free packaging. The review synthesizes literature from 2004 to 2025 on pure sodium alginate films that are plasticized and ionically crosslinked without additional modifiers or nanofillers. While alginate provides excellent oxygen and fat barriers, its high water vapor permeability and brittleness limit broader use. Ionic crosslinking improves strength and water resistance, yet non-uniform networks remain a key challenge. Film performance is also influenced by drying temperature, mixing speed, molecular weight, and protein incorporation. This review differs from previous studies by highlighting the coupled effects of plasticization, ionic crosslinking, and processing limitations that together determine alginate’s industrial feasibility. Research gaps concern long-term stability and behavior under industrial packaging conditions. Given environmental and regulatory pressures to replace fossil-based plastics, sodium alginate shows strong potential as a scalable, renewable material for sustainable food packaging. Full article
(This article belongs to the Special Issue Biocompatible and Biodegradable Polymer Materials)
►▼ Show Figures

Figure 1

13 pages, 468 KB  
Review
Biocompatibility and Safety of 3D Printing Resins for Orthodontic Aligners: A Critical Review of Current Evidence
by Cecilia Goracci, Utkarsh Mangal, Stevan M. Čokić, Annalisa Mazzoni, Alessandro Vichi and Uros Josic
Polymers 2025, 17(22), 3060; https://doi.org/10.3390/polym17223060 - 19 Nov 2025
Cited by 2 | Viewed by 2299
Abstract
Orthodontic aligners 3D-printed in resin currently provide a viable alternative to thermoformed ones. However, concerns have been raised regarding their biocompatibility. This review addressed the available scientific evidence on the biological properties of marketed resins for 3D printing of orthodontic aligners, encompassing cytotoxicity, [...] Read more.
Orthodontic aligners 3D-printed in resin currently provide a viable alternative to thermoformed ones. However, concerns have been raised regarding their biocompatibility. This review addressed the available scientific evidence on the biological properties of marketed resins for 3D printing of orthodontic aligners, encompassing cytotoxicity, estrogenicity, biofilm formation, and oral soft tissues reactions. A comprehensive literature search of several databases was conducted and PRISMA guidelines were followed to summarize the retrieval. Eleven studies were included in the review. They provided information on only three marketed resins: Tera Harz TC-85 DAC and Tera Harz TA-28 (Graphy) and Clear-A (Senertek). For the last two materials, only one investigation has been performed. Despite the large variability in experimental protocols, the lack of cytotoxicity of Tera Harz TC-85 DAC was a consistent finding. Also, no estrogenic effect was detected for this resin, in line with the lack of any bis-phenol A precursor in its chemical composition. In two clinical studies, oral soft tissue reactions were reported as rare and non-serious occurrences. Biofilm adhesion was regarded as critical for the clinical safety of 3D-printed aligners. Standardization of in vitro protocols, also including more clinically relevant settings, chemical characterization of the resins’ eluates, and collection of additional in vivo data are advised to improve the quality of the evidence. Full article
(This article belongs to the Section Polymer Applications)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-124
Previous Issue
Next Issue
Back to TopTop