Polymers

62 pages, 1729 KiB

Open AccessReview

Biodegradable Polymers: Properties, Applications, and Environmental Impact

by Rashid Dallaev, Nikola Papež, Mohammad M. Allaham and Vladimír Holcman

Polymers 2025, 17(14), 1981; https://doi.org/10.3390/polym17141981 - 18 Jul 2025

The accelerating global demand for sustainable materials has brought biodegradable polymers to the forefront of scientific and industrial innovation. These polymers, capable of decomposing through biological processes into environmentally benign byproducts, are increasingly seen as viable alternatives to conventional plastics in sectors such [...] Read more.

The accelerating global demand for sustainable materials has brought biodegradable polymers to the forefront of scientific and industrial innovation. These polymers, capable of decomposing through biological processes into environmentally benign byproducts, are increasingly seen as viable alternatives to conventional plastics in sectors such as packaging, agriculture, and biomedicine. However, despite significant advancements, the field remains fragmented due to the diversity of raw materials, synthesis methods, degradation mechanisms, and application requirements. This review aims to provide a comprehensive synthesis of the current state of biodegradable polymer development, including their classifications, sources (natural, synthetic, and microbially derived), degradation pathways, material properties, and commercial applications. It highlights critical scientific and technological challenges—such as optimizing degradation rates, ensuring mechanical performance, and scaling up production from renewable feedstocks. By consolidating recent research findings and regulatory considerations, this review serves as a crucial reference point for researchers, material scientists, and policymakers. It strives to bridge knowledge gaps in order to accelerate the deployment of biodegradable polymers as integral components of a circular and low-impact material economy. Full article

(This article belongs to the Special Issue Biodegradable Polymers for Sustainable Solutions: Innovations and Applications)

21 pages, 2152 KiB

Open AccessArticle

Effect of 2000-Hour Ultraviolet Irradiation on Surface Degradation of Glass and Basalt Fiber-Reinforced Laminates

by Irina G. Lukachevskaia, Aisen Kychkin, Anatoly K. Kychkin, Elena D. Vasileva and Aital E. Markov

Polymers 2025, 17(14), 1980; https://doi.org/10.3390/polym17141980 - 18 Jul 2025

Abstract

This study focuses on the influence of prolonged ultraviolet (UV) irradiation on the mechanical properties and surface microstructure of glass fiber-reinforced plastics (GFRPs) and basalt fiber-reinforced plastics (BFRPs), which are widely used in construction and transport infrastructure. The relevance of the research lies [...] Read more.

This study focuses on the influence of prolonged ultraviolet (UV) irradiation on the mechanical properties and surface microstructure of glass fiber-reinforced plastics (GFRPs) and basalt fiber-reinforced plastics (BFRPs), which are widely used in construction and transport infrastructure. The relevance of the research lies in the need to improve the reliability of composite materials under extended exposure to harsh climatic conditions. Experimental tests were conducted in a laboratory UV chamber over 2000 h, simulating accelerated weathering. Mechanical properties were evaluated using three-point bending, while surface conditions were assessed via profilometry and microscopy. It was shown that GFRPs exhibit a significant reduction in flexural strength—down to 59–64% of their original value—accompanied by increased surface roughness and microdefect depth. The degradation mechanism of GFRPs is attributed to the photochemical breakdown of the polymer matrix, involving free radical generation, bond scission, and oxidative processes. To verify these mechanisms, FTIR spectroscopy was employed, which enabled the identification of structural changes in the polymer phase and the detection of mass loss associated with matrix decomposition. In contrast, BFRP retained up to 95% of their initial strength, demonstrating high resistance to UV-induced aging. This is attributed to the shielding effect of basalt fibers and their ability to retain moisture in microcavities, which slows the progress of photo-destructive processes. Comparison with results from natural exposure tests under extreme climatic conditions (Yakutsk) confirmed the reliability of the accelerated aging model used in the laboratory. Full article

(This article belongs to the Special Issue New Green Polymer Materials and Their Promising Applications Towards Artefacts Surface Treatments)

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19 pages, 3578 KiB

Open AccessArticle

Internal Dynamics of Pyrene-Labeled Polyols Studied Through the Lens of Pyrene Excimer Formation

by Franklin Frasca and Jean Duhamel

Polymers 2025, 17(14), 1979; https://doi.org/10.3390/polym17141979 - 18 Jul 2025

Abstract

Series of pyrene-labeled diols (Py₂-DOs) and polyols (Py-POs) were synthesized by coupling a number (n_PyBA) of 1-pyrenebutyric acids to diols and polyols to yield series of end-labeled linear (n_PyBA = 2) and branched (n_PyBA [...] Read more.

Series of pyrene-labeled diols (Py₂-DOs) and polyols (Py-POs) were synthesized by coupling a number (n_PyBA) of 1-pyrenebutyric acids to diols and polyols to yield series of end-labeled linear (n_PyBA = 2) and branched (n_PyBA > 2) oligomers, respectively. Pyrene excimer formation (PEF) between an excited and a ground-state pyrene was studied for the Py₂-DO and Py-PO samples by analyzing their fluorescence spectra and decays in tetrahydrofuran, dioxane, N,N-dimethylformamide, and dimethyl sulfoxide. Global model-free analysis (MFA) of the pyrene monomer and excimer fluorescence decays yielded the average rate constant (<k>) for PEF. After the calculation of the local pyrene concentration ([Py]_loc) for the Py₂-DO and Py-PO samples, the <k>-vs.-[Py]_loc plots were linear in each solvent, with larger and smaller slopes for the Py₂-DO and Py-PO samples, respectively, resulting in a clear kink in the middle of the plot. The difference in slope was attributed to a bias for PEF between pyrenes close to one another on the densely branched Py-PO constructs resulting in lower apparent [Py]_loc and <k> values. This study illustrated the ability of PEF to probe how steric hindrance along a main chain affects the dynamic encounters between substituents in multifunctional oligomers such as diols and polyols. Full article

(This article belongs to the Section Polymer Chemistry)

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17 pages, 3122 KiB

Open AccessArticle

Carbon:Nitrogen Ratio Affects Differentially the Poly-β-hydroxybutyrate Synthesis in Bacillus thuringiensis Isolates from México

by Marco Tulio Romero Sanchez, Shirlley Elizabeth Martínez Tolibia, Laura Jeannette García Barrera, Pavel Sierra Martínez, Jorge Noel Gracida Rodríguez, Valentín López Gayou and Víctor Eric López y López

Polymers 2025, 17(14), 1978; https://doi.org/10.3390/polym17141978 - 18 Jul 2025

Abstract

Poly-β-hydroxybutyrate (P(3HB)) represents a suitable alternative for plastic replacement, since it consists of intracellularly produced polyesters by different microorganisms including Bacillus thuringiensis (Bt). P(3HB) conserves most of the properties of petroleum-derived plastics; however, some drawbacks are the production costs, processing times, and bioseparation [...] Read more.

Poly-β-hydroxybutyrate (P(3HB)) represents a suitable alternative for plastic replacement, since it consists of intracellularly produced polyesters by different microorganisms including Bacillus thuringiensis (Bt). P(3HB) conserves most of the properties of petroleum-derived plastics; however, some drawbacks are the production costs, processing times, and bioseparation techniques, limiting its extended use. Bt has production advantages over other microorganisms, such as those growing in conventional or non-conventional substrates, with short periods of fermentation, which make it an interesting candidate to develop optimized production processes. In this work, we identified P(3HB) producers from 72 isolates of Bt, from which we selected four potential candidates. These isolates were cultivated under different carbon:nitrogen (C:N) ratios of 3, 7, 30, and 50 in a complex medium named (CM). Here, the best conditions for growth in Bt isolates were C:N 3 and 7 ratios, whereas for P(3HB) production they were C:N 7 and 30. Following this, an experiment in a bioreactor was conducted with isolate 81C with the selected C:N ratio of 30, where the produced P(3HB) achieved a maximum at 10 h. Fourier transform infrared spectroscopy (FTIR)was used to characterize flask and bioreactor cultures. It must be mentioned that although a higher concentration of medium was used, this did not improve P(3HB) accumulation. This research demonstrates that C:N ratios can differentially influence growth and P(3HB) accumulation in Bt isolates, which can serve as a reference to develop P(3HB) production processes using Bt as a microbial production platform. Full article

(This article belongs to the Special Issue Microbial Biopolymers: Trends in Synthesis, Modification, and Applications (2nd Edition))

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15 pages, 1445 KiB

Open AccessArticle

Thermal and Flammability Analysis of Polyurethane Foams with Solid and Liquid Flame Retardants: Comparative Study

by Dorota Głowacz-Czerwonka, Patrycja Zakrzewska, Beata Zygmunt-Kowalska and Iwona Zarzyka

Polymers 2025, 17(14), 1977; https://doi.org/10.3390/polym17141977 - 18 Jul 2025

Abstract

The thermal properties and flammability of rigid polyurethane foams (RPUFs) containing various flame retardants, including solid (melamine, expanded graphite (EG), Exolit OP 935, ammonium polyphosphate (APP)) and liquid (Roflam B7, Roflam PLO) types, added at 30 wt.% and 60 wt.% by weight have [...] Read more.

The thermal properties and flammability of rigid polyurethane foams (RPUFs) containing various flame retardants, including solid (melamine, expanded graphite (EG), Exolit OP 935, ammonium polyphosphate (APP)) and liquid (Roflam B7, Roflam PLO) types, added at 30 wt.% and 60 wt.% by weight have been evaluated. Thermogravimetric analysis (TGA) demonstrated enhanced thermal stability, with the maximum 10% weight loss temperature (292 °C, +34 °C vs. reference) observed for foams containing 60 wt.% Exolit OP 935 and APP. The limiting oxygen index (LOI) test demonstrated the optimal performance for 30 wt.% APP and melamine (26.4 vol.% vs. 18.7 vol.% reference). In the UL-94 test, Exolit OP 935 and APP achieved a V-0 rating. The 60 wt.% Exolit with an EG blend also demonstrated a substantial reduction in heat release rate. These findings underscore the cooperative effects of hybrid flame retardants, thereby supporting their utilization in fire-safe RPUFs for construction and transport. Full article

(This article belongs to the Special Issue Polyurethane Composites: From Material Innovations to Multifunctional Applications)

43 pages, 3663 KiB

Open AccessReview

Smart and Biodegradable Polymers in Tissue Engineering and Interventional Devices: A Brief Review

by Rashid Dallaev

Polymers 2025, 17(14), 1976; https://doi.org/10.3390/polym17141976 - 18 Jul 2025

Abstract

Recent advancements in polymer science have catalyzed a transformative shift in biomedical engineering, particularly through the development of biodegradable and smart polymers. This review explores the evolution, functionality, and application of these materials in areas such as tissue scaffolding, cardiovascular occluders, and controlled [...] Read more.

Recent advancements in polymer science have catalyzed a transformative shift in biomedical engineering, particularly through the development of biodegradable and smart polymers. This review explores the evolution, functionality, and application of these materials in areas such as tissue scaffolding, cardiovascular occluders, and controlled drug delivery systems. Emphasis is placed on shape-memory polymers (SMPs), conductive polymers, and polymer-based composites that combine tunable degradation, mechanical strength, and bioactivity. The synergy between natural and synthetic polymers—augmented by nanotechnology and additive manufacturing—enables the creation of intelligent scaffolds and implantable devices tailored for specific clinical needs. Key fabrication methods, including electrospinning, freeze-drying, and emulsion-based techniques, are discussed in relation to pore structure and functionalization strategies. Finally, the review highlights emerging trends, including ionic doping, 3D printing, and multifunctional nanocarriers, outlining their roles in the future of regenerative medicine and personalized therapeutics. Full article

(This article belongs to the Section Biobased and Biodegradable Polymers)

13 pages, 6483 KiB

Open AccessArticle

Polyelectrolyte Microcapsule-Assembled Colloidosomes: A Novel Strategy for the Encapsulation of Hydrophobic Substances

by Egor V. Musin, Alexey V. Dubrovskii, Yuri S. Chebykin, Aleksandr L. Kim and Sergey A. Tikhonenko

Polymers 2025, 17(14), 1975; https://doi.org/10.3390/polym17141975 - 18 Jul 2025

Abstract

The encapsulation of hydrophobic substances remains a significant challenge due to limitations such as low loading efficiency, leakage, and poor distribution within microcapsules. This study introduces a novel strategy utilizing colloidosomes assembled from polyelectrolyte microcapsules (PMCs). PMCs were fabricated via layer-by-layer (LbL) assembly [...] Read more.

The encapsulation of hydrophobic substances remains a significant challenge due to limitations such as low loading efficiency, leakage, and poor distribution within microcapsules. This study introduces a novel strategy utilizing colloidosomes assembled from polyelectrolyte microcapsules (PMCs). PMCs were fabricated via layer-by-layer (LbL) assembly on manganese carbonate (MnCO₃) or calcium carbonate (CaCO₃) cores, followed by core dissolution. A solvent gradient replacement method was employed to substitute the internal aqueous phase of PMCs with kerosene, enabling the formation of colloidosomes through self-assembly upon resuspension in water. Comparative analysis revealed that MnCO₃-based PMCs with smaller diameters (2.5–3 µm vs. 4.5–5.5 µm for CaCO₃) exhibited 3.5-fold greater stability, attributed to enhanced inter-capsule interactions via electrostatic and hydrophobic forces. Confocal microscopy confirmed the structural integrity of colloidosomes, featuring a liquid kerosene core encapsulated within a PMC shell. Temporal stability studies indicated structural degradation within 30 min, though 5% of colloidosomes retained integrity post-water evaporation. PMC-based colloidosomes exhibit significant application potential due to their integration of colloidosome functionality with PMC-derived structural features—semi-permeability, tunable shell thickness/composition, and stimuli-responsive behavior—enabling their adaptability to diverse technological and biomedical contexts. This innovation holds promise for applications in drug delivery, agrochemicals, and environmental technologies, where controlled release and stability are critical. The findings highlight the role of core material selection and solvent engineering in optimizing colloidosome performance, paving the way for advanced encapsulation systems. Full article

(This article belongs to the Section Polymer Applications)

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15 pages, 1397 KiB

Open AccessArticle

Impact of Temperature, pH, Electrolytes, Approach Speed, and Contact Area on the Coalescence Time of Bubbles in Aqueous Solutions with Methyl Isobutyl Carbinol

by Jorge H. Saavedra, Gonzalo R. Quezada, Paola D. Bustos, Joaquim Contreras, Ignacio Salazar, Pedro G. Toledo and Leopoldo Gutiérrez

Polymers 2025, 17(14), 1974; https://doi.org/10.3390/polym17141974 - 18 Jul 2025

Abstract

The prevention of bubble coalescence is essential in various industrial processes, such as mineral flotation, where the stability of air–liquid interfaces significantly affects performance. The combined influence of multiple physicochemical parameters on bubble coalescence remains insufficiently understood, particularly under conditions relevant to flotation. [...] Read more.

The prevention of bubble coalescence is essential in various industrial processes, such as mineral flotation, where the stability of air–liquid interfaces significantly affects performance. The combined influence of multiple physicochemical parameters on bubble coalescence remains insufficiently understood, particularly under conditions relevant to flotation. This study explores the key factors that influence the inhibition of bubble coalescence in aqueous solutions containing methyl isobutyl carbinol (MIBC), providing a systematic comparative analysis to assess the effect of each variable on coalescence inhibition. An experimental method was employed in which two air bubbles were formed from identical capillaries and brought into contact either head-to-head or side-by-side, then held until coalescence occurred. This setup allows for reliable measurements of coalescence time with minimal variability regarding the conditions under which the bubbles interact. The study examined the effects of several factors: temperature, pH, salt concentration and type, bubble approach speed, contact area, and contact configuration. The results reveal that coalescence is delayed at lower temperatures, alkaline pH conditions, high salt concentrations, and larger interfacial contact areas between bubbles. Within the range studied, the influence of approach speed was found to be insignificant. These findings provide valuable insights into the fundamental mechanisms governing bubble coalescence and offer practical guidance for optimizing industrial processes that rely on the controlled stabilization of air–liquid interfaces. By understanding and manipulating the factors that inhibit coalescence, it is possible to design more efficient and sustainable mineral flotation systems, thereby reducing environmental impact and conserving water resources. Full article

(This article belongs to the Special Issue Polymers at Surfaces and Interfaces)

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16 pages, 4723 KiB

Open AccessArticle

The Effect of the Fiber Diameter, Epoxy-to-Amine Ratio, and Degree of PVA Saponification on CO₂ Adsorption Properties of Amine-Epoxy/PVA Nanofibers

by Chisato Okada, Zongzi Hou, Hiroaki Imoto, Kensuke Naka, Takeshi Kikutani and Midori Takasaki

Polymers 2025, 17(14), 1973; https://doi.org/10.3390/polym17141973 - 18 Jul 2025

Abstract

Achieving carbon neutrality requires not only reducing CO₂ emissions but also capturing atmospheric CO₂. Direct air capture (DAC) using amine-based adsorbents has emerged as a promising approach. In this study, we developed amine-epoxy/poly(vinyl alcohol) (AE/PVA) nanofibers via electrospinning and in [...] Read more.

Achieving carbon neutrality requires not only reducing CO₂ emissions but also capturing atmospheric CO₂. Direct air capture (DAC) using amine-based adsorbents has emerged as a promising approach. In this study, we developed amine-epoxy/poly(vinyl alcohol) (AE/PVA) nanofibers via electrospinning and in situ thermal polymerization. PVA was incorporated to enhance spinnability, and B-staging of AE enabled fiber formation without inline heating. We systematically investigated the effects of electrospinning parameters, epoxy-to-amine ratios (E/A), and the degree of PVA saponification on CO₂ adsorption performance. Thinner fibers, obtained by adjusting spinning conditions, exhibited faster adsorption kinetics due to increased surface area. Varying the E/A revealed a trade-off between adsorption capacity and low-temperature desorption efficiency, with secondary amines offering a balanced performance. Additionally, highly saponified PVA improved thermal durability by minimizing side reactions with amines. These findings highlight the importance of optimizing fiber morphology, chemical composition, and polymer properties to enhance the performance and stability of AE/PVA nanofibers for DAC applications. Full article

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

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30 pages, 15336 KiB

Open AccessReview

Transparent Wood and Bamboo for Next-Generation Flexible Electronics: A Review

by Xiaorong Yin, Yaling Chai and Caichao Wan

Polymers 2025, 17(14), 1972; https://doi.org/10.3390/polym17141972 - 18 Jul 2025

Abstract

As naturally derived composite materials, flexible transparent wood and bamboo (FTW, FTB) present notable advantages, such as straightforward preparation, high light transmittance, exceptional environmental sustainability, superior mechanical properties, low thermal conductivity, and multifunctional capabilities. Their high conductivity and sensing capabilities provide viable alternatives [...] Read more.

As naturally derived composite materials, flexible transparent wood and bamboo (FTW, FTB) present notable advantages, such as straightforward preparation, high light transmittance, exceptional environmental sustainability, superior mechanical properties, low thermal conductivity, and multifunctional capabilities. Their high conductivity and sensing capabilities provide viable alternatives to conventional materials in flexible electronics. This article reviews the preparation of FTW and FTB through a top-down approach, beginning with examining how the microstructure of wood and bamboo affects the properties of these materials. It subsequently summarizes various manufacturing techniques and explores potential applications across diverse sectors. Finally, the article addresses current challenges and emphasizes the necessity for further research and innovation to promote the sustainable development of FTW and FTB in advanced applications. Full article

(This article belongs to the Section Smart and Functional Polymers)

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1 pages, 133 KiB

Open AccessRetraction

RETRACTED: Zoromba et al. Polymeric Solar Cell with 19.69% Efficiency Based on Poly(o-phenylene diamine)/TiO₂ Composites. Polymers 2023, 15, 1111

by M. Sh. Zoromba, M. H. Abdel-Aziz, A. R. Ghazy, N. Salah and A. F. Al-Hossainy

Polymers 2025, 17(14), 1971; https://doi.org/10.3390/polym17141971 - 18 Jul 2025

Abstract

The journal retracts the article “Polymeric Solar Cell with 19 [...] Full article

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

15 pages, 3095 KiB

Open AccessArticle

Effect of Silver/Reduced Graphene Oxide@Titanium Dioxide (Ag/rGO@TiO₂) Nanocomposites on the Mechanical Characteristics and Biocompatibility of Poly(Styrene-co-Methyl Methacrylate)-Based Bone Cement

by Mohan Raj Krishnan, Reem M. Alshabib and Edreese H. Alsharaeh

Polymers 2025, 17(14), 1970; https://doi.org/10.3390/polym17141970 - 18 Jul 2025

Abstract

This study reports the impact of a silver nanoparticles/reduced graphene oxide@titanium dioxide nanocomposite (Ag/rGO@TiO₂) on the mechanical and biocompatibility properties of poly(styrene-co-methylmethacrylate)/poly methyl methacrylate (PS-PMMA/PMMA)-based bone cement. The chemical, structural, mechanical, and thermal characteristics of Ag/rGO@TiO₂ nanocomposite-reinforced PS-PMMA bone cement [...] Read more.

This study reports the impact of a silver nanoparticles/reduced graphene oxide@titanium dioxide nanocomposite (Ag/rGO@TiO₂) on the mechanical and biocompatibility properties of poly(styrene-co-methylmethacrylate)/poly methyl methacrylate (PS-PMMA/PMMA)-based bone cement. The chemical, structural, mechanical, and thermal characteristics of Ag/rGO@TiO₂ nanocomposite-reinforced PS-PMMA bone cement ((Ag/rGO@TiO₂)/(PS-PMMA)/PMMA) were evaluated using Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction (XRD), nano-indentation, and electron microscopy. FT-IR, XRD, and transmission electron microscopy results confirmed the successful synthesis of the nanocomposite and the nanocomposite-incorporated bone cement. The elastic modulus (E) and hardness (H) of the ((Ag/rGO@TiO₂)/(PS-PMMA)/PMMA) bone cement were measured to be 5.09 GPa and 0.202 GPa, respectively, compared to the commercial counterparts, which exhibited E and H values of 1.7 GPa to 3.7 GPa and 0.174 GPa, respectively. Incorporating Ag/rGO@TiO₂ nanocomposites significantly enhanced the thermal properties of the bone cement. Additionally, in vitro studies demonstrated that the bone cement was non-toxic to the MG63 cell line. Full article

(This article belongs to the Special Issue Recent Advances and Applications of Polymer Nanocomposites)

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13 pages, 1694 KiB

Open AccessArticle

The Microscopic Mechanism of High Temperature Resistant Core-Shell Nano-Blocking Agent: Molecular Dynamics Simulations

by Zhenghong Du, Jiaqi Xv, Jintang Wang, Juyuan Zhang, Ke Zhao, Qi Wang, Qian Zheng, Jianlong Wang, Jian Li and Bo Liao

Polymers 2025, 17(14), 1969; https://doi.org/10.3390/polym17141969 - 17 Jul 2025

Abstract

China has abundant shale oil and gas resources, which have become a critical pillar for future energy substitution. However, due to the highly heterogeneous nature and complex pore structures of shale reservoirs, traditional plugging agents face significant limitations in enhancing plugging efficiency and [...] Read more.

China has abundant shale oil and gas resources, which have become a critical pillar for future energy substitution. However, due to the highly heterogeneous nature and complex pore structures of shale reservoirs, traditional plugging agents face significant limitations in enhancing plugging efficiency and adapting to extreme wellbore environments. In response to the technical demands of nanoparticle-based plugging in shale reservoirs, this study systematically investigated the microscopic interaction mechanisms of nano-plugging agent shell polymers (Ployk) with various reservoir minerals under different temperature and salinity conditions using molecular simulation methods. Key parameters, including interfacial interaction energy, mean square displacement, and system density distribution, were calculated to thoroughly analyze the effects of temperature and salinity variations on adsorption stability and structural evolution. The results indicate that nano-plugging agent shell polymers exhibit pronounced mineral selectivity in their adsorption behavior, with particularly strong adsorption performance on SiO₂ surfaces. Both elevated temperature and increased salinity were found to reduce the interaction strength between the shell polymers and mineral surfaces and significantly alter the spatial distribution and structural ordering of water molecules near the interface. These findings not only elucidate the fundamental interfacial mechanisms of nano-plugging agents in shale reservoirs but also provide theoretical guidance for the precise design of advanced nano-plugging agent materials, laying a scientific foundation for improving the engineering application performance of shale oil and gas wellbore-plugging technologies. Full article

(This article belongs to the Special Issue Polymers in Petroleum Engineering: Enhancing Performance and Sustainability)

26 pages, 2731 KiB

Open AccessReview

Recent Advances in PEEK for Biomedical Applications: A Comprehensive Review of Material Properties, Processing, and Additive Manufacturing

by Samreen Dallal, Babak Eslami and Saeed Tiari

Polymers 2025, 17(14), 1968; https://doi.org/10.3390/polym17141968 - 17 Jul 2025

Abstract

Polyetheretherketone (PEEK) is a high-performance thermoplastic polymer widely recognized for its distinct mechanical strength, chemical resistance, and biocompatibility. These characteristics make it suitable for a wide range of applications, particularly in medical, aerospace, chemical, and electronics fields. Conventional processing techniques, such as 3D [...] Read more.

Polyetheretherketone (PEEK) is a high-performance thermoplastic polymer widely recognized for its distinct mechanical strength, chemical resistance, and biocompatibility. These characteristics make it suitable for a wide range of applications, particularly in medical, aerospace, chemical, and electronics fields. Conventional processing techniques, such as 3D printing, molding, and extrusion, are widely employed for PEEK fabrication. This review critically examines recent advancements in PEEK research, with an emphasis on additive manufacturing techniques that are expanding its applications in the medical field. We provide an in-depth analysis of PEEK’s intrinsic properties, diverse processing methods, and current challenges that hinder its wider adoption. In addition to evaluating PEEK’s performance, this review compares it with alternative biomaterials—such as titanium and ultra-high molecular weight polyethylene (UHMWPE)—to explore its advantages and limitations in biomedical applications. Furthermore, this review discusses cost considerations, regulatory constraints, long-term clinical performance challenges, and failure modes that are essential for validating and ensuring the reliability of PEEK in clinical use. By synthesizing the recent literature, particularly from the last decade, this review highlights the significant potential of PEEK and underscores ongoing research efforts aimed at overcoming its limitations, paving the way for its broader implementation in advanced technological applications. Full article

(This article belongs to the Special Issue Advancements in Fused Deposition Modeling 3D Printing of Polymers: Material Properties and Thermal Behavior)

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11 pages, 2537 KiB

Open AccessArticle

Hydrosilylation vs. Piers–Rubinsztajn: Synthetic Routes to Chemically Cross-Linked Hybrid Phosphazene-Siloxane 3D-Structures

by Andrey S. Esin, Anna I. Chernysheva, Ekaterina A. Yurasova, Ekaterina A. Karpova, Vyacheslav V. Shutov, Igor S. Sirotin, Mikhail A. Soldatov, Mikhail V. Gorlov and Oleg A. Raitman

Polymers 2025, 17(14), 1967; https://doi.org/10.3390/polym17141967 - 17 Jul 2025

Abstract

Exploration of new ways for the direct preparation of cross-linked structures is a significant problem in terms of materials for biomedical applications, lithium batteries electrolytes, toughening of thermosets (epoxy, benzoxazine, etc.) with interpenetrating polymer network, etc. The possibility to utilize hydrosilylation and Piers–Rubinsztajn [...] Read more.

Exploration of new ways for the direct preparation of cross-linked structures is a significant problem in terms of materials for biomedical applications, lithium batteries electrolytes, toughening of thermosets (epoxy, benzoxazine, etc.) with interpenetrating polymer network, etc. The possibility to utilize hydrosilylation and Piers–Rubinsztajn reactions to obtain cross-linked model phosphazene compounds containing eugenoxy and guaiacoxy groups has been studied. It was shown that Piers–Rubinsztajn reaction cannot be used to prepare phosphazene-based tailored polymer matrix due to the catalyst deactivation by nitrogen atoms of main chain units. Utilizing the hydrosilylation reaction, a series of cross-linked materials were obtained, and their properties were studied by NMR spectroscopy, FTIR, DSC, and TGA. Rheological characterizations of the prepared tailored matrices were conducted. This work showed a perspective of using eugenoxy functional groups for the preparation of three-dimensional hybrid phosphazene/siloxane-based materials for various applications. Full article

(This article belongs to the Section Polymer Chemistry)

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16 pages, 5516 KiB

Open AccessArticle

Preparation of Barium Europium Phosphate and Its Performance in Acrylic Resin Anti-Corrosion Coating

by Xuying Deng, Jihu Wang, Shaoguo Wen, Jiale Zhao, Xue Zhang, Yicheng Zhao and Zhiying Deng

Polymers 2025, 17(14), 1966; https://doi.org/10.3390/polym17141966 - 17 Jul 2025

Abstract

Acrylic resin is a polymer with strong crosslinking density and strength, and it is commonly used as a matrix in water-based coatings. Barium europium phosphate (Ba₃Eu(PO₄)₃) is a novel functional filler that is expected to provide anti-corrosive [...] Read more.

Acrylic resin is a polymer with strong crosslinking density and strength, and it is commonly used as a matrix in water-based coatings. Barium europium phosphate (Ba₃Eu(PO₄)₃) is a novel functional filler that is expected to provide anti-corrosive effects to coatings. In this study, Ba₃Eu(PO₄)₃ was prepared by the high-temperature solid-phase method and applied to acrylic anti-corrosion coatings. The influence of the molar ratio of reactants on Ba₃Eu(PO₄)₃ purity was studied. The anti-corrosion performance of the coating was investigated. It was found that, when BaCO₃:Eu₂O₃:(NH₄)H₂PO₄ = 3:0.5:3 and the reaction was carried out at 950 °C for 1000 min, high-purity Ba₃Eu(PO₄)₃ can be obtained, according to XRD and EDS tests. SEM shows that Ba₃Eu(PO₄)₃ has good crystal morphology and a porous morphology. TEM revealed that its structure was intact. When Ba₃Eu(PO₄)₃ was added to a relative resin content of 5 wt%, the anti-corrosion performance of the coating was the best after 168 h, with the lowest Tafel current density of 9.616 μA/cm² and the largest capacitance arc curvature radius. The salt spray resistance test showed that the corrosion resistance of the 5 wt% Ba₃Eu(PO₄)₃ coating was also the best, which is consistent with the results of the electrochemical test. Ba₃Eu(PO₄)₃ as a pigment and filler can effectively improve the anti-corrosion performance of water-based industrial coatings. Full article

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

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19 pages, 3284 KiB

Open AccessArticle

A Novel Parametrical Approach to the Ribbed Element Slicing Process in Robotic Additive Manufacturing

by Ivan Gajdoš, Łukasz Sobaszek, Pavol Štefčák, Jozef Varga and Ján Slota

Polymers 2025, 17(14), 1965; https://doi.org/10.3390/polym17141965 - 17 Jul 2025

Abstract

Additive manufacturing is one of the most common technologies used in prototyping and manufacturing usable parts. Currently, industrial robots are also increasingly being used to carry out this process. This is due to a robot’s capability to fabricate components with structural configurations that [...] Read more.

Additive manufacturing is one of the most common technologies used in prototyping and manufacturing usable parts. Currently, industrial robots are also increasingly being used to carry out this process. This is due to a robot’s capability to fabricate components with structural configurations that are unattainable using conventional 3D printers. The number of degrees of freedom of the robot, combined with its working range and precision, allows the construction of parts with greater dimensions and better strength in comparison to conventional 3D printing. However, the implementation of a robot into the 3D printing process requires the development of novel solutions to streamline and facilitate the prototyping and manufacturing processes. This work focuses on the need to develop new slicing methods for robotic additive manufacturing. A solution for alternative control code generation without external slicer utilization is presented. The implementation of the proposed method enables a reduction of over 80% in the time required to generate new G-code, significantly outperforming traditional approaches. The paper presents a novel approach to the slicing process in robotic additive manufacturing that is adopted for the fused granular fabrication process using thermoplastic polymers. Full article

(This article belongs to the Special Issue Additive Manufacturing Based on Polymer Materials)

17 pages, 5663 KiB

Open AccessArticle

Ultra-Stable, Conductive, and Porous P-Phenylenediamine-Aldehyde-Ferrocene Micro/Nano Polymer Spheres for High-Performance Supercapacitors with Positive Electrodes

by Xin Wang, Qingning Li, Zhiruo Bian, Da Wang, Cong Liu, Zhaoxu Yu, Xuewen Li and Qijun Li

Polymers 2025, 17(14), 1964; https://doi.org/10.3390/polym17141964 - 17 Jul 2025

Abstract

Supercapacitors, with their remarkable attributes such as including a high power density, an extended cycle life, and inherent safety, have emerged as a major research area for electrochemical energy storage. In this paper, phenylenediamine and glyoxal were used as raw material to prepare [...] Read more.

Supercapacitors, with their remarkable attributes such as including a high power density, an extended cycle life, and inherent safety, have emerged as a major research area for electrochemical energy storage. In this paper, phenylenediamine and glyoxal were used as raw material to prepare p-phenylenediamine glyoxal (PGo) with one single step. p-phenylenediamine glyoxal-ferrocene (PGo-Fc_x, x = 1, 0.3, 0.2, 0.1) composites were synthesized based on a poly-Schiff base. FTIR and XRD results indicated that ferrocene doping preserves the intrinsic PGo framework while inducing grain refinement, as evidenced by the narrowing of the XRD diffraction peaks. SEM observations further revealed distinct morphological evolution. CV (cyclic voltammetry), EIS (electrochemical impedance spectroscopy), and GCD (galvanostatic charge–discharge) were conducted on PGo-Fc_x in order to examine its electrochemical performance. The PGo-Fc_0.3 in PGo-Fc_x electrode material had a specific capacitance of 59.6 F/g at a current density of 0.5 A/g and 36 F/g at a current density of 10 A/g. Notably, even after undergoing 5000 charging–discharging cycles at 10 A/g, the material retained 76.2% of its specific capacitance compared to the initial cycle. Therefore, taking conductive polymers and metal oxide materials for modification can improve the stability and electrochemical performance of supercapacitors. Full article

(This article belongs to the Special Issue Design and Characterization of Polymer-Based Electrode Materials)

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18 pages, 3981 KiB

Open AccessArticle

Copolymerization Behavior of Acrylamide-Based Polymers in Ionic Liquid Media

by Gaoshen Su, Jingyi Cui, Chaoyang Li, Ping Chen, Yong Li, Wenxue Jiang, Huan Yang, Xiaorong Yu and Liangliang Wang

Polymers 2025, 17(14), 1963; https://doi.org/10.3390/polym17141963 - 17 Jul 2025

Abstract

To examine how reaction media influence the copolymerization processes of acrylamide-based copolymers, [BMIM]Oac and water were utilized as the reaction media. Four copolymers P(AM-SSS) (H₂O), P(AM-UA) (H₂O), P(AM-SSS) (ILs), and P(AM-UA) (ILs) were synthesized using the soluble monomer sodium [...] Read more.

To examine how reaction media influence the copolymerization processes of acrylamide-based copolymers, [BMIM]Oac and water were utilized as the reaction media. Four copolymers P(AM-SSS) (H₂O), P(AM-UA) (H₂O), P(AM-SSS) (ILs), and P(AM-UA) (ILs) were synthesized using the soluble monomer sodium p-styrene sulfonate (SSS), the insoluble monomer 10-undecylenoic acid (UA), and acrylamide (AM). The properties of the copolymers were characterized using infrared spectroscopy and ¹H NMR, and the copolymerization rates of the monomers and the segment sequences of the copolymers were calculated. The results indicated that copolymerization of SSS in ionic liquids could reduce the length of the continuous units of AM in the copolymer’s molecular chain from 231.2866 to 91.1179, with a more uniform distribution within the molecular chain. The thermal stability and micro-morphology of the copolymers were tested using a synchronous thermal analyzer and scanning electron microscopy, and the resistance of the copolymer solutions to temperature, salt, and shear were evaluated. Comparisons revealed that the three-dimensional spatial structure formed by the copolymers in ionic liquids is robust and loose. When AM and SSS polymerize in [BMIM]Oac, the resulting copolymer exhibits a higher viscosity retention rate in temperature and shear resistance tests, with a thermal decomposition temperature reaching 260 °C. Conversely, when AM and UA polymerize in [BMIM]Oac, the copolymer demonstrates good salt resistance, maintaining a viscosity retention rate of 259.04% at a Na⁺ concentration of 200,000 mg/L. Therefore, the ionic liquid [BMIM]Oac can enhance the various application performances of copolymers formed by monomers with different solubilities and AM. Full article

(This article belongs to the Section Polymer Chemistry)

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