Polymers

21 pages, 2377 KiB

Open AccessArticle

Closed-Loop Recycling of Poly(vinyl butyral) Interlayer Film via Restabilization Technology

by Vasilis Nikitakos, Athanasios D. Porfyris, Konstantinos Beltsios, Rudolf Pfaendner, Beatriz Yecora, Angelica Perez, Filip Brkić, Filip Miketa and Constantine D. Papaspyrides

Polymers 2025, 17(3), 317; https://doi.org/10.3390/polym17030317 (registering DOI) - 24 Jan 2025

Abstract

Polyvinyl butyral (PVB) is a specialty polymer primarily used as an interlayer in laminated glass applications with no current circularity plan after the end of its life. This study presents a comprehensive recycling strategy for postconsumed PVB wastes based on a remelting–restabilization approach. [...] Read more.

Polyvinyl butyral (PVB) is a specialty polymer primarily used as an interlayer in laminated glass applications with no current circularity plan after the end of its life. This study presents a comprehensive recycling strategy for postconsumed PVB wastes based on a remelting–restabilization approach. Thermo-oxidative degradation of PVB was analyzed under heat and shear stress conditions in an internal mixer apparatus. The degradation mechanism of plasticized PVB (p-PVB) and unplasticized PVB (u-PVB) was identified as chain scission through melt flow rate (MFR), intrinsic viscosity (IV), and yellowness index (YI) characterization. Six different antioxidant (AO) formulations were screened for their effectiveness in inhibiting degradation in both neat u-PVB and p-PVB, as well as retrieved PVB. The phenolic antioxidants 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-di-tert-butylphenol were found to be the most effective ones based on MFR, oxidation onset temperature (OOT), and YI evaluations, while the optimal AO concentration was determined at 0.3% w/w. Furthermore, upscaling of the process was achieved by mixing virgin PVB and high-quality retrieved PVB wastes with AOs in a twin-screw extruder. Testing of the recycled samples confirmed that the selected AOs offered resilience against degradation at reprocessing and protection during the next service life of the material. Full article

(This article belongs to the Section Polymer Chemistry)

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30 pages, 1754 KiB

Open AccessReview

Three-Dimensional-Printed Photopolymer Resin Materials: A Narrative Review on Their Production Techniques and Applications in Dentistry

by Özge Mine Yüceer, Esra Kaynak Öztürk, Elif Su Çiçek, Nagehan Aktaş and Merve Bankoğlu Güngör

Polymers 2025, 17(3), 316; https://doi.org/10.3390/polym17030316 (registering DOI) - 24 Jan 2025

Abstract

Additive manufacturing (3D printing) has transformed dentistry by providing solutions with high precision and accuracy achieved through digital workflows, which facilitate the creation of intricate and personalized structures. Additionally, 3D printing promotes cost efficiency by reducing material waste and errors while enabling on-demand [...] Read more.

Additive manufacturing (3D printing) has transformed dentistry by providing solutions with high precision and accuracy achieved through digital workflows, which facilitate the creation of intricate and personalized structures. Additionally, 3D printing promotes cost efficiency by reducing material waste and errors while enabling on-demand production, minimizing the need for extensive inventories. Recent advancements in 3D-printed resin materials have enhanced their clinical applications by improving mechanical strength, biocompatibility, esthetics, and durability. These innovations have facilitated the fabrication of complex and patient-specific structures, such as dental prostheses, surgical guides, and orthodontic appliances, while significantly reducing production time and material waste. Ongoing research and innovation are expected to strengthen resin properties, including strength, translucency, and durability, broadening their clinical applications. The ongoing evolution of 3D printing technology is poised to play a critical role in driving personalized treatments, streamlining clinical workflows, and shaping the future of dental care. This narrative review comprehensively examines the production techniques and clinical applications of 3D-printed photopolymer resins across various dental specialties, including prosthodontics, orthodontics, pediatric dentistry, maxillofacial surgery, periodontology, endodontics, and conservative dentistry. Additionally, the review provides insight into the transformative impact of these technologies on patient care, highlights existing challenges, and suggests future directions for advancing resin properties and their integration into routine dental practice. Full article

(This article belongs to the Special Issue Advances in Polymeric Dental Materials)

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13 pages, 6214 KiB

Open AccessArticle

Crashworthy Performance of Sustainable Filled Structures Using Recycled Beverage Cans and Eco-Friendly Multi-Cell Fillers

by Huijing Gao, Jiangyang Xiang, Junyu Lu, Qianbing Tan, Frédéric Addiego, Yong Peng and Kui Wang

Polymers 2025, 17(3), 315; https://doi.org/10.3390/polym17030315 (registering DOI) - 24 Jan 2025

Abstract

The recycling of resources is an important measure to achieve circular economy and sustainable development. In this paper, a sustainable filled structure was proposed and realized by combining recycled empty beverage cans with eco-friendly multi-cell fillers. Quasi-static axial compressions were carried out to [...] Read more.

The recycling of resources is an important measure to achieve circular economy and sustainable development. In this paper, a sustainable filled structure was proposed and realized by combining recycled empty beverage cans with eco-friendly multi-cell fillers. Quasi-static axial compressions were carried out to characterize the energy absorption performance and synergistic effect of the filled tubes. Experimental results showed that the crashworthiness of sustainable filled structures varied with both filling densities and materials. With the increase in filling density, the specific energy absorption of the filled tubes presented an upward trend. With the variation in filling materials, the filled tubes exhibited different crashworthiness performances. The PLA multi-cell filled tube could withstand larger external force and exhibited higher SEA values, with a maximum value of 9.64 J/g. The PLAS multi-cell filled tube showed excellent loading stability and lower ULC value, with a minimum value of 10%. These findings provided valuable insights for designing novel sustainable energy absorption structures. Full article

(This article belongs to the Special Issue Mechanical and Structural Properties of Polymer Materials)

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28 pages, 8575 KiB

Open AccessArticle

Binary and Ternary Nanocomposite Membranes for Gas Separation Incorporating Finely Dispersed Carbon Nanotubes in a Polyether Block Amide Matrix

by Danilo Vuono, Gabriele Clarizia, Daniela Clotilde Zampino and Paola Bernardo

Polymers 2025, 17(3), 314; https://doi.org/10.3390/polym17030314 (registering DOI) - 24 Jan 2025

Abstract

This work addressed the fine dispersion of Multiwalled Carbon Nanotubes (MWCNTs) in a polymer matrix to obtain Mixed Matrix Membranes (MMMs) suited for gas separation. Not-purified MWCNTs were effectively loaded within a polyether block amide (Pebax^®2533) matrix, up to 24 wt%, [...] Read more.

This work addressed the fine dispersion of Multiwalled Carbon Nanotubes (MWCNTs) in a polymer matrix to obtain Mixed Matrix Membranes (MMMs) suited for gas separation. Not-purified MWCNTs were effectively loaded within a polyether block amide (Pebax^®2533) matrix, up to 24 wt%, using ultrasonication as well as a third component (polysorbate) in the dope solution. The obtained flexible thin films were investigated in terms of morphology, thermal properties, characterized by SEM, FT-IR, DSC, TGA, and gas permeation tests. The response to temperature variations of gas permeation through these nanocomposite specimens was also investigated in the temperature range of 25–55 °C. Defect-free samples were successfully obtained even at a significantly high loading of CNTs (up to 18 wt%), without a pre-treatment of the fillers. A remarkable enhancement of gas permeability upon the nanocarbons loading was reached, with a threshold value at a loading of ca. 7 wt%. The addition of polysorbates in the ternary MMMs further improves the dispersion of the filler, enhancing also the permselectivity of the membrane. Full article

(This article belongs to the Special Issue Carbon-Based Polymer Nanocomposites: Preparation, Characterization, and Applications)

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11 pages, 6568 KiB

Open AccessArticle

Polyhydroxybutyrate as a Novel Biopolymer for Dental Restorative Materials: Biological and Morphological Analysis

by Cigdem Atalayin Ozkaya, Beliz Ertan, Gizem Kaftan Ocal, Guliz Armagan, Gokhan Gungor, Murat Demirbilek, Huseyin Tezel, Vincenzo Notaro, Nicola Scotti and Andrea Baldi

Polymers 2025, 17(3), 313; https://doi.org/10.3390/polym17030313 (registering DOI) - 24 Jan 2025

Abstract

Polyhydroxybutyrate (PHB) is a biopolymer produced by bacteria. This study aimed to implement the production process of experimental medical-grade PHB and to evaluate its morphology and biocompatibility compared to conventional resin-based composites (RBCs). PHB raw material was produced via biological process and then [...] Read more.

Polyhydroxybutyrate (PHB) is a biopolymer produced by bacteria. This study aimed to implement the production process of experimental medical-grade PHB and to evaluate its morphology and biocompatibility compared to conventional resin-based composites (RBCs). PHB raw material was produced via biological process and then the membrane was generated via electrospinning specifically for this study and imaged with Micro-Computed Tomography (Micro-CT) and scanning electron microscopy (SEM). MTS assay was used to assess the cytotoxicity of PHB compared to other materials. Test groups included two packable resin composites (Point 4-Kerr, G-aenial anterior-GC), two flowable resin composites (Filtek Ultimate Flowable-3M ESPE, Nova Compo HF-Imicryl), a compomer (Nova Compomer-Imicryl), a fissure-sealant (Fissured Nova Plus-Imicryl), and the PHB membrane (Innovaplast Biotechnology Inc., Eskisehir, Turkey). A control group consisting of cells without any test material was also produced. To perform the MTS assay, disc-shaped specimens of the aforementioned materials were prepared and then incubated with mouse fibroblast cells (L929) for 24 and 48 h. Micro-CT and SEM images revealed a homogeneous and fibrillary structure of the PHB. MTS assay revealed the highest cell viability in the PHB, Nova Compomer, and Fissured Nova Plus groups after 24 h. PHB and Nova Compomer showed the highest viability rates at 48 h while other RBCs had rates below 25% (p < 0.05). Considering the cell viability data and its fibrillary structure, from a biological point of view, PHB seems a promising biopolymer that might have applications in the field of dental restorative materials. Full article

(This article belongs to the Special Issue Advanced Study on Natural Polymers and Their Applications)

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16 pages, 3730 KiB

Open AccessArticle

Study of the Physical–Chemical, Thermal, Structural, and Rheological Properties of Four High Andean Varieties of Germinated Chenopodium quinoa

by Betsy S. Ramos-Pacheco, Carlos A. Ligarda-Samanez, David Choque-Quispe, Yudith Choque-Quispe, Aydeé M. Solano-Reynoso, Katia Choque-Quispe, Henry Palomino-Rincón, Fredy Taipe-Pardo, Diego E. Peralta-Guevara, Elibet Moscoso-Moscoso, Yasmine Diaz-Barrera and Henrry Wilfredo Agreda-Cerna

Polymers 2025, 17(3), 312; https://doi.org/10.3390/polym17030312 (registering DOI) - 24 Jan 2025

Abstract

Chenopodium quinoa, a high Andean grain with excellent nutritional value and complex molecular structure, presents significant challenges in the bioavailability of nutrients and the functionality of its components. Germination as a biotechnological strategy generated significant modifications in four varieties of quinoa. The [...] Read more.

Chenopodium quinoa, a high Andean grain with excellent nutritional value and complex molecular structure, presents significant challenges in the bioavailability of nutrients and the functionality of its components. Germination as a biotechnological strategy generated significant modifications in four varieties of quinoa. The ungerminated and germinated samples’ physical–chemical, thermal, structural, and rheological properties were determined. Results showed increases in protein bioavailability (14.13% in Black Collana Quinoa (BCQ) and 12.79% in Red Pasankalla Quinoa (RPQ)), phenolic compounds (30.81 mg Gallic Acid Equivalent/100 g in RPQ), flavonoids (108.53 mg Quercetin Equivalent/100 g in Yellow Marangani Quinoa (YMQ)), and antioxidant capacity (up to 241.43 μmol Trolox Equivalent/g in BCQ). Thermal analysis showed increases in gelatinization temperature (57.53 °C to 59.45 °C in RPQ) and a reduction in enthalpy (1.38 J/g to 0.67 J/g). Structural analysis showed similar functional groups, but variation in spectra intensity was related to starches and proteins. Rheological properties exhibited pseudoplastic behavior at 80 °C. Principal component analysis showed a clear difference between germinated and non-germinated samples. The germination process significantly modified quinoa, improving its nutritional and functional properties and generating new opportunities for its application in the development of biodegradable materials and functional foods. Full article

(This article belongs to the Special Issue Functional Bio-Based Polymers and Composites for Multipurpose Applications)

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15 pages, 12357 KiB

Open AccessArticle

Fabrication of Polydopamine/hemin/TiO₂ Composites with Enhanced Visible Light Absorption for Efficient Photocatalytic Degradation of Methylene Blue

by Zhuandong Zhu, Shengrong Zhou, Debin Tian, Guang-Zhao Li, Gang Chen, Dong Fang, Jiaxuan Cao, Fumei Wang, Wenyan Wang, Xuewei He and Wei Zhang

Polymers 2025, 17(3), 311; https://doi.org/10.3390/polym17030311 (registering DOI) - 24 Jan 2025

Abstract

With the rapid progression of industrialization, water pollution has emerged as an increasingly critical issue, especially due to the release of organic dyes such as methylene blue (MB), which poses serious threats to both the environment and human health. Developing efficient photocatalysts to [...] Read more.

With the rapid progression of industrialization, water pollution has emerged as an increasingly critical issue, especially due to the release of organic dyes such as methylene blue (MB), which poses serious threats to both the environment and human health. Developing efficient photocatalysts to effectively degrade these pollutants is therefore of paramount importance. In this work, titanium dioxide (TiO₂) was modified with the photosensitizer hemin and the hydroxyl-rich polymer polydopamine (PDA) to enhance its photocatalytic degradation performance. Hemin and PDA function as photosensitizers, extending the light absorption of TiO₂ into the visible spectrum, reducing its bandgap energy, and effectively promoting separation of photogenerated electron–hole pairs through conjugated structures. Additionally, the strong adhesion of PDA enabled the rapid transfer and effective utilization of photogenerated electrons, while its abundant phenolic hydroxyls increased MB adsorption on the photocatalyst’s surface. Experimental results demonstrated a significant enhancement in photocatalytic activity, with the 1%PDA/3%hemin/TiO₂ composite achieving degradation rates of 91.79% under UV light and 71.53% under visible light within 120 min, representing 2.22- and 2.05-fold increases compared to unmodified TiO₂, respectively. This research presents an effective modification approach and provides important guidance for designing high-performance TiO₂-based photocatalysts aimed at environmental remediation. Full article

(This article belongs to the Special Issue Multifunctional Polymers and Their Composites and Structures: Design, Preparation and Properties—Second Edition)

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23 pages, 2716 KiB

Open AccessArticle

Impact of Polymer Physicochemical Features on the Amorphization and Crystallization of Citric Acid in Solid Dispersions

by Seda Arioglu-Tuncil and Lisa J. Mauer

Polymers 2025, 17(3), 310; https://doi.org/10.3390/polym17030310 (registering DOI) - 24 Jan 2025

Abstract

The amorphization and crystallization of citric acid in the presence of a variety of polymers were investigated. Polymers were chosen for their different physicochemical features, including hygroscopicity, glass transition temperature (T_g), and functional groups capable of forming intermolecular non-covalent interactions with [...] Read more.

The amorphization and crystallization of citric acid in the presence of a variety of polymers were investigated. Polymers were chosen for their different physicochemical features, including hygroscopicity, glass transition temperature (T_g), and functional groups capable of forming intermolecular non-covalent interactions with citric acid. Citric acid solutions with varying amounts of pectin (PEC), guar gum (GG), κ-carrageenan (KG), gelatin (GEL), (hydroxypropyl)methylcellulose (HPMC), and carboxymethylcellulose sodium (CMC-Na) were lyophilized. Dispersions were stored for up to 6 months in controlled temperature and relative humidity environments and periodically monitored using powder X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopy. Moisture sorption isotherms and moisture contents were determined. Amorphous solid dispersions of citric acid were successfully formed in the presence of ≥20% w/w CMC-Na and PEC or ≥30% w/w of the other polymers except KG which required a minimum of 40% polymer. All samples remained amorphous even in their rubbery state at 0% RH (25 °C and 40 °C), but increasing the RH to 32% RH resulted in citric acid crystallization in the KG dispersions, and further increasing to 54% RH resulted in crystallization in all samples. Polymer effectiveness for inhibiting citric acid crystallization was CMC-Na > PEC ≥ GEL > HPMC > GG > KG. To create and maintain amorphous citric acid, polymer traits in order of effectiveness were as follows: greater propensity for intermolecular non-covalent interactions (both ionic and hydrogen bonding) with the citric acid, carbonyl groups, higher T_g, and then lower hygroscopicity. Full article

(This article belongs to the Special Issue Polymer Physics: From Theory to Experimental Applications: 2nd Edition)

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Graphical abstract

20 pages, 9784 KiB

Open AccessArticle

Transparent Poly(amide-imide)s with Low Coefficient of Thermal Expansion from Trifluoromethylated Trimellitic Anhydride

by Seong Jong Kim, SeongUk Jeong, Taejoon Byun, Jun Sung Kim, Haeshin Lee and Sang Youl Kim

Polymers 2025, 17(3), 309; https://doi.org/10.3390/polym17030309 (registering DOI) - 24 Jan 2025

Abstract

Making transparent aromatic polymers with high T_g and low thermal expansion behavior, like glass, is challenging. We report transparent and soluble poly(amide-imide)s (PAIs) with high dimensional stability synthesized from the new monomer, trifluoromethylated trimellitic anhydride. Insertion of trifluoromethyl (CF₃) groups [...] Read more.

Making transparent aromatic polymers with high T_g and low thermal expansion behavior, like glass, is challenging. We report transparent and soluble poly(amide-imide)s (PAIs) with high dimensional stability synthesized from the new monomer, trifluoromethylated trimellitic anhydride. Insertion of trifluoromethyl (CF₃) groups into polymer chains enhanced solubility and the optical properties of polymers without sacrificing high thermal stability. Model reactions were utilized to study how the CF₃ group in trimellitic anhydride affects the polymerization reaction with aromatic diamine monomers, and a series of new PAIs were synthesized. All the polymers were soluble in polar organic solvents and can be solution-cast into nearly colorless and flexible freestanding films. The obtained PAI films possessed high thermal stability (T_d5: 437–452 °C in N₂) and high transparency (84~87% transmittance at 550 nm). Interestingly, PAIs prepared in this study exhibited high thermodimensional stability with low CTE values from 9 to 26 ppm/°C. The transparent poly(amide-imide) film with low CTE value finds its application in display and optical devices that require flexible and transparent form factors. Full article

(This article belongs to the Special Issue Functional Polymeric Materials: Synthesis, Characterization and Applications)

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20 pages, 3010 KiB

Open AccessArticle

Synthesis of Acrylic–Urethane Hybrid Polymer Dispersions and Investigations on Their Properties as Binders in Leather Finishing

by Selime Keskin, Catalina N. Cheaburu-Yilmaz, Aylin Altinisik Tagac, Raluca Nicoleta Darie-Nita and Onur Yilmaz

Polymers 2025, 17(3), 308; https://doi.org/10.3390/polym17030308 (registering DOI) - 24 Jan 2025

Abstract

This study investigates the synthesis and application of acrylic–urethane hybrid polymer dispersions as advanced binders for leather finishing. Two polymerization techniques—seeded emulsion and miniemulsion—were used to produce hybrid polymer dispersions by varying the ratios of polyurethane (PU) and acrylic (AC). The synthesized dispersions, [...] Read more.

This study investigates the synthesis and application of acrylic–urethane hybrid polymer dispersions as advanced binders for leather finishing. Two polymerization techniques—seeded emulsion and miniemulsion—were used to produce hybrid polymer dispersions by varying the ratios of polyurethane (PU) and acrylic (AC). The synthesized dispersions, i.e., the hybrid polyurethanes, showed stable, uniform particle sizes, inferring good compatibility and interaction between the PU and AC phases, as confirmed by particle sizes, FTIR, and DSC analyses. The performance of the coating on leather surfaces was assessed by using standard physical tests, including rubbing fastness, flexing endurance, water spot resistance, and grain strength. The results showed that the hybrid polymers outperformed their individual PU and AC counterparts, particularly in terms of abrasion resistance and mechanical integrity. Of the two polymerization techniques, the seeded emulsion hybrids exhibited superior coating properties, providing greater resistance to cracking and abrasion under stress, improved grain strength, and better color retention during rubbing tests. These findings highlight the potential of acrylic–urethane hybrids, particularly those prepared via seeded emulsion polymerization, to address the limitations of traditional binders in high-performance leather applications. Full article

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

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27 pages, 2737 KiB

Open AccessArticle

Thermal Decomposition of Date Seed/Polypropylene Homopolymer: Machine Learning CDNN, Kinetics, and Thermodynamics

by Zaid Abdulhamid Alhulaybi Albin Zaid and Abdulrazak Jinadu Otaru

Polymers 2025, 17(3), 307; https://doi.org/10.3390/polym17030307 (registering DOI) - 23 Jan 2025

Abstract

The buildup of abandoned plastics in the environment and the need to optimize agricultural waste utilization have garnered scrutiny from environmental organizations and policymakers globally. This study presents an assessment of the thermal decomposition of date seeds (DS), polypropylene homopolymer (PP), and their [...] Read more.

The buildup of abandoned plastics in the environment and the need to optimize agricultural waste utilization have garnered scrutiny from environmental organizations and policymakers globally. This study presents an assessment of the thermal decomposition of date seeds (DS), polypropylene homopolymer (PP), and their composites (DS/PP) through experimental measurements, machine learning convolutional deep neural networks (CDNN), and kinetic and thermodynamic analyses. The experimental measurements involved the pyrolysis and co-pyrolysis of these materials in a nitrogen-filled thermogravimetric analyzer (TGA), investigating degradation temperatures between 25 and 600 °C with heating rates of 10, 20, and 40 °C.min⁻¹. These measurements revealed a two-stage process for the bio-composites and a decrease in the thermal stability of pure PP due to the moisture, hemicellulose, and cellulose content of the DS material. By utilizing machine learning CDNN, algorithms and frameworks were developed, providing responses that closely matched (

R^{2} ~ 0.942

) the experimental data. After various modelling modifications, adjustments, and regularization techniques, a framework comprising four hidden neurons was determined to be most effective. Furthermore, the analysis revealed that temperature was the most influential parameter affecting the thermal decomposition process. Kinetic and thermodynamic analyses were performed using the Coats–Redfern and general Arrhenius model-fitting methods, as well as the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose model-free approaches. The first-order reaction mechanism was identified as the most appropriate compared to the second and third order F-Series solid-state reaction mechanisms. The overall activation energy values were estimated at 51.471, 51.221, 156.080, and 153.767 kJ·mol⁻¹ for the respective kinetic models. Additionally, the kinetic compensation effect showed an exponential increase in the pre-exponential factor with increasing activation energy values, and the estimated thermodynamic parameters indicated that the process is endothermic, non-spontaneous, and less disordered. Full article

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

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26 pages, 9856 KiB

Open AccessArticle

Experiment and Mechanism of Ecological Restoration of Water Level Fluctuation Zone Based on Redbed Composite Polymer Materials

by Cuiying Zhou, Qingxiu Zhang, Jin Liao, Haoqiang Lai and Zhen Liu

Polymers 2025, 17(3), 306; https://doi.org/10.3390/polym17030306 - 23 Jan 2025

Abstract

The water level fluctuation zone, as a transition zone between water and terrestrial ecosystems, is important in maintaining bank stability and regulating the ecological balance of water. The ecosystem residing within the water level fluctuation zone exhibits pronounced fragility, which has resulted in [...] Read more.

The water level fluctuation zone, as a transition zone between water and terrestrial ecosystems, is important in maintaining bank stability and regulating the ecological balance of water. The ecosystem residing within the water level fluctuation zone exhibits pronounced fragility, which has resulted in the recurrent manifestation of soil erosion alongside a myriad of other ecological issues. The existing ecological restoration techniques can solidify the soil and protect the slopes but fail to effectively solve soil erosion, which affects the recovery of vegetation. Therefore, in this study, a vegetation survival test under high water head conditions in the water level fluctuation zone and an ecological restoration modeling study of the fluctuation zone based on redbed composite polymer materials were conducted using redbed composite polymer materials as the soil restoration material. The experimental results showed that there were significant differences in the survival status of different classes of plants under high head stress, with different adaptations to environmental stress. In addition, the redbed composite polymer materials effectively improved the water level fluctuation zone, soil water content, conductivity, pH, and other physicochemical properties and improved the stability of soil aggregates. This study reveals the mechanism of action of the material on the soil of the water level fluctuation zone based on the microstructure of the soil, evaluates the restoration effect of the material, verifies the effectiveness of the redbed composite polymer materials in the restoration of the water level fluctuation zone, and provides an effective method for the ecological restoration of the water level fluctuation zone to solve the problem of soil loss and vegetation restoration. Full article

(This article belongs to the Special Issue Green Polymeric Materials for Geological Engineering and Geotechnical Engineering)

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17 pages, 10470 KiB

Open AccessArticle

Decellularization and an In Situ Tissue Engineering Approach in the Development of an Aortic Graft: Technological Features and Mechanobiological Studies

by David Sergeevichev, Vladislav Fomenko, Elena Chepeleva, Elena Kuznetsova, Andrey Vaver, Maxim Zhulkov and Maria Vasiliyeva

Polymers 2025, 17(3), 305; https://doi.org/10.3390/polym17030305 - 23 Jan 2025

Abstract

This study presents a novel method to enhance the biocompatibility of decellularized porcine aortic segments while preserving their mechanical properties and histological structure. Detergent-decellularized aortic segments were treated with modified globular chitosan (Novochizol™) at varying concentrations (0.5%, 1%, 2%, and 3%) by sonication [...] Read more.

This study presents a novel method to enhance the biocompatibility of decellularized porcine aortic segments while preserving their mechanical properties and histological structure. Detergent-decellularized aortic segments were treated with modified globular chitosan (Novochizol™) at varying concentrations (0.5%, 1%, 2%, and 3%) by sonication and subsequently subjected to mechanical testing. To further improve cell infiltration, blind-ended laser channels were created within the decellularized segments. The modified grafts were then seeded with porcine vascular interstitial cells in vitro for 7 days or implanted into the thoracic aorta of minipigs for 30 days. Histological analysis was performed at each stage of the study. Impregnation with Novochizol™ significantly increased the specific strength (from 0.97 ± 0.19 MPa to 4.99 ± 2.43 MPa) and Young’s modulus (from 0.73 ± 0.06 MPa to 14.66 ± 7.14 MPa) of the decellularized aortic segments. Histological examination confirmed the preservation of the connective tissue matrix’s morphological structure. Optimal modification conditions were identified as a 30 min sonication in a 1% Novochizol™ solution at 25 °C. A 35 ms continuous laser treatment was sufficient to create a 1 mm deep blind-ended channel, thereby promoting the seeding of vascular interstitial cells within the acellular graft, as confirmed by implantation in minipigs. Full article

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

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16 pages, 6384 KiB

Open AccessArticle

Preparation and Characterizations of Intrinsically Black Polyesterimide Films with Good Thermal Endurance at Elevated Temperatures for Potential Two-Layer Flexible Copper Clad Laminate Applications

by Shujun Han, Xi Ren, Duanyi Li, Zhenyang Song, Changxu Yang, Zhenzhong Wang and Jingang Liu

Polymers 2025, 17(3), 304; https://doi.org/10.3390/polym17030304 - 23 Jan 2025

Abstract

Polymer films with combined properties of good thermoplasticity, good electrical properties, and good thermal endurance are highly required for two-layer flexible copper clad laminate (FCCL) applications. Meanwhile, the black appearance is also required for specific FCCL applications. Therefore, in the present work, a [...] Read more.

Polymer films with combined properties of good thermoplasticity, good electrical properties, and good thermal endurance are highly required for two-layer flexible copper clad laminate (FCCL) applications. Meanwhile, the black appearance is also required for specific FCCL applications. Therefore, in the present work, a series of ester-linked polyimide (PEsI) films were designed and developed via the copolymerization chemistry of an ester-containing dianhydride of biphenyl dibenzoate-3,3ʹ,4,4ʹ-tetracarboxylic acid dianhydride (BPTME), a rigid-rod dianhydride of 3,3’,4,4’-biphenyltetracarboxylic acid dianhydride (BPDA), an ester-bridged diamine of 2-(4-aminobenzoate)-5-aminobiphenyl (ABABP), and a functional diamine of 4,4’-iminodianiline (NDA). The molar proportion of the BPTME/BPDA was fixed to be 20:80 and that of ABABP/NDA increased from 50:50 for PEsI-1 to 0:100 for PEsI-VI. The afforded PEsI films showed obviously enhanced blackness with the increasing molar ratio of NDA in the polymers. The PEsI-VI film exhibited the optical transmittance values of 0 and 27.4% at the wavelength of 500 nm (T₅₀₀) and 760 nm (T₇₆₀), respectively. The values were apparently lower than those of the standard PI-ref produced from common pyromellitic dianhydride (PMDA) and 4,4’-oxydianiline (ODA) (T₅₀₀ = 63.2%; T₇₆₀ = 86.3%). Meanwhile, the PEsI-V film showed good blackness with the CIE Lab optical parameters of 1.83 for L^*, 11.46 for a^*, 3.13 for b^*, and 0 for haze. The PEsI samples exhibited good thermoplasticity and the storage and loss modulus of the films rapidly decreased around the glass transition temperatures (T_g) in the dynamic mechanical analysis (DMA) tests. The PEsI samples revealed the T_g values from 247.2 °C to 286.1 °C in the differential scanning calorimetry (DSC) measurements. The PEsI samples exhibited the linear coefficients of thermal expansion (CTE) of (27.1~33.4) × 10⁻⁶/K from 50 to 250 °C, which was comparable to that of the PI-ref sample (CTE = 29.5 × 10⁻⁶/K), however, a bit higher than that of the copper foil (CTE = 17.0 × 10⁻⁶/K). Full article

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

14 pages, 7247 KiB

Open AccessArticle

Development of Recombinant Human Collagen-Based Porous Scaffolds for Skin Tissue Engineering: Enhanced Mechanical Strength and Biocompatibility

by Yang Yang, Ting Yu, Mengdan Tao, Yong Wang, Xinying Yao, Chenkai Zhu, Fengxue Xin and Min Jiang

Polymers 2025, 17(3), 303; https://doi.org/10.3390/polym17030303 - 23 Jan 2025

Abstract

Skin tissue engineering scaffolds should possess key properties such as porosity, degradability, durability, and biocompatibility to effectively facilitate skin cell adhesion and growth. In this study, recombinant human collagen (RHC) was used to fabricate porous scaffolds via freeze-drying, offering an alternative to animal-derived [...] Read more.

Skin tissue engineering scaffolds should possess key properties such as porosity, degradability, durability, and biocompatibility to effectively facilitate skin cell adhesion and growth. In this study, recombinant human collagen (RHC) was used to fabricate porous scaffolds via freeze-drying, offering an alternative to animal-derived collagen where bovine collagen (BC)-based scaffolds were also prepared for comparison. The internal morphology of the RHC scaffolds were characterized by scanning electron microscopy (SEM) and the pore size ranged from 68.39 to 117.52 µm. The results from compression and fatigue tests showed that the mechanical strength and durability of RHC scaffolds could be tailored by adjusting the RHC concentration, and the maximum compressive modulus reached to 0.003 MPa, which is comparable to that of BC scaffolds. The degradation test illustrated that the RHC scaffolds had a slower degradation rate compared to BC scaffolds. Finally, the biocompatibilities of the porous scaffolds were studied by seeding and culturing the human foreskin fibroblasts (HFFs) and human umbilical vein endothelial cells (HUVECs) in samples. The fluorescent images and Cell Counting Kit-8 (CCK-8) assay revealed RHC porous scaffolds were non-cytotoxic and supported the attachment as well as the proliferation of the seeded cells. Overall, the results demonstrated that RHC-based scaffolds exhibited adequate mechanical strength, ideal biodegradability, and exceptional biocompatibility, making them highly suitable for skin-tissue-engineering applications. Full article

(This article belongs to the Special Issue Biopolymers for Drug Delivery and Tissue Engineering)

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14 pages, 4718 KiB

Open AccessArticle

Highly Transparent Anti-Smudge Coatings for Self-Cleaning, Controllable Liquid Transport, and Corrosion Resistance

by Hua Xu, Chao Chen, Shunfeng Hu, Yiqi Chen, Dengle Duan, Guowei Liang and Ximing Zhong

Polymers 2025, 17(3), 302; https://doi.org/10.3390/polym17030302 - 23 Jan 2025

Abstract

Highly transparent anti-smudge coatings are attractive for diverse fields due to their inherent repellency against various contaminants and the ability to keep surfaces clean. In this work, a novel fluorine-free anti-smudge coating system was developed by using poly(dimethysiloxane), tris(hydroxymethyl) aminomethane, and isophorone diisocynate [...] Read more.

Highly transparent anti-smudge coatings are attractive for diverse fields due to their inherent repellency against various contaminants and the ability to keep surfaces clean. In this work, a novel fluorine-free anti-smudge coating system was developed by using poly(dimethysiloxane), tris(hydroxymethyl) aminomethane, and isophorone diisocynate to synthesize a hexa-functional coating precursor and utilizing hexamethylene diisocyanate trimer as a curing agent. The resultant anti-smudge coatings are highly transparent and can be applied to various substrates. These coatings exhibit repellency against water, hexadecane, ink, pump oil, and crude oil and show self-cleaning performance in air and oily environments. Moreover, they display anti-ink ability and can be employed to reduce bacterial contamination. Of note, they can endow substrates with protection against corrosion from strong acids, strong bases, salt solutions, and even aqua regia. The developed coatings also show potential for controllable liquid transport. Moreover, these versatile coatings are mechanically robust, demonstrating tolerance against abrasion, impact, and bending and also exhibiting excellent adhesion to various substrates, indicative of their availability for widespread applications. Full article

(This article belongs to the Section Polymer Applications)

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18 pages, 5439 KiB

Open AccessArticle

Nickel Oxide Nanoparticles Derived from Coordination Polymer of PVA and Aminobenzoic Acid Derivative: Synthesis, Characterization and Antimicrobial Activity

by Maged S. Al-Fakeh, Roaa O. Alsaedi, Maryam Aldoghaim, Ahmed B. M. Ibrahim and Ayman M. Mostafa

Polymers 2025, 17(3), 301; https://doi.org/10.3390/polym17030301 - 23 Jan 2025

Abstract

This study focused on the synthesis, properties, and antibiological activity of NiO nanoparticles derived from polyvinyl alcohol (PVA) and aminobenzoic acid (P-ABA) derivatives by calcination method. The nanoparticles were synthesized using a simple, cost-effective method that involved the thermal decomposition of PVA and [...] Read more.

This study focused on the synthesis, properties, and antibiological activity of NiO nanoparticles derived from polyvinyl alcohol (PVA) and aminobenzoic acid (P-ABA) derivatives by calcination method. The nanoparticles were synthesized using a simple, cost-effective method that involved the thermal decomposition of PVA and the incorporation of aminobenzoic acid. Characterization techniques such as X-ray diffraction (XRD), Kinetic analysis, and the thermal properties of nickel(II) metal complex in dynamic air were analyzed via TG and DTG. The kinetic analyses and thermodynamic parameters (∆H*, ∆G*, and ∆S*) for this compound were calculated by the Coats–Redfern and Horowitz–Metzger methods. The obtained kinetic parameters displayed the kinetic compensation effect. Electron microscopy (SEM and TEM) and (FT-IR) were employed to confirm the formation, morphology, and structural properties of the nanoparticles. The results indicated the successful synthesis of NiO nanoparticles with distinct crystalline phases and difference distributions. XRD confirmed that the resulting oxide was pure single-crystalline NiO nanoparticles. Scanning electron microscopy indicated that the crystallite size of nickel oxide nano-crystals was in the range of 26–36 nm. The magnetic moment was 2.59 B.M for Ni(II) complex. The antibiological activity of the synthesized nanoparticles was evaluated against bacterial strains, both Gram-positive and Gram-negative bacteria. The findings revealed significant antimicrobial properties, with the NiO nanoparticles demonstrating higher inhibitory effects against bacterial and fungal strains. This study highlights the potential of PVA and aminobenzoic acid derivatives as effective precursors for producing metal oxide nanoparticles with promising applications in antimicrobial treatments and materials science. Full article

(This article belongs to the Section Polymer Applications)

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14 pages, 793 KiB

Open AccessArticle

Effect of Hydrocolloids on Penetration Tests, Sensory Evaluation, and Syneresis of Milk Pudding

by Hong-Ting Victor Lin, Jenn-Shou Tsai, Hsiao-Hui Liao and Wen-Chieh Sung

Polymers 2025, 17(3), 300; https://doi.org/10.3390/polym17030300 - 23 Jan 2025

Abstract

This study evaluated how added gums, starch amounts, and sucrose levels affect the texture, sensory acceptability, and syneresis of milk puddings. The puddings were prepared with four ingredients, namely 0.3% polysaccharide (κ,ι-carrageenan, gellan gum, gelatin, or agar), 2.5–7.5% sucrose, 1–5% modified waxy corn [...] Read more.

This study evaluated how added gums, starch amounts, and sucrose levels affect the texture, sensory acceptability, and syneresis of milk puddings. The puddings were prepared with four ingredients, namely 0.3% polysaccharide (κ,ι-carrageenan, gellan gum, gelatin, or agar), 2.5–7.5% sucrose, 1–5% modified waxy corn starch, and whole milk. The physical and sensory properties were assessed through measurements of gel strength, breaking point, breaking force, rigidity, and hedonic testing. Results show that syneresis increased in all milk puddings during two weeks of refrigerated storage. Among the five polysaccharides, agar and κ-carrageenan showed the most significant effect on gel rigidity and strength, while gellan gum and ι-carrageenan were more effective at preventing syneresis compared to three commercial milk pudding products after 14 days of storage. As modified corn starch concentration increased (1 to 5%), gel strength, breaking force, and rigidity decreased. Lower modified waxy corn starch concentrations (5% to 1%) led to reduced syneresis when stored at 4 °C for 7 and 14 days. Sucrose significantly increased gel strength and breaking force in puddings containing κ-carrageenan, gellan gum, and agar. Gellan gum improved overall pudding acceptability. Based on sensory and syneresis data, the most acceptable milk pudding formulation contained 5% sucrose, 0.3% gellan gum, and 1% modified waxy corn starch. Full article

(This article belongs to the Special Issue Advanced Study on Natural Polymers and Their Applications)

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18 pages, 6925 KiB

Open AccessArticle

Improvement of Polymer/Metal Adhesion Using Anodizing Treatment and 3D Printing Process

by Seung Wan Ryu, Dong Hyun Kim, Wonhwa Lee, Jin-Yong Hong, Young-Pyo Jeon and Jea Uk Lee

Polymers 2025, 17(3), 299; https://doi.org/10.3390/polym17030299 - 23 Jan 2025

Abstract

Joining materials with different physicochemical properties presents significant challenges. This study investigates the one-step anodization of aluminum in a mixed phosphoric acid and hydrogen peroxide solution, followed by the direct injection molding of polymer resin to enhance joint properties. The anodizing treatment is [...] Read more.

Joining materials with different physicochemical properties presents significant challenges. This study investigates the one-step anodization of aluminum in a mixed phosphoric acid and hydrogen peroxide solution, followed by the direct injection molding of polymer resin to enhance joint properties. The anodizing treatment is performed at constant electrical current with phosphoric acid solutions of various concentrations. Phosphoric acid anodizing enables the formation of 3D channeling pore structure with micropits and uniform nanopores on the aluminum surface. Hydrogen peroxide acts as an oxidizing agent and promotes the dissolution reaction, thereby increasing the size of the nanopores. Larger pores facilitated the penetration of polymer resin into the aluminum oxide layer during injection molding, resulting in bonding strengths up to 40.34 MPa. This improvement is substantial when compared to the bonding strengths achieved through conventional injection molding processes. These results highlight that the increase in nanopore size due to hydrogen peroxide addition played a critical role in enhancing the bonding strength, as it facilitated better penetration and interlocking of the polymer resin within the anodized aluminum layer. Furthermore, a three-dimensional (3D) printing process was able to join polymer resins to the anodized aluminum surface, where the larger nanopores with the addition of the hydrogen peroxide is more beneficial to the bonding strengths than the direct injection molding is. This alternative approach addresses the environmental issues associated with the use of Cr(VI)-based anodizing solutions and the lightweight composites with applicability to various industries that could be produced using this method. Full article

(This article belongs to the Special Issue 3D Printing of Polymer Composites, 2nd Edition)

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