Polymers

16 pages, 3399 KiB

Open AccessArticle

Relationship Between Filler Type, Thermomechanical Properties, and Aging of RTV Silicone Foams

by Xavier M. Torres, John R. Stockdale, Adam Pacheco, Shelbie A. Legett, Lindsey B. Bezek, Bart Benedikt, Andrea Labouriau and Santosh Adhikari

Polymers 2025, 17(14), 1998; https://doi.org/10.3390/polym17141998 - 21 Jul 2025

Viewed by 307

Abstract

Room-temperature vulcanizing (RTV) silicone foams are used in many industrial applications that require the material to perform over long time periods. However, mechanical properties tend to deteriorate when these foams age under a compressive load. The chemical aging is attributed to the presence [...] Read more.

Room-temperature vulcanizing (RTV) silicone foams are used in many industrial applications that require the material to perform over long time periods. However, mechanical properties tend to deteriorate when these foams age under a compressive load. The chemical aging is attributed to the presence of unreacted functional groups of the prepolymers, residues from acid, and catalytically active tin (II) species. Here, an optimized thermal treatment of an RTV foam that achieves completion of curing reactions and deactivation of reactive species is proposed. Foams that were thermally aged for three months under compressive load showed no signs of compression set, indicative of the effectiveness of the implemented post-curing approach. In addition, the effects of fillers (diatomaceous earth, fumed silica, and carbon nanofibers) on thermomechanical properties were investigated. Tensile strength, tear strength, and thermal conductivity increased when these fillers were added to the unfilled RTV formulation, with carbon nanofibers (CNFs) being the most effective filler. Rheological studies of RTV formulations indicated that 2.5 wt.% of CNFs is the upper limit that can be added to the RTV formulation. Full article

(This article belongs to the Special Issue Functional Polymer Composites: Synthesis and Application)

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14 pages, 2390 KiB

Open AccessArticle

Synthesis, Thermal Behavior and Mechanical Property of Fully Biobased Poly(hexamethylene Furandicarboxylate-co-hexamethylene Thiophenedicarboxylate) Copolyesters

by Haidong Yang, Shiwei Feng and Zhaobin Qiu

Polymers 2025, 17(14), 1997; https://doi.org/10.3390/polym17141997 - 21 Jul 2025

Viewed by 250

Abstract

In order to increase the toughness of poly(hexamethylene furandicarboxylate) (PHF) without severely compromising its strength at break, novel biobased poly(hexamethylene furandicarboxylate-co-hexamethylene thiophenedicarboxylate) (PHFTh) copolyesters and their parent homopolyesters, PHF and poly(hexamethylene thiophenedicarboxylate), were successfully synthesized through melt polycondensation in this research. [...] Read more.

In order to increase the toughness of poly(hexamethylene furandicarboxylate) (PHF) without severely compromising its strength at break, novel biobased poly(hexamethylene furandicarboxylate-co-hexamethylene thiophenedicarboxylate) (PHFTh) copolyesters and their parent homopolyesters, PHF and poly(hexamethylene thiophenedicarboxylate), were successfully synthesized through melt polycondensation in this research. Despite the variation in their compositions, all the PHFTh copolyesters exhibited excellent thermal stability. The PHFTh copolyesters were semicrystalline in nature, showing the lowest eutectic melting points and isodimorphism behaviors over the whole composition range. As the hexamethylene thiophenedicarboxylate (HTh) unit content increased, the glass transition temperature of the copolyesters gradually decreased, while the chain mobility was accordingly enhanced. Therefore, the introduction of the HTh unit significantly increased the elongation at break of the PHFTh, achieving a balance between strength and toughness. The biobased PHFTh copolyesters showed tunable thermal behaviors and excellent mechanical properties and may find potential end uses from a practical application viewpoint. Full article

(This article belongs to the Special Issue Biobased Polymers and Their Structure-Property Relationships)

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35 pages, 3170 KiB

Open AccessReview

Effects of Moisture Absorption on the Mechanical and Fatigue Properties of Natural Fiber Composites: A Review

by Ana Pavlovic, Lorenzo Valzania and Giangiacomo Minak

Polymers 2025, 17(14), 1996; https://doi.org/10.3390/polym17141996 - 21 Jul 2025

Viewed by 289

Abstract

This review critically examines the effects of moisture absorption on the mechanical and fatigue properties of natural fiber composites (NFCs), with a focus on tensile strength, elastic modulus, and long-term durability. Moisture uptake can cause reductions in tensile strength of up to 40% [...] Read more.

This review critically examines the effects of moisture absorption on the mechanical and fatigue properties of natural fiber composites (NFCs), with a focus on tensile strength, elastic modulus, and long-term durability. Moisture uptake can cause reductions in tensile strength of up to 40% and in elastic modulus by 20–30% depending on fiber type, mass fraction (typically in the range of 30–60%), and surface treatments. The review highlights Ithat while surface modifications (e.g., alkaline and silane treatments) significantly mitigate moisture-induced degradation, their effectiveness is highly sensitive to the processing conditions. Additionally, hybridization strategies and optimized fiber orientations show promise in enhancing fatigue resistance under humid environments. Despite substantial progress, major challenges remain, including the lack of standardized testing protocols and the limited understanding of multiscale aging mechanisms. Future research directions include developing predictive models that couple moisture diffusion and mechanical deterioration, implementing advanced in situ monitoring of damage evolution, and exploring novel bio-based treatments. By addressing these gaps, NFCs can become more reliable and widely adopted as sustainable alternatives in structural applications. Full article

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

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15 pages, 3554 KiB

Open AccessArticle

A Composite Substrate of Ag Nanoparticle-Decorated Inverse Opal Polydimethylsiloxane for Surface Raman Fluorescence Dual Enhancement

by Zilun Tang, Hongping Liang, Zhangyang Chen, Jianpeng Li, Jianyu Wu, Xianfeng Li and Dingshu Xiao

Polymers 2025, 17(14), 1995; https://doi.org/10.3390/polym17141995 - 21 Jul 2025

Viewed by 316

Abstract

It is difficult to simultaneously achieve surface-enhanced Raman scattering (SERS) and surface-enhanced fluorescence (SEF) for noble metals. Herein, a composite substrate is demonstrated based on the rational construction of Ag nanoparticles (Ag NPs) and inverse opal polydimethylsiloxane (PDMS) for surface Raman fluorescence dual [...] Read more.

It is difficult to simultaneously achieve surface-enhanced Raman scattering (SERS) and surface-enhanced fluorescence (SEF) for noble metals. Herein, a composite substrate is demonstrated based on the rational construction of Ag nanoparticles (Ag NPs) and inverse opal polydimethylsiloxane (PDMS) for surface Raman fluorescence dual enhancement. The well-designed Ag nanoparticle (Ag NP)-decorated inverse opal PDMS (AIOP) composite substrate is fabricated using the polystyrene (PS) photonic crystal method and the sensitization reduction technique. The inverse opal PDMS enhances the electromagnetic (EM) field by increasing the loading of Ag NPs and plasmonic coupling of Ag NPs, leading to SERS activity. The thin shell layer of polyvinyl pyrrolidone (PVP) in core–shell Ag NPs isolates the detected molecule from the Ag core to prevent the fluorescence resonance energy transfer and charge transfer to eliminate fluorescence quenching and enable SEF performance. Based on the blockage of the core–shell structure and the enhanced EM field originating from the inverse opal structure, the as-fabricated AIOP composite substrate shows dual enhancement in surface Raman fluorescence. The AIOP composite substrate in this work, which combines improved SERS activity and SEF performance, not only promotes the development of surface-enhanced spectroscopy but also shows promise for applications in flexible sensors. Full article

(This article belongs to the Special Issue Polymer-Based Flexible Materials, 3rd Edition)

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15 pages, 3645 KiB

Open AccessArticle

PVP-Regulated Self-Assembly of High-Strength Micrometer-Scale Al/CuO/AP Energetic Microspheres with Enhanced Reactivity

by Xuyang Wu, Hongbao Wang, Chenglong Jiao, Benbo Zhao, Shixiong Sun and Yunjun Luo

Polymers 2025, 17(14), 1994; https://doi.org/10.3390/polym17141994 - 21 Jul 2025

Viewed by 231

Abstract

Al-based nanocomposite energetic materials have broad application prospects in explosives and propellants, owing to their excellent energy release efficiency. However, their insufficient reliability, poor stability, and difficulty of formation limit their practical application. This study employed self-assembly using a hydrophilic polymer polyvinylpyrrolidone (PVP) [...] Read more.

Al-based nanocomposite energetic materials have broad application prospects in explosives and propellants, owing to their excellent energy release efficiency. However, their insufficient reliability, poor stability, and difficulty of formation limit their practical application. This study employed self-assembly using a hydrophilic polymer polyvinylpyrrolidone (PVP) together with nano-aluminum powder (Al), copper oxide (CuO), and ammonium perchlorate (AP) to obtain high-strength and high-activity composite micrometer-sized microspheres. The influence of PVP concentration on the mechanical behavior of Al/AP composite microspheres was systematically investigated, and Al was replaced with ultrasonically dispersed Al/CuO to explore the mechanism of action of PVP in the system and the catalytic behavior of CuO. PVP significantly enhanced the interfacial bonding strength. The Al/AP/5%PVP microspheres achieved a strength of 8.4 MPa under 40% compressive strain, representing a 365% increase relative to Al/AP. The Al/CuO/AP/5%PVP microspheres achieved a strength of 10.2 MPa, representing a 309% increase relative to Al/CuO. The mechanical properties of the composite microspheres were improved by more than threefold, and their thermal reactivities were also higher. This study provides a new method for the controlled preparation of high-strength, high-activity, micrometer-sized energetic microspheres. These materials are expected to be applied in composite solid propellants to enhance their combustion efficiency. Full article

(This article belongs to the Special Issue Eco-Friendly Polymeric Coatings and Adhesive Technology, 2nd Edition)

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33 pages, 4464 KiB

Open AccessArticle

Physicochemical and Structural Characteristics of Date Seed and Starch Composite Powder as Prepared by Heating at Different Temperatures

by Muna Al-Mawali, Maha Al-Khalili, Mohammed Al-Khusaibi, Myo Tay Zar Myint, Htet Htet Kyaw, Mohammad Shafiur Rahman, Abdullahi Idris Muhammad and Nasser Al-Habsi

Polymers 2025, 17(14), 1993; https://doi.org/10.3390/polym17141993 - 21 Jul 2025

Viewed by 502

Abstract

Date seeds, a by-product of the pitted-date industry, are often discarded as waste. This study investigated the interaction between date seed powder and starch at different concentrations (0, 1, 5, 10, and 20 g/25 g composite) and temperatures (40 °C and 70 °C). [...] Read more.

Date seeds, a by-product of the pitted-date industry, are often discarded as waste. This study investigated the interaction between date seed powder and starch at different concentrations (0, 1, 5, 10, and 20 g/25 g composite) and temperatures (40 °C and 70 °C). The results revealed that the hygroscopicity of date seed powder (9.94 g/100 g) was lower than starch (13.39 g/100 g), and its water absorption (75.8%) was also lower than starch (88.3%), leading to a reduced absorbance capacity in composites. However, the solubility increased with a higher date seed content due to its greater solubility (17.8 g/L) compared to starch (1.6 g/L). A morphological analysis showed rough, agglomerated particles in date seed powder, while starch had smooth, spherical shapes. This study also found that the composites formed larger particles at 40 °C and porous structures at 70 °C. Crystallinity decreased from 41.6% to 12.8% (40 °C) and from 24.0% to 11.3% (70 °C). A thermal analysis revealed three endothermic peaks (glass transitions and solid melting), with an additional oil-melting peak in high-seed samples. FTIR spectra showed changes in peak intensities and locations upon seed incorporation. Overall, these findings revealed that, the incorporation of date seed powder–starch composites into bakery formulations offers a promising strategy for developing fiber-enriched products, positioning them as functional ingredients with added nutritional value. Full article

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

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19 pages, 2191 KiB

Open AccessArticle

In Vivo Study on 3D-Printed Polylactic Acid Nerve Tubes for Sciatic Nerve Injury Treatment

by Salih Kavuncu, Rauf Hamid and Ömer Faruk Sarıahmetoğlu

Polymers 2025, 17(14), 1992; https://doi.org/10.3390/polym17141992 - 21 Jul 2025

Viewed by 334

Abstract

Background/Objectives: Nerve injuries cause functional loss and psychosocial issues due to prolonged rehabilitation. Recently, 3D-modeled nerve conduits have been used to aid in surgical planning. This study investigated the impact of 3D-bioprinted PLA, chitosan, alginate, and collagen conduits on nerve regeneration in a [...] Read more.

Background/Objectives: Nerve injuries cause functional loss and psychosocial issues due to prolonged rehabilitation. Recently, 3D-modeled nerve conduits have been used to aid in surgical planning. This study investigated the impact of 3D-bioprinted PLA, chitosan, alginate, and collagen conduits on nerve regeneration in a rat sciatic nerve crush injury model. Methods: This study, conducted at Kütahya University of Health Sciences, involves 50 rats were divided into four groups: (1) sham-operated controls, (2) sciatic nerve injury without treatment, (3) injury treated with a PLA conduit, and (4) injury treated with 3D-printed tubes composed of chitosan and alginate. The procedures were performed, blood was collected, and the rats were sacrificed after two months. Weekly checks for infection, scar healing, and motor responses were performed. Results: Rats with nerve conduits showed less macroscopic scarring. Weekly assessments of motor nerve recovery showed no movement restrictions in limbs treated with PLA conduits, graft conduits, or conduits bridging retracted nerve stumps, based on responses to stimulus checks. An infection developed in the sciatic nerve and surrounding muscle tissue of one rat with a bio-graft conduit, prompting histopathological examination to investigate its cause. Conclusions: This proof-of-principle study demonstrates the feasibility of using 3D-printed biocompatible nerve conduits for peripheral nerve repair, providing a basis for future, more comprehensive investigations. Full article

(This article belongs to the Topic Future Trends in Polymer Science: Materials, Design, and Advanced Applications)

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12 pages, 4279 KiB

Open AccessArticle

Dynamic Ester-Linked Vitrimers for Reprocessable and Recyclable Solid Electrolytes

by Xiaojuan Shi, Hui Zhang and Hongjiu Hu

Polymers 2025, 17(14), 1991; https://doi.org/10.3390/polym17141991 - 21 Jul 2025

Viewed by 288

Abstract

Traditional covalently cross-linked solid-state electrolytes exhibit desirable mechanical durability but suffer from limited processability and recyclability due to their permanent network structures. Incorporating dynamic covalent bonds offers a promising solution to these challenges. In this study, we report a reprocessable and recyclable polymer [...] Read more.

Traditional covalently cross-linked solid-state electrolytes exhibit desirable mechanical durability but suffer from limited processability and recyclability due to their permanent network structures. Incorporating dynamic covalent bonds offers a promising solution to these challenges. In this study, we report a reprocessable and recyclable polymer electrolyte based on a dynamic ester bond network, synthesized from commercially available materials. Polyethylene glycol diglycidyl ether (PEGDE) and glutaric anhydride (GA) were cross-linked and cured in the presence of benzyl dimethylamine (BDMA), forming an ester-rich polymer backbone. Subsequently, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was introduced as a transesterification catalyst to facilitate network rearrangement. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was incorporated to establish efficient ion transport pathways. By tuning the cross-linking density and catalyst ratio, the electrolyte achieved an ionic conductivity of 1.89 × 10⁻⁵ S/cm at room temperature along with excellent reprocessability. Full article

(This article belongs to the Special Issue Recycling and Circularity of Polymeric Materials)

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Graphical abstract

13 pages, 6483 KiB

Open AccessArticle

Design of I-WP Gradient Metamaterial Broadband Electromagnetic Absorber Based on Additive Manufacturing

by Yi Qin, Yuchuan Kang, He Liu, Jianbin Feng and Jianxin Qiao

Polymers 2025, 17(14), 1990; https://doi.org/10.3390/polym17141990 - 20 Jul 2025

Viewed by 418

Abstract

The proliferation of electromagnetic wave applications has accentuated electromagnetic pollution concerns, highlighting the critical importance of electromagnetic wave absorbers (EMA). This study proposes innovative I-Wrapped Package Lattice electromagnetic wave absorbers (IWP–EMA) based on the triply periodic minimal surface (TPMS) lattice structure. Through a [...] Read more.

The proliferation of electromagnetic wave applications has accentuated electromagnetic pollution concerns, highlighting the critical importance of electromagnetic wave absorbers (EMA). This study proposes innovative I-Wrapped Package Lattice electromagnetic wave absorbers (IWP–EMA) based on the triply periodic minimal surface (TPMS) lattice structure. Through a rational design of porous gradient structures, broadband wave absorption was achieved while maintaining lightweight characteristics and mechanical robustness. The optimized three-dimensional configuration features a 20 mm thick gradient structure with a progressive relative density transition from 10% to 30%. Under normal incidence conditions, this gradient IWP–EMA basically achieves broadband absorption with a reflection loss below −10 dB across the 2–40 GHz frequency band, with absorption peaks below −19 dB, demonstrating good impedance-matching characteristics. Additionally, due to the complex interactions of electromagnetic waves within the structure, the proposed IWP–EMA achieves a wide-angle absorption range of 70° under Transverse Electric (TE) polarization and 70° under Transverse Magnetic (TM) polarization. The synergistic integration of the TPMS design and additive manufacturing technology employed in this study significantly expands the design space and application potential of electromagnetic absorption structures. Full article

(This article belongs to the Special Issue Advanced Additive Processes and 3D Printing for Polymer Composites, 2nd Edition)

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14 pages, 2050 KiB

Open AccessArticle

Electrospun PANI/PEO-Luffa Cellulose/TiO₂ Nanofibers: A Sustainable Biocomposite for Conductive Applications

by Gözde Konuk Ege, Merve Bahar Okuyucu and Özge Akay Sefer

Polymers 2025, 17(14), 1989; https://doi.org/10.3390/polym17141989 - 20 Jul 2025

Viewed by 472

Abstract

Herein, electrospun nanofibers composed of polyaniline (PANI), polyethylene oxide (PEO), and Luffa cylindrica (LC) cellulose, reinforced with titanium dioxide (TiO₂) nanoparticles, were synthesized via electrospinning to investigate the effect of TiO₂ nanoparticles on PANI/PEO/LC nanocomposites and the effect of conductivity [...] Read more.

Herein, electrospun nanofibers composed of polyaniline (PANI), polyethylene oxide (PEO), and Luffa cylindrica (LC) cellulose, reinforced with titanium dioxide (TiO₂) nanoparticles, were synthesized via electrospinning to investigate the effect of TiO₂ nanoparticles on PANI/PEO/LC nanocomposites and the effect of conductivity on nanofiber morphology. Cellulose extracted from luffa was added to the PANI/PEO copolymer solution, and two different ratios of TiO₂ were mixed into the PANI/PEO/LC biocomposite. The morphological, vibrational, and thermal characteristics of biocomposites were systematically investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). As anticipated, the presence of TiO₂ enhanced the electrical conductivity of biocomposites, while the addition of Luffa cellulose further improved the conductivity of the cellulose-based nanofibers. FTIR analysis confirmed chemical interactions between Luffa cellulose and PANI/PEO matrix, as evidenced by the broadening of the hydroxyl (OH) absorption band at 3500–3200 cm⁻¹. Additionally, the emergence of characteristic peaks within the 400–1000 cm⁻¹ range in the PANI/PEO/LC/TiO₂ spectra signified Ti–O–Ti and Ti–O–C vibrations, confirming the incorporation of TiO₂ into the biocomposite. SEM images of the biocomposites reveal that the thickness of nanofibers decreases by adding Luffa to PANI/PEO nanofibers because of the nanofibers branching. In addition, when blending TiO₂ nanoparticles with the PANI/PEO/LC biocomposite, this increment continued and obtained thinner and smother nanofibers. Furthermore, the incorporation of cellulose slightly improved the crystallinity of the nanofibers, while TiO₂ contributed to the enhanced crystallinity of the biocomposite according to the XRD and DCS results. Similarly, the TGA results supported the DSC results regarding the increasing thermal stability of the biocomposite nanofibers with TiO₂ nanoparticles. These findings demonstrate the potential of PANI/PEO/LC/TiO₂ nanofibers for advanced applications requiring conductive and structurally optimized biomaterials, e.g., for use in humidity or volatile organic compound (VOC) sensors, especially where flexibility and environmental sustainability are required. Full article

(This article belongs to the Special Issue Polymer-Based Electrospun Fibers: Advancements, Applications, and Future Prospects)

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18 pages, 2803 KiB

Open AccessArticle

Single-Gelator Structuring of Hemp Oil Using Agarose: Comparative Assembly, Electronic Nose Profiling, and Functional Performance of Hydroleogels Versus Oleogels in Shortbread Cookies

by Oliwia Paroń and Joanna Harasym

Polymers 2025, 17(14), 1988; https://doi.org/10.3390/polym17141988 - 20 Jul 2025

Viewed by 309

Abstract

This study demonstrates an innovative single-gelator approach using agarose (1% and 2% w/w) to structure cold-pressed hemp oil into functional fat replacers for shortbread cookies, achieving a 40% reduction in saturated fatty acids compared to butter. Comprehensive characterization revealed that hydroleogels exhibited [...] Read more.

This study demonstrates an innovative single-gelator approach using agarose (1% and 2% w/w) to structure cold-pressed hemp oil into functional fat replacers for shortbread cookies, achieving a 40% reduction in saturated fatty acids compared to butter. Comprehensive characterization revealed that hydroleogels exhibited superior crispiness (45.67 ± 3.86 N for 2% agarose hydroleogel—HOG 2%) but problematic water activity (0.39–0.61), approaching microbial growth thresholds. Conversely, oleogels showed lower crispiness (2.27–3.43 N) but optimal moisture control (aw = 0.12–0.16) and superior color stability during 10-day storage. Electronic nose analysis using 10 metal oxide sensors revealed that oleogel systems preserved characteristic aroma profiles significantly better than hydroleogels, with 2% agarose oleogel (OG 2%) showing 34% less aroma decay than pure hemp oil. The 2% agarose oleogel demonstrated optimal performance with minimal baking loss (5.87 ± 0.20%), excellent structural integrity, and stable volatile compound retention over storage. Morphological analysis showed that hemp oil cookies achieved the highest specific volume (2.22 ± 0.07 cm³/g), while structured systems ranged from 1.12 to 1.31 cm³/g. This work establishes agarose as a versatile single gelator for hemp oil structuring and validates electronic nose technology for the objective quality assessment of fat-replaced bakery products, advancing healthier food design through molecular approaches. Full article

(This article belongs to the Section Polymer Networks and Gels)

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26 pages, 4992 KiB

Open AccessArticle

Composites from Recycled HDPE and ZnO Nanopowder with Improved Insulation and Weathering Features for Cable Jacketing Applications

by Alina Ruxandra Caramitu, Magdalena Valentina Lungu, Romeo Cristian Ciobanu, Ioana Ion, Eduard Marius Lungulescu, Gabriela Beatrice Sbarcea, Virgil Emanuel Marinescu, Sebastian Aradoaei, Mihaela Aradoaei and Raducu Machidon

Polymers 2025, 17(14), 1987; https://doi.org/10.3390/polym17141987 - 20 Jul 2025

Viewed by 364

Abstract

In this study, polymer matrix composites based on high-density polyethylene (HDPE) and recycled HDPE (HDPEr) were reinforced with zinc oxide nanoparticles (ZnO NPs). Four formulations (M1-M4) with HDPE/HDPEr/ZnO NP mass ratios of 50/50/0, 48/47/5, 45/45/10, and 43/42/15 were produced via melt injection molding. [...] Read more.

In this study, polymer matrix composites based on high-density polyethylene (HDPE) and recycled HDPE (HDPEr) were reinforced with zinc oxide nanoparticles (ZnO NPs). Four formulations (M1-M4) with HDPE/HDPEr/ZnO NP mass ratios of 50/50/0, 48/47/5, 45/45/10, and 43/42/15 were produced via melt injection molding. Disc-shaped samples (Ø30 ± 0.1 mm × 2 ± 0.1 mm) were evaluated in unaged and aged states (840 h at 100% humidity and 100 °C) using scanning electron microscopy, X-ray diffraction, ultraviolet–visible and Fourier-transform infrared spectroscopy, water absorption, thermal resistance, and mechanical and dielectric testing. Among all composites, M2 showed the best performance, with the highest aging resistance (estimated lifetime of 3891 h in humidity and 2361 h in heat). It also exhibited superior mechanical properties, with the highest indentation hardness, Vickers hardness, and elastic modulus before (0.042 GPa, 3.846 HV, and 0.732 GPa) and after aging under humidity (0.042 GPa, 3.932 HV, 0.706 GPa) and elevated temperature (0.085 GPa, 7.818 HV, 1.871 GPa). Although ZnO NPs slightly reduced electrical resistivity, M2 showed the most stable dielectric properties. In its unaged state, M2 had 22%, 30%, and 3% lower surface resistivity, volume resistivity, and dielectric strength, respectively, than M1 polymer. M2 was identified as the optimal formulation, combining mechanical strength, dielectric stability, and resistance to moisture and heat. Full article

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29 pages, 5210 KiB

Open AccessArticle

Ion Conduction Dynamics, Characterization, and Application of Ionic Liquid Tributyl Methyl Phosphonium Iodide (TMPI)-Doped Polyethylene Oxide Polymer Electrolyte

by Suneyana Rawat, Monika Michalska, Pramod K. Singh, Karol Strzałkowski, Nisha Pal, Markus Diantoro, Diksha Singh and Ram Chandra Singh

Polymers 2025, 17(14), 1986; https://doi.org/10.3390/polym17141986 - 19 Jul 2025

Viewed by 344

Abstract

The increasing demand for high-performance energy storage devices has stimulated interest in advanced electrolyte materials. Among them, ionic liquids (

I L s

) stand out for their thermal stability, wide electrochemical windows, and good ionic conductivity. When doped into polymeric matrices, these [...] Read more.

The increasing demand for high-performance energy storage devices has stimulated interest in advanced electrolyte materials. Among them, ionic liquids (

I L s

) stand out for their thermal stability, wide electrochemical windows, and good ionic conductivity. When doped into polymeric matrices, these ionic liquids form hybrid polymeric electrolytes that synergize the benefits of both liquid and solid electrolytes. This study explores a polymeric electrolyte based on polyethylene oxide (

P E O

) doped with tributylmethylphosphonium iodide

(T M P I)

and ammonium iodide (

N H_{4} I

), focusing on its synthesis, structural and electrical properties, and performance in energy storage devices such as dye-sensitized solar cells and supercapacitors. Strategies to improve its ionic conductivity, mechanical and chemical stability, and electrode compatibility are also discussed, along with future directions in this field. Full article

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22 pages, 12915 KiB

Open AccessArticle

Preparation of Tung Oil Microcapsules Coated with Chitosan–Arabic Gum and Its Effect on the Properties of UV Coating

by Jinzhe Deng and Xiaoxing Yan

Polymers 2025, 17(14), 1985; https://doi.org/10.3390/polym17141985 - 19 Jul 2025

Cited by 1 | Viewed by 256

Abstract

Tung oil, as dry oil, can quickly dry and polymerize into tough and glossy waterproof coatings, with a very high application value. Tung oil was used as a core material to prepare Tung oil microcapsules coated with chitosan–Arabic gum, and the preparation process [...] Read more.

Tung oil, as dry oil, can quickly dry and polymerize into tough and glossy waterproof coatings, with a very high application value. Tung oil was used as a core material to prepare Tung oil microcapsules coated with chitosan–Arabic gum, and the preparation process of the microcapsules was optimized. The effect of adding a UV coating on the performance of the microcapsules was explored. Under the conditions of a core–wall mass ratio of 0.5:1.0, pH value of 3.5, mass ratio of chitosan to Arabic gum of 1.0:4.0, and spray drying temperature of 130 °C, Tung oil microcapsules coated with chitosan–Arabic gum had a higher yield and coverage rate, which were 32.85% and 33.20%, respectively. With the increase of the spray drying temperature during preparation, the roughness of the coating first increased and then decreased, the visible light transmittance decreased first and then increased, and the glossiness showed an overall downward trend. The self-repairing rate decreased gradually. When the microcapsules #11 were added to the UV topcoat at 5%, the coating can obtain excellent comprehensive properties; the roughness was 0.79 μm, elongation at break was 5.04%, visible light transmittance was 77.96%, gloss loss rate was 10.95%, and self-repairing rate was 20.47%. Full article

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

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18 pages, 2822 KiB

Open AccessArticle

Temperature/Stress-Dependent Fractional Creep Models of Thermoplastic Polymers

by Leixiao Wu, Wei Cai and Jie Yang

Polymers 2025, 17(14), 1984; https://doi.org/10.3390/polym17141984 - 19 Jul 2025

Viewed by 302

Abstract

The creep behavior of thermoplastic polymeric materials is highly dependent on loading conditions, which must be accounted for in the intrinsic model. In this paper, fractional creep models have been developed to describe the temperature/stress-dependent creep/creep–recovery and accelerated creep damage behavior, with the [...] Read more.

The creep behavior of thermoplastic polymeric materials is highly dependent on loading conditions, which must be accounted for in the intrinsic model. In this paper, fractional creep models have been developed to describe the temperature/stress-dependent creep/creep–recovery and accelerated creep damage behavior, with the construction of a criterion correlating model parameters with temperature and initial stress. The fractional order in the fractional creep/creep–recovery model can be physically interpreted by the well-known master curve, and the creep rupture time can be predicted by combining the Monkman–Grant law with the fractional creep damage model. Extensive experimental data are employed to substantiate the model’s applicability under different loading conditions. Moreover, a comparative analysis highlights the proposed model’s superior simplicity and performance over existing models. Full article

(This article belongs to the Special Issue Multiscale Design for Polymer Advanced Manufacturing)

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14 pages, 2149 KiB

Open AccessArticle

Polymer Prosthetic Hand with Finger Copies for Persons with Congenital Defects or After Amputation Using 3D Printing Technology

by Anna Włodarczyk-Fligier, Magdalena Polok-Rubiniec, Aneta Kania, Sebastian Jakubik, Jakub Painta, Justyna Ryś, Jakub Wieczorek, Marta Marianek, Agata Ociepka, Mikołaj Micuła and Jakub Osuch

Polymers 2025, 17(14), 1983; https://doi.org/10.3390/polym17141983 - 19 Jul 2025

Viewed by 406

Abstract

The research presented in this paper focuses on the utilization of 3D printing technology in the design and manufacture of a prosthetic hand, equipped with a digit replicator. The subject of this study was a young man who had undergone the amputation of [...] Read more.

The research presented in this paper focuses on the utilization of 3D printing technology in the design and manufacture of a prosthetic hand, equipped with a digit replicator. The subject of this study was a young man who had undergone the amputation of two fingers on his right hand. The electronic control of the movement of the finger copy was developed using Arduino language. A concept and outline drawings were developed in ProCreate. Three-dimensional scan of the hand and forearm was made using an EinScan PRO HD SHINING 3D scanner. Using CAD software—Autodesk Inventor and Autodesk Meshmixer, the prosthesis was designed. Printing was carried out on a 3D printer of the i3 MK3 and MK3+ series using a PLA (polylactic acid) filament. It was determined that PLA is an optimal material for printing, as it is considered to be safe for future patients’ skin. Work on the electronic circuitry started in Autodesk TinkerCad simulation software, allowing the code to be verified and ensuring the safety of the control system. The prosthesis’s design demonstrates the potential to reach as many people in need as possible by using readily available, low-cost, and easy-to-use components. Full article

(This article belongs to the Special Issue 3D Printing Polymer Materials and Their Biomedical Applications)

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37 pages, 4317 KiB

Open AccessReview

Polymeric 3D-Printed Microneedle Arrays for Non-Transdermal Drug Delivery and Diagnostics

by Mahmood Razzaghi

Polymers 2025, 17(14), 1982; https://doi.org/10.3390/polym17141982 - 18 Jul 2025

Viewed by 326

Abstract

Microneedle arrays (MNAs) are becoming increasingly popular due to their ease of use and effectiveness in drug delivery and diagnostic applications. Improvements in three-dimensional (3D) printing techniques have made it possible to fabricate MNAs with high precision, intricate designs, and customizable properties, expanding [...] Read more.

Microneedle arrays (MNAs) are becoming increasingly popular due to their ease of use and effectiveness in drug delivery and diagnostic applications. Improvements in three-dimensional (3D) printing techniques have made it possible to fabricate MNAs with high precision, intricate designs, and customizable properties, expanding their potential in medical applications. While most studies have focused on transdermal applications, non-transdermal uses remain relatively underexplored. This review summarizes recent developments in 3D-printed MNAs intended for non-transdermal drug delivery and diagnostic purposes. It includes a literature review of studies published in the past ten years, organized by the target delivery site—such as the brain and central nervous system (CNS), oral cavity, eyes, gastrointestinal (GI) tract, and cardiovascular and reproductive systems, among other emerging areas. The findings show that 3D-printed MNAs are more adaptable than skin-based delivery, opening up exciting new possibilities for use in a variety of organs and systems. To guarantee the effective incorporation of polymeric non-transdermal MNAs into clinical practice, additional research is necessary to address current issues with materials, manufacturing processes, and regulatory approval. Full article

(This article belongs to the Special Issue Polymer-Based 3D Printing for Drug Delivery and Diagnostic Applications)

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61 pages, 2268 KiB

Open AccessEditor’s ChoiceReview

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

Viewed by 533

Abstract

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)

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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

Viewed by 375

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

Viewed by 290

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

Cited by 1 | Viewed by 301

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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14 pages, 1928 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

Viewed by 252

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)

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42 pages, 4253 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

Viewed by 293

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)

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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

Viewed by 262

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

Viewed by 292

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

Viewed by 286

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

Viewed by 411

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

Viewed by 219

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

Viewed by 296

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, 2340 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

Viewed by 309

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)

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