Polymers

42 pages, 6173 KB

Open AccessReview

Integrating Artificial Intelligence into Circular Strategies for Plastic Recycling and Upcycling

by Allison Vianey Valle-Bravo, Carlos López González, Rosalía América González-Soto, Luz Arcelia García Serrano, Juan Antonio Carmona García and Emmanuel Flores-Huicochea

Polymers 2026, 18(2), 306; https://doi.org/10.3390/polym18020306 - 22 Jan 2026

Cited by 2 | Viewed by 2170

Abstract

The increasing urgency to mitigate plastic pollution has accelerated the shift from linear manufacturing toward circular systems. This review synthesizes current advances in mechanical, chemical, biological, and upcycling pathways, emphasizing how artificial intelligence (AI) is reshaping decision-making, performance prediction, and system-level optimization. Intelligent [...] Read more.

The increasing urgency to mitigate plastic pollution has accelerated the shift from linear manufacturing toward circular systems. This review synthesizes current advances in mechanical, chemical, biological, and upcycling pathways, emphasizing how artificial intelligence (AI) is reshaping decision-making, performance prediction, and system-level optimization. Intelligent sensing technologies—such as FTIR, Raman spectroscopy, hyperspectral imaging, and LIBS—combined with Machine Learning (ML) classifiers have improved material identification, reduced reject rates, and enhanced sorting precision. AI-assisted kinetic modeling, catalyst performance prediction, and enzyme design tools have improved process intensification for pyrolysis, solvolysis, depolymerization, and biocatalysis. Life Cycle Assessment (LCA)-integrated datasets reveal that environmental benefits depend strongly on functional-unit selection, energy decarbonization, and substitution factors rather than mass-based comparisons alone. Case studies across Europe, Latin America, and Asia show that digital traceability, Extended Producer Responsibility (EPR), and full-system costing are pivotal to robust circular outcomes. Upcycling strategies increasingly generate high-value materials and composites, supported by digital twins and surrogate models. Collectively, evidence indicates that AI moves from supportive instrumentation to a structural enabler of transparency, performance assurance, and predictive environmental planning. The convergence of AI-based design, standardized LCA frameworks, and inclusive governance emerges as a necessary foundation for scaling circular plastic systems sustainably. Full article

(This article belongs to the Special Issue New Progress in the Recycling of Plastics)

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25 pages, 2766 KB

Open AccessArticle

Design and Optimization of Pullulan-Isononanoate Films with Bioactive-Loaded Liposomes for Potential Biomedical Use

by Amjed A. Karkad, Aleksandar Marinković, Aleksandra Jovanović, Katarina Simić, Stefan Ivanović, Milena Milošević and Tamara Erceg

Polymers 2026, 18(2), 305; https://doi.org/10.3390/polym18020305 - 22 Jan 2026

Viewed by 705

Abstract

This study reports the synthesis and detailed characterization of pullulan-isononanoate (Pull-Iso), as well as the preparation and characterization of Pull-Iso films incorporating liposomes loaded with silibinin (SB) and smoke tree (Cotinus coggygria) extract (STExt), to explore the physicochemical and functional properties [...] Read more.

This study reports the synthesis and detailed characterization of pullulan-isononanoate (Pull-Iso), as well as the preparation and characterization of Pull-Iso films incorporating liposomes loaded with silibinin (SB) and smoke tree (Cotinus coggygria) extract (STExt), to explore the physicochemical and functional properties of pullulan-based biomaterials for potential biomedical applications. Pullulan was successfully esterified with isononanoic acid chloride, as confirmed by ¹H and ¹³C NMR (Nuclear Magnetic Resonance) and Fourier Transform Infrared (FTIR) spectroscopy. Modification significantly reduced the glass transition temperature (Tg), indicating enhanced chain mobility due to the introduction of bulky side chains. Prepared liposomes, embedding SB and extracted smoke tree compounds, exhibited particle sizes ~2000 nm with moderate polydispersity (~0.340) and zeta potential values around –20 mV, demonstrating lower colloidal stability over 60 days, thereby justifying their encapsulation within films. Optical microscopy revealed uniform liposome dispersion in Pull-Iso film with 0.5 g of liposomes, while higher liposome loading (0.75 g of liposomes) induced aggregation and microstructural irregularities. Mechanical analysis showed a reduction in tensile strength and strain at higher liposome content. The incorporation of liposomes encapsulating STExt and SB significantly enhanced the antioxidant activity of Pull-Iso-based films in a concentration-dependent manner, as demonstrated by DPPH and ABTS radical scavenging assays. These preliminary findings suggest that pullulan esterification and controlled liposome incorporation may enable the development of flexible, bioactive-loaded films, which could represent a promising platform for advanced wound dressing applications, warranting further investigation. Full article

(This article belongs to the Special Issue Biomedical Applications of Polymeric Materials, 3rd Edition)

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22 pages, 3233 KB

Open AccessArticle

Synthesis and Degradation Behavior of Poly(glycerol sebacate)-Isophorone Diisocyanate Scaffolds Reinforced with Hydroxyapatite for Biomedical Applications

by Aleksandra Korbut, Agnieszka Sobczak-Kupiec, Monika Biernat and Sonia Zielińska

Polymers 2026, 18(2), 304; https://doi.org/10.3390/polym18020304 - 22 Jan 2026

Viewed by 584

Abstract

Poly(glycerol sebacate) (PGS) is a biodegradable elastomer with high potential for tissue engineering. However, its limited structural stability and degradation control restrict broader biomedical applications. This study presents an integrated fabrication strategy for highly porous PGS-IPDI scaffolds reinforced with two types of hydroxyapatite [...] Read more.

Poly(glycerol sebacate) (PGS) is a biodegradable elastomer with high potential for tissue engineering. However, its limited structural stability and degradation control restrict broader biomedical applications. This study presents an integrated fabrication strategy for highly porous PGS-IPDI scaffolds reinforced with two types of hydroxyapatite of distinct origin (HAP_B and HAP_ICMB). By combining low-temperature urethane crosslinking with thermally induced phase separation and salt leaching, we obtained scaffolds with interconnected micro–macroporous architectures and exceptionally high porosity (up to 98%). The comparative incorporation of phase-pure nanometric HAP_B and biphasic HAP_ICMB enabled the identification of composition-dependent differences in water uptake, structural stability, and mineralization tendencies. Furthermore, degradation behavior was systematically evaluated in four physiologically relevant media (PBS, SBF, artificial saliva, Ringer’s solution), revealing distinct degradation pathways associated with each environment. The results provide new insight into how hydroxyapatite type and incubation medium collectively govern the long-term performance of chemically crosslinked PGS-based scaffolds. Full article

(This article belongs to the Special Issue From Polymers Design to Advanced Structures for Biomedical Applications)

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23 pages, 4378 KB

Open AccessArticle

pH-Responsive mPEG-PLGA/Dexamethasone Coatings for Corrosion Control and Osteo-Immune Modulation of Biodegradable Magnesium

by Yu-Kyoung Kim, Seo-Young Kim, Yong-Seok Jang and Min-Ho Lee

Polymers 2026, 18(2), 303; https://doi.org/10.3390/polym18020303 - 22 Jan 2026

Cited by 2 | Viewed by 573

Abstract

This study aimed to control rapid localized corrosion and inflammation of biodegradable magnesium implants by developing a pH-responsive mPEG-PLGA coating loaded with dexamethasone (Dex). The mPEG-PLGA layer was designed to selectively degrade in alkaline conditions, thereby moderating pH elevation at the implant surface [...] Read more.

This study aimed to control rapid localized corrosion and inflammation of biodegradable magnesium implants by developing a pH-responsive mPEG-PLGA coating loaded with dexamethasone (Dex). The mPEG-PLGA layer was designed to selectively degrade in alkaline conditions, thereby moderating pH elevation at the implant surface while enabling controlled Dex release. By varying the molecular weight of mPEG and PLGA, the degradation rate and microsphere size were tunable, allowing adjustment of the drug release profile. Among the tested coating solution concentrations (1.5–7.5 mg/mL), the formulation with 3 mg/mL Dex yielded a final cumulative release concentration of 0.02 mg/mL over a two-week period, which suppressed inflammatory responses in RAW 264.7 macrophages with minimal cytotoxicity, while enhancing BMP-2 and RUNX2 expression in mesenchymal stem cells. In a rat femur defect model, Mg implants coated with mPEG-PLGA containing 3 mg/mL Dex significantly increased bone volume and bone mineral density and reduced early TNF-α expression, accompanied by continuous new bone formation and strong BSP-positive osseointegration. These findings suggest that the proposed pH-responsive mPEG-PLGA/Dex coating provides a promising strategy to simultaneously regulate corrosion, attenuate inflammation, and promote bone regeneration around magnesium implants. Full article

(This article belongs to the Special Issue Hydrogels, Biopolymers, and Applications as Antimicrobial Agents)

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24 pages, 5920 KB

Open AccessArticle

Mechanical, Fatigue, and Thermal Characterization of ASA, Nylon 12, PC, and PC-ABS Manufactured by Fused Filament Fabrication (FFF)

by Ângela Rodrigues, Ricardo Branco, Margarida Franco, Rui Silva, Cândida Malça and Rui F. Martins

Polymers 2026, 18(2), 302; https://doi.org/10.3390/polym18020302 - 22 Jan 2026

Cited by 1 | Viewed by 781

Abstract

Additive manufacturing has been widely adopted in industry as an alternative to traditional manufacturing processes for complex component production. In fact, a diverse range of materials, particularly polymers, can be processed using 3D printing for biomechanical applications (e.g., prosthetics). However, in-depth evaluation of [...] Read more.

Additive manufacturing has been widely adopted in industry as an alternative to traditional manufacturing processes for complex component production. In fact, a diverse range of materials, particularly polymers, can be processed using 3D printing for biomechanical applications (e.g., prosthetics). However, in-depth evaluation of these materials is necessary to determine their suitability for demanding applications, such as those involving cyclic loading. Following previous work that studied Polylactic Acid (PLA) and Polyethylene Terephthalate Glycol-modified (PETG) under experimental fatigue testing, this study examines the fatigue behaviour of other current 3D-printed polymeric materials, namely Acrylonitrile Styrene Acrylate (ASA), Polycarbonate (PC), Polyamide 12 (Nylon 12), and Polycarbonate–Acrylonitrile Butadiene Styrene (blend) (PC-ABS), for which fatigue data remain limited or even non-existent. The findings revealed performance differences on Tensile Strength (σ_R), Young’s Modulus and Ultimate Strain among tensile specimens made from these materials and characterised S-N curves for both high-cycle (HCF) and low-cycle (LCF) fatigue regimes at room temperature, with a tensile load ratio (R = 0.05). These results establish relationships among fatigue limit and quasi-static mechanical properties, namely 25% × σ_r for ASA (8 MPa), 7% × σ_r for PC (3.6 MPa), 17% × σ_r for Nylon 12 (7.4 MPa), and 15% × σ_r for PC-ABS (4.7 MPa), as well as between mechanical properties and preliminary potential biomechanical applications. Main conclusions were further supported by micro-computed tomography (micro-CT), which revealed levels of porosity in between 4% and 11%, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). Full article

(This article belongs to the Special Issue Research Progress on Mechanical Behavior of Polymers, 2nd Edition)

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56 pages, 5116 KB

Open AccessReview

Biobased Polymers in Printed Electronics: From Renewable Resources to Functional Devices

by Dimitra Karavasili, Kyriaki Lazaridou, Maria Angeliki Ntrivala, Andreas Chrysovalantis Pitsavas, Zafeiria Baziakou, Maria Papadimitriou, Nikolaos D. Bikiaris, Evangelia Balla and Ζoi Terzopoulou

Polymers 2026, 18(2), 301; https://doi.org/10.3390/polym18020301 - 22 Jan 2026

Cited by 3 | Viewed by 1274

Abstract

Printed electronics (PE) have emerged as a rapidly growing technology owing to their potential for low-cost fabrication, flexibility, and scalable device manufacturing. The dependence on fossil-based components raises environmental concerns, leading the scientific community toward sustainable solutions, aiming to reduce the accumulation of [...] Read more.

Printed electronics (PE) have emerged as a rapidly growing technology owing to their potential for low-cost fabrication, flexibility, and scalable device manufacturing. The dependence on fossil-based components raises environmental concerns, leading the scientific community toward sustainable solutions, aiming to reduce the accumulation of electronic waste (e-waste) in the environment and the emission of toxic gases, as well as to offer a circular solution in the sector. This review presents an in-depth overview of biobased polymeric materials in printed and organic (bio-)electronics. Firstly, the principal printing techniques are presented in detail. The review proceeds by outlining the various biobased synthetic and natural polymers, along with their blends, that are employed in the fabrication of biobased substrates for printed devices. Finally, the review emphasizes the existing challenges and constraints in the field of PE, along with the promising opportunities for its future advancement. Full article

(This article belongs to the Collection Biodegradable Polymers and Polymeric Composite)

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16 pages, 5786 KB

Open AccessArticle

Advancing Circular Composite Strategies by Vitrimer-Enabled Reuse of Unidirectional Laminates

by Jannick Fuchs, Nico Schuhmann, Jonathan Alms and Christian Hopmann

Polymers 2026, 18(2), 300; https://doi.org/10.3390/polym18020300 - 22 Jan 2026

Cited by 1 | Viewed by 539

Abstract

To efficiently reuse endless fibre-reinforced composites after their life cycle, the recovery of endless fibres including matrix material with subsequent reprocessing in their original state is desirable. Thanks to their covalent adaptive networks, vitrimers offer ideal properties for enabling new repair and circular [...] Read more.

To efficiently reuse endless fibre-reinforced composites after their life cycle, the recovery of endless fibres including matrix material with subsequent reprocessing in their original state is desirable. Thanks to their covalent adaptive networks, vitrimers offer ideal properties for enabling new repair and circular strategies for composites. In order to evaluate the detachability—meaning the separation of single laminate layers—and recycling potential for continuous fibre reinforcement, process routes and quality parameters must be established. In this study, the double cantilever beam test is used to test the adhesion based on the detachment of continuous fibre layers, and the interlaminare fracture toughness of mode I (G_IC) is measured as a parameter for the required energy for detachment. It was shown that G_IC increases above the vitrimer transition temperature and is higher than for reference specimens with an epoxy matrix. Surface roughness is measured to determine the mechanical and thermal degradation of the chemical network structure and additionally shows fibre cracking and defects in fibre–matrix interfaces. This allows the recycling process to be evaluated up to the production of a second generation, with the aim of identifying the recycling potential of the vitrimer matrix and implementing it for industrial processes. An efficient recycling strategy of the continuous fibre-reinforced vitrimers was thus demonstrated by hot pressing at 190 °C for 45 min, giving vitrimer samples a second life. Full article

(This article belongs to the Section Innovation of Polymer Science and Technology)

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38 pages, 7740 KB

Open AccessReview

Waterborne Poly(urethane-urea)s for Lithium-Ion/Lithium-Metal Batteries

by Bushra Rashid, Anjum Hanief Kohli and In Woo Cheong

Polymers 2026, 18(2), 299; https://doi.org/10.3390/polym18020299 - 22 Jan 2026

Viewed by 1049

Abstract

Waterborne polyurethane (WPU) and waterborne poly(urethane-urea) (WPUU) dispersions allow safer and more sustainable manufacturing of rechargeable batteries via water-based processing, while offering tunable adhesion and segmented-domain mechanics. Beyond conventional roles as binders and coatings, WPU/WPUU chemistries also support separator/interlayer and polymer-electrolyte designs for [...] Read more.

Waterborne polyurethane (WPU) and waterborne poly(urethane-urea) (WPUU) dispersions allow safer and more sustainable manufacturing of rechargeable batteries via water-based processing, while offering tunable adhesion and segmented-domain mechanics. Beyond conventional roles as binders and coatings, WPU/WPUU chemistries also support separator/interlayer and polymer-electrolyte designs for lithium-ion and lithium metal systems, where interfacial integrity, stress accommodation, and ion transport must be balanced. Here, we review WPU/WPUU fundamentals (building blocks, dispersion stabilization, morphology, and film formation) and review prior studies through a battery-centric structure–processing–property lens. We point out key performance-limiting trade-offs—adhesion versus electrolyte uptake and ionic conductivity versus storage modulus—and relate them to practical formulation variables, including soft-/hard-segment selection, ionic center/counterion design, molecular weight/topology control, and crosslinking strategies. Applications are reviewed for (i) electrode binders (graphite/Si; cathodes such as LFP and NMC), (ii) separator coatings and functional interlayers, and (iii) gel/solid polymer electrolytes and hybrid composites, with a focus on practical design guidelines for navigating these trade-offs. Future advancements in WPU/WPUU chemistries will depend on developing stable, low-impedance interlayers, enhancing electrochemical behavior, and establishing application-specific design guidelines to optimize performance in lithium metal batteries (LMB). Full article

(This article belongs to the Section Polymer Applications)

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27 pages, 6495 KB

Open AccessArticle

Linear Polyethyleneimine-Coated Gold Nanoparticles as a Platform for Central Nervous System Targeting

by Agustín J. Byrne, Antonia Infantes-Molina, Enrique Rodríguez-Castellón, Romina J. Glisoni, María J. Pérez, Patrizia Andreozzi, Barbara Richichi, Marco Marradi, Paula G. Franco and Juan M. Lázaro-Martínez

Polymers 2026, 18(2), 298; https://doi.org/10.3390/polym18020298 - 22 Jan 2026

Cited by 1 | Viewed by 932

Abstract

The unique physicochemical properties of gold nanoparticles (GNPs) have made them versatile tools for biomedical applications, such as imaging, therapy, and drug delivery. The surface modification of GNPs with polymers or biomolecules can enhance their colloidal stability and facilitate internalization into cells. However, [...] Read more.

The unique physicochemical properties of gold nanoparticles (GNPs) have made them versatile tools for biomedical applications, such as imaging, therapy, and drug delivery. The surface modification of GNPs with polymers or biomolecules can enhance their colloidal stability and facilitate internalization into cells. However, the efficient and biocompatible delivery to the central nervous system remains a major challenge, as many existing nanocarriers show poor capacity to cross the blood-brain barrier. We developed a method to coat GNPs with linear polyethyleneimine (GNP@PEI) through a chemical reduction bottom-up approach, in which linear PEI hydrochloride acts simultaneously as a reducing and stabilizing agent of colloidal dispersion. This strategy yielded monodisperse spherical GNP@PEI nanoparticles with an average diameter of 50 nm. The physicochemical profile, biocompatibility, and capacity for neural uptake of this potentially brain-targeted nanoplatform were then evaluated. GNP@PEI nanoparticles exhibited high biocompatibility in several primary neural cultures and cell lines, with cellular uptake showing clear cell-type-dependent differences. In vivo studies carried out in a murine model demonstrated that after the intranasal or intraperitoneal administrations of GNP@PEI nanoparticles, detectable levels of gold were found in several organs, including the brain. Collectively, these findings highlight the potential of GNP@PEI as a promising nanoplatform for brain-targeted delivery and for advancing the development of therapeutic strategies for neurological disorders. Full article

(This article belongs to the Topic Polymer and Biopolymer Nanocomposites for Emerging Medical, Industrial, and Environmental Applications)

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12 pages, 2588 KB

Open AccessArticle

Low-Odor High-Density Fiberboard Enabled by Supramolecular Interactions in Wood Fibers

by Xia Yu, Zongying Fu, Bo Liu, Xiaoxuan Guo, Yun Lu and Lihong Yao

Polymers 2026, 18(2), 297; https://doi.org/10.3390/polym18020297 - 22 Jan 2026

Cited by 2 | Viewed by 443

Abstract

The development of sustainable wood-based composites has driven increasing interest in formaldehyde-free, low-odor, and recyclable bonding systems. However, achieving high mechanical performance and dimensional stability in high-density fiberboards (HDFs) without synthetic adhesives remains a challenge. Here, we report a two-step strategy combining oxidative [...] Read more.

The development of sustainable wood-based composites has driven increasing interest in formaldehyde-free, low-odor, and recyclable bonding systems. However, achieving high mechanical performance and dimensional stability in high-density fiberboards (HDFs) without synthetic adhesives remains a challenge. Here, we report a two-step strategy combining oxidative pretreatment of wood fibers with supramolecular assembly of tannic acid (TA) and sodium ions (Na⁺) to fabricate low-odor, recyclable HDF. Oxidation generated abundant carboxyl groups on the fiber surface, enabling strong coordination and hydrogen-bonding interactions between TA and Na⁺, which constructed robust inter-fiber supramolecular networks without formaldehyde-based adhesives. The resulting HDF exhibited excellent mechanical properties, with an internal bond strength of 3.1 MPa, a modulus of rupture of 49 MPa, and 24 h water thickness swelling of only 12%. Odor and VOC analysis revealed only trace benzene, demonstrating markedly low odor. Furthermore, the reversible nature of Na⁺-TA interactions allowed efficient fiber separation and recyclability under mild aqueous conditions. This oxidation-assisted supramolecular approach provides a sustainable route for producing high-performance, low-odor, and recyclable fiberboards, offering a viable alternative to conventional polymer-bonded wood composites. Full article

(This article belongs to the Section Polymer Chemistry)

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16 pages, 1662 KB

Open AccessArticle

Shear Bond Strength of Additively and Subtractively Manufactured CAD/CAM Restorative Materials After Different Surface Treatments and Adhesive Strategies: An In Vitro Study

by Sevim Atilan Yavuz, Ayse Tugba Erturk-Avunduk, Omer Sagsoz, Ebru Delikan and Ozcan Karatas

Polymers 2026, 18(2), 296; https://doi.org/10.3390/polym18020296 - 22 Jan 2026

Viewed by 559

Abstract

This study aims to evaluate the effects of different surface treatments and adhesive systems on the shear bond strength (SBS) of additively manufactured (AM) and subtractively manufactured (SM) restorative materials. A total 675 rectangular specimens of three AM (Saremco Crowntec/SC, VarseoSmile CrownPlus/VC, and [...] Read more.

This study aims to evaluate the effects of different surface treatments and adhesive systems on the shear bond strength (SBS) of additively manufactured (AM) and subtractively manufactured (SM) restorative materials. A total 675 rectangular specimens of three AM (Saremco Crowntec/SC, VarseoSmile CrownPlus/VC, and VarseoSmile TriniQ/VT) and two SM (Vita Enamic/VE and Cerasmart/CS) restorative materials were fabricated. Each material was randomly divided into three groups regarding surface treatments: control/C, sandblasting/S, and etching/E. Following surface treatments, each AM and SM restorative material was then divided into three subgroups (15 specimens/subgroup) on the basis of adhesive systems (etch-and-rinse, self-etch, and universal). All specimens were thermocycled at 10,000 cycles, 5–55 °C, 30 s dwell time, and tested under SBS until failure, and failure types were examined under a stereomicroscope. Representative specimens were examined by SEM to evaluate fracture morphology. Statistical analysis was set at p < 0.05. There were significant differences in bond strength according to the material, surface treatment, adhesives, and their interactions (p < 0.05). The highest SBS value was obtained with SC × sandblasting × etch-and-rinse (16.45 ± 0.93 MPa), while the lowest value was found in the CS × control × universal interaction (4.68 ± 1.1 MPa). Outcomes varied according to the materials, surface treatment, and adhesive strategy. Clinically, these findings indicate that SM materials may require various surface treatment to achieve reliable adhesion, whereas AM materials provide more similar bond strength performance with no surface treatment. Full article

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

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15 pages, 3071 KB

Open AccessArticle

Green-Synthesized TiO₂ Nanoparticles Improve Mechanical Performance of Glass Ionomer Cements

by Nevra Karamüftüoğlu, Süha Kuşçu, İpek Kuşçu and Nesrin Korkmaz

Polymers 2026, 18(2), 295; https://doi.org/10.3390/polym18020295 - 22 Jan 2026

Viewed by 472

Abstract

Glass ionomer cements (GICs) are widely used in restorative and luting dentistry due to their fluoride release and chemical adhesion to dental tissues; however, their limited mechanical strength necessitates reinforcement strategies. The objective of this study was to investigate the effects of hemp-derived, [...] Read more.

Glass ionomer cements (GICs) are widely used in restorative and luting dentistry due to their fluoride release and chemical adhesion to dental tissues; however, their limited mechanical strength necessitates reinforcement strategies. The objective of this study was to investigate the effects of hemp-derived, green-synthesized titanium dioxide (TiO₂) nanoparticles on the surface and mechanical properties of two commercially available GICs with different clinical indications. TiO₂ nanoparticles were synthesized using Cannabis sativa leaf extract via a biogenic reduction method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX), confirming anatase-phase crystallinity, spherical morphology, and nanoscale particle size (28–49 nm). The nanoparticles were incorporated into Ketac™ Molar Easymix (restorative) and Ketac™ Cem Radiopaque (luting) GICs at 1%, 3%, and 5% (w/w), with nanoparticle-free formulations serving as controls (n = 10). Surface roughness, Vickers microhardness, and flexural strength were evaluated. Surface roughness increased in a concentration-dependent manner in both materials, with the highest values observed at 5% TiO₂ incorporation. In Ketac™ Molar Easymix, 1% and 3% TiO₂ significantly enhanced flexural strength and microhardness, whereas 5% resulted in reduced performance, consistent with SEM-observed nanoparticle agglomeration. In contrast, Ketac™ Cem Radiopaque exhibited no significant changes in flexural strength, although maximum microhardness values were recorded at 1% TiO₂ concentration. These findings demonstrate that low concentrations of hemp-derived TiO₂ nanoparticles can effectively reinforce restorative GICs and highlight the potential of green nanotechnology as a sustainable approach for improving dental biomaterials. Full article

(This article belongs to the Section Polymer Applications)

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22 pages, 5760 KB

Open AccessArticle

Polylactide/Polycaprolactone Nanofiber Scaffold Enhances Primary Cortical Neuron Growth

by Valeriia S. Shtol, Anastasiia D. Tsareva, Kirill A. Arsentiev, Sophia P. Konovalova, Suanda A. Tlimahova, Dmitry V. Klinov, Dimitri A. Ivanov and Pavel E. Musienko

Polymers 2026, 18(2), 294; https://doi.org/10.3390/polym18020294 - 21 Jan 2026

Viewed by 863

Abstract

Spinal cord injury (SCI) remains a major clinical challenge due to the limited regenerative capacity of the central nervous system (CNS). Effective scaffolds for repair must combine mechanical compatibility with host tissue, controlled degradation matching the time course of regeneration, and microarchitectural features [...] Read more.

Spinal cord injury (SCI) remains a major clinical challenge due to the limited regenerative capacity of the central nervous system (CNS). Effective scaffolds for repair must combine mechanical compatibility with host tissue, controlled degradation matching the time course of regeneration, and microarchitectural features that promote neuronal survival. Electrospun nanofibrous scaffolds mimic the structural and mechanical features of the extracellular matrix, providing critical cues for neuronal adhesion and glial modulation in neural regeneration. Here, we fabricated biodegradable poly(lactic acid)/poly(ε-caprolactone) (PLA/PCL) scaffolds using a dichloromethane/tetrahydrofuran (DCM/THF) solvent system to induce surface porosity via solvent-driven phase separation. The DCM/THF solvent system formulation produced nanofibers with porous surfaces and increased area for cell interaction. PLA/PCL scaffolds showed a Young’s modulus of ~26 MPa and sustained degradation, particularly under oxidative conditions simulating the post-injury microenvironment. In vitro, these scaffolds enhanced neuronal density up to fivefold and maintained ~80% viability over 10 days in primary neuron–glia cultures. Morphometric analysis revealed that DCM/THF-based scaffolds supported astrocytes with preserved process complexity and reduced circularity, indicative of a less reactive morphology. In contrast, scaffolds fabricated with 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) displayed reduced bioactivity and promoted morphological features associated with astrocyte reactivity, including cell rounding and process retraction. These findings demonstrate that solvent-driven control of scaffold microarchitecture is a powerful strategy to enhance neuronal integration and modulate glial morphology, positioning DCM/THF-processed PLA/PCL scaffolds as a promising platform for CNS tissue engineering. Full article

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

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15 pages, 13801 KB

Open AccessArticle

Multiscale Interlaminar Enhancement of CNT Network/CF Hybrid Composites and In Situ Monitoring of Crack Propagation Behavior

by Tianshu Li, Fenghui Shi, Hongchen Yan, Min Li, Shaokai Wang, Yizhuo Gu and Baoyan Zhang

Polymers 2026, 18(2), 293; https://doi.org/10.3390/polym18020293 - 21 Jan 2026

Viewed by 396

Abstract

It has long been desired to achieve mechanical enhancement and structural health monitoring by introducing carbon nanotubes (CNTs) into traditional carbon fiber (CF) composites. Herein, the initiation of micro-damage and crack propagation has been investigated by utilizing in situ electrical resistance changes in [...] Read more.

It has long been desired to achieve mechanical enhancement and structural health monitoring by introducing carbon nanotubes (CNTs) into traditional carbon fiber (CF) composites. Herein, the initiation of micro-damage and crack propagation has been investigated by utilizing in situ electrical resistance changes in interlaminar hybrid CNT network/CF composites during the shear loading process. The results show a clear relationship between the crack propagation and the electrical resistance response particularly when approaching the failure of the single-layer CNT network hybrid composites. Furthermore, the chemically modified CNT network exhibits evident enhancement on main mechanical properties of the CF composites, superior to the thermoplastic toughening method. The characterizations manifest that the multiscale interlayered CNT/CF structure can simultaneously resist the crack propagation along both the in-plane direction and the cross-plane direction, which consequently enhances the flexural and compressive strengths of the composite material. This discovery provides a novel idea for the potential application of CNT network/CF hybrid composites in the integration of mechanical reinforcement and structural health monitoring, namely, that the CNT network acts not only as a reinforcing phase but also as a sensor for the structural health monitoring of the composites. Full article

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

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16 pages, 3370 KB

Open AccessEditor’s ChoiceArticle

Numerical Investigation of Dynamic Wrinkling Behaviors in Stiff-Film/PDMS-Substrate Structure

by Haohao Bi, Wenjie Li, Liuyun Wang and Bo Wang

Polymers 2026, 18(2), 292; https://doi.org/10.3390/polym18020292 - 21 Jan 2026

Viewed by 394

Abstract

Thin film/substrate structures based on the principle of buckling mechanics exhibit both excellent stretchability and mechanical stability, and they have been recognized as a critical configuration in the design of flexible electronic devices. During application, flexible electronic devices are usually subjected to complex [...] Read more.

Thin film/substrate structures based on the principle of buckling mechanics exhibit both excellent stretchability and mechanical stability, and they have been recognized as a critical configuration in the design of flexible electronic devices. During application, flexible electronic devices are usually subjected to complex dynamic environments. Therefore, it is of great significance to investigate the dynamic behavior of thin film/substrate structures for the design of flexible electronic devices. The bending energy, membrane energy, and kinetic energy of the thin film and the elastic energy of the substrate were calculated. On this basis, the dynamic equation of the thin film/substrate structure with a checkerboard wrinkled pattern was derived by applying the principle of minimum energy combined with the Lagrangian function. Numerical simulations were conducted on the system to analyze the effect of pre-strain and the Young’s modulus of substrate on the system’s potential energy function, simulate the temporal response of the system’s dynamic behavior, and investigate the influences of pre-strain and the Young’s modulus of substrate on system stability and the chaos critical value. Theoretical support is expected to be provided for the design of two-dimensional (2D) thin film/substrate structures through this research. Full article

(This article belongs to the Special Issue Dynamic Behavior of Polymer Composite Materials and Structures, 2nd Edition)

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16 pages, 3798 KB

Open AccessArticle

Tailoring Thermal Conductivity Anisotropy in Poly(vinylidene fluoride)/Boron Nitride Nanosheet Composites via Processing-Induced Filler Orientation

by Yan-Zhou Lei and De-Xiang Sun

Polymers 2026, 18(2), 291; https://doi.org/10.3390/polym18020291 - 21 Jan 2026

Viewed by 536

Abstract

To address the thermal management challenges in electronic devices, this study systematically investigates the effects of injection molding and compression molding on the microstructure and thermal conductivity of poly(vinylidene fluoride)/boron nitride nanosheet (PVDF/BNNs) composites. Using 10 μm diameter BNNs as thermal conductive fillers [...] Read more.

To address the thermal management challenges in electronic devices, this study systematically investigates the effects of injection molding and compression molding on the microstructure and thermal conductivity of poly(vinylidene fluoride)/boron nitride nanosheet (PVDF/BNNs) composites. Using 10 μm diameter BNNs as thermal conductive fillers and PVDF as the matrix, the composites were characterized via scanning electron microscopy (SEM), thermal conductivity measurements, rheological analysis, X-ray diffraction (XRD), and mechanical tests. The results demonstrate that the strong shear stress in injection molding induces significant alignment of BNNs along the flow direction, leading to remarkable thermal conductivity anisotropy. At a PVDF/BNNs mass ratio of 90/10, the in-plane thermal conductivity of the injection-molded composite reaches 1.26 W/(m·K), while the through-plane conductivity is only 0.40 W/(m·K). In contrast, compression molding, which involves minimal shear, results in randomly dispersed BNNs and isotropic thermal conductivity, with both in-plane and through-plane values around 0.41 W/(m·K) at the same filler loading. Both processing methods preserve the coexistence of α- and β-crystalline phases in PVDF. However, injection molding enhances matrix crystallinity through stress-induced crystallization, yielding composites with higher density and superior tensile properties. Compression molding, due to slower cooling, leads to incomplete PVDF crystallization, as evidenced by a shoulder peak near 164 °C in differential scanning calorimetry (DSC) curves. This study elucidates the mechanism by which processing methods regulate the structure and properties of PVDF/BNNs composites, offering theoretical and practical guidance for designing high-performance thermally conductive materials. Full article

(This article belongs to the Special Issue Modifications of Polymer Materials for Toughness, Thermal Conductivity)

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17 pages, 2503 KB

Open AccessArticle

Effect of Resin Type, Layer Thickness, and Printing Orientation on the Mechanical and Surface Properties of 3D-Printed Occlusal Splints

by Beyza Tandogan, Faruk Emir and Gulsum Ceylan

Polymers 2026, 18(2), 290; https://doi.org/10.3390/polym18020290 - 21 Jan 2026

Viewed by 607

Abstract

This in vitro study aimed to evaluate the effects of resin type, layer thickness, and printing orientation on the surface and mechanical properties of 3D-printed occlusal splints fabricated using digital light processing (DLP) technology. Three commercially available splint resins (KeySplint Hard, Freeprint Splint [...] Read more.

This in vitro study aimed to evaluate the effects of resin type, layer thickness, and printing orientation on the surface and mechanical properties of 3D-printed occlusal splints fabricated using digital light processing (DLP) technology. Three commercially available splint resins (KeySplint Hard, Freeprint Splint 2.0, and V-Print Splint) were used to fabricate 180 rectangular specimens with two-layer thicknesses (50 µm and 100 µm) and three printing orientations (0°, 45°, 90°). Surface roughness (Ra, Rz), gloss, microhardness, flexural strength, and elastic modulus were measured. Statistical analysis was performed using robust ANOVA with Bonferroni correction. Resin type and printing orientation significantly influenced all surface and mechanical properties (p < 0.001), while layer thickness had a limited effect. Keystone resin exhibited the smoothest surface and highest gloss, whereas Freeprint resin showed the highest microhardness and elastic modulus. Printing at 45° generally enhanced flexural strength and provided more balanced mechanical performance. SEM analysis confirmed that surface morphology varied with orientation, correlating with profilometric and gloss measurements. Resin composition and printing orientation are critical determinants of the mechanical and surface performance of 3D-printed occlusal splints. Optimizing these parameters can improve durability, esthetics, and clinical functionality. All tested materials achieved clinically acceptable surface smoothness, supporting their suitability for intraoral use. Full article

(This article belongs to the Special Issue Polymers for Dental, Oral, and Craniofacial Applications)

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34 pages, 7481 KB

Open AccessReview

Recent Advances in Thermoplastic Starch (TPS) and Biodegradable Polyester Blends: A Review of Compatibilization Strategies and Bioactive Functionalities

by Elizabeth Moreno-Bohorquez, Mary Judith Arias-Tapia and Andrés F. Jaramillo

Polymers 2026, 18(2), 289; https://doi.org/10.3390/polym18020289 - 21 Jan 2026

Viewed by 1507

Abstract

Thermoplastic starch (TPS) blended with biodegradable polyesters such as polyhydroxybutyrate (PHB), polylactic acid (PLA), polybutylene succinate (PBS), and polycaprolactone (PCL) represents a promising route toward sustainable alternatives to petroleum-based plastics. TPS offers advantages related to abundance, low cost, and biodegradability, while polyesters provide [...] Read more.

Thermoplastic starch (TPS) blended with biodegradable polyesters such as polyhydroxybutyrate (PHB), polylactic acid (PLA), polybutylene succinate (PBS), and polycaprolactone (PCL) represents a promising route toward sustainable alternatives to petroleum-based plastics. TPS offers advantages related to abundance, low cost, and biodegradability, while polyesters provide improved mechanical strength, thermal stability, and barrier performance. However, the intrinsic incompatibility between hydrophilic TPS and hydrophobic polyesters typically leads to immiscible systems with poor interfacial adhesion and limited performance. This review critically examines recent advances in the development of TPS/polyester blends, with emphasis on compatibilization strategies based on chemical modification, natural and synthetic compatibilizers, bio-based additives, and reinforcing agents. Particular attention is given to the role of organic acids, essential oils, phenolic compounds, nanofillers, and natural reinforcements in controlling morphology, crystallinity, interfacial interactions, and thermal–mechanical behavior. In addition, the contribution of bioactive additives to antimicrobial and antioxidant functionality is discussed as an emerging multifunctional feature of some TPS/polyester systems. Finally, current limitations related to long-term stability, scalability, and life cycle assessment are highlighted, identifying key challenges and future research directions for the development of advanced biodegradable materials with tailored properties. Full article

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

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16 pages, 5027 KB

Open AccessArticle

Surface Properties of Dental Materials Influence the In Vitro Multi-Species Biofilm Formation

by Sabina Noreen Wuersching, David Manghofer, Bogna Stawarczyk, Jan-Frederik Gueth and Maximilian Kollmuss

Polymers 2026, 18(2), 288; https://doi.org/10.3390/polym18020288 - 21 Jan 2026

Viewed by 664

Abstract

This study examined the association between biofilm growth and surface properties of 3D printed, milled, and conventional materials used for manufacturing fixed dental prostheses. Disc-shaped specimens were produced and finished from five 3D-printing resins (VarseoSmile Crown plus [VSC], NextDent C&B MFH [ND], VarseoSmile [...] Read more.

This study examined the association between biofilm growth and surface properties of 3D printed, milled, and conventional materials used for manufacturing fixed dental prostheses. Disc-shaped specimens were produced and finished from five 3D-printing resins (VarseoSmile Crown plus [VSC], NextDent C&B MFH [ND], VarseoSmile Temp [VST], Temp PRINT [TP], P Pro Crown & Bridge [P]), two polymer milling blocks (composite: TetricCAD [TC], PMMA: TelioCAD [TEL]), two conventional polymer materials (Tetric EvoCeram [TEC], Protemp 4 [PT]), and zirconia (ZR). Surface roughness (R_a), wettability, interfacial tension (IFT) and surface topography were examined. Three-day biofilms were grown on the specimens using A. naeslundii, S. gordonii, S. mutans, S. oralis, and S. sanguinis in a multi-species suspension. Biofilms were quantified by crystal violet staining and with a plating and culture method (CFU/mL). Linear regression analysis was computed to demonstrate associations between the surface properties and biofilm growth. The strength of this relationship was quantified by calculating Spearman’s ρ. TC exhibited the highest, and TP the lowest IFT. TEC showed the highest R_a, while TEL had the lowest, with significant differences detected particularly between milled and 3D-printed specimens. TP specimens exhibited the highest biofilm mass, while ZR surfaces retained the least. Bacterial viability within the biofilms remained similar across all tested materials. There was a strong negative correlation between total IFT and biofilm mass, and a moderate positive correlation between R_a and CFU/mL. Surface properties are shaped by material composition, microstructure, and manufacturing methods and play a crucial role in biofilm formation on dental restorations. Full article

(This article belongs to the Special Issue Polymers for Dental Applications: From New Materials and Processes to Clinical Translation)

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16 pages, 4603 KB

Open AccessArticle

Modeling and Evaluation of Customizable Immobilization Masks for Precision Radiotherapy

by Diana Adlienė, Antonio Jreije, Paulius Griškevičius, Neringa Keršienė and Rūta Nedzinskienė

Polymers 2026, 18(2), 287; https://doi.org/10.3390/polym18020287 - 21 Jan 2026

Viewed by 587

Abstract

Accurate immobilization is critical in head and neck (H&N) radiotherapy to ensure precise dose delivery while minimizing irradiation of surrounding healthy tissues. However, conventional thermoplastic masks cannot secure 100% replicas of the patient’s surface and are often limited by mechanical weakness, patient discomfort, [...] Read more.

Accurate immobilization is critical in head and neck (H&N) radiotherapy to ensure precise dose delivery while minimizing irradiation of surrounding healthy tissues. However, conventional thermoplastic masks cannot secure 100% replicas of the patient’s surface and are often limited by mechanical weakness, patient discomfort, and workflow inefficiencies. Recently, the best replicas of the patient’s face have been obtained by exploring personal CT or MRI scans of patients that are used for manufacturing of immobilization masks. This study aimed to design and evaluate customizable immobilization masks using acrylonitrile butadiene styrene (ABS)-based composites reinforced with bismuth oxide (Bi₂O₃) and to compare their mechanical performance against commercial thermoplastic masks. ABS and ABS/Bi₂O₃ composite filaments (5, 10, and 20 wt%) were fabricated and characterized by tensile testing. A patient-specific virtual mask was modeled and subjected to finite element analysis (FEA) under clinically relevant loading scenarios, including neck flexion and lateral bending. Results were benchmarked against two commercial thermoplastic masks. ABS and ABS-based composites exhibited significantly higher stiffness (1.7–2.5 GPa) and yield strength (20–25 MPa) compared to commercial thermoplastics (0.25–0.3 GPa, ~7 MPa; p < 0.001). FEA simulations revealed markedly reduced displacement in ABS masks (1–5 mm at 2 mm thickness; <1 mm at 4 mm thickness) relative to commercial masks, which exceeded 20 mm under lateral load. Hybrid configurations with reinforced edges further optimized rigidity while limiting material usage. Customized ABS-based immobilization masks outperform conventional thermoplastics in mechanical stability and displacement control, with the potential to reduce planning margins and improve patient comfort. In addition, ABS-based masks can be recycled, and Bi₂O₃-filled composites can be reused for printing new immobilization masks, thus contributing to a reduced amount of plastic waste. These findings support their promise as next-generation immobilization devices for precision radiotherapy, warranting further clinical validation, workflow integration and sustainable implementation within a circular economy. Full article

(This article belongs to the Special Issue Polymeric Materials and Their Application in 3D Printing, 3rd Edition)

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14 pages, 1502 KB

Open AccessArticle

Demethylation and Acetylation Modification of Alkali Lignin and Their Potential Applications in Sunscreen

by Jianan Hu, Yunni Zhan and Xuelian Zhou

Polymers 2026, 18(2), 286; https://doi.org/10.3390/polym18020286 - 21 Jan 2026

Cited by 1 | Viewed by 533

Abstract

In order to improve the utilization of alkali lignin (AL) as an effective component for ultraviolet (UV) shielding, demethylation and acetylation modification were carried out to improve the UV absorption performance of lignin. Then, lignin-based sunscreens were successfully prepared by mixing the modified [...] Read more.

In order to improve the utilization of alkali lignin (AL) as an effective component for ultraviolet (UV) shielding, demethylation and acetylation modification were carried out to improve the UV absorption performance of lignin. Then, lignin-based sunscreens were successfully prepared by mixing the modified lignin and commercial cream without UV shielding ingredients. The modified alkali lignin was comprehensively characterized in terms of its molecular weight, functional groups and structural properties by GPC, UV spectroscopy and ³¹P NMR. The results showed that the Mw of all three lignin feedstocks (AL, AL_MeOH and AL_Acetone) was decreased with prolonged demethylation time. Compared to the original feedstock, demethylated AL had a darker color and improved UV absorption performance due to the increased phenolic hydroxyl content (approximately 4.35 mmol/g). ³¹P-NMR spectra showed that the guaiacyl phenolic hydroxyl content decreased rapidly after acetylation, causing the sample color to become lighter. Among all lignin-based sunscreens, DAL_Acetone achieved the highest SPF value of 11.23, a 69.4% increase over its pre-reaction level and a 7.58-fold enhancement compared to the original lignin. In summary, this study opens a promising avenue for repurposing industrial lignin as a sustainable biomaterial in high-value sectors like UV-blocking agents and cosmetic formulations. Full article

(This article belongs to the Special Issue Valorization of Polymers in Wood)

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23 pages, 3399 KB

Open AccessArticle

Assessment of the Oil Release and Insect Repellent Activity of Spray-Dried Gum Arabic/Citronella Oil Microcapsules

by Dilayda Kanmaz, Serkan Yildiz, Serpil Koral Koc, Gizem Manasoglu, Cansu Aras, Rumeysa Celen, Mehmet Tiritoglu, Sebnem Duzyer Gebizli, Ozgur Vatan and Esra Karaca

Polymers 2026, 18(2), 285; https://doi.org/10.3390/polym18020285 - 21 Jan 2026

Viewed by 833

Abstract

Essential oils are natural insect repellents, which can be microencapsulated and protected by wall materials to provide prolonged protection against insects. The protection and release of these repellents depend on various parameters, including morphology and production conditions. Herein, twenty-seven gum arabic/citronella essential oil [...] Read more.

Essential oils are natural insect repellents, which can be microencapsulated and protected by wall materials to provide prolonged protection against insects. The protection and release of these repellents depend on various parameters, including morphology and production conditions. Herein, twenty-seven gum arabic/citronella essential oil (GA/CEO) spray-dried microcapsules were produced by using three wall-to-core ratios (3:1, 4:1, 6:1), three inlet temperatures (120, 150, 180 °C), and three feed rates (1, 2.5, 5 mL/min). The morphology, particle size, encapsulation efficiency, and release rates were evaluated. The insect repellent activity of microcapsules (0.25, 0.5, and 1 g) against Drosophila melanogaster flies was tested. A systematic process optimization was carried out by evaluating the effects of both emulsion concentration and process parameters on the release rates. Microcapsules with smooth surfaces and homogeneous particle sizes were produced. Encapsulation efficiency reached 90% by increasing the inlet temperature and feed rate. Slower release rates (approximately 40%) were achieved with higher concentrations of the wall material and temperatures, generally. Optimal process conditions were determined as a wall-to-core ratio of 4:1, temperatures exceeding 150 °C, and feed rates above 2.5 mL/min. The highest repellent activity achieved was 95%, indicating effectiveness of GA/CEO microcapsules as insect repellent materials. Full article

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

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15 pages, 6527 KB

Open AccessArticle

Tribological Performance of Grease-Coated Rubber in High-Pressure Hydrogen Storage Applications

by Sheng Ye, Haijie Zhi, Wenqiang Wu, Sohail Yasin, Chaohua Gu, Jianfeng Shi and Sheng Zeng

Polymers 2026, 18(2), 284; https://doi.org/10.3390/polym18020284 - 21 Jan 2026

Viewed by 447

Abstract

Rubber materials undergo continuous wear in high-pressure seal applications. To address the risk of adhesive wear and consequent leakage of rubber seals operating under reciprocating sliding in high-pressure hydrogen storage and refueling systems, this study employed high-pressure hydrogen tribology testing. Ball-on-disk reciprocating tests [...] Read more.

Rubber materials undergo continuous wear in high-pressure seal applications. To address the risk of adhesive wear and consequent leakage of rubber seals operating under reciprocating sliding in high-pressure hydrogen storage and refueling systems, this study employed high-pressure hydrogen tribology testing. Ball-on-disk reciprocating tests were conducted using a 316L stainless-steel ball against silica-filled nitrile butadiene rubber (NBR), and the friction response and wear-morphology evolution were compared under ambient air, 1 MPa hydrogen (H₂), 50 MPa H₂, 50 MPa nitrogen (N₂), and grease-coated conditions. Under dry sliding, the coefficient of friction (COF) of NBR in air and hydrogen ranged from 1.34 to 1.44, whereas it decreased markedly to 0.942 in 50 MPa N₂. The wear volume under the four dry conditions was concentrated in the range of ~0.292–0.320 mm³. After grease coating, the steady-state COF in air and at 50 MPa H₂ dropped to 0.099 and 0.105, respectively, and the wear features changed from ridge-like wear patterns/tear pits to regular, smooth indentations with slight running marks. The results demonstrate that a lubricating film can effectively separate direct metal–rubber contact and suppress stick–slip, enabling a low-friction, low-wear, and highly stable interface in high-pressure hydrogen, and providing a practical engineering route for reliable operation of rubber seals in hydrogen service. Full article

(This article belongs to the Special Issue Advancements in Mechanical Properties and Material Testing in Polymer Science)

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20 pages, 4640 KB

Open AccessArticle

Cooperative Effect of Ammonium Polyphosphate and Talcum for Enhancing Fire-Proofing Performance of Silicone Rubber-Based Insulators via Formation of a HIGH-Strength Barrier Layer

by Dong Zhao, Yihan Jiang, Yong Fang, Tingwei Wang and Yucai Shen

Polymers 2026, 18(2), 283; https://doi.org/10.3390/polym18020283 - 20 Jan 2026

Cited by 1 | Viewed by 1856

Abstract

Enhancing the flame retardancy of polymeric materials by adding only eco-friendly ammonium polyphosphate (APP) while simultaneously maintaining high-temperature resistance has become a challenge. Talcum has been introduced as a cooperative agent into the silicone rubber/APP system to investigate the effect of talcum on [...] Read more.

Enhancing the flame retardancy of polymeric materials by adding only eco-friendly ammonium polyphosphate (APP) while simultaneously maintaining high-temperature resistance has become a challenge. Talcum has been introduced as a cooperative agent into the silicone rubber/APP system to investigate the effect of talcum on flame retardancy, thermal stability, and high-temperature resistance. The machining process induces the orientation of talcum in the system. The ceramifiable silicone rubber blends containing oriented talcum (e.g., sample SA₆T₄) exhibited superb flame retardancy, including an LOI of 29.4%, a UL-94 rating of V-0, and a peak heat release rate (PHRR) of 250.2 kW·m⁻². More importantly, the blends present excellent thermal stability and high-temperature resistance, characterized by outstanding self-supporting properties and dimensional stability. Based on the structural analysis of the blends and their residues, the made of action for the improved flame retardancy may be attributed to the formation of a compact barrier layer. This layer is formed by oriented talcum platelets combined with phosphoric acid, from the thermal decomposition of APP, promoting crosslinking, thereby achieving a good inhibition barrier to inhibit heat feedback from the condensation zone. The excellent thermal stability and high-temperature resistance of the ceramifiable silicone rubber blends may be ascribed to a cooperative effect between APP and talcum at high temperatures, which facilitates the formation of ceramic structures. The novel ceramifiable silicone rubber composite has potential applications as flame-retardant sealing components for rail transit equipment and encapsulation materials for new energy battery modules. Full article

(This article belongs to the Special Issue Challenges and Innovations in Fire Safety Polymeric Materials)

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28 pages, 5291 KB

Open AccessReview

Pitch-Based Activated Carbon Fibers: Activation Influences and Supercapacitor Applications

by Matthew Joe and Heon E. Park

Polymers 2026, 18(2), 282; https://doi.org/10.3390/polym18020282 - 20 Jan 2026

Viewed by 577

Abstract

Pitch-based activated carbon fibers, recognized for their excellent electrical conductivity, mechanical strength and durability, offer a compelling electrode alternative in the development of next-generation supercapacitors. In this review, we provide insight into the critical role of porosity in enhancing pitch-based carbon fiber performance [...] Read more.

Pitch-based activated carbon fibers, recognized for their excellent electrical conductivity, mechanical strength and durability, offer a compelling electrode alternative in the development of next-generation supercapacitors. In this review, we provide insight into the critical role of porosity in enhancing pitch-based carbon fiber performance in supercapacitors, with a focus on the processes and enhancements employed for pore introduction. The background and theoretical underpinnings for the necessity of porosity are briefly introduced, providing a rationale for the optimization of pore distribution. Moreover, the practical outcomes of these treatments are explored in supercapacitor applications, demonstrating the energy storage capabilities of pitch-based activated carbon fibers. In preparing this review, we surveyed the literature and found that pore introduction onto pitch-based carbon fibers is achieved almost solely through activation, which invites future research into alternative techniques. Additionally, it is apparent that future comparisons will benefit from the establishment of a standardized protocol for the reporting of supercapacitor performance. Full article

(This article belongs to the Special Issue Advances in High-Performance Polymer Fibers: Synthesis, Structure, and Applications)

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19 pages, 4692 KB

Open AccessArticle

Molecularly Imprinted Polymer Nanoparticles for Lung-Cancer-Cell-Surface Proteomics

by Kirabo Magumba, Elena Piletska, Thong Huy Cao, Donald Jones, Salvador Macip and Sergey Piletsky

Polymers 2026, 18(2), 281; https://doi.org/10.3390/polym18020281 - 20 Jan 2026

Cited by 1 | Viewed by 672

Abstract

The identification and targeting of lung-cancer-cell-surface proteins are important for drug development. Molecularly imprinted polymer nanoparticles (nanoMIPs) offer a synthetic approach for the recognition of proteins on the cell surfaces. This work outlines the use of a novel ‘snapshot imprinting’ approach to characterize [...] Read more.

The identification and targeting of lung-cancer-cell-surface proteins are important for drug development. Molecularly imprinted polymer nanoparticles (nanoMIPs) offer a synthetic approach for the recognition of proteins on the cell surfaces. This work outlines the use of a novel ‘snapshot imprinting’ approach to characterize differences in the cell-surface proteomes of lung cancer cell lines (A549, H460, H522) and a non-cancerous cell line (BEAS-2B) to potential protein targets for diagnostic and therapeutic applications. The mass spectrometry-based quantitative proteomics identified 2381 proteins. Fold change and p-value thresholds were used to define statistically and biologically significant differentially expressed proteins (DEPs) across cell lines, yielding 353, 426, and 274 DEPs for A549, H460, and H522, respectively, when compared to BEAS-2B. The DEPs identified across overlapping cell line comparisons were analyzed using Gene Ontology enrichment and a protein–protein network to identify hub proteins. Among these hub proteins, five proteins (NPM1, TOP2A, EZH2, PRKDC, and HNRNPK) were identified as clinically relevant when cross-referenced with the Human Protein Atlas database and the literature, highlighting their potential as diagnostic and therapeutic targets. These findings highlight the potential of nanoMIP-based snapshot imprinting as an alternative to ‘classical’ approaches for identifying potential protein targets for diagnostic and therapeutic applications. Full article

(This article belongs to the Special Issue Advances in Molecularly Imprinted Polymer Materials)

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19 pages, 9557 KB

Open AccessArticle

The Effect of Thermal Annealing on Optical Properties and Surface Morphology of a Polymer: Fullerene- and Non-Fullerene-Blend Films Used in Organic Solar Cells

by Bożena Jarząbek, Muhammad Raheel Khan, Barbara Hajduk, Andrzej Marcinkowski, Paweł Chaber, Adrian Cernescu and Yasin C. Durmaz

Polymers 2026, 18(2), 280; https://doi.org/10.3390/polym18020280 - 20 Jan 2026

Cited by 1 | Viewed by 834

Abstract

The optical properties, electronic structure and morphology of thin films of the polymer donor PTB7-Th blended with either the fullerene acceptor PC70BM or the non-fullerene acceptor ZY-4Cl were systematically investigated to evaluate their annealing-induced evolution. Thin films were characterized using UV–Vis–NIR absorption spectroscopy, [...] Read more.

The optical properties, electronic structure and morphology of thin films of the polymer donor PTB7-Th blended with either the fullerene acceptor PC70BM or the non-fullerene acceptor ZY-4Cl were systematically investigated to evaluate their annealing-induced evolution. Thin films were characterized using UV–Vis–NIR absorption spectroscopy, spectroscopic ellipsometry, ATR-FTIR spectroscopy, atomic force microscopy (AFM), and nano-IR analysis. In situ stepwise thermal annealing revealed distinct changes in absorption edge parameters, indicating thermally induced modifications in the electronic structure of the blend films. Ellipsometric analysis showed that elevated temperatures significantly affect the refractive index and extinction coefficient spectra. AFM measurements demonstrated markedly different surface morphology evolution for the two blend systems, with pronounced needle-shaped crystallites formation observed in PTB7-Th:ZY-4Cl films after annealing at 100 °C. Nano-IR characterization identified these crystallites as predominantly PTB7-Th, indicating phase separation driven by thermal treatment. The combined optical and structural results reveal distinct annealing-induced changes in the blend. Finally, BHJ solar cells, based on PTB7-Th:PC70BM and PTB7-Th:ZY-4Cl active layers, were fabricated, and their photovoltaic response was demonstrated. Full article

(This article belongs to the Special Issue Polymeric Materials for Solar Cell Applications)

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24 pages, 1710 KB

Open AccessArticle

Polyacid Solutions as an Analogue of a Neural Network

by Sherniyaz Kabdushev, Dina Shaltykova, Eldar Kopishev, Gaini Seitenova, Rizagul Dyusssova and Ibragim Suleimenov

Polymers 2026, 18(2), 279; https://doi.org/10.3390/polym18020279 - 20 Jan 2026

Cited by 1 | Viewed by 444

Abstract

Despite the increased interest in neuromorphic materials—a physical implementation of neural networks that could overcome the so-called von Neumann architecture’s limitations—most studies have been performed on the basis of systems specially constructed for this purpose. It has previously been shown that analogues of [...] Read more.

Despite the increased interest in neuromorphic materials—a physical implementation of neural networks that could overcome the so-called von Neumann architecture’s limitations—most studies have been performed on the basis of systems specially constructed for this purpose. It has previously been shown that analogues of neural networks can spontaneously arise in solutions of hydrophilic polymers, but these systems involved molecules of different natures or required direct interaction between macromolecular clusters. The present paper proposes a theory that indicates the possibility of an analogue of neural network formation even in a single-component solution of a relatively weak polyacid. A model is suggested based on the account of heterogeneous distribution of polymer ionogenic groups within the volume leading to the fluctuations of electric fields and, as a result, to the local changes in the degree of ionisation of functional groups. Theoretical description of the system shows how it was reduced to a solution of the analogue based on the Poisson–Boltzmann equation. The results obtained showed that it is just fluctuations in the distribution of charges that provide the collective response of the system to external influences and serve as an argument in favour of analogy of such a solution within a neural network. The results are discussed in the context of a potential simple hydrophilic polymer system as a prototypical neuromorphic and evolving material that is relevant for organic electronics, metamaterials, and studies on prebiological evolution. Full article

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

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10 pages, 1504 KB

Open AccessArticle

Molecular Dynamics Simulation of Silicone Oil: Degradation upon Oscillatory Testing

by Pascal Puhlmann and Dirk Zahn

Polymers 2026, 18(2), 278; https://doi.org/10.3390/polym18020278 - 20 Jan 2026

Viewed by 460

Abstract

The fate of a selection of linear and cyclic silicone oil formulations in heavy-duty fluid dampers is studied from molecular dynamics simulations. Mimicking cyclic agitation to all-atom simulation models, we elaborate oscillatory compression/decompression runs that feature degradation reactions within only hundreds of loading [...] Read more.

The fate of a selection of linear and cyclic silicone oil formulations in heavy-duty fluid dampers is studied from molecular dynamics simulations. Mimicking cyclic agitation to all-atom simulation models, we elaborate oscillatory compression/decompression runs that feature degradation reactions within only hundreds of loading cycles. This enables the assessment of chain scission, reassembly and cyclization mechanisms from ns-scale molecular dynamics simulations. Using analogous testing scenarios, we compare the degradation reactions of linear and cyclic silicone chains and demonstrate the importance of silicone ring formation. In turn, cyclic silicone moieties show relative persistence in our compression/decompression runs. We conclude that long-term degradation finally leads to a manifold of cyclic silicone molecules, featuring rings of up to tens of monomeric units. The underlying molecules are not inert to Si-O bond cleavage and reformation, but feature reactivity in terms of the fusion of small to large rings and vice versa. Full article

(This article belongs to the Special Issue Silicon-Based Polymers: From Synthesis to Applications)

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23 pages, 6872 KB

Open AccessArticle

Experimental Evaluation of Tensile Behavior and Hygrothermal Degradation of Glass Fiber Composites

by Ciprian Ionuț Morăraș, Viorel Goanță, Lucia Raluca Maier, Teodor Adrian Badea and Paul Doru Bârsănescu

Polymers 2026, 18(2), 277; https://doi.org/10.3390/polym18020277 - 20 Jan 2026

Viewed by 451

Abstract

Glass fiber-reinforced polymer (GFRP) composites are widely used in structural applications due to their high specific strength and durability; however, their mechanical performance strongly depends on fiber architecture and environmental exposure. This study evaluates the mechanical behavior and moisture-induced degradation of GFRP laminates [...] Read more.

Glass fiber-reinforced polymer (GFRP) composites are widely used in structural applications due to their high specific strength and durability; however, their mechanical performance strongly depends on fiber architecture and environmental exposure. This study evaluates the mechanical behavior and moisture-induced degradation of GFRP laminates through tensile tests, impact tests, dynamic mechanical analysis (DMA), and thermomechanical analysis (TMA) performed on a bi-directional glass–epoxy GFRP laminate ([0°/90°]). Tensile tests revealed a maximum longitudinal strength of 369 MPa in dry specimens, while water immersion for up to 21 days led to a significant reduction in tensile strength, from 207 MPa to 63 MPa, in diagonally cut specimens. Impact tests conducted at 12 J showed larger displacements in specimens cut along directions not aligned with the fibers, indicating matrix-dominated behavior. Dynamic mechanical analysis demonstrated strong dependence of stiffness on fiber orientation, with storage modulus values decreasing by approximately 45% in 45° specimens compared with the principal directions, while the glass transition temperature remained within 59–62 °C. Thermomechanical analysis confirmed an increase in the coefficient of thermal expansion after aging, from 205.6 to 291.65 µm/(m·°C) below Tg. These results provide insights into the structure–property–environment relationships governing the durability of GFRP composites and support the optimization of their design for long-term polymer-based applications. Full article

(This article belongs to the Special Issue Fiber-Reinforced Polymer Composites: Progress and Prospects)

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