Polymers

32 pages, 14465 KB

Open AccessArticle

Active Starch Films Incorporated with Citrus Essential Oils: Properties, Bioactivity, and Biodegradability

by Jasamim Moreira Lemos, José Elias Machado Lopes, José Hilton Gomes Rangel, Sebastião Pereira Protázio, Gricirene Sousa Correia, Samuel Filgueiras Rodrigues, Walter José Martinez Burgos, Paula Beatricy Weba Moreira, Kiany Sirley Brandão Cavalcante and Josilene Lima Serra Pereira

Polymers 2026, 18(14), 1794; https://doi.org/10.3390/polym18141794 - 22 Jul 2026

Viewed by 258

Abstract

The demand for sustainable food preservation has driven the development of biodegradable alternatives to conventional, petroleum-based plastics. This study developed and evaluated bioactive starch-based films incorporated with citrus peel essential oils (lemon, orange, and tangerine) at concentrations ranging from 0.5% to 2% ( [...] Read more.

The demand for sustainable food preservation has driven the development of biodegradable alternatives to conventional, petroleum-based plastics. This study developed and evaluated bioactive starch-based films incorporated with citrus peel essential oils (lemon, orange, and tangerine) at concentrations ranging from 0.5% to 2% (w/w). The physical, chemical, mechanical, and antimicrobial properties of all film formulations containing 0.5–2% (w/w) essential oils were evaluated. Based on the experimental design, only the selected formulations containing 1 and 2% essential oils were subjected to structural and thermal characterization (XRD, SEM, FTIR, and TGA/DTG), transparency measurements, soil biodegradation, and phytotoxicity assays. FTIR spectroscopy revealed that oil incorporation did not alter the characteristic chemical bands of starch, indicating predominantly physical interactions. The essential oils modulated the physical and mechanical performance of the films. The films containing lemon and tangerine essential oils exhibited superior antimicrobial activity against foodborne pathogens. Furthermore, soil biodegradation was concentration-dependent, with mass loss exceeding 50% within 15 days, while phytotoxicity tests confirmed the environmental safety of the degraded residues. These findings demonstrate that the developed citrus-infused starch films hold great promise as active biodegradable packaging to extend the shelf life of bakery products and mitigate plastic waste. Full article

(This article belongs to the Special Issue Application and Degradation of Polymeric Materials in Agriculture)

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19 pages, 4836 KB

Open AccessArticle

Adsorption Kinetics of Chromium (VI) from Aqueous Solution Using Agroindustrial Waste-Based Biochars Derived from Orange Peels and Peanut Shells

by Adrian Ferrucio Garcia-Morales, Oscar Eduardo Ortiz-Contreras, Alejandra Álvarez-López, Vanessa Vallejo-Becerra, Juan Campos-Guillén, Miguel Angel Ramos-López, Mónica López-Velarde Santos, Ricardo Chaparro-Sánchez, Sarai E. Favela-Camacho, Oscar Yael Barrón-García, José Alberto Rodríguez-Morales and Aldo Amaro-Reyes

Polymers 2026, 18(14), 1793; https://doi.org/10.3390/polym18141793 - 22 Jul 2026

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Abstract

Hexavalent chromium (Cr(VI)) is a highly toxic, non-biodegradable, and carcinogenic heavy metal. Its continuous release into aquatic ecosystems demands efficient, low-cost adsorbents. In this study, orange peel and peanut shell residues were thermally modified at 250 °C to enhance Cr(VI) remediation. Structural characterization [...] Read more.

Hexavalent chromium (Cr(VI)) is a highly toxic, non-biodegradable, and carcinogenic heavy metal. Its continuous release into aquatic ecosystems demands efficient, low-cost adsorbents. In this study, orange peel and peanut shell residues were thermally modified at 250 °C to enhance Cr(VI) remediation. Structural characterization confirmed that low-temperature calcination transforms raw agroindustrial wastes into functional biochars with a chemical architecture primed for cooperative Cr(VI) removal. N₂ physisorption revealed a hierarchical mesoporous network with average pore diameters of 30.6 nm (calcined orange peel) and 15.4 nm (calcined peanut shell), despite low specific surface areas. Batch adsorption experiments demonstrated that removal kinetics reached equilibrium within 5 min for the modified biochars. Isotherm modeling showed that the adsorption process was best described by the Freundlich and Sips models. The calculated Sips heterogeneity factors (β_S > 1) provided evidence of a cooperative multi-layer adsorption mechanism, attributed to the induced mesoporosity: initial chemisorption at high-energy sites facilitates the continuous anchoring of additional Cr(VI) ions without premature saturation. Ultimately, this study demonstrates that low-temperature calcination is a viable strategy to transform agricultural waste into kinetically efficient, cooperative adsorbents for wastewater treatment. Full article

(This article belongs to the Special Issue Cellulose-Based Functional Materials: Preparation and Applications)

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18 pages, 6745 KB

Open AccessArticle

New Biocidal Additive for Resin-Based Dental Composites: Is Modification with Didodecyldimethylammonium Bromide (DDAB) Effective?

by Maja Zalega, Witold Jakubowski, Joanna Nowak and Kinga Bociong

Polymers 2026, 18(14), 1792; https://doi.org/10.3390/polym18141792 - 22 Jul 2026

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Abstract

The study aimed to develop and preliminarily characterize experimental resin-based dental composites (RBCs). In addition to the composites, didodecyldimethylammonium bromide (DDAB) was used as a biocide in various concentrations (0–3 wt%). Hardness (HV), flexural strength (FS), and modulus of elasticity, as well as [...] Read more.

The study aimed to develop and preliminarily characterize experimental resin-based dental composites (RBCs). In addition to the composites, didodecyldimethylammonium bromide (DDAB) was used as a biocide in various concentrations (0–3 wt%). Hardness (HV), flexural strength (FS), and modulus of elasticity, as well as diametral tensile strength (DTS) of composites, were examined. Additionally, shrinkage stress, surface free energy (SFE), water sorption (Wsp), and solubility (Wsl) were determined. Cytometric analysis, including biocidal surface testing and susceptibility to colonization by Streptococcus mutans, Escherichia coli, and Candida albicans, assessed antibacterial activity. The HV of RBCs varied from 27.2 ± 1.5 to 31.5 ± 1.8 depending on DDAB amount, FS—67.0 ± 16.1 MPa for control composite and 79.2 ± 14.5 MPa for modified composite. All DTS values exceed 24 MPa. Shrinkage stress is highest for the composite with 0.25 wt% DDAB—18.5 ± 1.9 MPa—and lowest for the composite with 1 wt% DDAB—15.0 ± 2.5 MPa. Wsp is lowest in the control group (37.19 ± 1.69 µg/mm³) and highest for 1 wt% modifier (42.11 ± 2.75 µg/mm³). Wsl was at its lowest in control group (1.98 ± 1.58 µg/mm³), and highest for modification with 1 wt% (3.91 ± 1.74 µg/mm³). For RBCs modified with 3 wt% DDAB after 60 min, an increase in dead cells is observed: 51% for Escherichia coli, 71% for Streptococcus mutans, and 24% for Candida albicans. Preliminary results show that DDAB effectively reduced the presence of the tested pathogens and contraction stress; however, at certain concentrations it negatively influences hardness and water sorption of composites. The presented findings highlight both the potential and the limitations of DDAB-modified RBCs and underline the need for further studies, including cytotoxicity and genotoxicity assessments, release analyses and evaluation of composites’ ageing behavior. Full article

(This article belongs to the Special Issue Polymers Composites for Dental Applications, 2nd Edition)

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22 pages, 6327 KB

Open AccessArticle

Mixing Workability of Polymer-Modified Asphalt Mixtures Based on Discrete Element Modeling

by Yiqian Lin, Shanghui Li, Jinlong Huang and Zhenliang Jiang

Polymers 2026, 18(14), 1791; https://doi.org/10.3390/polym18141791 - 22 Jul 2026

Viewed by 317

Abstract

Workability of asphalt is crucial for pavement construction and quality assurance. The macroscopic and mesoscopic mixing workability of different base and polymer-modified asphalt mixtures was evaluated using a modified testing device and simulated by the three-dimensional discrete element method via the three-dimensional Particle [...] Read more.

Workability of asphalt is crucial for pavement construction and quality assurance. The macroscopic and mesoscopic mixing workability of different base and polymer-modified asphalt mixtures was evaluated using a modified testing device and simulated by the three-dimensional discrete element method via the three-dimensional Particle Flow Code, respectively. The experimental results demonstrate that polymer-modified asphalt mixtures exhibited inferior mixing workability compared with base asphalt mixtures, consistent with their higher binder viscosity. The mixing workability decreased with the elevated nominal maximum aggregate size, and the open-graded mixtures showed inferior mixing ability compared with those of continuous and gap-graded mixtures. The sensitivity analysis demonstrates that temperature appeared to be the most significant influencing factor of the mixing workability, followed by gradation and asphalt binder type. The denser contact force chains of mixtures under lower temperatures observed by the numerical simulation provided evidence of the decreased mixing workability. The gradation appeared to only provide a path for load transfer without influencing the contact force properties. These findings provide a theoretical basis for understanding the mixing behaviors of asphalt mixtures. Full article

(This article belongs to the Special Issue Polymers in Infrastructural Engineering: Fundamentals and Applications)

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10 pages, 2542 KB

Open AccessArticle

In Vitro Comparison Between Different Types of Fissure Sealants in Permanent Teeth—Micro-CT Study

by Shara I. Sajini, Jehad Al-Mutiri, Fares Al-Harbi and Mai Almarzouki

Polymers 2026, 18(14), 1790; https://doi.org/10.3390/polym18141790 - 22 Jul 2026

Viewed by 460

Abstract

Occlusal pits and fissures remain the most vulnerable tooth surfaces for caries initiation, and selecting a sealant that seals these areas reliably is a clinically meaningful question. We investigated the internal adaptation of four pit and fissure sealants—two resin-based and two glass ionomer-based—applied [...] Read more.

Occlusal pits and fissures remain the most vulnerable tooth surfaces for caries initiation, and selecting a sealant that seals these areas reliably is a clinically meaningful question. We investigated the internal adaptation of four pit and fissure sealants—two resin-based and two glass ionomer-based—applied to permanent premolar teeth. Forty extracted premolars were randomly assigned to four groups (n = 10): Group 1, BeautiSealant (BS); Group 2, 3M Clinpro Sealant; Group 3, GC Fuji IX without surface coating; and Group 4, GC Fuji IX with G-Coat Plus. Following 15,000 thermal cycles, internal adaptation was assessed by X-ray microtomography (micro-CT) using silver nitrate as a tracer. No statistically significant difference was found in the overall mean gap volumes between groups (p = 0.774). The 3M™ Clinpro™ Sealant group exhibited the lowest mean gap value (3.45 ± 1.71), followed by BeautiSealant (3.89 ± 1.34) and GC Fuji IX GP^® with G-Coat Plus™ (4.93 ± 4.09), whereas the GC Fuji IX GP^® without coating group showed the highest mean value (5.56 ± 5.35). Resin-based sealants achieved better fissure penetration and marginal adaptation than the glass ionomer formulations tested, though the differences did not reach statistical significance under the conditions of this study. Full article

(This article belongs to the Special Issue Advanced Polymeric Materials for Medical Applications)

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27 pages, 27990 KB

Open AccessArticle

Fabrication and Characterization of Electrospun Cardiac Patches Functionalized with Microbiota-Derived Postbiotics and Decellularized Neonatal Porcine Myocardial Extracellular Matrix for Cardiac Repair

by Buket Celik, Ahmet Ceylan, Okan Ali Aksoy, Berk Alp Goksel, Mehmet Fazıl Tolga Soyal and Fadime Kiran

Polymers 2026, 18(14), 1789; https://doi.org/10.3390/polym18141789 - 22 Jul 2026

Viewed by 334

Abstract

Myocardial infarction remains a leading cause of heart failure owing to the limited regenerative capacity of adult cardiac tissue, underscoring the need for biomimetic therapeutic platforms that combine structural support with biological functionality. Accordingly, this study aimed to develop a multifunctional electrospun cardiac [...] Read more.

Myocardial infarction remains a leading cause of heart failure owing to the limited regenerative capacity of adult cardiac tissue, underscoring the need for biomimetic therapeutic platforms that combine structural support with biological functionality. Accordingly, this study aimed to develop a multifunctional electrospun cardiac patch by integrating decellularized neonatal porcine myocardial extracellular matrix (dECM), gelatin, and microbiota-derived postbiotics for cardiac tissue engineering. The fabricated patches were comprehensively characterized in terms of their morphology, mechanical properties, biodegradation behavior, antibacterial activity, antioxidant capacity, and in vitro biocompatibility. Postbiotics derived from Lactiplantibacillus plantarum EIR/IF-1 exhibited potent antimicrobial activity against methicillin-resistant Staphylococcus aureus, strong antioxidant capacity, and significant anti-inflammatory activity through the suppression of pro-inflammatory mediators and upregulation of IL-10 expression. Moreover, they protected H9c2 cardiomyoblasts from oxidative stress, promoted COL1A1 expression, and supported ECM remodeling. The fabricated electrospun cardiac patches exhibited a homogeneous nanofibrous architecture, mechanically suitable properties (Young’s modulus ~4 MPa), controlled biodegradation over 7 days, favorable cell viability, and maintained the biological functionality of the incorporated postbiotics. Overall, the synergistic integration of tissue-specific dECM and microbiota-derived postbiotics yielded a multifunctional biohybrid cardiac patch with favorable structural and biological properties, supporting its potential as a promising platform for myocardial regeneration and next-generation cardiac tissue engineering. Full article

(This article belongs to the Special Issue Bio-Based Polymeric Materials for Biomedical Applications)

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19 pages, 5692 KB

Open AccessArticle

Fire Growth Behavior and Predictive Modeling of 3D-Printed Triply Periodic Minimal Surface (TPMS) Porous PLA Structures

by Mingyang Guo, Yachao Wang, Dongzhao Lu and Henri Vahabi

Polymers 2026, 18(14), 1788; https://doi.org/10.3390/polym18141788 - 22 Jul 2026

Viewed by 313

Abstract

Triply periodic minimal surfaces (TPMSs) are increasingly used in thermal management systems due to their high surface area and interconnected porous architecture. However, how TPMS geometry influences fire growth remains poorly understood. Herein, Gyroid, Diamond, and Schwarz-P PLA structures were fabricated through additive [...] Read more.

Triply periodic minimal surfaces (TPMSs) are increasingly used in thermal management systems due to their high surface area and interconnected porous architecture. However, how TPMS geometry influences fire growth remains poorly understood. Herein, Gyroid, Diamond, and Schwarz-P PLA structures were fabricated through additive manufacturing, and their fire behavior was characterized via cone calorimetry. Univariate experiments demonstrate that flame propagation is primarily governed by cell structure, rather than porosity or specific surface area. The orthogonal array L₉(3³), covering three factors of wall thickness, cell size and cell type (Gyroid, Diamond, and Schwarz-P), indicates that their effects on the flame growth index (FGI) rank as: cell size > unit cell > thickness. Meanwhile, a multivariate regression model was developed to predict the FGI of TPMS porous PLA, exhibiting high prediction accuracy (R² = 0.95) and low residual standard deviation. These results provide quantitative insights into the correlation between TPMS geometric features and fire growth, which facilitates the design of safer porous structures for thermal management applications. Full article

(This article belongs to the Special Issue Simulation and Modeling on Polymer Surfaces/Interfaces)

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27 pages, 4156 KB

Open AccessArticle

Morphology-Guided Screening of PLA/Cellulose Biocomposites for Melt-Spun Monofilaments: Micronized Eucalyptus Kraft Pulp Versus Microcrystalline Cellulose

by Mário Pinto, Susana Gomes, Manuel Vieira, Juliana Silva, Alexandre Gaspar, Bruno F. A. Valente, Tomás Duarte and Paulo F. Teixeira

Polymers 2026, 18(14), 1787; https://doi.org/10.3390/polym18141787 - 22 Jul 2026

Viewed by 323

Abstract

Poly(lactic acid) (PLA) is a promising bio-based polymer for melt-spun fibres, but its low melt strength, brittleness and narrow processing window limit broader use. This study evaluates PLA/cellulose biocomposites for monofilament melt spinning by comparing micronized bleached Eucalyptus kraft pulp-derived fibres (P200) with [...] Read more.

Poly(lactic acid) (PLA) is a promising bio-based polymer for melt-spun fibres, but its low melt strength, brittleness and narrow processing window limit broader use. This study evaluates PLA/cellulose biocomposites for monofilament melt spinning by comparing micronized bleached Eucalyptus kraft pulp-derived fibres (P200) with microcrystalline cellulose (MCC) as a particulate reference, within a fixed compatibilizer/processing-aid formulation. Composites containing different cellulose contents were prepared by melt compounding and assessed by thermal analysis, oscillatory rheology, mechanical testing and fracture morphology; selected 5 wt.% formulations were then processed into monofilaments. Cellulose incorporation increased the onset degradation temperature of the PLA reference, while the rheological and mechanical responses depended strongly on reinforcement morphology. P200 promoted stronger low-frequency melt structuring, stiffness and crystallization tendency, but also a greater reduction in ductility, with notched impact strength decreasing significantly only at the highest P200 loading. MCC produced a more moderate composite-level response. Stable continuous monofilaments were obtained from both selected cellulose-containing formulations, although neither matched the drawable window or draw-induced mechanical development of the PLA reference formulation. Among the cellulose-containing systems, the 5 wt.% MCC formulation retained the more favourable balance between reinforcement and melt-spinning processability. Full article

(This article belongs to the Special Issue Natural Fiber-Based Green Materials, Second Edition)

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29 pages, 2012 KB

Open AccessReview

Ammonium Polyphosphate: Modification Strategies and Synergistic Flame-Retardant Applications

by Yina Liu, Rongjie Yang, Zhaolu Qin, Wenchao Zhang and Dinghua Li

Polymers 2026, 18(14), 1786; https://doi.org/10.3390/polym18141786 - 21 Jul 2026

Viewed by 495

Abstract

Ammonium polyphosphate (APP) is widely used in intumescent flame-retardant (IFR) systems because of its environmental friendliness, low cost, and high flame-retardant efficiency. However, its practical applications are limited by high hygroscopicity, poor compatibility with organic substrates, and the high loading required in single-component [...] Read more.

Ammonium polyphosphate (APP) is widely used in intumescent flame-retardant (IFR) systems because of its environmental friendliness, low cost, and high flame-retardant efficiency. However, its practical applications are limited by high hygroscopicity, poor compatibility with organic substrates, and the high loading required in single-component systems. To address these limitations, extensive studies have been conducted on APP modification and synergistic flame-retardant systems. This review systematically summarizes the modification strategies and flame-retardant mechanisms of APP. The synergistic flame-retardant effects and mechanisms of APP combined with silicon-, boron-, and metal-containing compounds are also discussed. In addition, the effects on the flame-retardant performance of different structural characteristics, such as nanostructures, layered structures, and ring structures, are reviewed. Finally, the current challenges and future perspectives of APP-based flame-retardant systems are highlighted. This review provides useful guidance for the design, optimization, and practical application of advanced APP-based intumescent flame-retardant materials. Full article

(This article belongs to the Special Issue Novel Developments in Flame-Retardant Polymeric Materials)

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17 pages, 8453 KB

Open AccessArticle

Structural and Thermal Assessment of POE Encapsulant Residues from Laser-Treated Photovoltaic Laminate Fragments

by Szymon Tofil, Shuyang Lin, Jianhua Yao, Qunli Zhang, Liang Wang, Leonardo Orazi, António B. Pereira and Filipe J. Oliveira

Polymers 2026, 18(14), 1785; https://doi.org/10.3390/polym18141785 - 21 Jul 2026

Viewed by 294

Abstract

End-of-life photovoltaic modules represent a complex waste stream in which polyolefin elastomer (POE) encapsulants are increasingly important but insufficiently characterized after recovery. This study evaluates the structural, morphological and thermal state of POE-rich encapsulant residues obtained from laser-treated fragments of a crystalline-silicon photovoltaic [...] Read more.

End-of-life photovoltaic modules represent a complex waste stream in which polyolefin elastomer (POE) encapsulants are increasingly important but insufficiently characterized after recovery. This study evaluates the structural, morphological and thermal state of POE-rich encapsulant residues obtained from laser-treated fragments of a crystalline-silicon photovoltaic module after approximately five years of field operation, focusing on material quality rather than process optimization. Reference POE and representative polymer-rich residues were examined by FTIR-ATR, TGA/DTG under nitrogen and SEM/EDS. FTIR-ATR showed characteristic polyolefin bands at approximately 2915–2847, 1463 and 718–719 cm⁻¹ in both reference POE and treated residues, indicating retention of the hydrocarbon backbone. Treated residues exhibited additional features in the 1800–1500 and 1100–1000 cm⁻¹ regions, attributed to oxygen-containing surface species and interfacial glass/silicon contributions. TGA/DTG revealed a similar main decomposition range for the POE-rich residues, with DTG peaks mainly between 471.5 and 474.3 °C, while residual mass varied from 1.94 to 23.03%, compared with 0.04% for reference POE. SEM/EDS confirmed heterogeneous surfaces and local silicon/oxygen-rich particles attached to or embedded in the polymer-rich residues. The results show that POE-rich waste fractions can preserve the main polyolefin structure, but their valorization requires control of inorganic contamination, especially for cut, cracked or mechanically damaged modules. Full article

(This article belongs to the Special Issue Plastic Waste Management: Recycling, Sustainable Alternatives and Innovative Solutions)

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16 pages, 3851 KB

Open AccessArticle

High-Temperature Energy Storage Performance of Polyimide Nanocomposites Enhanced by Core–Shell BT-BMT@SiO₂

by Zunpeng Feng, Xingyu Hou, Sitian Ren, Xinyao Zhuang, Wei Chen, Haoran Liu, Chaoqiong Zhu, Ziming Cai and Peizhong Feng

Polymers 2026, 18(14), 1784; https://doi.org/10.3390/polym18141784 - 21 Jul 2026

Viewed by 454

Abstract

Advanced electrical and electronic systems are placing increasingly stringent demands on high-temperature dielectric capacitors. Polyimide (PI) possesses excellent thermal stability, but its low dielectric constant and breakdown strength limit its energy storage performance. To address this, a nanocomposite was designed consisting of the [...] Read more.

Advanced electrical and electronic systems are placing increasingly stringent demands on high-temperature dielectric capacitors. Polyimide (PI) possesses excellent thermal stability, but its low dielectric constant and breakdown strength limit its energy storage performance. To address this, a nanocomposite was designed consisting of the amorphous SiO₂-coated relaxor ferroelectric ceramic 0.6BaTiO₃-0.4Bi(Mg_0.5Ti_0.5)O₃ (BT-BMT@SiO₂) and PI. This core–shell structure improves the organic-inorganic interface and mitigates dielectric mismatch, thereby synergistically enhancing the composite’s dielectric constant, breakdown strength, and energy storage performance. At 150 °C, the breakdown field strength and maximum discharge energy density of the 0.25 vol.% BT-BMT@SiO₂/PI composite reached 381.81 MV/m and 1.14 J/cm³, respectively, representing increases of 32% and 67% compared to pure PI. These results indicate that the synergistic design of relaxor ferroelectric ceramics and core–shell interfaces is an effective strategy for enhancing the high-temperature energy storage performance of PI-based dielectric materials, providing important guidance for the development of high-performance capacitor materials. Full article

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

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47 pages, 36779 KB

Open AccessReview

Redefining Stability in Cultural Heritage Through Polymer Design: From Conservation Strategies to Plastic Degradation

by Elisabetta Ranucci and Jenny Alongi

Polymers 2026, 18(14), 1783; https://doi.org/10.3390/polym18141783 - 21 Jul 2026

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Abstract

Polymers play a central and multifaceted role in cultural heritage science, serving both as functional materials in conservation treatments, such as cleaning, consolidation, adhesion and protection, and as constituents of a wide range of historical artefacts, including paper and canvas, waterlogged wooden wrecks, [...] Read more.

Polymers play a central and multifaceted role in cultural heritage science, serving both as functional materials in conservation treatments, such as cleaning, consolidation, adhesion and protection, and as constituents of a wide range of historical artefacts, including paper and canvas, waterlogged wooden wrecks, musical instruments, and modern plastics used in art. Although numerous studies have examined the use of polymers in archaeology and cultural heritage conservation, most have focused on specific polymers, individual conservation treatments, or categories of artefacts. A comprehensive and integrated assessment of the multifunctional role of polymers, both as conservation materials and as constituents of heritage objects, remains lacking. The aim of this review is to provide a critical and comprehensive overview of natural and synthetic polymers in cultural heritage science, examining their applications in conservation treatments, their long-term stability and aging, and the challenges and opportunities associated with their preservation and sustainable use. This review examines the main classes of natural and synthetic polymers used in conservation, evaluating their mechanisms of action, performance, limitations, and long-term behavior across different applications. It also examines the chemical decomposition pathways and the resulting degradation phenomena occurring in polymeric materials, both as conservation products and as constituents of cultural artefacts, together with current stabilization strategies aimed at mitigating aging and deterioration. This review provides a critical appraisal of current challenges and future perspectives in cultural heritage conservation, highlighting emerging trends and research directions for the development of more effective, sustainable, and compatible polymer-based solutions for cultural heritage conservation. Full article

(This article belongs to the Section Polymer Chemistry)

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20 pages, 4823 KB

Open AccessArticle

Effect of the Compatibiliser on the Poly(Lactic Acid)—Polyamide 11 Blends with and Without Metal Oxides: Properties, Performance and Durability

by Giulia Infurna, Federico Ferrante, Elisabetta Morici, Giuseppe Pecoraro and Nadka Tz. Dintcheva

Polymers 2026, 18(14), 1782; https://doi.org/10.3390/polym18141782 - 21 Jul 2026

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Abstract

It can be argued that blends of biopolymers can be regarded as an economical and efficacious method for formulating blends with customised properties. In the context of immiscible and/or incompatible constituents, the use of a compatibiliser agent (i.e., physical or chemical compatibiliser) has [...] Read more.

It can be argued that blends of biopolymers can be regarded as an economical and efficacious method for formulating blends with customised properties. In the context of immiscible and/or incompatible constituents, the use of a compatibiliser agent (i.e., physical or chemical compatibiliser) has been demonstrated to enhance specific properties, including ductility and hydrophobicity. In this study, biopolymer blends based on polylactic acid (PLA) and polyamide 11 (PA11), with and without a compatibiliser (ethylene butyl-acrylate glycidyl methacrylate; Elvaloy), and also in the presence of metal oxides, such as zinc oxide (ZnO) and titanium dioxide (TiO₂), were processed by melt mixing and characterised for their mechanical, rheological, thermal and hydrophobic behaviour, as well as for their photo-oxidation resistance. The presence of a compatibiliser appeared to have a beneficial effect on the system’s ductility and hydrophobicity, also changing the blend morphology and reducing the dimensions of the PA11-droplets. The complex nature of the systems in question means that the beneficial effect of the compatibiliser on the dispersion of metal oxides cannot be fully appreciated. The favourable dispersion of metal oxide particles, in conjunction with their selective location at the interphase between the two polymeric phases and/or in the more polar phase, reduces the photo-oxidation resistance of these systems. This aspect must be given due consideration. Full article

(This article belongs to the Special Issue Multifunctional Hybrid Organic/Inorganic Sol–Gel-Derived Polymer Nanocomposites for Advanced Sustainable Applications)

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27 pages, 2361 KB

Open AccessReview

Polymeric Biomaterials for the Delivery of Stem Cell-Derived Exosomes in Inflammatory Skin Diseases: Engineering Strategies and Synergistic Effects

by Myungkyung Noh, Tae-Hyun Heo, Min-Kyu Kang and Gun-Jae Jeong

Polymers 2026, 18(14), 1781; https://doi.org/10.3390/polym18141781 - 21 Jul 2026

Viewed by 410

Abstract

Skin tissue engineering has emerged as a promising therapeutic strategy for severe wounds and inflammatory skin diseases. Stem cell-derived exosomes (SC-Exos) have recently gained increasing attention as cell-free therapeutic agents with regenerative and immunomodulatory potential, offering possible advantages over direct stem cell transplantation. [...] Read more.

Skin tissue engineering has emerged as a promising therapeutic strategy for severe wounds and inflammatory skin diseases. Stem cell-derived exosomes (SC-Exos) have recently gained increasing attention as cell-free therapeutic agents with regenerative and immunomodulatory potential, offering possible advantages over direct stem cell transplantation. To fully realize their therapeutic potential, however, efficient delivery platforms are needed to enhance local retention, preserve vesicle integrity, and support sustained release within the diseased skin microenvironment. In this review, we discuss advanced polymeric biomaterials as functional delivery platforms for SC-Exos in skin tissue engineering. We focus on natural and synthetic polymers engineered into nanofibrous scaffolds, hydrogels, and microneedles, and examine how these systems enhance exosome loading, protect vesicle integrity, improve local retention, and modulate release kinetics. We further highlight the therapeutic effects and underlying mechanisms of polymer–exosome systems in skin lesion repair, focusing on their roles in promoting angiogenesis, modulating local inflammation and immune responses, and facilitating extracellular matrix remodeling. Finally, we address remaining challenges and future directions for translating polymer-based SC-Exos delivery platforms into clinically relevant skin regenerative therapies. Full article

(This article belongs to the Special Issue Polymers for Skin Tissue Engineering)

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21 pages, 11563 KB

Open AccessArticle

Study of a Sorption Activity of the Amberlite IR120:KU-2-8 Interpolymer Systems in Relation to Dysprosium, Neodymium and Samarium Ions

by Talkybek Jumadilov, Madina Kabulova, Khuangul Khimersen and Jozef Haponiuk

Polymers 2026, 18(14), 1780; https://doi.org/10.3390/polym18141780 - 21 Jul 2026

Viewed by 314

Abstract

This study investigates the sorption, structural, and morphological properties of an interpolymer system (IPS) based on Amberlite IR120 (H⁺) and KU-2-8 (H⁺) cation exchangers with acidic sulfonic groups (−SO₃H), applied for the selective sorption of dysprosium (Dy [...] Read more.

This study investigates the sorption, structural, and morphological properties of an interpolymer system (IPS) based on Amberlite IR120 (H⁺) and KU-2-8 (H⁺) cation exchangers with acidic sulfonic groups (−SO₃H), applied for the selective sorption of dysprosium (Dy³⁺), neodymium (Nd³⁺), and samarium (Sm³⁺) ions from aqueous solutions. The sorption activity was evaluated for seven systems with molar ratios ranging from 6:0 to 0:6 over a contact time of up to 48 h within a pH range of 2.0 to 5.0. The interpolymer pair with a molar ratio of 5:1 demonstrated the highest sorption efficiency at pH 5.0, yielding extraction degrees of 61.8% for Dy³⁺, 62.0% for Nd³⁺, and 64.4% for Sm³⁺. Equilibrium data were accurately described by the Langmuir isotherm model (R² > 0.974), indicating a dominant monolayer chemisorption mechanism. The maximum monolayer adsorption capacities (q_m) followed the order Dy(III) (189.59 ± 31.52 mg/g) > Sm(III) (162.27 ± 52.38 mg/g) > Nd(III) (139.90 ± 35.40 mg/g). The selectivity toward dysprosium was supported by distribution coefficients (Kd) and separation coefficients (β_Dy/Nd = 1.557 and β_Dy/Sm = 1.757 for the 6:0 system). FTIR analysis confirmed the direct coordination of lanthanide ions by sulfonic groups, as evidenced by the shifts in the νas(S=O) bands. SEM-EDX characterization revealed distinct post-sorption morphological changes (surface cracking and flaking) and confirmed significant REE accumulation on the resins (up to 4.04 wt.%) coupled with a stoichiometric decrease in sulfur content, validating the ion-exchange mechanism. These findings provide a deeper insight into the remote conformational effects governing interpolymer interactions and offer a highly promising approach for the selective recovery of REEs in hydrometallurgy. Full article

(This article belongs to the Special Issue Organic Polymers for Adsorbent Applications)

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19 pages, 13914 KB

Open AccessArticle

Thermal and Mechanical Behavior of Polyimide–Polyurea Copolymers: Insights from Molecular Dynamics Simulations

by Shuaijiang Ma, Yizi Chen, Desen Cheng, Dongwei Xu, Xuyan Li, Baocheng Yang and Shiwei Wang

Polymers 2026, 18(14), 1779; https://doi.org/10.3390/polym18141779 - 21 Jul 2026

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Abstract

Polyimide (PI) exhibits outstanding thermal stability and mechanical rigidity; however, their inherently rigid backbones lead to intrinsic brittleness, poor fracture toughness, and inferior impact resistance. Conversely, polyurea (PUA) features excellent elasticity, tunable soft–hard segment architectures, and a favorable balance of tensile strength and [...] Read more.

Polyimide (PI) exhibits outstanding thermal stability and mechanical rigidity; however, their inherently rigid backbones lead to intrinsic brittleness, poor fracture toughness, and inferior impact resistance. Conversely, polyurea (PUA) features excellent elasticity, tunable soft–hard segment architectures, and a favorable balance of tensile strength and elongation at break. Herein, we systematically investigate the thermal and mechanical properties of 12 distinct PI, PUA, and PI-PUA copolymer systems via all-atom molecular dynamics simulations. Simulations demonstrate that rigid aromatic moieties significantly increase T_g and elastic modulus, while flexible hexamethylene diisocyanate (HDI) yields the highest elastic modulus via dense hydrogen-bond networks despite lowering T_g. Fluorine substitution effectively increases fractional free volume and moderately reduces T_g. Toughness is evaluated by K/G. System L with bulky phthalide side groups exhibits the highest K/G of 3.24, suggesting potential for improved plastic deformability as a preliminary screening indicator. In contrast, HDI-containing systems E and H show the lowest K/G ratios, as strong interchain hydrogen bonding severely restricts segmental slippage and induces brittle fracture. PI-PUA copolymerization proves to be an effective strategy to balance stiffness and toughness over a broad performance range. This work establishes structure–property correlations for PI-PUA systems, offering molecular-level insights for the rational design of advanced high-performance polymers, which require further experimental validation. Full article

(This article belongs to the Section Polymer Physics and Theory)

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15 pages, 6280 KB

Open AccessArticle

Study on UV Aging of Thermoplastic Polyurethane and Its Crosslinked Product

by Hanyang Zhao, Qingjun Jin, Hongwei Zhao, Yunkai Yang, Xiang Cheng, Xiujuan Ren and Hongxing Shi

Polymers 2026, 18(14), 1778; https://doi.org/10.3390/polym18141778 - 21 Jul 2026

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Abstract

To elucidate the formation of crosslinked products and their influence on material degradation, thermoplastic polyurethane (TPU) films were subjected to accelerated UV aging for various durations. Post-aging, the samples underwent Soxhlet extraction with tetrahydrofuran (THF), yielding an insoluble fraction—operationally defined as the crosslinked [...] Read more.

To elucidate the formation of crosslinked products and their influence on material degradation, thermoplastic polyurethane (TPU) films were subjected to accelerated UV aging for various durations. Post-aging, the samples underwent Soxhlet extraction with tetrahydrofuran (THF), yielding an insoluble fraction—operationally defined as the crosslinked product—and a soluble uncrosslinked fraction. The mechanical properties, molecular weight distribution, swelling behavior, thermal properties, and chemical structure were analyzed. As UV aging progressed, both tensile strength and elongation at break deteriorated markedly. Concurrently, GPC analysis revealed a continuous decrease in molecular weight and a broadening of the molecular weight distribution, confirming that chain scission was the dominant degradation pathway. An insoluble network-like residue, defined as the crosslinked product, first appeared after 12 h of aging, with its content increasing to 22.9% after 300 h. Swelling tests showed that the crosslinked product had a high gel fraction, and its swelling ratio decreased from 196.8% to 157.4%, indicating the formation of a stable and increasingly dense network. DSC and TG results revealed restricted segmental motion, altered thermal transition behavior, and enhanced char-forming ability. The glass transition temperature of the crosslinked product exceeded that of the pristine TPU film. FTIR analysis showed variations in the -NH₂, C=O, C-O, and C-O-C bands, confirming structural evolution within both hard and soft segments. In summary, UV aging of TPU involves a complex interplay among chain scission, degradation of soft segments, rearrangement of hard segments, evolution of hydrogen bonds, and radical-induced crosslinking. Crucially, the crosslinked network formed during aging plays a pivotal role in determining the macroscopic structural, thermal, and mechanical properties of the polymer. Full article

(This article belongs to the Special Issue State-of-the-Art Polyurethane Research and Technology)

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24 pages, 5861 KB

Open AccessArticle

A Structure–Property Screening Framework for Polymer Shell Encapsulation of Phase-Change Materials: Random Forest and Bayesian Gaussian Process Surrogates with Multi-Objective Optimization of Polymerization Routes

by Faris Alqurashi and Muhammed Anaz Khan

Polymers 2026, 18(14), 1777; https://doi.org/10.3390/polym18141777 - 21 Jul 2026

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Abstract

Confining a phase-change material (PCM) within a polymer shell yields leak-proof, mechanically robust latent-heat storage media, but selecting a shell chemistry and polymerization route requires balancing competing targets: latent-heat storage density (ΔH, the melting enthalpy per unit capsule mass), core loading content (LC), [...] Read more.

Confining a phase-change material (PCM) within a polymer shell yields leak-proof, mechanically robust latent-heat storage media, but selecting a shell chemistry and polymerization route requires balancing competing targets: latent-heat storage density (ΔH, the melting enthalpy per unit capsule mass), core loading content (LC), capsule diameter (d), and a melting temperature (T_m) matched to the application. Because the literature characterizes each method–shell–core combination in isolation, these structure–property relationships cannot be compared quantitatively across studies. We present a proof-of-concept, data-driven framework linking shell and process descriptors to encapsulation performance. From a curated dataset of 90 micro- and nano-encapsulated PCM records (53 with measured ΔH) spanning 11 encapsulation routes and eight shell material families, Random Forest (RF) and Gaussian Process (GP) surrogates predict ΔH, and a non-dominated sorting genetic algorithm (NSGA-II) optimizes ΔH, LC, and d over the continuous (T_m, LC) space for every method–shell–core trio with at least three records (n = 11). Benchmarked against mean, linear-LC, and physics-informed baselines under repeated cross-validation, the surrogates match but do not exceed the elementary baselines (median R² ≈ 0.33), a result we report honestly given the modest sample size. The Matérn GP provides borderline-calibrated uncertainty, supporting a robust, extrapolation-penalizing NSGA-II. Hypervolume rankings place emulsion polymerization, sol–gel silica, and in situ polymerization as the top-performing methods under both nominal and robust criteria. Presented as a methodology demonstration rather than a definitive ranking, the framework, with full code and data, is a reusable approach for structure–property quantification of polymer-encapsulated PCMs as experimental data accumulate. Full article

(This article belongs to the Special Issue Artificial Intelligence in Polymers)

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21 pages, 25074 KB

Open AccessArticle

Investigation of Surface–Liquid Interaction Relationships in Attapulgite Loaded Wet-Spun Polyurethane Composite Fibers Using Multivariate Analysis

by Cansu Aras

Polymers 2026, 18(14), 1776; https://doi.org/10.3390/polym18141776 - 20 Jul 2026

Viewed by 462

Abstract

Attapulgite (ATP)-loaded wet-spun polyurethane (PU) fibers were produced to investigate the effect of ATP on the surface structure and liquid interaction behavior of PU fibers under static immersion. ATP incorporation changed the surface morphology of PU fibers from smooth and compact to rougher [...] Read more.

Attapulgite (ATP)-loaded wet-spun polyurethane (PU) fibers were produced to investigate the effect of ATP on the surface structure and liquid interaction behavior of PU fibers under static immersion. ATP incorporation changed the surface morphology of PU fibers from smooth and compact to rougher and more porous structures, as confirmed by SEM-EDS and BET analyses. ATP incorporation increased BET surface area from 2.236 to 17.144 m²/g and the total pore volume from 0.0050 to 0.0755 cm³/g. These structural changes promoted water uptake and methylene blue interaction by improving wetting-assisted liquid penetration and dye diffusion through accessible mesoporous pathways. ATP incorporation also improved the thermal and mechanical behavior of the fibers at appropriate loading levels. The onset degradation temperature increased from 252.35 °C for neat PU to 270.53 °C with 3 wt.% ATP loading. The highest tensile strength value of 10.026 MPa was achieved at 1 wt.% ATP loading. Pearson correlation and principal component analyses showed that methylene blue interaction was more closely associated with pore diameter and pore volume than with ATP content alone. The results also indicate that ATP incorporation is an effective strategy for tailoring the pore accessibility, liquid interaction, and structure-dependent performance of wet-spun PU composite fibers. Full article

(This article belongs to the Section Polymer Fibers)

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20 pages, 9211 KB

Open AccessArticle

Degumming of Ramie Bast Fibers by Pectobacterium carotovorum HG-49: Mechanisms and High-Efficiency Strategies

by Tong Shu, Tianyi Yu, Pandeng Li, Ziqi Hou, Huihui Wang, Yulong Chen, Chunhua Fu and Longjiang Yu

Polymers 2026, 18(14), 1775; https://doi.org/10.3390/polym18141775 - 20 Jul 2026

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Abstract

Microbial degumming offers an eco-friendly alternative to chemical methods for ramie fiber production, but industrial application is constrained by low efficiency stemming from limited mechanistic insight. This study systematically investigates the process using Pectobacterium carotovorum HG-49. Strain HG-49 showed a lag phase of [...] Read more.

Microbial degumming offers an eco-friendly alternative to chemical methods for ramie fiber production, but industrial application is constrained by low efficiency stemming from limited mechanistic insight. This study systematically investigates the process using Pectobacterium carotovorum HG-49. Strain HG-49 showed a lag phase of 0–4 h, a logarithmic phase of 6–10 h, and peak biomass at 12 h. Pectin (97.05%) and water-soluble substances (98.45%) were nearly fully removed, whereas hemicellulose removal was only 73.54%, rendering it the primary residual gum component. Pectinase activity peaked at 120.75 U/mL, while mannanase (35.85 U/mL) and xylanase (30.20 U/mL) reached roughly one-quarter of that level; cellulase activity remained minimal. Scanning electron microscopy (SEM) indicated that 6–12 h constituted the main gum degradation phase. Fourier transform infrared spectroscopy (FTIR) and micro-FTIR showed progressive decreases in pectin, hemicellulose, and lignin absorption peaks with degumming. X-ray diffraction (XRD) revealed increased crystallinity from 72.07% to 80.02%, and thermogravimetric analysis (TGA) showed elevated degradation temperature from 417 °C to 435 °C. Collectively, these data confirm progressive removal of gummy substances and enhanced cellulose purity. Transcriptomic profiling further revealed that low abundance and reduced expression of hemicellulases significantly limited degumming performance. Therefore, enhancing efficiency should focus on: supplementing pectin-rich substrates to accelerate bacterial proliferation and enzyme production, broadening the hemicellulase spectrum and enhancing catalytic activities and establishing effective pretreatment protocols for ramie bast. These findings provide a theoretical foundation for improving microbial degumming efficiency and advancing industrial feasibility. Full article

(This article belongs to the Special Issue Perspectives of Biopolymer Functionalization for New Materials)

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30 pages, 5147 KB

Open AccessArticle

Spatially Compartmentalized Electrospun/Electrosprayed PHB/PEO/Zein Fibrous Platforms for Dual Delivery of Rutin and Melissa officinalis Extract

by Dilyana Paneva, Selin Kyuchyuk, Milena Ignatova, Nevena Manolova, Iliya Rashkov, Ani Georgieva, Reneta Toshkova and Mariana Kamenova-Nacheva

Polymers 2026, 18(14), 1774; https://doi.org/10.3390/polym18141774 - 20 Jul 2026

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Abstract

Spatially separated dual-bioactive delivery platform from electrospun polyhydroxybutyrate/poly(ethylene oxide) fibers loaded with rutin (PHB/PEO/RUT) and decorated with zein/Melissa officinalis particles (zein/MO) were obtained by simultaneous electrospinning/electrospraying. The morphology of the materials, their thermal properties and chemical composition were systematically studied by scanning [...] Read more.

Spatially separated dual-bioactive delivery platform from electrospun polyhydroxybutyrate/poly(ethylene oxide) fibers loaded with rutin (PHB/PEO/RUT) and decorated with zein/Melissa officinalis particles (zein/MO) were obtained by simultaneous electrospinning/electrospraying. The morphology of the materials, their thermal properties and chemical composition were systematically studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR–FTIR). The incorporation of PEO into the fabricated fibrous materials enhanced their wettability. It was demonstrated that the newly developed materials had high encapsulation efficiency (99.8 ± 0.1%) of RUT and/or MO. The architecture of the materials affected the in vitro release profile of the bioactive agents. RUT exerted its DPPH^• scavenging capacity upon incorporation into the fibers. An increase in antioxidant activity was observed in the fibrous mats loaded with both RUT and MO. Moreover, the developed materials decreased the viability of SH-4 melanoma cells to a greater extent than that of non-cancerous HaCaT keratinocytes. The combined rapid release and sustained release of bioactive agents and the antioxidant and anticancer activity of the newly developed materials render them promising candidates as platforms for local drug delivery. Full article

(This article belongs to the Special Issue Electrospinning of Polymer Systems)

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35 pages, 7195 KB

Open AccessArticle

Preparation and Performance Characterization of Melamine Resin-Coated Water-Based Primer Microcapsule–Brass Powder–Water-Based Acrylic Coating

by Xue Chen, Yan Han and Xiaoxing Yan

Polymers 2026, 18(14), 1773; https://doi.org/10.3390/polym18141773 - 20 Jul 2026

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Abstract

The method of how microcapsules and brass powder are added significantly affects the overall effectiveness of decorative coatings. An innovative self-repairing decorative coating for Basswood surfaces was created using melamine resin-coated water-based primer microcapsules as the repair agent under the coating process of [...] Read more.

The method of how microcapsules and brass powder are added significantly affects the overall effectiveness of decorative coatings. An innovative self-repairing decorative coating for Basswood surfaces was created using melamine resin-coated water-based primer microcapsules as the repair agent under the coating process of “three coats of primer, two coats of topcoat, and introducing brass powder and microcapsules into the primer”. The optical and mechanical properties of this coating were significantly impacted by the curing temperature and brass powder content, respectively. The optical qualities, mechanical properties, liquid resistance, aging resistance, and self-repairing performance of the coating improved at higher curing temperatures under varying brass powder contents. The water-based acrylic wood coating obtained at 60 °C with 3% brass powder and 3% primer microcapsules, featuring a core-wall ratio of 0.58:1, provided the best overall qualities. It has a gloss of 34.1 GU, color difference of 0.00, visible light reflectance of 0.6038, visible light transmittance of 76.20%, color main wavelength of 589.79 nm, hardness of HB, impact resistance of 2 kg·cm, adhesion of grade 1, roughness of 1.125 µm, excellent aging and liquid resistance, and repair rate of 22.93%. This study provides an effective and new strategy for simultaneously improving the decorative, mechanical, and self-repairing properties of water-based wood coatings. Full article

(This article belongs to the Special Issue Polymeric Coatings for High Performance Applications)

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15 pages, 1064 KB

Open AccessArticle

Balancing Mass Fraction and Performance of Corn Husk/PLA Biocomposites for Moderate-Load Furniture Applications

by Fangmin Yuan, S. Siti Suhaily and Yuqing Wang

Polymers 2026, 18(14), 1772; https://doi.org/10.3390/polym18141772 - 20 Jul 2026

Viewed by 417

Abstract

Corn husk is widely available as an agricultural by-product, yet its use in higher-value composite materials is still limited. This study examined how corn husk mass fraction affects the performance balance of corn husk/poly(lactic acid) (PLA) biocomposites (CHB) intended for moderate-load furniture board [...] Read more.

Corn husk is widely available as an agricultural by-product, yet its use in higher-value composite materials is still limited. This study examined how corn husk mass fraction affects the performance balance of corn husk/poly(lactic acid) (PLA) biocomposites (CHB) intended for moderate-load furniture board components. CHB containing 10 wt% and 30 wt% corn husk was prepared by hot pressing at 200 °C, 10 MPa, and 5 min. Density, water absorption, tensile, compressive, and flexural strength, Shore D hardness, and screw withdrawal resistance were evaluated. Increasing corn husk content from 10 wt% to 30 wt% reduced tensile strength, Shore D hardness, and screw withdrawal resistance. However, flexural strength increased from 22.8 ± 0.5 to 39.8 ± 1.1 MPa, while density decreased from 1.30 ± 0.03 to 1.09 ± 0.05 g/cm³. By contrast, 10 wt% CHB showed higher Shore D hardness and screw withdrawal resistance, reaching 84.1 ± 1.4 and 528.9 ± 22.9 N, respectively. The results indicate that 30 wt% CHB is more suitable for lightweight board components where flexural load-bearing is prioritized, whereas 10 wt% CHB is preferable for parts requiring higher surface hardness and screw connection reliability. Full article

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

17 pages, 2350 KB

Open AccessArticle

In Vitro Measurement of Genotoxicity of Antimicrobial Dextrin–Polyvinyl Alcohol–Iodine Complex

by Tamara Bukeyeva, Seitzhan Turganbay, Ardak Jumagaziyeva, Zhanar Iskakbayeva, Saltanat Jumabayeva, Anar Seysembekova, Jingcheng Hao, Dana Askarova, Alina Sabdanbekova, Dokturbek Adambekov, Amir Azembayev and Gaukhar Askhatkyzy

Polymers 2026, 18(14), 1771; https://doi.org/10.3390/polym18141771 - 20 Jul 2026

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Abstract

Iodine-based antimicrobial materials are widely considered for biomedical applications due to their broad-spectrum antimicrobial activity; however, their potential genotoxicity requires systematic evaluation prior to clinical use. The aim of this study was to assess the genotoxic potential of a dextrin–polyvinyl alcohol–iodine (D/PVA/I-1) complex [...] Read more.

Iodine-based antimicrobial materials are widely considered for biomedical applications due to their broad-spectrum antimicrobial activity; however, their potential genotoxicity requires systematic evaluation prior to clinical use. The aim of this study was to assess the genotoxic potential of a dextrin–polyvinyl alcohol–iodine (D/PVA/I-1) complex in accordance with OECD guidelines. Genotoxicity was evaluated in vitro using two complementary assays: the mammalian cell micronucleus test (OECD TG 487) in L5178Y TK^+/− cells and the bacterial reverse mutation assay (Ames test, OECD TG 471) using Salmonella typhimurium strains TA98, TA100, TA1535, TA1537 and Escherichia coli WP2 uvrA, both in the presence and absence of metabolic activation (S9). In the micronucleus assay, no statistically significant increase in micronucleus frequency was observed at concentrations ranging from 0.039 to 0.625 mg/mL compared with the negative control. In the Ames test, no increase in revertant colony numbers was detected in any tested bacterial strain at concentrations up to 1250 μg/plate. At higher concentrations, pronounced cytotoxic and bactericidal effects were observed without evidence of mutagenic activity. Overall, the results demonstrate that the D/PVA/I-1 complex does not exhibit genotoxic or mutagenic potential under the tested in vitro conditions, indicating a favorable genetic safety profile and supporting further preclinical evaluation for potential biomedical applications. Full article

(This article belongs to the Section Polymer Applications)

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35 pages, 2328 KB

Open AccessArticle

Protein-Rich Uronic Acid-Containing Polysaccharides from Juglans regia Root Bark: Structural Characterization and Structure–Bioactivity Relationships Underlying Multifunctional Biological Activities

by Souha Chokri, Takoua Ben Attia, Asma Haffouz, Basma Hadj Kacem, Sami Mnif, Assad Sila, Ahmed Slaheddine Masmoudi, Ali Ellafi and Sonia Ben Younes

Polymers 2026, 18(14), 1770; https://doi.org/10.3390/polym18141770 - 20 Jul 2026

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Abstract

Protein-rich polysaccharides are increasingly recognized as multifunctional biopolymers with significant biomedical potential. In this study, a protein–polysaccharide complex (JrPRP) was isolated for the first time from the root bark of Juglans regia L. and comprehensively characterized. JrPRP was obtained with a yield of [...] Read more.

Protein-rich polysaccharides are increasingly recognized as multifunctional biopolymers with significant biomedical potential. In this study, a protein–polysaccharide complex (JrPRP) was isolated for the first time from the root bark of Juglans regia L. and comprehensively characterized. JrPRP was obtained with a yield of 4.7% (w/w) and exhibited an acidic composition enriched in uronic acid-related components, together with minor neutral sugars. Spectroscopic analyses (FTIR and UV–Vis) confirmed the coexistence of carbohydrate and protein domains, while chromatographic profiling (TLC and HPLC) indicated a heterogeneous monosaccharide composition. Scanning electron microscopy revealed a porous and irregular microstructure, consistent with a structured biopolymeric network exhibiting pronounced anionic character. Functionally, JrPRP demonstrated notable antioxidant activity, with IC₅₀ values of 405 ± 1.8 µg/mL (DPPH), 225 ± 3.5 µg/mL (ABTS), and 229 ± 1.7 µg/mL (metal chelation), along with strong ferric-reducing capacity. The complex exhibited antibacterial activity against Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus (MIC: 2–9 mg/mL), as well as potent antibiofilm activity, inhibiting up to 94% of Escherichia coli biofilm formation. Biocompatibility assays indicated low hemolytic activity, supporting its favorable safety profile. In addition, JrPRP showed moderate anticoagulant effects and strong anti-inflammatory activity, reaching 98% inhibition of protein denaturation, comparable to or exceeding diclofenac under similar conditions. These findings identify J. regia root bark as a promising and previously underexplored source of structurally distinctive uronic acid-containing protein-rich polysaccharides and provide new insights into the relationship between their compositional features and multifunctional biological activities. Full article

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

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23 pages, 4243 KB

Open AccessArticle

Drainage-Controlled Cellulose-Fiber Stabilization and Skeleton–Mastic Response of Polymer-Modified Stone Mastic Asphalt

by Ahmet Umutlu and Başak Varli Bingöl

Polymers 2026, 18(14), 1769; https://doi.org/10.3390/polym18141769 - 20 Jul 2026

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Abstract

Stone mastic asphalt (SMA) derives its performance from the coupled action of a load-bearing coarse aggregate skeleton and a binder-rich mastic phase. This study evaluates polymer-modified SMA using an integrated drainage–skeleton–mastic framework that combines drainage-based cellulose fiber selection, controlled gradation variation, aggregate-type comparison, [...] Read more.

Stone mastic asphalt (SMA) derives its performance from the coupled action of a load-bearing coarse aggregate skeleton and a binder-rich mastic phase. This study evaluates polymer-modified SMA using an integrated drainage–skeleton–mastic framework that combines drainage-based cellulose fiber selection, controlled gradation variation, aggregate-type comparison, binder-content sensitivity analysis, pre-compaction laboratory conditioning, and FTIR–SEM–EDX characterization. A 50/70 penetration-grade bitumen modified with 4.5% SBS was used with basalt and limestone aggregates, limestone filler, and Viatop cellulose fiber. The fiber dosage was selected using the Schellenberg binder-drainage test, while a separate preliminary load–deformation series was used to examine the response sensitivity to higher fiber contents. Increasing fiber content from 0.30% to 0.35% reduced mean binder drainage from 0.27% to 0.18% and decreased the standard deviation from 0.020% to 0.006%, supporting 0.35% as a drainage-based design dosage rather than a mechanical optimum. Higher fiber contents increased the maximum recorded load within the fixed test window; however, these results were interpreted only as preliminary load–deformation sensitivity rather than as conventional Marshall stability or MQ responses. The binder-content series showed that lower- and upper-limit gradations followed different volumetric and Marshall response patterns; therefore, these results were interpreted as binder-content sensitivity rather than complete optimum binder content determination. Aggregate-type comparisons showed the mechanical advantage of basalt, while the non-replicated post-extraction gradation results were directionally consistent with greater skeleton preservation in basalt mixtures. FTIR, SEM, and EDX observations indicated that cellulose fiber acted mainly through physical mastic stabilization rather than chemical binder modification. Overall, the results demonstrate that SMA response is governed by the combined contribution of drainage-controlled fiber dosage, SBS-modified binder, aggregate skeleton configuration, and limestone-filler mastic integrity. Full article

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

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24 pages, 13293 KB

Open AccessArticle

Development and Performance Evaluation of a Temperature- and Salt-Resistant Bio-Based Profile-Control and Oil Displacement System

by Xianglong Yu, Baoshan Guan, Lixin Huang, Yilin Xin, Kaiqi Leng and Jianlong Xiu

Polymers 2026, 18(14), 1768; https://doi.org/10.3390/polym18141768 - 20 Jul 2026

Viewed by 332

Abstract

High-temperature and high-salinity reservoirs (typically referring here to temperatures ≥ 100 °C and salinities > 100 g/L) impose stringent requirements on chemical flooding and profile-control agents, particularly in terms of thermal stability, salt tolerance, injectivity, and environmental compatibility. In this study, a bio-based [...] Read more.

High-temperature and high-salinity reservoirs (typically referring here to temperatures ≥ 100 °C and salinities > 100 g/L) impose stringent requirements on chemical flooding and profile-control agents, particularly in terms of thermal stability, salt tolerance, injectivity, and environmental compatibility. In this study, a bio-based composite mobility-control and oil-displacement system was developed by combining carbonized corn-straw particles with the biopolymer scleroglucan. Corn-straw biomass particles were prepared by pyrolysis at 500 °C followed by ball milling for 2 h. Their particle-size distribution, elemental composition, and suspension stability were characterized, and the rheological behavior, thermal and salt tolerance, long-term aging stability, injectivity, plugging performance, and enhanced-oil-recovery efficiency of the composite system were evaluated systematically. The average particle size decreased from 25.6 μm for mechanically ground straw to 2.8 μm after carbonization and ball milling. The H/C atomic ratio of the carbonized particles was 0.31, indicating enhanced aromatization and structural stability. A scleroglucan concentration of 1000 ppm provided a suspension rate of 97%, balancing suspension stability and chemical dosage. The composite system maintained stable viscosity and viscoelasticity from 30 to 130 °C in deionized water, saturated NaCl solution, and saturated CaCl₂ solution, with viscosity loss below 10%. After sealed anaerobic aging at 100 °C for 28 days, the viscosity retention remained above 90%. Sand-pack tests showed stable injectivity in media with permeabilities of 1235 and 2064 mD and a plugging efficiency of 95.7% in a 2846 mD model. In oil-displacement experiments, the composite system increased the final recovery factor from 46.6% for scleroglucan flooding alone to 53.3%, corresponding to an additional 6.7 percentage points. These results demonstrate that the carbonized biomass particle-scleroglucan system has promising thermal stability, salt tolerance, plugging capacity, and oil-displacement performance, providing a potential green strategy for mobility control in harsh reservoir environments. Full article

(This article belongs to the Special Issue Structure, Characterization and Application of Bio-Based Polymers, 2nd Edition)

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18 pages, 4022 KB

Open AccessArticle

Enhancing PLA Strength and Layer Adhesion: Physical and Microstructural Insights from Vibration-Assisted FFF/FDM

by Lotfi Ben Said, Fouzi Alhadar, Hamdi Hentati, Mondher Wali, Badreddine Ayadi, Sattam Alharbi and Muapper Alhadri

Polymers 2026, 18(14), 1767; https://doi.org/10.3390/polym18141767 - 20 Jul 2026

Viewed by 491

Abstract

Material Extrusion (MEX), particularly Fused Filament Fabrication (FFF), commercially known as Fused Deposition Modeling (FDM), has become one of the most widely used additive manufacturing technologies for producing polymer components. However, the mechanical performance of printed parts remains limited by weak interlayer bonding [...] Read more.

Material Extrusion (MEX), particularly Fused Filament Fabrication (FFF), commercially known as Fused Deposition Modeling (FDM), has become one of the most widely used additive manufacturing technologies for producing polymer components. However, the mechanical performance of printed parts remains limited by weak interlayer bonding and internal porosity. This study investigates the effectiveness of controlled low-frequency bed vibration in improving the physical and mechanical properties of PLA components manufactured by vibration-assisted FFF/FDM. The influence of printing speed, raster angle, and vibration level was experimentally evaluated through tensile, flexural, surface roughness, Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) analyses. Response Surface Methodology (RSM) was employed to optimize the process parameters with respect to tensile strength, yield strength, flexural strength, and surface quality. The results demonstrate that moderate bed vibration (Level 2) provides the best overall performance, improving the mechanical properties by approximately 8–15% compared with conventional printing. SEM observations revealed an approximately 60% reduction in average pore size, together with enhanced filament fusion and interlayer adhesion, while FTIR analysis confirmed that the chemical structure of PLA remained unchanged. These findings demonstrate that controlled mechanical bed vibration is a simple and effective strategy for enhancing the quality, reliability, and structural performance of FFF/FDM-printed PLA components. The proposed approach also provides practical guidelines for optimizing additive manufacturing processes and supports the development of advanced polymer manufacturing capabilities in Hail’s growing industrial sector. Full article

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

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20 pages, 1599 KB

Open AccessArticle

Amine-Selective Crosslinking of Collagen via Pre-Activated L-Glutamic Acid for Maintaining Ionic Interactions and Enhancing Mechanical and Biological Performance

by Senthilkumar Muthu, Seonae Kim, Jinsang Kim, Yongseon Wang and Inn Kyu Kang

Polymers 2026, 18(14), 1766; https://doi.org/10.3390/polym18141766 - 20 Jul 2026

Viewed by 405

Abstract

Collagen-based biomaterials possess many advantages, such as low immunogenicity, biodegradability, biocompatibility, hydrophilicity, and ease of processability. Nevertheless, natural collagen has inherent limitations as an in vivo scaffold, including insufficient mechanical strength, low thermal stability, and low resistance to enzymatic degradation. To overcome these [...] Read more.

Collagen-based biomaterials possess many advantages, such as low immunogenicity, biodegradability, biocompatibility, hydrophilicity, and ease of processability. Nevertheless, natural collagen has inherent limitations as an in vivo scaffold, including insufficient mechanical strength, low thermal stability, and low resistance to enzymatic degradation. To overcome these drawbacks, various approaches have been studied, such as mixing collagen with other biopolymers or inducing physical and chemical crosslinking. However, using non-biologically derived polymers or crosslinking agents carries the risk of persistence in the body, potentially causing cytotoxicity. Considering this, recent studies have reported that the molecular flexibility of collagen networks can be improved by activating the carboxyl groups of collagen chains using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide and then crosslinking them through amide bonding with the amino groups present in the collagen chains, or by adding free L-lysine to induce a crosslinking reaction. When the carboxyl groups of collagen are activated and form covalent bonds with amino groups, native ionic interactions (e.g., salt bridges) may be reduced, which can potentially influence the stability of its inherent higher-order structure. In this study, we proposed a selective amine-targeted cross-linking strategy designed to minimize modification of collagen carboxyl groups while enhancing mechanical properties and cellular compatibility. First, free L-glutamic acid was pre-activated to cross-link collagen chains through amide bonds with the amino groups of L-lysine residues, thereby providing a cross-linking pathway intended to reduce the involvement of collagen carboxyl groups in the reaction. By controlling the concentration of L-glutamic acid, the cross-linking rate of the collagen could be controlled within a range of 10.26% to 25.02%. All cross-linked collagen scaffolds exhibited higher tensile strength compared to non-cross-linked scaffolds. Although the scaffolds with a high cross-linking rate (25.02%) displayed excellent mechanical properties, their cellular compatibility was relatively low. Conversely, collagen scaffolds with cross-linking rates of 10.26% and 14.43% demonstrated excellent mechanical properties and very high cellular compatibility, suggesting potential applications in the fields of biomedicine and tissue engineering. The present findings are consistent with the proposed selective cross-linking strategy; however, direct experimental verification of collagen carboxyl-group preservation will require complementary analytical studies. Full article

(This article belongs to the Special Issue Polymeric Materials for Wound Dressing)

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23 pages, 5868 KB

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Surface Engineering for PMMA-Based Removable Prostheses: A Narrative Review

by Jamal Al Ashkar, Nicoleta Ioanid, Delia Teodora Dima, Ruxandra Teodora Stan, Andreas Katsonis, Ana-Maria Raluca Pauna and Roxana-Ionela Vasluianu

Polymers 2026, 18(14), 1765; https://doi.org/10.3390/polym18141765 - 20 Jul 2026

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Abstract

Polymethylmethacrylate (PMMA) is still the most widely used prosthetic polymer, although its biological inertness and vulnerability to mechanical stress and microbiological colonization are gradually restricting its therapeutic lifespan. This narrative review develops a conceptual framework, three ceramic modifiers corresponding to three distinct biofunctional [...] Read more.

Polymethylmethacrylate (PMMA) is still the most widely used prosthetic polymer, although its biological inertness and vulnerability to mechanical stress and microbiological colonization are gradually restricting its therapeutic lifespan. This narrative review develops a conceptual framework, three ceramic modifiers corresponding to three distinct biofunctional strategies, to logically guide the design of the next generation of PMMA-based prosthetic dentures. We critically analyze the transformation of hydroxyapatite (HA), silica (SiO₂), and titanium dioxide (TiO₂) from passive fillers to active functional phases, offering unique, complementary therapeutic advantages. Therefore, HA confers osteoconductive and bone affinity, SiO₂ provides surface reactivity, tunable bioactivity, and drug release capacity, while TiO₂ provides mechanical reinforcement, chemical stability, and photocatalytic antibacterial activity. These ceramics used in PMMA matrices result in hybrid materials that outperform standard resins in terms of structural, mechanical, and biological performance. Recent research on binary and ternary systems (e.g., HA–TiO₂, SiO₂–HA, and HA–SiO₂–TiO₂ in PMMA) has indicated synergistic effects, such as increased osteoblast proliferation, reduced biofilm development, improved fracture toughness, and favorable corrosion resistance in simulated oral environments. A decision matrix is also provided to assist the clinician in selecting the best ceramic for a given clinical function of a prosthetic base or provisional repair. Although polymer–ceramic hybrid systems show remarkable translational potential, there are still obstacles to be addressed in terms of long-term interfacial stability, standardized synthesis processes, and regulatory mechanisms. This review proposes a framework of PMMA as a multimodal biofunctional engineering platform rather than a basic structural polymer and provides a roadmap for the development of intelligent, interactive, and clinically durable prosthetic materials. Full article

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

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Polymers, Volume 18, Issue 14 (July-2 2026) – 114 articles

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