Polymers

25 pages, 7135 KB

Open AccessEditor’s ChoiceArticle

Synthesis and Evaluation of Eleven Novel Renewable Plasticizers for Polylactic Acid (PLA): Linking Molecular Structure to Performance

by Ferry Oomen, Marc Crockatt, Eric Mattheussens, Ivan Bakker, Michał Pstrowski, Maddalena Logrieco, Moctar Coulibaly, Han van Kasteren and Sandra Corderí Gándara

Polymers 2026, 18(17), 2070; https://doi.org/10.3390/polym18172070 - 26 Aug 2026

Viewed by 363

Abstract

The development of bio-based plasticizers is increasingly important due to regulatory restrictions on several phthalates, growing concerns over plasticizer migration and toxicity, and the demand for renewable materials. In this work, eleven novel furfural-derived bio-based plasticizers were synthesized and evaluated in polylactic acid [...] Read more.

The development of bio-based plasticizers is increasingly important due to regulatory restrictions on several phthalates, growing concerns over plasticizer migration and toxicity, and the demand for renewable materials. In this work, eleven novel furfural-derived bio-based plasticizers were synthesized and evaluated in polylactic acid (PLA) at 15 wt% loading via melt compounding. Their influence on the thermomechanical properties of PLA was investigated, enabling the establishment of structure–property relationships. Hansen Solubility Parameters (HSPs) were used to predict plasticizer–PLA compatibility and correlate theoretical predictions with experimental performance. All developed bio-plasticizers exhibited onset degradation temperatures exceeding 225 °C, ensuring suitability for melt processing with PLA. Increasing the alkyl chain length in the diester bio-plasticizers reduced plasticization efficiency, consistent with lower predicted compatibility based on HSP analysis. The most promising candidates, namely 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid 2,3-dihexyl ester (F/MA-C6), 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid 2,3-dioctyl ester (F/MA-C8), and 1,1′-[oxybis(1-methyl-2,1-ethanediyl)]bistetrahydrofuroate (Bis-THF), substantially enhanced polymer chain mobility, reducing the glass transition temperature to approximately 28–35 °C compared to 60 °C for neat PLA. These bio-plasticizers also demonstrated outstanding plasticizing efficiency, achieving elongations at break exceeding 245%, compared with 4.5% for neat PLA. These results demonstrate that furfural-derived plasticizers are promising sustainable alternatives to conventional fossil-based plasticizers for flexible PLA applications. Full article

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

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24 pages, 5990 KB

Open AccessEditor’s ChoiceArticle

Meniscus Morphology-Based Prediction of Backup Roll Eccentricity for Stable Slot-Die Coating on Polymer Films

by Mingi Kim, Chanwoo Kim, Jeongdai Jo, Byungho Park and Changwoo Lee

Polymers 2026, 18(16), 2007; https://doi.org/10.3390/polym18162007 - 17 Aug 2026

Viewed by 1233

Abstract

In roll-to-roll slot-die coating systems, backup roll eccentricity induces periodic fluctuations in key process parameters, leading to coating defects. Therefore, accurate prediction of backup roll eccentricity during operation is essential for maintaining stable coating quality. However, conventional methods based on web tension signals [...] Read more.

In roll-to-roll slot-die coating systems, backup roll eccentricity induces periodic fluctuations in key process parameters, leading to coating defects. Therefore, accurate prediction of backup roll eccentricity during operation is essential for maintaining stable coating quality. However, conventional methods based on web tension signals have limitations in clearly distinguishing and quantitatively evaluating subtle eccentricities. To address this issue, this study proposes a data-driven framework for predicting backup roll eccentricity using meniscus image information. Representative morphological features are defined to describe the global shape, local shape, and curvature characteristics of the meniscus. Since these features are sensitive to eccentricity-induced process variations, they can serve as effective indicators for eccentricity prediction. The defined features are used to train regression models, and the model with the highest predictive accuracy is selected. Experimental results confirm that the proposed meniscus-based approach significantly outperforms conventional tension-based methods. The proposed method achieves an average Root Mean Square Error (RMSE) of approximately 0.63 μm, an average Normalized Root Mean Square Error (NRMSE) of approximately 0.34, and a coefficient of determination (R²) greater than 0.93 across all test cases. These results demonstrate the feasibility of robust process monitoring using a simple vision sensor configuration. Full article

(This article belongs to the Special Issue Polymer-Based Coatings: Principles, Development and Applications)

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17 pages, 946 KB

Open AccessEditor’s ChoiceArticle

Aloe vera/Chondrus crispus Hydrocolloid Emulgels as Polymer-Structured Colloidal Carriers for Cannabidiol Incorporation

by Claudia C. Polanía, Luis Alfonso Trujillo-Cayado and Jenifer Santos

Polymers 2026, 18(16), 1988; https://doi.org/10.3390/polym18161988 - 15 Aug 2026

Viewed by 372

Abstract

Cannabidiol (CBD) is a lipophilic phytocannabinoid of interest for dermocosmetic and topical applications, but its poor aqueous solubility and sensitivity to environmental conditions make its formulation challenging. This work aimed to develop avocado oil-in-water emulgels for CBD incorporation using a mixed emulsifying system [...] Read more.

Cannabidiol (CBD) is a lipophilic phytocannabinoid of interest for dermocosmetic and topical applications, but its poor aqueous solubility and sensitivity to environmental conditions make its formulation challenging. This work aimed to develop avocado oil-in-water emulgels for CBD incorporation using a mixed emulsifying system based on Kolliphor EL and cricket protein and a commercial Aloe vera/Chondrus crispus gel as the structuring phase. First, different Kolliphor EL:cricket protein ratios were evaluated according to droplet size distribution. No significant differences in droplet size were found among formulations containing at least 67% Kolliphor EL (p > 0.05); therefore, 67K-33G was selected because it maximized the substitution of Kolliphor EL with cricket protein without significantly affecting droplet size. Progressive replacement of water by the commercial hydrocolloid gel markedly increased consistency and viscoelasticity, producing a transition from fluid emulsions to elastic emulgels between 50 AV and 75 AV. The 75 AV formulation showed low Turbiscan Stability Index values, a predominantly elastic response, and a more balanced structure than 100 AV. The selected emulgel showed a total analytical recovery of 96.2 ± 1.2% for CBD and retained 97.3 ± 0.7% of the initially recovered CBD after 30 days of storage at 4 °C protected from light. These results support the potential of Aloe vera/Chondrus crispus-based emulgels as semisolid carriers for lipophilic bioactive compounds. Full article

(This article belongs to the Special Issue Advances in Natural Polymers and Active Compounds: Extraction Methods and Applications)

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30 pages, 34579 KB

Open AccessEditor’s ChoiceArticle

Effect of Different PTFE Coatings Applied to 18CrNiMo7-6 Steel on the Coefficient of Friction and Wear Under Dry Sliding Contact Using the Ball-on-Disk Method at Different Loads

by Michal Krbata, Marcel Kohutiar, Mariana Janeková, Branislav Hoferica, Daniel Krizan, Jana Escherova, Andrej Dubec, Bohdan Trembach, Pavol Mikuš and Alena Breznicka

Polymers 2026, 18(16), 1991; https://doi.org/10.3390/polym18161991 - 15 Aug 2026

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Abstract

This study investigates the tribological performance of three commercial PTFE-based Xylan^® coatings—Xylan^® 1425, Xylan^® 1052, and Xylan^® 1010—applied to 18CrNiMo7-6 steel under dry sliding conditions. Ball-on-Disk tests were conducted at normal loads of 5, 7.5, and 10 N, wear-track [...] Read more.

This study investigates the tribological performance of three commercial PTFE-based Xylan^® coatings—Xylan^® 1425, Xylan^® 1052, and Xylan^® 1010—applied to 18CrNiMo7-6 steel under dry sliding conditions. Ball-on-Disk tests were conducted at normal loads of 5, 7.5, and 10 N, wear-track radii of 12, 16, and 20 mm, and corresponding sliding velocities of 0.31–0.52 m·s⁻¹. The tribological evaluation was complemented by measurements of coating thickness, surface roughness, nanoindentation, wear-track profilometry, scanning electron microscopy, EDS mapping, and post-test cross-sectional microscopy. All coatings reduced the coefficient of friction from approximately 0.49–0.64 for the uncoated steel to 0.09–0.13, corresponding to an average reduction of 78–80%. Xylan^® 1425 exhibited the highest nanohardness of 57.02 MPa, the highest reduced elastic modulus of 3.33 GPa, and the most favorable elastoplastic indices. It also achieved the lowest wear, with a volumetric loss of approximately 0.03 mm³ under the most severe conditions, representing a reduction of more than 99% compared with the substrate. Xylan^® 1010 provided the lowest friction but showed pronounced plastic deformation, whereas Xylan^® 1052 exhibited fragmentation and increased wear. Post-test cross-sectional microscopy confirmed local exposure of the steel substrate in both coatings. Overall, Xylan^® 1425 provided the best balance of low friction, mechanical stability, coating continuity, and wear resistance. Full article

(This article belongs to the Topic Production, Processing, Microstructure and Functional Properties in Materials Engineering)

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16 pages, 6413 KB

Open AccessEditor’s ChoiceArticle

Fluorine-Modulated Reactivity Enables One-Pot Kinetic Sequence Programming of Block Copolyesters

by Chun-Yao Ke, Ryota Suzuki, Takuya Yamamoto, Takuya Isono, Guey-Sheng Liou and Toshifumi Satoh

Polymers 2026, 18(16), 1977; https://doi.org/10.3390/polym18161977 - 14 Aug 2026

Viewed by 373

Abstract

Monomer sequence strongly influences copolymer properties, but direct block formation from a monomer mixture requires a large reactivity contrast. Here, fluorination was used to regulate anhydride reactivity in the cesium pivalate-catalyzed ring-opening alternating copolymerization (ROAC) of tetrafluorophthalic anhydride (FPA), phthalic anhydride (PA), and [...] Read more.

Monomer sequence strongly influences copolymer properties, but direct block formation from a monomer mixture requires a large reactivity contrast. Here, fluorination was used to regulate anhydride reactivity in the cesium pivalate-catalyzed ring-opening alternating copolymerization (ROAC) of tetrafluorophthalic anhydride (FPA), phthalic anhydride (PA), and 3-perfluorohexyl-1,2-epoxypropane (PFE). Time-resolved nuclear magnetic resonance (NMR) spectroscopy showed that FPA reached >99% conversion before detectable PA incorporation. With 1,4-benzenedimethanol as a bidirectional initiator, this sequential consumption generated a central poly(FPA-alt-PFE) segment followed by poly(PA-alt-PFE) growth from both chain ends. Molar mass evolution, end-group analysis, and diffusion-ordered spectroscopy (DOSY) NMR collectively supported covalent block formation. Sequential incorporation was retained across three different FPA:PA feed ratios, and Beckingham–Sanoja–Lynd analysis yielded large and reciprocal effective reactivity-ratio descriptors (

r_{F P A} \approx 8.3 - 8.6 \times 10^{2}

and

r_{P A} \approx 1.2 \times 10^{- 3}

), consistent with the experimentally observed real-block regime. Matched model reactions further indicated faster FPA ring-opening and higher observed epoxide-opening reactivity in a fluorinated aromatic carboxylate model system. These results demonstrate that H-to-F substitution can provide the kinetic bias required to program block copolyester sequence within a single ROAC platform. Full article

(This article belongs to the Section Polymer Chemistry)

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26 pages, 2618 KB

Open AccessEditor’s ChoiceArticle

Transient Thermal Conductivity Minimum in Phenolic Foam Insulation: Closed-Cell Structural Dependence and Long-Term Aging Behavior

by Minjung Bae, Jaesik Kang and Hosang Ahn

Polymers 2026, 18(15), 1862; https://doi.org/10.3390/polym18151862 - 29 Jul 2026

Viewed by 301

Abstract

Closed-cell phenolic foam (PF) insulation is widely assumed to exhibit monotonically increasing thermal conductivity after cutting, driven by progressive blowing agent release. This study reports a previously uncharacterized behavior: a consistent decrease–minimum–rebound pattern in the days to weeks after cutting, defined here as [...] Read more.

Closed-cell phenolic foam (PF) insulation is widely assumed to exhibit monotonically increasing thermal conductivity after cutting, driven by progressive blowing agent release. This study reports a previously uncharacterized behavior: a consistent decrease–minimum–rebound pattern in the days to weeks after cutting, defined here as the transient thermal conductivity minimum (TTCM). Using n-pentane-blown PF foam, thermal conductivity and mass were tracked under standard (23 °C) and accelerated aging conditions (70 °C, 110 °C; slicing per KS M ISO 11561), complemented by gas chromatography–flame ionization detection (GC-FID), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FT-IR), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), and scanning electron microscopy (SEM). TTCM reductions of 3.8–16.7% were observed across all closed-cell specimens; a reference PF foam with cell-wall micro-perforations showed no TTCM, establishing intact closed-cell structure as a prerequisite. The mechanism is attributed to redistribution of dissolved n-pentane from the polymer matrix into the cell gas phase, thermodynamically favored by the proximity of n-pentane’s boiling point (36.07 °C) to the heat flow meter (HFM) hot plate temperature (33 °C). In the post-TTCM phase, thermal conductivity rises progressively as n-pentane is displaced by air; the rate of this rise is strongly dependent on diffusion path length. These results establish two mechanistically distinct aging stages and identify their respective governing factors. Full article

(This article belongs to the Special Issue Aging Behavior and Durability of Polymer Materials, 2nd Edition)

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17 pages, 6047 KB

Open AccessEditor’s ChoiceArticle

Influence of Polymer Inclusion Membrane Composition on Cd(II) Transport in Seawater and Desalination Brines

by Nasim Khatir, Magdalena Cifuentes-Cabezas, Enriqueta Anticó and Clàudia Fontàs

Polymers 2026, 18(15), 1854; https://doi.org/10.3390/polym18151854 - 29 Jul 2026

Viewed by 367

Abstract

The transport of metal ions from highly saline matrices remains challenging due to the elevated ionic strength and complex chemical speciation that characterize seawater and desalination brines. In this work, the influence of membrane composition on Cd(II) transport through polymer inclusion membranes (PIMs) [...] Read more.

The transport of metal ions from highly saline matrices remains challenging due to the elevated ionic strength and complex chemical speciation that characterize seawater and desalination brines. In this work, the influence of membrane composition on Cd(II) transport through polymer inclusion membranes (PIMs) was evaluated using cellulose triacetate (CTA), poly(vinyl chloride) (PVC), and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membranes containing Aliquat 336. Membranes were tested using model NaCl solutions, seawater, and desalination brine, and the effects of membrane mass, polymer matrix, carrier/plasticizer composition, and receiving phase were investigated. Reducing the CTA membrane mass by 50% did not significantly affect transport efficiency, indicating that membrane composition had a greater influence on Cd(II) transport than membrane mass under the conditions evaluated. Among the evaluated formulations, the optimum PVDF-HFP membrane contained 60 wt.% PVDF-HFP, 30 wt.% Aliquat 336, and 10 wt.% butyl stearate (BTS), achieving a transport efficiency of 95.5% and an initial flux of 2.7 × 10⁻⁶ mol m⁻² s⁻¹ in desalination brine. The use of 0.5 M HNO₃ as the receiving phase markedly improved Cd(II) transport in both synthetic saline solutions and real seawater and desalination brine compared with ultrapure water. These results highlight the importance of polymer–plasticizer interactions in controlling Cd(II) transport and demonstrate the potential of PVDF-HFP/Aliquat 336/BTS membranes for metal recovery from complex saline media. Full article

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

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19 pages, 6060 KB

Open AccessEditor’s ChoiceArticle

Production of FeCl₃-Treated Amine Functional Polymer Gel for Enhanced Removal of Methyl Orange and Congo Red Anionic Dyes

by Şeyda Getir, Atakan Toprak and Baki Hazer

Polymers 2026, 18(15), 1838; https://doi.org/10.3390/polym18151838 - 27 Jul 2026

Viewed by 364

Abstract

Synthetic dyes such as Methyl Orange (MO) and Congo Red (CR) are recalcitrant, toxic, mutagenic and resistant to conventional biodegradation, and their industrial discharge continues to contaminate aqueous ecosystems worldwide. This study reports the synthesis and characterization of a poly(MMA-co-2-AEMA) copolymer gel (Fe-Copolymergel-NH [...] Read more.

Synthetic dyes such as Methyl Orange (MO) and Congo Red (CR) are recalcitrant, toxic, mutagenic and resistant to conventional biodegradation, and their industrial discharge continues to contaminate aqueous ecosystems worldwide. This study reports the synthesis and characterization of a poly(MMA-co-2-AEMA) copolymer gel (Fe-Copolymergel-NH₂) treated with FeCl₃. It evaluates its adsorption performance from aqueous solution against the anionic azo dyes MO and CR. Extensive characterization using N₂ adsorption–desorption at 77 K, FTIR-ATR, XPS, SEM, and TEM revealed that Fe modification significantly improved the material’s textural properties, increasing its specific surface area from 8.11 m²/g to 12.55 m²/g and creating a highly irregular, interconnected, sponge-like morphology. Adsorption experiments showed that Fe-Copolymergel-NH₂ achieved competitive Langmuir maximum monolayer adsorption capacities of 3201.9 mg/g for CR and 1089.8 mg/g for MO. Kinetic modeling demonstrated that adsorption strictly followed the PSO model, primarily governed by chemisorption via electrostatic attractions and complexation within the internal structure at Fe³⁺ coordination centers. Thermodynamic analysis revealed that the dye removal process was spontaneous and exothermic. Consequently, the successful integration of Fe³⁺ coordination centers resolves the adsorption and structural limitations of pure polymer matrices, positioning Fe-Copolymergel-NH₂ as a highly promising and efficient adsorbent for the remediation of dye-contaminated industrial wastewater. Full article

(This article belongs to the Special Issue Polymer Materials for Ecological and Environmental Applications)

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18 pages, 7245 KB

Open AccessEditor’s ChoiceArticle

Cold-Resistance Plasticizers Derived from Bio-Based Trans-Aconitic Acid with High Performance on Solvent Extraction Resistance and Volatility Resistance

by Yirui Shen, Xiaomei Wang, Yangyang Xiong, Xinmeng He, Pingping Jiang and Guizhen Xing

Polymers 2026, 18(13), 1671; https://doi.org/10.3390/polym18131671 - 6 Jul 2026

Viewed by 551

Abstract

Dioctyl adipate (DOA) and dioctyl sebacate (DOS) are widely used cold-resistance plasticizers; however, their low molecular weight and weak polarity result in poor thermal stability and migration resistance. Here, we report the synthesis and performance of bio-based cold-resistance plasticizers derived from trans-aconitic [...] Read more.

Dioctyl adipate (DOA) and dioctyl sebacate (DOS) are widely used cold-resistance plasticizers; however, their low molecular weight and weak polarity result in poor thermal stability and migration resistance. Here, we report the synthesis and performance of bio-based cold-resistance plasticizers derived from trans-aconitic acid with enhanced migration resistance. Tri-n-butyl trans-aconitate (TBTA), tri-n-hexyl trans-aconitate (THTA), and tri-n-octyl trans-aconitate (TOTA) were synthesized via one-step esterification with aliphatic alcohols and applied in poly(vinyl chloride) (PVC). Compared with commercial plasticizers di-(2-ethylhexyl) phthalate (DEHP), tributyl citrate (TBC) and DOA, the synthesized plasticizers demonstrated excellent thermal stability and cold-resistance. After freezing treatment, the

T_{g}

values of TBTA/PVC (18.99 °C) and THTA/PVC (20.88 °C) were lower than those of DEHP/PVC (22.74 °C). The branched architecture was supposed to strengthen interactions between plasticizers and PVC, improving volatility resistance and solvent extraction resistance. Compared with DOA/PVC at 48 h, TBTA/PVC, THTA/PVC and TOTA/PVC displayed volatility mass loss reduction of ~1.5%, 4% and 7%, respectively. Their extraction mass loss in ethanol decreased by 5–6%, while in petroleum ether, TBTA/PVC and TOTA/PVC dropped by 11.95% and 2.63%, respectively. These bio-based plasticizers are promising alternatives to the poor migration resistance of conventional low-temperature plasticizers. Full article

(This article belongs to the Section Polymer Chemistry)

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25 pages, 18288 KB

Open AccessEditor’s ChoiceArticle

Infill Pattern-Dependent Mechanical Properties and In Vitro Release Behavior of FDM 3D-Printed Resveratrol Amorphous Solid Dispersion Matrix Tablets

by Lianghao Huang, Kai Zheng, Xiaofeng Chen, Yunping Zhao, Tiantian Yang, Hang Yu, Wei Zhao, Xia Zhao and Jiaxiang Zhang

Polymers 2026, 18(12), 1531; https://doi.org/10.3390/polym18121531 - 19 Jun 2026

Viewed by 529

Abstract

Resveratrol (RSV) is a poorly water-soluble polyphenolic compound with various potential health benefits, but its pharmaceutical application is limited by low aqueous solubility and poor oral bioavailability. Additive manufacturing (AM), particularly fused deposition modeling (FDM) 3D printing, offers a flexible approach for fabricating [...] Read more.

Resveratrol (RSV) is a poorly water-soluble polyphenolic compound with various potential health benefits, but its pharmaceutical application is limited by low aqueous solubility and poor oral bioavailability. Additive manufacturing (AM), particularly fused deposition modeling (FDM) 3D printing, offers a flexible approach for fabricating oral dosage forms with customized geometry and internal architecture. In this study, hot-melt extrusion (HME) combined with fused deposition modeling (FDM) 3D printing was used to prepare RSV-loaded tablets with different infill patterns. Hydroxypropyl methylcellulose acetate succinate and hydroxypropyl cellulose were selected as polymeric carriers to prepare RSV-loaded filaments suitable for FDM printing. The effects of infill pattern on the solid-state characteristics, dimensional accuracy, mechanical properties, floating behavior, and in vitro drug release of the printed tablets were systematically investigated. Differential scanning calorimetry, powder X-ray diffraction, and polarized light microscopy indicated that RSV was mainly converted into an amorphous or molecularly dispersed state after HME and FDM processing. All designed tablets were successfully printed and showed acceptable shape fidelity, while different infill patterns resulted in variations in tablet weight, mechanical strength, floating duration, and release behavior. In vitro dissolution studies showed that the RSV release profiles were dependent on the internal infill architecture. Tablets with more complex infill patterns generally exhibited slower drug release, which may be related to differences in internal pore structure, medium penetration pathways, matrix hydration, and diffusion distance. Release kinetic analysis further suggested that RSV release from the printed tablets involved a combination of diffusion and polymer relaxation processes. These results demonstrate that infill pattern is an important structural parameter for modulating the mechanical performance and drug release behavior of FDM 3D-printed RSV tablets. This study provides useful guidance for the design of 3D-printed oral dosage forms with tunable release characteristics. Full article

(This article belongs to the Special Issue Advancements in Polymeric Materials for Precision Drug Delivery)

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38 pages, 10000 KB

Open AccessEditor’s ChoiceArticle

Lignin–Sustainable Polymer for Mn(II) Biosorption from Aqueous Media

by Elena Ungureanu, Bogdan M. Tofanică, Maria E. Fortună, Ovidiu C. Ungureanu, Răzvan Rotaru and Valentin I. Popa

Polymers 2026, 18(12), 1523; https://doi.org/10.3390/polym18121523 - 18 Jun 2026

Viewed by 626

Abstract

In the context of the circular bioeconomy and environmental protection trends, the efficient use of renewable resources has become a driving force for industry, and lignin represents precisely a renewable carbon resource, abundant in terrestrial biomass that could become a sustainable substitute for [...] Read more.

In the context of the circular bioeconomy and environmental protection trends, the efficient use of renewable resources has become a driving force for industry, and lignin represents precisely a renewable carbon resource, abundant in terrestrial biomass that could become a sustainable substitute for fossil resources, under conditions of full exploitation. This study systematically evaluates the biosorption of Manganese (Mn(II)) from aqueous media using unmodified Tripidium bengalense (Sarkanda grass) lignin. Under optimal operating conditions (adsorbent dosage of 5 g/L, pH 6.5, and 20 °C), a highly competitive experimental adsorption capacity of 12.52 mg/g was achieved. Kinetic studies revealed exceptionally rapid uptake rates, with thermodynamic equilibrium established within the first 30 min, fitting perfectly with the pseudo-second-order (Ho-McKay) model (R² ≥ 0.9998). Equilibrium data were best described by the Freundlich isotherm (R² ≥ 0.9886), confirming chemisorption via preferential inner-sphere complexation on a heterogeneous surface. Thermodynamic analysis verified that the process is spontaneous (ΔG ranging from −13.24 to −26.19 kJ/mol) and endothermic (ΔH from 11.21 to 14.83 kJ/mol). FTIR, SEM-EDX, and TG/DTG analyses confirmed successful Mn–O coordination involving phenolic hydroxyl and carboxylic groups. Furthermore, the lignin showed excellent recyclability, maintaining a retention efficiency over 70% (70.7–85.8%) after three desorption-resorption cycles using 1N HCl. Ecotoxicological validation via Sorghum bicolor L. germination tests confirmed the complete detoxification of the post-adsorption filtrates (up to 100% germination capacity), while the Mn(II)-loaded lignin completely suppressed seed germination (0%), proving secure metal immobilization. These findings establish raw Sarkanda grass lignin as an efficient, scalable, and ecologically sustainable biosorbent for heavy metal remediation. Full article

(This article belongs to the Special Issue Sustainable Bio-Based and Circular Polymers and Composites—2nd Edition)

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23 pages, 11636 KB

Open AccessEditor’s ChoiceArticle

Design and Processing of Novel PBS/PVOH Blown Films for Food Packaging: Effect of PVOH Phase Structuring on Morphology and Functional Performance

by Antonio Barbato, Francesco Palmieri, Emilia Garofalo, Annalisa Apicella, Loredana Incarnato and Luciano Di Maio

Polymers 2026, 18(11), 1367; https://doi.org/10.3390/polym18111367 - 31 May 2026

Viewed by 757

Abstract

Biodegradable polymer blends are promising materials for flexible packaging films with tunable properties. In this work, poly(butylene succinate)/poly(vinyl alcohol) (PBS/PVOH) blown films were produced by twin-screw melt compounding followed by film blowing, and the effect of PVOH content on phase organization, processability, morphology, [...] Read more.

Biodegradable polymer blends are promising materials for flexible packaging films with tunable properties. In this work, poly(butylene succinate)/poly(vinyl alcohol) (PBS/PVOH) blown films were produced by twin-screw melt compounding followed by film blowing, and the effect of PVOH content on phase organization, processability, morphology, and functional performance was investigated. The blends showed phase-separated morphologies and composition-dependent structural evolution. DSC indicated that both polymers largely retained their crystallization ability, although the crystallinity decrease was more evident for PVOH. Rheological analysis revealed limited compatibility and increasing elastic response at higher PVOH contents, consistent with the formation of structured PVOH insoluble gel-like domains. SEM confirmed droplet–matrix morphologies, becoming coarser and more heterogeneous at high PVOH content, with film-blowing instability for PBS/PVOH 20/80. PVOH incorporation improved oxygen and water-vapor barrier properties and increased stiffness, but progressively reduced ductility. Model fitting supported the structure–property correlations, relating film performance to blend composition, morphology, and PVOH phase organization. Among the processable formulations, PBS/PVOH 80/20 showed the best balance between improved barrier properties and acceptable extensibility for food packaging application. Overall, PBS/PVOH blown films are promising biodegradable systems for flexible food packaging, provided that PVOH phase structuring is properly controlled. Full article

(This article belongs to the Special Issue Polymer Manufacturing Processes)

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19 pages, 6325 KB

Open AccessEditor’s ChoiceArticle

Development of Poly(lactic acid)/Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Biocomposite Films: Influence of Cellulose Microfiber Source on Structural and Functional Properties

by Luis Jaime Pérez-Córdoba, Diana Carmona-Cantillo, Cristian Polo-Zamora, Edwin Fuentes-Ordóñez and Rodrigo Ortega-Toro

Polymers 2026, 18(11), 1350; https://doi.org/10.3390/polym18111350 - 29 May 2026

Viewed by 630

Abstract

The incorporation of cellulosic-based fillers as reinforcements into biocomposites represents a promising strategy to enhance the performance of sustainable packaging materials. In this study, poly(lactic acid)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PLA/PHBV) films reinforced with 1 and 3 wt% of cellulose microfibers (CM) derived from yam, potato, and [...] Read more.

The incorporation of cellulosic-based fillers as reinforcements into biocomposites represents a promising strategy to enhance the performance of sustainable packaging materials. In this study, poly(lactic acid)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PLA/PHBV) films reinforced with 1 and 3 wt% of cellulose microfibers (CM) derived from yam, potato, and cassava hulls were developed through melt extrusion followed by compression molding. The physicochemical, mechanical, optical, microstructural, thermal, and molecular properties of the films were evaluated. Results showed that both the CM source and concentration significantly influenced the biocomposites performance. Cassava-derived CM at 3 wt% provided the best barrier properties, while increasing CM content, regardless of the source, generally reduced solubility, increased moisture content, enhanced stiffness, and decreased elongation at break, although excessive loading negatively affected structural homogeneity. CM incorporation also reduced film gloss and transparency, particularly in yam-based composites. Thermal analysis indicated a multi-step degradation process with only minor variations in thermal stability, and no major chemical modifications of the biocomposites were detected. Overall, cassava-derived CM produced the most balanced performance, highlighting the importance of filler source and loading in tailoring PLA/PHBV biocomposite functional properties. Full article

(This article belongs to the Special Issue Polymer Composites for Smart and Eco-Friendly Systems)

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38 pages, 47158 KB

Open AccessEditor’s ChoiceArticle

Development and Characterization of Thermoplastic Composites Based on Recycled HDPE from Railway Sleepers’ Fastening Bushes and Scraped Fractions from Carbon Fiber Waste Upcycling

by Roberto Petrucci, Marco Rallini, Maurizio Natali and Luigi Torre

Polymers 2026, 18(11), 1309; https://doi.org/10.3390/polym18111309 - 26 May 2026

Viewed by 733

Abstract

The railway sector is crucial for transportation, but infrastructure maintenance generates significant waste and requires large amounts of materials, increasing environmental impact. Circular economy integration mitigates this impact through material recovery. This study focused on the recycling of bushes embedded in railways sleepers, [...] Read more.

The railway sector is crucial for transportation, but infrastructure maintenance generates significant waste and requires large amounts of materials, increasing environmental impact. Circular economy integration mitigates this impact through material recovery. This study focused on the recycling of bushes embedded in railways sleepers, currently disposed of in landfills, obtaining high-density polyethylene (HDPE). The developed scalable process converted contaminated bushes into pellets, whose environmental sustainability was assessed through life cycle analysis. Challenges of the recycled material, such as high viscosity and heterogeneity, were partially addressed with a slipping agent and a compatibilizer, increasing the material melt index from 0.71 to 1.62 g/10 min. Carbon fiber waste addition improved thermal stability, mechanical stiffness, and electrical conductivity. Compatibilized blends offered the best balance of mechanical properties but lower electrical conductivity. The Young modulus was increased from 1.20 GPa for the neat matrix to 4.40 GPa for the system containing 30% carbon fibers in weight, with no significant decreases in the yield stress, while showing the lowest electrical conductivity. To reduce environmental impact and produce a tougher material without compromising conductivity, the compatibilizer was replaced with HDPE from PET bottle caps, resulting in comparable mechanical properties and higher electrical conductivity but reduced fiber/matrix interface. Full article

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

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24 pages, 8310 KB

Open AccessEditor’s ChoiceArticle

A Reaction–Diffusion Model for Capturing Mass Loss and Microstructure Evolution in Enzymatic Degradation of Poly(ε-Caprolactone) Films

by Nanshin Nansak, Leo Creedon, Denis O’Mahoney, Ramen Ghosh and Marion McAfee

Polymers 2026, 18(10), 1248; https://doi.org/10.3390/polym18101248 - 20 May 2026

Viewed by 601

Abstract

The microstructure of semicrystalline bioresorbable polymers is central to their biomedical performance because the crystalline content influences both the mechanical stability and the degradation behaviour. Experimental studies have shown that crystallinity evolves concurrently with mass loss during enzymatic degradation. However, most existing models [...] Read more.

The microstructure of semicrystalline bioresorbable polymers is central to their biomedical performance because the crystalline content influences both the mechanical stability and the degradation behaviour. Experimental studies have shown that crystallinity evolves concurrently with mass loss during enzymatic degradation. However, most existing models represent the material as a single homogeneous structure, preventing them from capturing this microstructural evolution or the state-selective mechanisms that drive it. We present a one-dimensional partial differential equation model for the enzymatic degradation of thin films, which treats the crystalline and amorphous states as distinct reactive components. Calibrated to poly(

ε

-caprolactone) (PCL) degraded by Candida antarctica lipase in vitro, the model accurately reproduces both the observed weight-loss profile and the concurrent decline in crystallinity. Parameter uncertainty analysis indicates that while there are varying degrees of confidence in individual parameter values, the overall model predictive uncertainty is well constrained. Parameter sensitivity analysis shows that the amorphous catalytic rate (the rate at which the enzyme degrades the amorphous region) is the dominant driver of degradation dynamics. The identified model parameters are used to explore the role of film thickness on the rates of mass and crystallinity loss. It was found that thin films remain largely reaction-limited, whereas thicker specimens become increasingly transport-influenced, with slower degradation and delayed structural evolution in the material interior. The model provides a useful tool to explore the effect of changing PCL film thickness on degradation rate and crystallinity-related properties without extensive experimentation. Full article

(This article belongs to the Special Issue Advances in Modeling and Simulations of Polymers)

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33 pages, 32347 KB

Open AccessEditor’s ChoiceReview

Functional Polymeric Materials for Micro- and Nanoplastic Removal from Waters

by Juan Carlos Bravo-Yagüe, Gema Paniagua-González, Rosa María Garcinuño, Asunción García-Mayor and Pilar Fernández-Hernando

Polymers 2026, 18(9), 1081; https://doi.org/10.3390/polym18091081 - 29 Apr 2026

Cited by 3 | Viewed by 1605

Abstract

Micro- and nanoplastic pollution poses an emerging challenge for aquatic environments, driving the need for efficient and scalable removal strategies. Functional polymeric materials (FPMs) have emerged as a versatile platform to address this issue, owing to their tunable chemical composition, structural diversity, and [...] Read more.

Micro- and nanoplastic pollution poses an emerging challenge for aquatic environments, driving the need for efficient and scalable removal strategies. Functional polymeric materials (FPMs) have emerged as a versatile platform to address this issue, owing to their tunable chemical composition, structural diversity, and ability to promote multiple removal mechanisms, including adsorption, filtration, and coagulation/flocculation. This review provides an overview of recent advances in polymer-based strategies for the removal of micro- and nanoplastics, with emphasis on material design, interaction mechanisms, and process performance. A broad range of materials, including natural hydrogels, polysaccharide aerogels, synthetic polymer composites, magnetic hybrids, and metal–organic frameworks (MOFs)–polymer systems, have demonstrated high removal efficiencies through electrostatic interactions, hydrogen bonding, hydrophobic effects, π–π stacking, and physical entrapment. Removal performance is strongly influenced by surface functionalization, porosity, surface area, and polymer network architecture, enabling targeted design for specific particle types and water matrices. Hybrid and multifunctional materials further enhance capacity and reusability, while natural polymers offer sustainable alternatives. Despite these advances, challenges remain in standardization, scalability, long-term stability, fouling resistance, and economic feasibility under realistic environmental conditions. Future research should focus on sustainable, multi-target, and scalable FPMs, integrating hybrid architectures, stimuli-responsive functionalities, and bioinspired design strategies. Particular attention should be given to mechanistic studies under environmentally relevant conditions and the establishment of structure–property design criteria to enable efficient removal of heterogeneous MPs/NPs mixtures. Overall, functional polymeric materials represent a flexible and high-performance platform for mitigating micro- and nanoplastic contamination, although their successful implementation will depend on bridging the gap between laboratory-scale performance and real-world water treatment applications. Full article

(This article belongs to the Special Issue Functional Polymeric Materials for Water Treatment)

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21 pages, 5265 KB

Open AccessEditor’s ChoiceArticle

Assessing Natural Fillers as Substitutes for Glass Fibers in Polyamide 6 Composites for Large-Format Additive Manufacturing

by Alessandro Sorze, Francesco Valentini, Sofia Santi, Matteo Perini, Nicole Soligo, Mauro Buccella, Laura Pasquardini and Andrea Dorigato

Polymers 2026, 18(9), 1049; https://doi.org/10.3390/polym18091049 - 26 Apr 2026

Cited by 1 | Viewed by 1281

Abstract

This work investigated the potential of different natural fillers, i.e., clay, calcium carbonate, and silica, as sustainable alternatives to glass fibers (GFs) in polyamide 6 (PA6) for Large-Format Additive Manufacturing (LFAM) applications in order to guarantee the chemical recyclability of the produced materials. [...] Read more.

This work investigated the potential of different natural fillers, i.e., clay, calcium carbonate, and silica, as sustainable alternatives to glass fibers (GFs) in polyamide 6 (PA6) for Large-Format Additive Manufacturing (LFAM) applications in order to guarantee the chemical recyclability of the produced materials. Specifically, PA6-based composites containing ≤ 10 wt% natural fillers were compared with a conventional system (30 wt% GF-reinforced PA6) from rheological, morphological and thermo-mechanical perspectives. Rheological analysis showed that silica- and clay-filled samples displayed similar rheological response to the GF-filled reference due to their large particle size. Thermal analyses revealed a slight increase in crystallinity (up to 32%) for filled samples, indicating a potential nucleating effect of the natural fillers. Calcium carbonate-filled composites achieved thermal conductivity values comparable to the GF-filled reference (≥0.42 W/mK) indicating a high heat dissipation capability during printing operations. Morphological analysis performed on preliminary LFAM components revealed satisfactory printing quality and good filler dispersion. Flexural tests showed that silica and calcium carbonate could provide a balanced mechanical response, thereby reducing the anisotropy of printed components. These results demonstrated that the addition of suitable natural fillers at limited concentrations (≤10 wt%) can represent a lightweight and eco-sustainable alternative to GF reinforcement in LFAM applications. Full article

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

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17 pages, 1612 KB

Open AccessEditor’s ChoiceArticle

Co-Pyrolysis of Polyolefins and Silicone Rubber: Effects on Mass Balancing, Product Distribution, and Potential Siloxane Recovery

by Lukas Eigenschink, Wolfgang Eder, Matthias Mastalir, Michael Harasek and Christian Paulik

Polymers 2026, 18(8), 989; https://doi.org/10.3390/polym18080989 - 18 Apr 2026

Cited by 2 | Viewed by 981

Abstract

Co-pyrolysis of polyolefins (LDPE, PP, PS) mixed with silicone rubber (SR) was investigated using a laboratory-scale pyrolysis apparatus to evaluate product composition, synergistic interactions, and siloxane recovery potential. Synergistic effects were assessed by comparing experimental mass balances and product distributions with calculated values [...] Read more.

Co-pyrolysis of polyolefins (LDPE, PP, PS) mixed with silicone rubber (SR) was investigated using a laboratory-scale pyrolysis apparatus to evaluate product composition, synergistic interactions, and siloxane recovery potential. Synergistic effects were assessed by comparing experimental mass balances and product distributions with calculated values derived from individual polymer pyrolysis. Co-pyrolysis resulted in a reduction in liquid yield and an increase in gaseous products and solid residue compared to calculated values, with liquid yields decreasing by up to ≈15 wt% at high SR content. This shift was accompanied by an enrichment in lighter hydrocarbons in both phases, reaching up to a ≈18% relative increase at high SR content, and by a redistribution towards smaller cyclic siloxanes. Chromatographic analysis confirmed that no new compounds were formed, but the proportion of low molecular weight species increased with silicone content. These effects are attributed to the distinct thermal behavior of the polymers, as silicone rubber does not melt but becomes brittle, allowing molten polyolefins to infiltrate surface cracks and prolong residence time, thereby promoting secondary cracking. Furthermore, recovery of hexamethylcyclotrisiloxane (D₃), the primary silicone pyrolysis product, was demonstrated from the liquid co-pyrolysis products via solvent-assisted filtration using ethanol, achieving purities above 99.5% and recovery rates up to ≈75% compared to other possible methods. These findings provide insights into co-pyrolysis behavior and offer a basis for developing strategies for the recovery of siloxane and advanced recycling of mixed polymer waste. Full article

(This article belongs to the Section Polymer Chemistry)

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25 pages, 3439 KB

Open AccessEditor’s ChoiceArticle

Electrospun Multilayer Scaffolds Based on Poly (L-Lactic Acid) and Poly (Acrylonitrile) Reinforced with CaO Nanoparticles for Enhanced Skin Regeneration and Wound Healing

by Eugenio Rivera, Lissette Montoille, Fabián Guajardo, Fabian Álvarez-Carrasco, Sebastián Romero, Mauricio Gómez-Barrena, Esmeralda Lopez, Carlos Loyo, Claudio García-Herrera, Paula A. Zapata, Diana Zárate-Triviño, Juan José Martinez and Daniel A. Canales

Polymers 2026, 18(8), 960; https://doi.org/10.3390/polym18080960 - 15 Apr 2026

Viewed by 1006

Abstract

This study reports the development and characterization of hierarchical electrospun scaffolds based on poly (L-lactic acid) (PLA) and polyacrylonitrile (PAN) reinforced with calcium oxide (CaO) nanoparticles (18.5 ± 4.7 nm) for skin regeneration. Six configurations, including two five-layer multilayer systems (PLA/PAN/CaO and PAN/PLA/CaO), [...] Read more.

This study reports the development and characterization of hierarchical electrospun scaffolds based on poly (L-lactic acid) (PLA) and polyacrylonitrile (PAN) reinforced with calcium oxide (CaO) nanoparticles (18.5 ± 4.7 nm) for skin regeneration. Six configurations, including two five-layer multilayer systems (PLA/PAN/CaO and PAN/PLA/CaO), were evaluated to determine how composition and deposition sequence influence physicochemical, mechanical, and biological performance. FT-IR, XRD and DSC confirmed the successful integration of CaO, while thermal analysis evidenced an effect of chain mobility and interfacial interactions within multilayer systems. Cross-sectional SEM revealed the presence of both fibers with continuous interfaces. Nitrogen adsorption showed that CaO significantly increased the specific surface area (e.g., from 4.6 m²/g in neat PLA to 21.65 m²/g in PLA/CaO), with type IV isotherms indicating mesoporosity. Wettability assays demonstrated reduced contact angle in PLA (from 126.3° to 91.8°) and sequence-dependent surface properties in multilayers. Tensile testing confirmed that the multilayer architecture bridged the mechanical gap between compliant PLA and high-strength PAN, yielding intermediate moduli (~10–11 MPa) and balanced toughness. Antibacterial assays against S. aureus and E. coli showed that CaO significantly reduced bacterial viability, with PLA/PAN/CaO achieving the highest inhibition (up to 37.1%). In vitro HaCaT assays and in vivo implantation in BALB/c mice confirmed high cytocompatibility and biocompatibility. These findings demonstrate that multilayer electrospinning of PLA/PAN/CaO enables the design of structurally integrated, bioactive, and mechanically balanced scaffolds for advanced wound healing and dermal repair. Full article

(This article belongs to the Special Issue Polymeric Materials in Tissue Engineering)

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19 pages, 3453 KB

Open AccessEditor’s ChoiceArticle

Mimicking Tissues in 3D-Printed Radiology Phantoms: Brand, Product, and Color of Printing Filaments Matter!

by Thomas Hofmann, Martin Buschmann, Adrian Belarra, Maria Castillo-Garcia, Margarita Chevalier, Irene Hernandez-Giron and Peter Homolka

Polymers 2026, 18(7), 851; https://doi.org/10.3390/polym18070851 - 31 Mar 2026

Cited by 1 | Viewed by 1300

Abstract

Additive manufacturing enables the rapid fabrication of radiographic phantoms for X-ray and CT imaging, supporting applications such as patient simulation, dosimetry, imaging protocol optimization, and quality assurance. Polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) are among the most widely used printing polymers [...] Read more.

Additive manufacturing enables the rapid fabrication of radiographic phantoms for X-ray and CT imaging, supporting applications such as patient simulation, dosimetry, imaging protocol optimization, and quality assurance. Polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) are among the most widely used printing polymers in phantoms; however, their X-ray attenuation properties can vary substantially among manufacturers, product lines within manufacturers, and even between colors of the same product. Cylindrical samples of 34 PLA filaments from 11 manufacturers and 13 ABS filaments from 9 manufacturers were evaluated for X-ray attenuation and energy dependence between 70 and 140 kV using a clinical CT scanner. Measured mass densities ranged from 1.17 to 1.34 g/cm³ for PLA and 1.03–1.11 g/cm³ for ABS. At 120 kV, Hounsfield unit (HU) values spanned 109 to 424 HU for PLA and −34 to 40 HU for ABS. Energy dependence, quantified as the HU at 70 kV minus HU at 140 kV, ranged from −29 to +172 HU for PLA filaments and −52 to −4 HU for ABS filaments. Identical products differing only in color showed HU variations from <2 HU to >90 HU at 120 kV, with no consistent pattern linking specific colors to highest or lowest attenuation. These findings demonstrate that 3D printing materials require individual characterization, as base polymer designation alone does not predict X-ray behavior accurately. The observed variability, however, enables the design of phantoms with tailored attenuation and energy-dependent contrast. Referring only to base polymers when specifying 3D printing materials for radiographic phantoms or suggesting printing materials as radiographic substitutes to mimic a specified tissue or reference material without naming the actual product, including color, is, thus, insufficient. Full article

(This article belongs to the Special Issue High-Performance Thermoplastic Polymer Composites: From Fabrication to Application)

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19 pages, 5545 KB

Open AccessEditor’s ChoiceArticle

Novel NTA-Ni²⁺ Agarose-Based Microspheres: Structural Features and Chromatographic Capacity

by Min Zhao, Chen Liang, Boheng Liu, Ahsan Javed, Ran Zhou, Xiaozhen Diao, Chuanyun Ren and Wenhui Wu

Polymers 2026, 18(5), 566; https://doi.org/10.3390/polym18050566 - 26 Feb 2026

Viewed by 1469

Abstract

The design and optimization of immobilized metal affinity chromatography (IMAC) media are crucial to enhancing the purification efficiency of recombinant proteins. In this study, the agarose-based microspheres are prepared by using a three-factorial Box–Behnken design followed by NTA-Ni²⁺ agarose-based microspheres (ABM) preparation [...] Read more.

The design and optimization of immobilized metal affinity chromatography (IMAC) media are crucial to enhancing the purification efficiency of recombinant proteins. In this study, the agarose-based microspheres are prepared by using a three-factorial Box–Behnken design followed by NTA-Ni²⁺ agarose-based microspheres (ABM) preparation by the “one-step” crosslinking of epichlorohydrin (ECH)–nitrilotriacetic acid (NTA) to efficiently couple the NTA ligand to the surface of the matrix. After preparation, various sophisticated techniques, including SEM, AFM, DSC, FTIR, and SDS-PAGE, were used to analyze the morphological structure, thermal stability, and chemical composition of NTA-Ni²⁺ ABM. The optimal conditions are identified as an emulsifier PP concentration of 8.12 wt%, a stirring speed of 1624.46 rpm, and an oil-phase temperature of 53.86 °C, giving a span value (Y) of 0.50684. SEM, AFM, DSC, and FTIR results showed that the fabricated NTA-Ni²⁺ ABM were structurally stable and had a uniform cross-linking network for up to 8 h of coupling reaction time. The performance results showed that the beads had a high binding capacity for His-tagged proteins (15.2 ± 0.8 mg/mL), and SDS-PAGE results demonstrated the efficient purification ability for target proteins. These findings provide the theoretical basis and a practical solution for the rational design and application of IMAC medium. Full article

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

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15 pages, 1414 KB

Open AccessEditor’s ChoiceArticle

Graphoepitaxial Control of Lamellar Block Copolymer Alignment in Wide Trenches: Effects of Trench Width and Sidewall Tilt

by June Huh

Polymers 2026, 18(5), 557; https://doi.org/10.3390/polym18050557 - 25 Feb 2026

Viewed by 712

Abstract

Graphoepitaxy provides a robust route to align lamellar block copolymers in topographic trenches, yet alignment often degrades rapidly as the trench width increases into the wide-trench regime. Here, mesoscale density functional simulations under thermal annealing are used to quantify width- and geometry-dependent ordering [...] Read more.

Graphoepitaxy provides a robust route to align lamellar block copolymers in topographic trenches, yet alignment often degrades rapidly as the trench width increases into the wide-trench regime. Here, mesoscale density functional simulations under thermal annealing are used to quantify width- and geometry-dependent ordering of symmetric lamella-forming block copolymers confined in trenches. A Fourier-based alignment metric reveals a sharp, sigmoidal decay of alignment with trench width normalized by the natural lamellar period, indicating a crossover between (i) a globally aligned state established by wall-guided propagation and (ii) a misoriented, kinetically trapped state produced by bulk-like interior nucleation followed by domain impingement. This width dependence is well captured by a logistic form, yielding a characteristic crossover width and transition sharpness that compactly describe the accessible alignment window. Parameter sweeps show that increasing incompatibility shifts the crossover to smaller widths, whereas stronger sidewall surface fields extend the accessible width range with diminishing returns at large fields; in the range examined, film thickness has little influence on the crossover. Finally, simulations in trapezoidal trenches demonstrate that high alignment persists for moderate sidewall taper, while larger taper promotes lamellar bending and defects. A geometric criterion based on the variation in trench width across the film thickness, using a numerical threshold derived from strong-segregation theory, rationalizes the observed onset of degradation when this variation approaches approximately 1.4 lamellar periods. These results provide a mechanistic framework and quantitative guidelines for extending graphoepitaxial lamellar alignment beyond the narrow-confinement regime. Full article

(This article belongs to the Special Issue New Advances in Theory and Simulation of Block Copolymers)

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31 pages, 2314 KB

Open AccessEditor’s ChoiceReview

Recent Trends in the Chemical Modification of Polysaccharides for Food Packaging: A Review

by Paramabhorn Tosuwan, Hannah S. Leese and Christopher J. Chuck

Polymers 2026, 18(4), 529; https://doi.org/10.3390/polym18040529 - 21 Feb 2026

Cited by 5 | Viewed by 2584

Abstract

The environmental impact of petroplastics that do not readily biodegrade has intensified the search for sustainable packaging materials. Polysaccharides derived from plant and marine sources are biodegradable and renewable, but their hydrophilicity and weak mechanical and barrier properties limit their use in high-performance [...] Read more.

The environmental impact of petroplastics that do not readily biodegrade has intensified the search for sustainable packaging materials. Polysaccharides derived from plant and marine sources are biodegradable and renewable, but their hydrophilicity and weak mechanical and barrier properties limit their use in high-performance packaging. Chemical modification offers an effective solution by introducing hydrophobic or functional groups that enhance physicochemical performance, making modified polysaccharides strong candidates for sustainable packaging applications. This review provides a comprehensive overview of recent advances in the chemical modification and development of plant-based polysaccharides (starch, cellulose and its derivatives, and pectin) and marine-based polysaccharides (agar, carrageenan, alginate, and chitosan) for food packaging applications. Emphasis on how chemical modifications influence key functional properties relevant to sustainable packaging, including barrier performance, biological activities, and freshness-monitoring capabilities. Film fabrication techniques such as solution casting, extrusion, coating, and electrospraying are also discussed regarding their impact on material performance. Overall, the reviewed studies demonstrate that chemical modification can substantially enhance the functional properties of polysaccharides and enable active and intelligent packaging functionalities. While challenges related to food safety, scalable production, environmental impact, and real-world performance remain, chemically modified polysaccharides show strong potential as sustainable and functional materials for the next generation of food packaging. Full article

(This article belongs to the Special Issue Modification of Natural Biodegradable Polymers)

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16 pages, 10128 KB

Open AccessEditor’s ChoiceArticle

Spatial Tribological Properties of PI/PTFE Based Self-Stratifying Composite Coatings Grafted by Amino-POSS

by Chuanyong Yu, Min Wei, Qiwei Wang and Wei Zhang

Polymers 2026, 18(4), 521; https://doi.org/10.3390/polym18040521 - 20 Feb 2026

Cited by 1 | Viewed by 834

Abstract

In low Earth orbit (LEO), special environments such as atomic oxygen (AO), alternating high and low temperatures, and high vacuum can seriously affect the reliability and service lifetime of moving parts of space equipment. Therefore, there is an increasingly urgent demand for long-life, [...] Read more.

In low Earth orbit (LEO), special environments such as atomic oxygen (AO), alternating high and low temperatures, and high vacuum can seriously affect the reliability and service lifetime of moving parts of space equipment. Therefore, there is an increasingly urgent demand for long-life, high-performance lubricating protective coatings with the rapid evolution of astronautical technology. In this study, polyimide (PI) was modified by polyhedral oligomeric silsesquioxane (POSS) with different numbers of functional groups to fabricate PI-based self-stratifying gradient composite lubricating coatings. The coating exhibited significantly enhanced AO resistance, and its vacuum tribological properties under alternating high and low temperature conditions were investigated. Results show that the mass loss of the gradient coating under AO exposure was significantly reduced by 78%, and the tribological properties of the coating under high and low temperature alternating conditions were significantly different. The friction coefficient was more stable and was smaller than that at high temperatures, and the wear rates of the POSS-modified coating also decreased by 77.5% and 50% for both high and low temperatures compared with that of the PI/PTFE coating. Full article

(This article belongs to the Special Issue Polymers for Protective Coatings)

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13 pages, 3254 KB

Open AccessEditor’s ChoiceArticle

Surface-Treated MDI-Compatibilized PPC-P/PPC-ECH Film with PVA/Tannic Acid Complex for High-Gas-Barrier Application

by Shuangshuang Yue, Jiangtao Deng, Guoshan He, Wanjuan Wang, Min Xiao, Sheng Huang, Shuanjin Wang, Dongmei Han and Yuezhong Meng

Polymers 2026, 18(4), 520; https://doi.org/10.3390/polym18040520 - 20 Feb 2026

Viewed by 862

Abstract

A novel low-cost poly(propylene carbonate-co-epichlorohydrin) (PPC-ECH) with mechanical properties similar to those of poly (butylene adipate-co-terephthalate) (PBAT) was developed and incorporated into a poly(propylene carbonate-co-phthalate) (PPC-P) matrix. Meanwhile, 4, 4′-diphenylmethane diisocyanate (MDI) was employed as a reactive compatibilizer and mixed with PPC-P and [...] Read more.

A novel low-cost poly(propylene carbonate-co-epichlorohydrin) (PPC-ECH) with mechanical properties similar to those of poly (butylene adipate-co-terephthalate) (PBAT) was developed and incorporated into a poly(propylene carbonate-co-phthalate) (PPC-P) matrix. Meanwhile, 4, 4′-diphenylmethane diisocyanate (MDI) was employed as a reactive compatibilizer and mixed with PPC-P and PPC-ECH to create a variety of PPC-P/PPC-ECH/MDI blends. The effects of PPC-ECH and MDI content on the mechanical, optical, thermal, morphological, and gas barrier properties of the blends were systematically investigated. Results demonstrated that MDI reacts with both PPC-P and PPC-ECH, forming a chemically bonded interface that significantly improves their compatibility. Notably, when 2 phr of MDI was incorporated, the elongation at break of the PPC-P/PPC-ECH/2MDI blend increased dramatically from 71% to 502%, while maintaining good tensile strength (~23 MPa) and light transmittance (~80%). To further enhance the gas barrier performance, a high-oxygen-barrier poly(vinyl alcohol) (PVA)/tannic acid (TA) complex coating was applied to the surface of the PPC-P/PPC-ECH/2MDI film. This coating synergistically leveraged the abundant hydroxyl groups in PVA and TA to form a dense hydrogen-bonded network, reducing oxygen permeability to an ultra-low value of 0.1 cm³·mm/(m²·day). This outstanding performance highlights the strong potential of PPC-P/PPC-ECH-based films for advanced packaging applications. Full article

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

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21 pages, 3905 KB

Open AccessEditor’s ChoiceReview

Molecular Doping Mechanisms and Rational Molecular Design Strategies for High Doping Efficiency

by Hyojin Kye, Min Seon Kim and Bong-Gi Kim

Polymers 2026, 18(4), 501; https://doi.org/10.3390/polym18040501 - 17 Feb 2026

Cited by 2 | Viewed by 1323

Abstract

This review provides a comprehensive overview of molecular doping in organic semiconductors (OSCs), with particular emphasis on the mechanistic understanding of doping processes, rational material design strategies, and processing approaches for achieving high doping efficiency and stability. We discuss fundamental doping mechanisms, including [...] Read more.

This review provides a comprehensive overview of molecular doping in organic semiconductors (OSCs), with particular emphasis on the mechanistic understanding of doping processes, rational material design strategies, and processing approaches for achieving high doping efficiency and stability. We discuss fundamental doping mechanisms, including integer charge transfer and orbital hybridization models, and highlight how molecular structure, polymer design, and dopant–host interactions influence electrical performance. Recent advances in processing strategies—such as sequential, vapor-phase, and hybrid doping methods—are also summarized in relation to microstructural control and charge transport optimization. In addition, the implications of molecular doping for emerging organic thermoelectric applications are addressed, emphasizing the interplay between dopant distribution, morphology, and device performance. By integrating mechanistic insights, material design principles, and application perspectives, this review aims to provide a unified framework for researchers in organic electronics, materials science, and thermoelectric device engineering seeking to develop highly efficient and stable molecularly doped organic conductors. Full article

(This article belongs to the Special Issue Advanced Polymers for Harnessing Power and Energy)

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16 pages, 2643 KB

Open AccessEditor’s ChoiceArticle

Hydrophobic Fibers with Hydrophilic Domains for Enhanced Fog Water Harvesting

by Joanna Knapczyk-Korczak, Katarzyna Marszalik, Marcin Gajek and Urszula Stachewicz

Polymers 2026, 18(3), 425; https://doi.org/10.3390/polym18030425 - 6 Feb 2026

Viewed by 1727

Abstract

Fog water collectors (FWCs) present a sustainable solution for arid regions where fog is a primary water source. To improve their efficiency, we developed a durable and high-performance mesh composed of electrospun hydrophobic thermoplastic polyurethane (TPU) fibers combined with hydrophilic cellulose acetate (CA) [...] Read more.

Fog water collectors (FWCs) present a sustainable solution for arid regions where fog is a primary water source. To improve their efficiency, we developed a durable and high-performance mesh composed of electrospun hydrophobic thermoplastic polyurethane (TPU) fibers combined with hydrophilic cellulose acetate (CA) microbeads. This hybrid design represents a novel biomimetic strategy, mimicking natural fog-harvesting mechanisms by optimizing wetting and drainage. Despite the significant reduction in average fiber diameter, the TPU-CA mesh maintained mechanical strength close to 1 MPa, comparable to pristine TPU. The introduction of hydrophilic domains into a hydrophobic fibrous network is a unique architectural approach that enhanced fog collection performance, achieving a high water harvesting rate of 127 ± 12 mg·cm⁻²·h⁻¹. Remarkably, although the mesh remained predominantly hydrophobic, droplets shed completely from its vertical surface, exhibiting near-zero contact angle hysteresis. This synergistic wetting concept enables performance unattainable with conventional single-wettability meshes. Compared to single-material meshes, the TPU-CA hybrid showed nearly double the water collection efficiency. The innovative interplay between surface chemistry, microscale heterogeneity, and mechanical robustness is key to maximizing water capture and transport, offering a promising path for scalable, efficient FWCs in poor water-stressed regions. Full article

(This article belongs to the Special Issue Synthesis, Production and Applications of Cellulose)

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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

Cited by 1 | Viewed by 646

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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11 pages, 1238 KB

Open AccessEditor’s ChoiceArticle

Advanced Green Materials: Sustainable Cellulose–Lignin Composite Films Prepared via Ionic Liquid Processing

by Witold Madaj, Michał Puchalski, Konrad Sulak, Dariusz Wawro and Ewelina Pabjańczyk-Wlazło

Polymers 2026, 18(2), 211; https://doi.org/10.3390/polym18020211 - 13 Jan 2026

Viewed by 2197

Abstract

The article presents the preparation method of a green composite material composed of cellulose and lignin using an ionic liquid as a solvent. In the process, cellulose and lignin are dissolved in the ionic liquid and subsequently regenerated into a composite film via [...] Read more.

The article presents the preparation method of a green composite material composed of cellulose and lignin using an ionic liquid as a solvent. In the process, cellulose and lignin are dissolved in the ionic liquid and subsequently regenerated into a composite film via coagulation in ethanol/water bath. The research focused on evaluating the mechanical properties of the resulting composite, which exhibited a high tensile strength exceeding 100 MPa, demonstrating its robustness and potential for various applications. Importantly, the simultaneous integration of lignin enabled a favorable balance between high mechanical strength and enhanced biodegradability, addressing a common trade-off in sustainable materials. Additionally, the biodegradation behavior of the composite in soil was investigated, showing that it gradually decomposes, making it environmentally friendly. Toxicity tests on soil bacteria indicated that the composite does not adversely affect microbial activity, supporting its suitability for ecological use. Furthermore, the gas permeability and water vapor transmission of the composite film was assessed, providing insight into its barrier properties. Overall, the study highlights the potential of cellulose-lignin composites produced via ionic liquids as sustainable and biodegradable materials with promising mechanical and environmental properties. Full article

(This article belongs to the Special Issue Cellulose and Its Composites: Preparation and Applications)

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21 pages, 974 KB

Open AccessEditor’s ChoiceReview

Natural Deep Eutectic Solvents for PHB Recovery: Mechanistic Insights and Implications for Sustainable Downstream Processing

by Antonio Zuorro, Roberto Lavecchia, Jefferson E. Contreras-Ropero, Janet B. García-Martínez and Andrés F. Barajas-Solano

Polymers 2026, 18(2), 169; https://doi.org/10.3390/polym18020169 - 8 Jan 2026

Cited by 5 | Viewed by 2584

Abstract

The growing concern over plastic pollution and the widespread presence of micro- and nanoplastics has renewed interest in polyhydroxybutyrate (PHB) as a biodegradable alternative; however, its industrial deployment remains constrained by costly recovery operations with a high environmental burden. This study examines how [...] Read more.

The growing concern over plastic pollution and the widespread presence of micro- and nanoplastics has renewed interest in polyhydroxybutyrate (PHB) as a biodegradable alternative; however, its industrial deployment remains constrained by costly recovery operations with a high environmental burden. This study examines how PHB biosynthesis and intracellular organization, physicochemical properties, and the characteristics of the producing microorganism influence the performance of conventional recovery routes, including extraction with organic solvents, alkaline/oxidative chemical digestion, and enzymatic–physical schemes coupled with mechanical disruption. Based on this foundation, quantitative data are analyzed for PHB content in bacteria, mixed microbial cultures, cyanobacteria, and microalgae, along with extraction yields, polymer purity, and solvent recyclability in processes employing chlorine-free solvents, green solvents, and hydrophobic natural deep eutectic solvents (NaDESs) formulated with terpenes and organic acids. The analysis integrates mechanistic perspectives on NaDES–cell and NaDES–PHB interactions with solvent design criteria, biorefinery configurations, and preliminary evidence from technoeconomic and life cycle assessments. The findings identify NaDES as an up-and-coming platform capable of reconciling biopolymer quality with the principles of green chemistry while delineating critical gaps in recovery efficiency, viscosity management, solvent recycling, and pilot-scale validation. Full article

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

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20 pages, 5622 KB

Open AccessEditor’s ChoiceArticle

Kraft Lignin-Based Polyurethane with GVL: A Sustainable Coating Alternative for Recycled Linerboard

by Julia C. Figueiredo, Roberto C. C. Lelis, Rosane N. Castro, Fernando J. B. Gomes, Ericka F. A. Redmond and Biljana M. Bujanovic

Polymers 2026, 18(1), 118; https://doi.org/10.3390/polym18010118 - 31 Dec 2025

Cited by 2 | Viewed by 1715

Abstract

Food packaging is the largest segment of the global plastics market, yet its low degradability and limited performance in preserving perishable goods highlight the need for more sustainable alternatives. This study investigates the use of industrial softwood kraft lignin, a renewable polyol, and [...] Read more.

Food packaging is the largest segment of the global plastics market, yet its low degradability and limited performance in preserving perishable goods highlight the need for more sustainable alternatives. This study investigates the use of industrial softwood kraft lignin, a renewable polyol, and γ-valerolactone (GVL), an excellent green lignin solvent, to synthesize bio-based polyurethane (PU) coatings for recycled linerboard. PU was synthesized with hexamethylene diisocyanate (HDI), GVL, and 1,4-diazabicyclo[2.2.2]octane (DABCO) as a catalyst and applied to recycled linerboard (166.6 g/m²) at three coating weights: 13.5, 16.5, and 23.5 g/m². The coating enhanced water resistance, as shown by the reduced water vapor transmission rate (WVTR) and Cobb₁₈₀₀ values. Oil resistance was also significantly improved, reaching a Kit rating of 11 at the highest coating weight. Mechanical performance was maintained or enhanced, with increases in ring crush strength (RCT) and tensile index. These findings confirm the effectiveness of lignin-based PU in improving both the barrier and mechanical properties of packaging paper. Additionally, this approach presents an environmentally responsible alternative to petroleum-based coatings, adding value to lignin as a byproduct of the pulp and paper industry and supporting the transition toward more circular and sustainable packaging materials. Full article

(This article belongs to the Special Issue Lignin-Based Polymers)

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12 pages, 2410 KB

Open AccessEditor’s ChoiceArticle

Modulating Cell–Scaffold Interaction via dECM-Decorated Melt Electrowriting PCL Scaffolds

by Wenchao Li, Xiang Gao and Peng Zhang

Polymers 2025, 17(23), 3133; https://doi.org/10.3390/polym17233133 - 25 Nov 2025

Cited by 2 | Viewed by 3053

Abstract

Aligned fibrous scaffolds are essential for directing soft-tissue regeneration, yet synthetic polymers lack native biochemical cues. To bridge this gap, bioactive and anisotropic scaffolds were developed by combining melt electrowriting (MEW) with decellularized extracellular matrix (dECM) decoration to enhance cell–scaffold interactions for soft [...] Read more.

Aligned fibrous scaffolds are essential for directing soft-tissue regeneration, yet synthetic polymers lack native biochemical cues. To bridge this gap, bioactive and anisotropic scaffolds were developed by combining melt electrowriting (MEW) with decellularized extracellular matrix (dECM) decoration to enhance cell–scaffold interactions for soft tissue engineering. Porous polycaprolactone (PCL) scaffolds with aligned microfibers and tunable pore architectures (aspect ratios 1:1, 1:2, and 1:3) were fabricated via MEW and subsequently coated with porcine skeletal muscle dECM using a dip-gelation method. Comprehensive surface characterization confirmed the presence and robust adhesion of the dECM coating on the PCL scaffolds, which concurrently enhanced surface hydrophilicity. Furthermore, mechanical testing demonstrated that the resulting composite scaffold retained the structural integrity required to meet the mechanical demands of tissue regeneration. In vitro studies using L929 fibroblasts demonstrated that dECM decoration significantly improved cell adhesion, proliferation, and alignment along the fiber direction. Notably, scaffolds with 1:1 and 1:2 aspect ratios supported the highest cell density and guided morphological elongation most effectively. These findings highlight the synergistic potential of topographical cues and biochemical signaling in scaffold design for functional tissue regeneration. Full article

(This article belongs to the Special Issue Advanced Polymeric Composites in Dentistry: Synthesis, Properties and Applications)

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15 pages, 604 KB

Open AccessEditor’s ChoiceArticle

Influence of the Resin Matrix Phase on the Fatigue Resistance of Model Dental Composite Resins

by Diana Leyva del Rio and Robert R. Seghi

Polymers 2025, 17(23), 3118; https://doi.org/10.3390/polym17233118 - 24 Nov 2025

Cited by 2 | Viewed by 1198

Abstract

This study aimed to assess how different resin matrix formulations affect the fatigue resistance of resin dental composites. Model dental composites were formulated using six distinct monomer mixtures: two Bis-GMA (bisphenol A-glycidyl methacrylate):TEGDMA (triethylene glycol dimethacrylate) (60:40 and 80:20 mole%), two UDMA (urethane [...] Read more.

This study aimed to assess how different resin matrix formulations affect the fatigue resistance of resin dental composites. Model dental composites were formulated using six distinct monomer mixtures: two Bis-GMA (bisphenol A-glycidyl methacrylate):TEGDMA (triethylene glycol dimethacrylate) (60:40 and 80:20 mole%), two UDMA (urethane dimethacrylate):TEGDMA (60:40 and 80:20 mole%), one Bis-GMA:UDMA:TEGDMA (35:35:30 mole%), and one Fit852:UDMA:TEGDMA (35:35:30 mole%). Cyclic fatigue resistance (CFR) of the resin composites was measured in a biaxial test mode using staircase analysis. Additional evaluations included biaxial flexural strength (BFS), degree of conversion (DC), water sorption (WS), and viscoelastic properties of the unfilled resins, such as the storage modulus (E′), loss modulus (E″), tan δ (E″/E′), and stiffness (k′). Data were subjected to one-way ANOVA with Tukey post hoc analyses. Pearson correlation and stepwise regression analyses were conducted to examine the relationships among variables. The UT6040 model composite exhibited the highest CFR (82.61 ± 8.83 MPa), significantly outperforming other formulations. Tan δ of the resin matrix showed the strongest correlation with CFR (r = 0.974), and was also shown to be the most influential predictor for the CFR of the particulate composites. The composition of the resin matrix has a significant impact on the CFR of dental composites. Among the properties evaluated, the viscoelastic parameter tan δ emerged as a strong and reliable predictor of CFR, emphasizing the importance of targeting viscoelastic behavior in the design of dental composite formulations. Full article

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

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19 pages, 6379 KB

Open AccessEditor’s ChoiceArticle

Ionic Conductive Hydrogels with Choline Salt for Potential Use in Electrochemical Capacitors

by Jan Malczak, Wiktoria Żyła, Piotr Gajewski, Katarzyna Szcześniak, Łukasz Popenda and Agnieszka Marcinkowska

Polymers 2025, 17(22), 3030; https://doi.org/10.3390/polym17223030 - 14 Nov 2025

Cited by 2 | Viewed by 1770

Abstract

Choline salts represent sustainable and safe electrolyte systems. In this study, an aqueous 1 M choline nitrate solution was employed to prepare hydrogel polymer electrolytes (HPE) via in situ photopolymerization. To enhance compatibility between the electrolyte and polymer matrix, choline methacrylate was synthesized [...] Read more.

Choline salts represent sustainable and safe electrolyte systems. In this study, an aqueous 1 M choline nitrate solution was employed to prepare hydrogel polymer electrolytes (HPE) via in situ photopolymerization. To enhance compatibility between the electrolyte and polymer matrix, choline methacrylate was synthesized and used as a functional monomer alongside HEMA and PEGDA. The photocurable formulation contained 70 wt.% electrolyte and 30 wt.% monomer mixture. Subsequent electrolyte uptake increased the electrolyte fraction in the HPE to 87 wt.%. The use of choline methacrylate enabled the formation of transparent HPE with favorable mechanical performance, showing puncture resistance of 0.33 N and 0.28 N at elongations of 7.9 mm and 4.4 mm for samples with 70 and 87 wt.% electrolyte, respectively. High ionic conductivity was achieved, reaching ~18 mS/cm and ~34 mS/cm for HPE with 70 and 87 wt.% electrolyte. Finally, a capacitor assembled with HPE containing 87 wt.% electrolyte demonstrated good operational parameters, confirming the applicability of this system in energy storage devices. This work highlights the potential of choline-based electrolytes and polymerizable choline derivatives as functional components for the design of efficient, safe, and environmentally friendly gel polymer electrolytes. Full article

(This article belongs to the Special Issue Active Polymeric Materials for Electrochemical Applications)

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24 pages, 8615 KB

Open AccessEditor’s ChoiceArticle

Xylitol Modification of Electrospun Polymer Scaffolds: Impact on Physicochemical and Antibacterial Properties

by Francesco Boschetto, Matteo Zanocco, Kaeko Kamei, Huaizhong Xu and Elia Marin

Polymers 2025, 17(22), 3024; https://doi.org/10.3390/polym17223024 - 14 Nov 2025

Cited by 1 | Viewed by 1440

Abstract

Electrospun fibrous scaffolds based on cellulose acetate (CA), polycaprolactone (PCL), and poly (L-lactic acid) (PLLA) are versatile materials with applications spanning diverse fields, but in their pristine form, they typically lack significant inherent antibacterial properties. To address this limitation and expand their utility, [...] Read more.

Electrospun fibrous scaffolds based on cellulose acetate (CA), polycaprolactone (PCL), and poly (L-lactic acid) (PLLA) are versatile materials with applications spanning diverse fields, but in their pristine form, they typically lack significant inherent antibacterial properties. To address this limitation and expand their utility, this study explored the incorporation of xylitol, a natural antibacterial sugar alcohol, into these polymer matrices to enhance their physicochemical and antimicrobial properties. Electrospinning was employed to fabricate pristine and xylitol-loaded scaffolds with varying xylitol concentrations. Morphological analysis revealed polymer-dependent changes in fiber diameter and porosity. Mechanical testing assessed the impact of xylitol on tensile properties, while thermal analysis investigated alterations in melting temperature and crystallinity. The antibacterial efficacy against Staphylococcus aureus and Escherichia coli was evaluated using WST assay and live/dead staining. Notably, xylitol significantly enhanced the antibacterial activity against both bacterial species, with a more pronounced and rapid effect observed against S. aureus. The tailored scaffold properties and imparted antimicrobial characteristics highlight the potential of these xylitol-modified electrospun materials: they are easily produced, low-cost, and appropriate for a range of applications (dental applications, filters, masks, wound dressing, and packaging) where preventing bacterial contamination is crucial. Full article

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

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15 pages, 4576 KB

Open AccessEditor’s ChoiceArticle

Impedance-Matched Iron-Added Polymeric Composite Film Incorporated with Iron Nanowire for Electromagnetic Absorption Application

by Yuh-Jing Chiou, Pei-Jung Chang, Pei-Ru Su, Sheng-Jung Tsou and Chung-Kwei Lin

Polymers 2025, 17(21), 2965; https://doi.org/10.3390/polym17212965 - 6 Nov 2025

Cited by 1 | Viewed by 1376

Abstract

Salisbury screen-type radar absorption structures (RASs) consisting of a resistance sheet, a spacer, and a conductive base provide an efficient method for microwave absorption. An impedance-matched resistance sheet allows microwaves to enter, whereas superior microwave absorbers enhance their performance further. In the present [...] Read more.

Salisbury screen-type radar absorption structures (RASs) consisting of a resistance sheet, a spacer, and a conductive base provide an efficient method for microwave absorption. An impedance-matched resistance sheet allows microwaves to enter, whereas superior microwave absorbers enhance their performance further. In the present work, an impedance matching composite film was prepared by using polymer/iron/iron nanowires. By varying the polymer, poly (methyl methacrylate) (PMMA), poly (vinylidene fluoride) (PVDF), and poly (vinyl alcohol) (PVA), to iron powder ratios (1:1, 2:1, and 4:1), composite films were synthesized and examined by scanning electron microscopy, X-ray diffraction, and the four-point probe method to determine the materials’ characteristics. An impedance-matched composite film was prepared based on the selected composition with 1–10 wt.% iron nanowire additions. Experimental results showed that the polymeric composite film prepared by a ratio of iron-PVA of 4:1 exhibited a sheet resistance of 49 ± 9.7 Ω/sq due to well dispersion of iron powder in PVA. With 1 wt.% Fe nanowire addition, the optimal composite sheet resistance was 329.7 ± 45.3 Ω/sq, which corresponded to an impedance matching degree (i.e., |Z_in/Z₀| value) of 0.88 ± 0.12 and can be used as a resistance sheet for a Salisbury screen-type absorber in RAS applications. Full article

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

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17 pages, 10249 KB

Open AccessEditor’s ChoiceArticle

Mater-Bi-Based Biocomposites Reinforced with Lemongrass: A Comparison Between Leaf- and Culm-Derived Particles

by Manuela Ceraulo, Luigi Botta, Carmelo Sanfilippo, Sanjay Mavinkere Rangappa, Suchart Siengchin and Vincenzo Fiore

Polymers 2025, 17(21), 2909; https://doi.org/10.3390/polym17212909 - 30 Oct 2025

Cited by 1 | Viewed by 1022

Abstract

In this study, aiming to develop novel biocomposites that offer competitive properties while retaining their renewable and biodegradable characteristics, a biodegradable polymer matrix (Mater-Bi^® HF51L2) was reinforced with natural particles extracted from the culm and leaf of Cymbopogon flexuosus (lemongrass). Particles (<500 [...] Read more.

In this study, aiming to develop novel biocomposites that offer competitive properties while retaining their renewable and biodegradable characteristics, a biodegradable polymer matrix (Mater-Bi^® HF51L2) was reinforced with natural particles extracted from the culm and leaf of Cymbopogon flexuosus (lemongrass). Particles (<500 µm) were incorporated at 10 and 20 wt.% via twin-screw extrusion followed by compression moulding. Morphological analysis via SEM revealed distinct structural differences between culm- and leaf-derived particles, with the latter exhibiting smoother surfaces, higher density, and better dispersion in the matrix, resulting in lower void content. Quasi-static mechanical tests showed increased stiffness with filler content, particularly for leaf-based composites. This material, at 20 wt.% filler loadings, enhanced the tensile and flexural moduli of the neat Mater-Bi approximately three and two times, respectively, a result attributed to enhanced interfacial adhesion. Rheological measurements (rotational and capillary) indicated significant increases in complex viscosity, particularly for leaf-filled systems, confirming restricted polymer chain mobility and good matrix–filler interaction. Dynamic mechanical thermal tests (DMTA) results showed an increased storage modulus and a shift in glass transition temperature (T_g) for all biocomposites in comparison to Mater-Bi matrix. Specifically, the neat matrix had a T_g of −28 °C, which increased to −24 °C and −18 °C for the 20 wt.% culm-reinforced and leaf-reinforced biocomposites, respectively. Overall, the leaf-derived particles demonstrated superior reinforcing potential, effectively improving the mechanical, rheological, and thermal properties of Mater-Bi-based biocomposites. Full article

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

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17 pages, 2578 KB

Open AccessEditor’s ChoiceArticle

Comparing the Printability, Biological and Physicochemical Properties of Bio-Based Photo-Crosslinkable Hydrogels

by Ane García-García, Unai Silván, Leyre Pérez-Álvarez and Senentxu Lanceros

Polymers 2025, 17(21), 2867; https://doi.org/10.3390/polym17212867 - 28 Oct 2025

Cited by 4 | Viewed by 1700

Abstract

Bio-based photo-crosslinkable hydrogels are used in tissue engineering as three-dimensional printable scaffolds due to their functional and biological similarities with the extracellular matrix (ECM). In this work, emerging bioink candidates such as chitosan, alginate and gelatin-based photo-crosslinkable hydrogel were developed using extrusion-based 3D [...] Read more.

Bio-based photo-crosslinkable hydrogels are used in tissue engineering as three-dimensional printable scaffolds due to their functional and biological similarities with the extracellular matrix (ECM). In this work, emerging bioink candidates such as chitosan, alginate and gelatin-based photo-crosslinkable hydrogel were developed using extrusion-based 3D printing to establish a better understanding of their applicability. The polymers were methacrylated by the same methacrylation reaction pathway, which enabled successful light-induced 3D printing. Morphology, swelling (6–40%), mechanical (Young’s modulus, 0.1–0.5 KPa) and rheological properties (300–1000 Pa), degradation kinetics (10->60 days) and printability of the gels were also characterized in identical conditions for the first time. 3D-printability results indicated that methacrylated gelatin enhanced printability, shape fidelity and integrity of printed structures compared to methacrylated alginate, which presents structural instability and poorer printing control due to its low crosslink density. Moreover, cell attachment and Live/Dead assays using bone marrow-derived mesenchymal stem cells (BM-MSCs) showed that all formulations have good biocompatibility for use as scaffolds. Specifically, gelatin-based hydrogels showed a higher level of BM-MSCs attachment and spreading than the other types of hydrogels. Overall, our results suggest that the hydrogels based on these three biopolymers present good potential as a biomaterial for light-induced extrusion-based 3D printing. Full article

(This article belongs to the Special Issue Advances in Sustainable Polymeric Materials, 3rd Edition)

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14 pages, 5797 KB

Open AccessEditor’s ChoiceArticle

Investigation of Blade Printing Technique for Nano-Structuring Piezoelectric Polymer Ink in a Porous Anodic Aluminum Oxide

by Tsvetozar Tsanev and Mariya Aleksandrova

Polymers 2025, 17(21), 2839; https://doi.org/10.3390/polym17212839 - 24 Oct 2025

Viewed by 1004

Abstract

In this work, we investigated the use of a piezoelectric flexible device for energy harvesting. The main goal of the study was to fill the nanostructured pores of anodic aluminum oxide (AAO) films with piezoelectric polymer (PVDF-TrFE) via a modified conventional screen printing [...] Read more.

In this work, we investigated the use of a piezoelectric flexible device for energy harvesting. The main goal of the study was to fill the nanostructured pores of anodic aluminum oxide (AAO) films with piezoelectric polymer (PVDF-TrFE) via a modified conventional screen printing technique using blade printing. In this way, it is possible to obtain a composite from nanostructured thin films of polymer nanorods that shows improved charge generation ability compared to other non-nanostructured composites or pure (non-composite) aluminum with similar dimensions. This behavior is due to the effect of the highly developed surface of the material used to fill in the AAO nanopore template and its ability to withstand the application of higher mechanical loads to the structured piezoelectric material during deformation. The contact blade print filling technique can produce nanostructured piezoelectric polymer films with precise geometric parameters in terms of thickness and nanorod diameters, at around 200 nm, and a length of 12 μm. At a low frequency of 17 Hz, the highest root-mean-square (RMS) voltage generated using the nanostructured AAO/PVDF-TrFE sample with aluminum electrodes was around 395 mV. At high frequencies above 1700 Hz, the highest RMS voltage generated using the nanostructured AAO/PVDF-TrFE sample with gold electrodes was around 680 mV. The RMS voltage generated using a uniform (non-nanostructured) layer of PVDF-TrFE was 15% lower across the whole frequency range. Full article

(This article belongs to the Special Issue Advanced Polymers for Harnessing Power and Energy)

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25 pages, 1716 KB

Open AccessEditor’s ChoiceReview

Sustainable Valorisation of End-of-Life Tyres Through Pyrolysis-Derived Recovered Carbon Black in Polymer Composites

by Dharanija Banala, Ylias Sabri, Namita Roy Choudhury and Rajarathinam Parthasarathy

Polymers 2025, 17(20), 2771; https://doi.org/10.3390/polym17202771 - 16 Oct 2025

Cited by 8 | Viewed by 5406

Abstract

More than one billion end-of-life tyres (EOLTs) are produced worldwide every year, and this is continuously increasing and has become an issue in sustainable development. This review discusses recent developments in the management of EOLTs and focuses on pyrolysis, which produces valuable tyre-derived [...] Read more.

More than one billion end-of-life tyres (EOLTs) are produced worldwide every year, and this is continuously increasing and has become an issue in sustainable development. This review discusses recent developments in the management of EOLTs and focuses on pyrolysis, which produces valuable tyre-derived products (TDPs) like steel, gas, oil, and char. This review focuses on recovered carbon black (rCB), a refined char with great potential as a sustainable alternative to commercial carbon black (CB). The review introduces a novel classification system for CB, virgin carbon black (vCB), recovered carbon black (rCB), and sustainable carbon black (sCB) to guide the transition toward environmentally friendly materials. It also examines how rCB enhances polymer properties for addressing price volatility and reducing carbon footprint. Additionally, a SWOT analysis evaluates the strengths (cost-effectiveness, reduced environmental impact), weaknesses (quality consistency), opportunities (emerging markets, circular economy integration), and threats (competition from virgin materials) of using rCB as a polymer reinforcement. By positioning rCB as a key material, this review outlines pathways for addressing the EOLT crisis and advancing a circular economy. Full article

(This article belongs to the Special Issue Polymer Recycling and Upcycling: Toward a Circular Materials Economy)

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17 pages, 4400 KB

Open AccessEditor’s ChoiceArticle

Advanced Polyamidoamine Hydrogels for the Selective Cleaning of Artifacts in Heritage Conservation

by Elisabetta Ranucci and Jenny Alongi

Polymers 2025, 17(19), 2680; https://doi.org/10.3390/polym17192680 - 3 Oct 2025

Cited by 2 | Viewed by 1314

Abstract

A polyamidoamine-based hydrogel (H-M-GLY) and its montmorillonite-based composite (H-M-GLY/MMT) were studied as selective cleaning materials for cultural heritage conservation. H-M-GLY was synthesized from a glycine-based polyamidoamine oligomer with acrylamide terminals (M-GLY) through radical polymerization at pH 7.3 and had a basic character. The [...] Read more.

A polyamidoamine-based hydrogel (H-M-GLY) and its montmorillonite-based composite (H-M-GLY/MMT) were studied as selective cleaning materials for cultural heritage conservation. H-M-GLY was synthesized from a glycine-based polyamidoamine oligomer with acrylamide terminals (M-GLY) through radical polymerization at pH 7.3 and had a basic character. The M-GLY oligomer was in turn synthesized from N,N′-methylenebisacrylamide and glycine in a 1:0.85 molar ratio. H-M-GLY/MMT was obtained by cross-linking a 1:0.1—weight ratio—M-GLY/MMT mixture at pH 4.0, to promote polyamidoamine-MMT interaction. The composite hydrogel absorbed less water than the plain hydrogel and proved tougher, due to montmorillonite’s electrostatic interactions with the positively charged M-GLY units. Scanning electron microscopic analysis showed that MMT was uniformly dispersed throughout the hydrogel. Both hydrogels were subjected to ink bleeding tests on papers written with either iron gall or India ink. Microscopic observation revealed neither bleeding nor release of hydrogel fragments. Being basic, H-M-GLY successfully deacidified the surface of aged paper. H-M-GLY/MMT, swollen in a 1:9 ethanol/water solution, was found to be effective in removing wax, known to trap carbonaceous particles and form dark stains on artistic artifacts. This study demonstrates the great potential of polyamidoamine-based hydrogels as versatile selective cleaning systems for cellulosic and other cultural heritage materials. Full article

(This article belongs to the Section Polymer Chemistry)

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14 pages, 1429 KB

Open AccessEditor’s ChoiceArticle

Diffusion Behavior of Polyethylene Furanoate (PEF) and Tritan as Sustainable Polyester Packaging Materials

by Frank Welle

Polymers 2025, 17(19), 2674; https://doi.org/10.3390/polym17192674 - 2 Oct 2025

Cited by 2 | Viewed by 2395

Abstract

Polyethylene furanoate (PEF) and Tritan^TM copolyester are sustainable polyester polymers. PEF is made from biobased resources, whereas Tritan is mainly used for reusable food contact articles. Both polyesters are alternatives for polyethylene terephthalate (PET), which is currently the most used polyester in [...] Read more.

Polyethylene furanoate (PEF) and Tritan^TM copolyester are sustainable polyester polymers. PEF is made from biobased resources, whereas Tritan is mainly used for reusable food contact articles. Both polyesters are alternatives for polyethylene terephthalate (PET), which is currently the most used polyester in food packaging. Like all packaging polymers, sustainable alternatives to fossil-based PET must also comply with food law requirements. Prediction of the migration can be used as an alternative to complex and time-consuming experimental migration measurements. Since there are no such predictive models for either PEF or Tritan, the modelling parameters for PEF and Tritan were determined in this study from experimentally determined diffusion coefficients and activation energies. The diffusivity of PEF and Tritan was compared with PET and polyethylene naphthalate (PEN). Of the four polyester polymers, PEF shows the lowest diffusion, followed by PEN, PET, and Tritan. Overall, the results show that the investigated polyesters are low-diffusivity polymers. Full article

(This article belongs to the Section Polymer Applications)

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12 pages, 717 KB

Open AccessEditor’s ChoiceArticle

Molecular Properties of Starch–Water Interactions in the Presence of Bioactive Compounds from Barley and Buckwheat—LF NMR Preliminary Study

by Greta Adamczyk, Łukasz Masewicz, Krzysztof Przybył, Aleksandra Zaryczniak, Przemysław Łukasz Kowalczewski, Monika Beszterda-Buszczak, Wojciech Cichocki and Hanna Maria Baranowska

Polymers 2025, 17(19), 2606; https://doi.org/10.3390/polym17192606 - 26 Sep 2025

Cited by 4 | Viewed by 1485

Abstract

The retrogradation of starch strongly influences the texture and stability of starchy foods. This study applied low-field nuclear magnetic resonance (LF NMR) to examine the effect of buckwheat hull (BH) fiber and green barley (GB) on water dynamics in normal (NPS) and waxy [...] Read more.

The retrogradation of starch strongly influences the texture and stability of starchy foods. This study applied low-field nuclear magnetic resonance (LF NMR) to examine the effect of buckwheat hull (BH) fiber and green barley (GB) on water dynamics in normal (NPS) and waxy (WPS) potato starch gels. Relaxation times (T₁, T₂) and mean correlation times (τ_c) were monitored during 15 days of storage to evaluate changes in water mobility and starch–polymer interactions. Results showed that WPS, with its high amylopectin content, retrograded earlier than NPS. The addition of BH inhibited conformational changes associated with water binding in WPS gels, indicating that insoluble fiber entrapped water within the amylopectin network. Conversely, GB promoted higher τ_c values in WPS, reflecting enhanced ordering and reduced water mobility, while its impact on NPS was minor. In NPS systems, BH decreased τ_c, suggesting disruption of amylose-driven structural reorganization. These findings demonstrate that BH and GB exert opposite effects on starch retrogradation and highlight their potential as functional additives for tailoring texture and stability in starch-based food systems. Full article

(This article belongs to the Special Issue Advanced Spectroscopy for Polymers: Design and Characterization)

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17 pages, 3397 KB

Open AccessEditor’s ChoiceArticle

Preparation and Performance of Poly(Butylene Succinate) (PBS) Composites Reinforced with Taxus Residue and Compatibilized with Branched PBS

by Shiwanyi Chen, Shufeng Li, Bing Wang, Chen Chen and Liuchun Zheng

Polymers 2025, 17(19), 2597; https://doi.org/10.3390/polym17192597 - 25 Sep 2025

Cited by 7 | Viewed by 2797

Abstract

In response to the escalating plastic pollution crisis, the development of high-performance biodegradable materials is critical. Poly(butylene succinate) (PBS) is an important biodegradable polymer as it possesses excellent biodegradability and processability. But it suffers from limitations such as low mechanical strength, poor thermal [...] Read more.

In response to the escalating plastic pollution crisis, the development of high-performance biodegradable materials is critical. Poly(butylene succinate) (PBS) is an important biodegradable polymer as it possesses excellent biodegradability and processability. But it suffers from limitations such as low mechanical strength, poor thermal stability, and high production costs. In this study, taxus residue (TF), a waste by-product, was utilized as a reinforcing filler to reduce PBS costs while enhancing its overall performance. To address the interfacial incompatibility between TF and PBS, branched PBS (T-PBS) was introduced as a compatibilizer. The TF was surface-modified via alkali treatment and silane coupling (KH550), and a series of PBS/TF/T-PBS composites with varying T-PBS viscosity grades were prepared by melt blending. The compatibilization mechanism of T-PBS and its influence on the composite structure, crystallization behavior, thermal stability, rheological, and mechanical properties were systematically investigated. Results show that the branched structure significantly enhanced T-PBS melt strength and reactivity. The introduction of T-PBS effectively improved interfacial compatibility between TF and PBS matrix, reducing phase separation and interfacial defects. Compared to uncompatibilized PBS/TF composites, those with appropriately viscous T-PBS exhibited improved tensile strength (increased by 19.7%) and elongation at break (increased by 78.8%), while flexural strength was also maintained at an enhanced level. The branched points acted as nucleating agents, increasing the onset temperature and degree of crystallinity. In the high-temperature region, the synergistic barrier effect from TF and char residue improved thermal stability (T_85% reached 408.19 °C). Rheological analysis revealed enhanced viscosity and elasticity of the system. This study provides a promising strategy and theoretical foundation for the high-value utilization of taxus waste and the development of high-performance biodegradable PBS-based composites. Full article

(This article belongs to the Special Issue Advancing Polyester: Novel Approaches and Applications in Materials Science)

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14 pages, 4453 KB

Open AccessEditor’s ChoiceArticle

Two-Component Response Regulators CitT, YvcP, and YycI Differentially Control Pectin and Hemicellulose Degradation in Degumming of Ramie Fibers by Bacillus subtilis Strain 168

by Qi Yang, Shihang Ma, Lifeng Cheng, Xiang Zhou, Guoguo Xi, Chen Chen, Zhenghong Peng, Yuqin Hu, Si Tan and Shengwen Duan

Polymers 2025, 17(18), 2473; https://doi.org/10.3390/polym17182473 - 12 Sep 2025

Cited by 1 | Viewed by 1026

Abstract

Exploring the metabolic regulatory mechanisms of bacteria for ramie degumming and constructing more efficient engineered strains are preferred strategies to solve the technical bottleneck of high residual gum content in fibers. Bacillus subtilis strain 168, an advantageous bacterium for microbial degumming, was previously [...] Read more.

Exploring the metabolic regulatory mechanisms of bacteria for ramie degumming and constructing more efficient engineered strains are preferred strategies to solve the technical bottleneck of high residual gum content in fibers. Bacillus subtilis strain 168, an advantageous bacterium for microbial degumming, was previously found to significantly up-regulate the expression of bast two-component system (TCS) response regulators CitT, YvcP, and YycI when using ramie as the sole carbon source. In this study, the genes encoding CitT, YvcP, and YycI proteins were knocked out and compared the effects between these gene knockouts and the original strain on the degumming efficiency. The aim was to identify the key TCS response regulators that significantly affect degumming efficiency and to explore the functions of these different response regulators. The results demonstrated that knockout of citT, yvcP, or yycI genes significantly reduced degumming efficiency. Specifically, CitT protein primarily regulated the degradation of pectin, YvcP protein mainly regulated the degradation of hemicellulose, and YycI protein was involved in the regulation of both pectin and hemicellulose degradation. Notably, the absence of CitT protein caused the most significant reduction in degumming efficiency. These findings provide valuable insights into the construction of engineered strains with high degumming efficiency for ramie fibers. Full article

(This article belongs to the Special Issue Application and Characterization of Cellulose-Based Polymers)

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19 pages, 3468 KB

Open AccessEditor’s ChoiceArticle

Density-Based Topology-Optimized 3D-Printed Fixtures for Cyclic Mechanical Testing of Lattice Structures

by Josué Castro, Rodrigo Valle, Jorge Leiva, Angelo Oñate, Enrico Saggionetto, Anne Mertens and Víctor Tuninetti

Polymers 2025, 17(18), 2468; https://doi.org/10.3390/polym17182468 - 12 Sep 2025

Cited by 11 | Viewed by 2672

Abstract

The reliable experimental characterization of architected lattice materials under cyclic loading requires accurate fixture systems that ensure proper load transfer without introducing parasitic effects. This study presents the design and validation of testing fixtures optimized using density-based topological optimization techniques for performing cyclic [...] Read more.

The reliable experimental characterization of architected lattice materials under cyclic loading requires accurate fixture systems that ensure proper load transfer without introducing parasitic effects. This study presents the design and validation of testing fixtures optimized using density-based topological optimization techniques for performing cyclic load tests on lattice structures. The supports were manufactured with PLA filaments and evaluated using finite element simulation and experimental testing. The results show that the final design achieved a safety factor of 4.25, significantly improving on the initial value of 2.08. Likewise, the optimized supports showed reduced deformations by around 80% compared to the machine clamps, ensuring rigid and reliable stress transfer. In particular, while the metal structure of the test system showed deformations of several millimeters, the optimized PLA supports recorded displacements around 0.73 mm, confirming that they remain virtually rigid and ensure correct transmission of forces to the Kelvin-type structure. These findings confirm the viability of using PLA as an alternative to conventional metal devices in fixtures for mechanical testing of lattice materials. Full article

(This article belongs to the Special Issue High-Performance Polymer Materials and Fiber-Reinforced Composites for Engineering Applications)

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24 pages, 4305 KB

Open AccessEditor’s ChoiceArticle

Driving the Green Transition: Innovative Tyre Formulation Using Agricultural and Pyrolysed Tyres Waste

by Carlo Di Bernardo, Francesca Demichelis, Mehran Dadkhah, Debora Fino, Massimo Messori and Camilla Noè

Polymers 2025, 17(17), 2275; https://doi.org/10.3390/polym17172275 - 22 Aug 2025

Cited by 2 | Viewed by 2151

Abstract

The rubber industry is facing increasing pressure to adopt sustainable practices due to environmental concerns associated with the use of non-renewable resources and the growing accumulation of waste tyres and agricultural byproducts. This study explores the potential of partially replacing conventional carbon black [...] Read more.

The rubber industry is facing increasing pressure to adopt sustainable practices due to environmental concerns associated with the use of non-renewable resources and the growing accumulation of waste tyres and agricultural byproducts. This study explores the potential of partially replacing conventional carbon black (CB) with sustainable alternatives derived from agricultural waste (wine by-products) and pyrolysed waste tyres in natural rubber/styrene-butadiene rubber (NR/SBR) composites for tyre applications. A series of NR/SBR composites were formulated with varying ratios of CB to agricultural waste and pyrolysed tyre waste, while maintaining consistent levels of other additives. The resulting composites were then subjected to a comprehensive suite of analyses, including scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area measurements, Fourier transform infrared spectroscopy (FTIR), bound rubber content determination, Payne effect analysis, thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and mechanical property testing. Furthermore, a Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) analysis were conducted to evaluate the environmental and economic viability of the proposed CB replacements. The results reveal that the incorporation of agricultural waste and pyrolysed tyre waste can significantly impact the curing behaviour, mechanical properties, and thermal stability of rubber composites. Importantly, some of the formulations demonstrate comparable tensile strength, elongation at break, and hardness compared to traditional CB-filled composites. The LCA and LCC analyses further highlight the potential for substantial reductions in greenhouse gas emissions, fossil resource depletion, and overall production costs, thereby supporting the transition toward more sustainable tyre manufacturing practices. Full article

(This article belongs to the Special Issue Sustainable Bio-Based and Circular Polymers and Composites)

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19 pages, 3530 KB

Open AccessEditor’s ChoiceReview

Direct Analysis of Solid-Phase Carbohydrate Polymers by Infrared Multiphoton Dissociation Reaction Combined with Synchrotron Radiation Infrared Microscopy and Electrospray Ionization Mass Spectrometry

by Takayasu Kawasaki, Heishun Zen, Kyoko Nogami, Ken Hayakawa, Takeshi Sakai and Yasushi Hayakawa

Polymers 2025, 17(17), 2273; https://doi.org/10.3390/polym17172273 - 22 Aug 2025

Cited by 1 | Viewed by 1788

Abstract

To determine the structure of carbohydrate polymers using conventional analytical technology, several complicated steps are required. We instead adopted a direct approach without the need for pretreatments, using an intense infrared (IR) laser for carbohydrate analysis. IR free-electron lasers (FELs) driven by a [...] Read more.

To determine the structure of carbohydrate polymers using conventional analytical technology, several complicated steps are required. We instead adopted a direct approach without the need for pretreatments, using an intense infrared (IR) laser for carbohydrate analysis. IR free-electron lasers (FELs) driven by a linear accelerator possess unique spectroscopic features, including extensive wavelength tunability and high laser energy in the IR region from 1000 cm⁻¹ (10 μm) to 4000 cm⁻¹ (2.5 μm). FELs can induce IR multiphoton dissociation reactions against various molecules by supplying vibrational excitation energy to the corresponding chemical bonds. Chitin from crayfish and cellulose fiber were irradiated by FELs tuned to νC–O (9.1–9.8 μm), νC–H (3.5 μm), and δH–C–O (7.2 μm) in glycosidic bonds, and their low-molecular-weight sugars were separated, which were revealed by combining synchrotron radiation IR spectroscopy and electrospray ionization mass spectrometry. An intense IR laser can be viewed as a “molecular scalpel” for dissecting and directly analyzing the internal components in rigid biopolymers. This method is simple and rapid compared with general analytical techniques. Full article

(This article belongs to the Special Issue Advanced Spectroscopy for Polymers: Design and Characterization)

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14 pages, 3778 KB

Open AccessEditor’s ChoiceArticle

A New Recycling Technology to Produce Premixed Thermal Insulating Mortars from Polyurethane Waste Foams

by Antonis Kountouris, Kypros Efstathiou, Nikolaos Kostoglou, Dimitrios Manolakos and Claus Rebholz

Polymers 2025, 17(16), 2233; https://doi.org/10.3390/polym17162233 - 17 Aug 2025

Cited by 3 | Viewed by 2052

Abstract

The increasing demand for sustainable construction materials has driven research into the reuse of plastic waste for renewable building applications. This study introduces a new lightweight insulating mortar for floor and roof systems, utilizing recycled rigid polyurethane (PU) foam as the primary aggregate. [...] Read more.

The increasing demand for sustainable construction materials has driven research into the reuse of plastic waste for renewable building applications. This study introduces a new lightweight insulating mortar for floor and roof systems, utilizing recycled rigid polyurethane (PU) foam as the primary aggregate. The binder mainly consists of Portland cement, with no added sand, and includes minor additives to enhance mechanical, physical, and thermal properties. Initial tests demonstrated that key performance metrics—density, compressive strength, and thermal conductivity—are significantly influenced by the PU content. As the proportion of PU increased, all three parameters decreased. The optimized formulation, comprising 92.25 vol.% PU foam, 6.75 vol.% cement, and 1 vol.% additives, achieved a low bulk density of 420 kg/m³, a compressive strength of 1 MPa, and a thermal conductivity of 0.07 W/m·K. A pilot-scale production system with a capacity of 1500 L/h (equivalent to 20 bags of 75 L) was subsequently designed, implemented, and validated. These findings underscore the potential of PU-based lightweight insulating mortars to reduce environmental impact and support the development of sustainable construction practices globally. Full article

(This article belongs to the Special Issue Sustainable Polymeric Materials in Building and Construction)

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27 pages, 4903 KB

Open AccessEditor’s ChoiceArticle

Biodegradation in Freshwater: Comparison Between Compostable Plastics and Their Biopolymer Matrices

by Valerio Bocci, Martina De Vivo, Sara Alfano, Simona Rossetti, Francesca Di Pippo, Loris Pietrelli and Andrea Martinelli

Polymers 2025, 17(16), 2236; https://doi.org/10.3390/polym17162236 - 17 Aug 2025

Cited by 6 | Viewed by 3094

Abstract

Plastic pollution in freshwater ecosystems is an increasing environmental concern, prompting the search for biodegradable polymer (BP) alternatives. However, their degradation in natural aquatic environments remains poorly investigated and understood. This four-month in situ study compared the degradation in a lentic freshwater ecosystem [...] Read more.

Plastic pollution in freshwater ecosystems is an increasing environmental concern, prompting the search for biodegradable polymer (BP) alternatives. However, their degradation in natural aquatic environments remains poorly investigated and understood. This four-month in situ study compared the degradation in a lentic freshwater ecosystem of two compostable items, Mater-Bi^® shopping bag and disposable dish, with their respective pure polymer matrices, poly(butylene adipate-co-terephthalate) (PBAT) and polylactic acid (PLA). Additionally, biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and oil-based polypropylene (PP) were also tested. Changes in morphology, chemical composition and thermal and mechanical properties, as well as microbial colonization, were analyzed over time. A validated cleaning protocol was employed to ensure accurate surface analysis. Results showed detectable but limited degradation of pure polymers and their matrices in commercial products after 120 days of immersion with variations observed among polymer materials. Compostable materials exhibited significant leaching of fillers (starch, inorganic particles), leading to morphological changes and fragmentation. PHBV showed the fastest degradation among tested polyesters. PP exhibited only minor surface changes. Microbial colonization varied with polymer structure and degradability, but long-term degradation was limited by polymer properties and the gradual development of the plastisphere. This study highlights that standard laboratory tests may overestimate the environmental degradability of BPs and emphasizes the importance of in situ assessments, careful cleaning procedures and property characterizations to accurately assess polymer degradation in freshwater systems. Full article

(This article belongs to the Special Issue Natural Degradation of Polymers)

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