Polymers

40 pages, 43449 KB

Open AccessArticle

Sustainable Rubberized RCC Using Locally Sourced Waste Rubber Tire Powder and GGBFS-Based Binder

by İrfan Ş. Öztürk, Furkan Abdurrahman Sarı, Yakup Önal, Sercan Serin, Mehmet Emiroğlu, Hakan Güler and Tahir Gönen

Polymers 2026, 18(17), 2046; https://doi.org/10.3390/polym18172046 (registering DOI) - 23 Aug 2026

Abstract

This study investigates roller-compacted concrete (RCC) in which fine aggregate was replaced with waste rubber tire powder (WRTP) at 0–16% by volume, using a binder containing 40% ground granulated blast-furnace slag (GGBFS). Fresh, mechanical, transport-related, microstructural, and environmental aspects were evaluated. While WRTP [...] Read more.

This study investigates roller-compacted concrete (RCC) in which fine aggregate was replaced with waste rubber tire powder (WRTP) at 0–16% by volume, using a binder containing 40% ground granulated blast-furnace slag (GGBFS). Fresh, mechanical, transport-related, microstructural, and environmental aspects were evaluated. While WRTP reduced workability, density, and ultrasonic pulse velocity (UPV), UPV values remained within the “excellent” classification range. Among the investigated mixtures, 2% WRTP provided the most favorable overall performance, increasing the 28-day compressive strength from 26.6 to 28.2 MPa, the 90-day compressive strength from 31.1 to 37.8 MPa, the flexural strength from 3.33 to 3.47 MPa, and the splitting tensile strength from 1.81 to 2.37 MPa. The 2% WRTP mixture also reduced the secondary capillary absorption coefficient by approximately 32.3%, from 0.00127 to 0.00086 mm/√s. Higher WRTP contents progressively decreased compressive strength and static modulus of elasticity, whereas flexural strength was comparatively less affected. SEM/EDS observations revealed more pronounced interfacial voids and discontinuities at higher WRTP contents, consistent with the observed performance decline. A simplified cradle-to-gate embodied-carbon assessment indicated that the 40% GGBFS binder substitution was the primary contributor to the estimated carbon reduction, with the reference and 2% WRTP mixtures exhibiting approximately 33.4% and 33.1% lower embodied carbon, respectively, than the hypothetical cement-only RCC baseline. In addition, the 2% WRTP mixture incorporated 6.43 kg/m³ of waste tire-derived rubber, providing an additional waste-utilization benefit. Overall, low WRTP incorporation, particularly at 2%, combined with a GGBFS-based binder provided a favorable balance between engineering performance, reduced embodied carbon, and waste utilization under the investigated conditions. Full article

(This article belongs to the Special Issue Polymer-Enabled Materials for Circular and Sustainable Pavements)

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16 pages, 7406 KB

Open AccessArticle

Mechanical and Sustained-Release Properties of Crosslinked Poly(vinyl alcohol)/Sodium Humate Composite Membranes

by Shuai Kuang, Enwei Chen, Tian-en Shui, Piyue Gong, Feng Wang and Haiying Huang

Polymers 2026, 18(17), 2045; https://doi.org/10.3390/polym18172045 (registering DOI) - 23 Aug 2026

Abstract

Humic acid, as a natural macromolecular aggregate rich in functional groups, offers abundant modification sites and tunable chemical functionality, making it a promising building block for three-dimensional network construction. In this study, glutaraldehyde (GA) was employed as a crosslinking agent to incorporate sodium [...] Read more.

Humic acid, as a natural macromolecular aggregate rich in functional groups, offers abundant modification sites and tunable chemical functionality, making it a promising building block for three-dimensional network construction. In this study, glutaraldehyde (GA) was employed as a crosslinking agent to incorporate sodium humate (NaHA, sodium salt of humic acid from alkaline treatment) into a polyvinyl alcohol (PVA) matrix, yielding composite membranes with enhanced structural stability and performance. The results demonstrate that NaHA effectively modulates the crosslinked network, and the physical and mechanical characteristics can be readily tailored by varying the PVA/NaHA/GA ratio. Compared with pristine PVA/GA hydrogel, the inclusion of NaHA significantly influences the mechanical response, with optimal comprehensive performance achieved at a NaHA content of 7.5 wt%, corresponding to a tensile strength of 60.4 MPa and an elongation at break of 74.2%. Furthermore, the cumulative release of NaHA after two days reached 64.4%, confirming that NaHA supramolecular aggregates were stably entrapped within the PVA/GA crosslinked matrix. The release kinetics were well described by the Korsmeyer–Peppas model. Overall, the covalent crosslinking of PVA with GA, together with hydrogen-bonding associations and physical entrapment mediated by NaHA, constructed a composite membrane network. This network exhibited tunable dry-state mechanical properties and sustained NaHA release, supporting its further evaluation as a prospective candidate for agricultural mulching films. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes: From Fabrication to Application)

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15 pages, 29933 KB

Open AccessArticle

Influence of Reconstitution Methods and Diluents on the Physicochemical Characteristics of Poly-L-Lactic Acid Suspensions: An In Vitro Study

by Woramate Bhorntarakcharoen, Sariya Sittiwanaruk, Wilailuck Phokai, Thanakorn Woramongkol and Thanya Techapichetvanich

Polymers 2026, 18(17), 2044; https://doi.org/10.3390/polym18172044 (registering DOI) - 23 Aug 2026

Abstract

Macroscopic and microscopic aggregation patterns of reconstituted poly-L-lactic acid (PLLA) products may vary with product formulation, diluent, preparation protocol, and time. This descriptive in vitro pilot study compared two commercial formulations, StiCol Volume (150 mg PLLA reconstituted to 9 mL) and StiCol Soft [...] Read more.

Macroscopic and microscopic aggregation patterns of reconstituted poly-L-lactic acid (PLLA) products may vary with product formulation, diluent, preparation protocol, and time. This descriptive in vitro pilot study compared two commercial formulations, StiCol Volume (150 mg PLLA reconstituted to 9 mL) and StiCol Soft (50 mg PLLA reconstituted to 6 mL), under 11 diluent conditions and 2 composite preparation protocols: roller mixing for 30 min and manual shaking for 3 min followed by 3 h of hydration. One preparation was evaluated for each formulation–diluent–protocol combination. Gross appearance was documented immediately and at 15, 30, 45, and 60 min and 24 h; microscopy was performed at ×40 and ×100 from 15 min onward. Two evaluators applied an ordinal visual aggregation scale, and the findings were analyzed descriptively. In the observed preparations, the StiCol Soft formulation generally showed lower aggregation grades than StiCol Volume; however, the products differed in nominal PLLA concentration, particle size, and excipient composition, so this pattern cannot be attributed to concentration alone. SWFI-based conditions tended to show fewer microscopic clusters than NSS-based conditions. The roller/30 min protocol also tended to show lower grades than the manual/3 h protocol, although mixing mode and hydration duration were inseparable. Macroscopic upper-layer accumulation was interpreted as vertical phase separation with creaming/flotation-like behavior rather than sedimentation. These exploratory findings generate hypotheses for replicated studies incorporating standardized sampling, redispersibility, particle size, rheological, and injectability testing; they do not establish an administration window or improved clinical safety. Full article

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

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22 pages, 4963 KB

Open AccessArticle

Study on CMC-Based Suppressant for Coal Dust and Spontaneous Combustion Control

by Jianguo Wang, Tianle Jia, Zhenzhen Zhang and Xinni He

Polymers 2026, 18(17), 2043; https://doi.org/10.3390/polym18172043 (registering DOI) - 23 Aug 2026

Abstract

Underground coal mining faces coupled hazards from respirable coal dust and spontaneous coal combustion. This study developed a dual-function flame-retardant dust suppressant comprising carboxymethyl cellulose (CMC), polycarbodiimide (PCDI), ammonium polyphosphate (APP), and zinc borate (ZB). A four-factor, three-level orthogonal design was used to [...] Read more.

Underground coal mining faces coupled hazards from respirable coal dust and spontaneous coal combustion. This study developed a dual-function flame-retardant dust suppressant comprising carboxymethyl cellulose (CMC), polycarbodiimide (PCDI), ammonium polyphosphate (APP), and zinc borate (ZB). A four-factor, three-level orthogonal design was used to screen formulations by penetration depth, followed by rheological, water-scour, simulated-roadway, temperature-programmed oxidation, contact-angle, Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscope (SEM) analyses. CMC and PCDI significantly affected penetration, whereas APP and ZB showed no significant effects within the tested ranges. The selected formulation (1% CMC, 12% APP, 3.5% ZB, and 1.5% PCDI) showed stable viscosity development and the lowest mass loss under repeated water scour. In simulated-roadway tests, the stock solution achieved an average dust-suppression efficiency of 59.7%. At 170 °C, a 10% treatment reduced CO release by 40.0% and increased the mean apparent activation energy of coal oxidation by 29.73%. Rapid wetting, intermolecular interactions, and formation of a continuous porous crosslinked film supported dust consolidation and oxidation inhibition. The developed material therefore offers a potential integrated approach for controlling coal dust and spontaneous combustion risks in underground mines. Full article

(This article belongs to the Section Polymer Applications)

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12 pages, 7239 KB

Open AccessArticle

Introducing Crack–Termination Sites to Improve the Resistance of Polycarbonate on Environmental Stress Cracking

by Minjian Ma, Qian Huang, Peitao Wang, Junwei Ai, Huiqiang Liang, Liang Yu, Minle Peng and Yin Cen

Polymers 2026, 18(17), 2042; https://doi.org/10.3390/polym18172042 (registering DOI) - 23 Aug 2026

Abstract

Environmental stress cracking (ESC) severely limits the long-term reliability and engineering application of polycarbonate (PC)-based materials. In this work, a universal strategy is proposed to enhance the ESC resistance of PC by introducing crack-termination sites, enabling efficient suppression of crack propagation without compromising [...] Read more.

Environmental stress cracking (ESC) severely limits the long-term reliability and engineering application of polycarbonate (PC)-based materials. In this work, a universal strategy is proposed to enhance the ESC resistance of PC by introducing crack-termination sites, enabling efficient suppression of crack propagation without compromising the intrinsic mechanical properties of PC. A quantitative evaluation framework based on a constant-strain method is established, and the critical strain rate (η) is defined as a key parameter for assessing ESC behavior under chemo-mechanical coupling. Systematic experiments reveal that chain entanglements, rubbery phases, and crystalline region can effectively increase η value of PC-based materials, demonstrating their superior crack-termination efficiency. Notably, the β-crystalline phase in PBT and microcrystalline domains induced by ethylene–acrylate copolymer tougheners are identified as the most efficient crack-termination structures, providing continuous energy-dissipation pathways and effectively halting crack propagation. This work not only establishes a practical and quantitative approach for evaluating ESC performance but also provides an integrated material-modification strategy. The proposed concept of crack-termination sites offers new insight into the development of high mechanical performance and ESC resistance PC-based polymer systems for advanced industrial applications. Full article

(This article belongs to the Section Polymer Applications)

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27 pages, 9840 KB

Open AccessArticle

Environmental Preconditioning Shapes the Expression and Post-Formulation Stability of Plant Growth-Promoting Traits in Native Actinobacteria

by María Elena Mancera-López and Josefina Barrera-Cortés

Polymers 2026, 18(17), 2041; https://doi.org/10.3390/polym18172041 (registering DOI) - 22 Aug 2026

Abstract

The functional expression of plant growth-promoting (PGP) traits in soil actinobacteria is conditioned by abiotic factors, yet the combined effects of pH and temperature on their metabolic profiles and the stability of these profiles after encapsulated formulation and post-processing stress remain insufficiently characterized. [...] Read more.

The functional expression of plant growth-promoting (PGP) traits in soil actinobacteria is conditioned by abiotic factors, yet the combined effects of pH and temperature on their metabolic profiles and the stability of these profiles after encapsulated formulation and post-processing stress remain insufficiently characterized. This study aimed to evaluate the physiological plasticity of native actinobacteria and the expression of plant growth-promoting (PGP) traits under different pH and temperature conditions, as well as their stability after encapsulation, dehydration, and exposure to UV irradiation. Strains isolated from a semi-arid agricultural soil were analyzed to determine their ability to produce indole-3-acetic acid (IAA), siderophores, and phosphatases, as well as their ability to fix nitrogen, degrade cellulose, and tolerate salt stress. Temperature and pH significantly affected all evaluated PGP traits (p < 0.001), and their expression was not directly associated with biomass production. Two strains, S1 and S4, exhibited the highest overall PGP indices. Strain S1 maximized IAA and siderophore production under neutral conditions (pH 7.0, 30 °C), whereas strain S4 maintained more stable phosphatase activity across the tested pH and temperature ranges. Cell viability remained above 85% after encapsulation and dehydration. Dehydration enhanced IAA and siderophore production in strain S1, while strain S4 exhibited transient metabolic activation under UV irradiation in non-dehydrated capsules. The encapsulation matrix preserved cell viability more effectively than it preserved the complete PGP functional profile, indicating that viability alone is an insufficient criterion for evaluating the technological success of alginate-based bioinoculant formulations. These findings highlight the importance of integrating environmental preconditioning and functional stability assessments into the development of robust microbial bioinoculants adapted to agricultural systems subjected to fluctuating environmental conditions. Full article

(This article belongs to the Special Issue Bio-Based Polymers from Proteins and Polysaccharides: Challenges and Opportunities)

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15 pages, 7582 KB

Open AccessArticle

Ultrastrong Host–Guest Recognition Driven Chiral Supramolecular Polymers with Circularly Polarized Luminescence in Water

by Ya-Ping Chen, Si-Dan Guo, Jinlei Zhou, Xiaoyu Luo and Kang Cai

Polymers 2026, 18(17), 2040; https://doi.org/10.3390/polym18172040 (registering DOI) - 22 Aug 2026

Abstract

Chiral supramolecular polymers offer a versatile platform for constructing dynamic functional materials, yet their development in aqueous media remains challenging due to weak host–guest interactions and limited chiral macrocyclic systems. Herein, we report a water-soluble chiral luminescent supramolecular polymer assembled from a pair [...] Read more.

Chiral supramolecular polymers offer a versatile platform for constructing dynamic functional materials, yet their development in aqueous media remains challenging due to weak host–guest interactions and limited chiral macrocyclic systems. Herein, we report a water-soluble chiral luminescent supramolecular polymer assembled from a pair of chiral macrocycle ((R)-/(S)-C[4]B) and an achiral bis-thiazole orange guest. The ultrahigh binding affinity between the host and guest enables stable one-dimensional polymerization in water. Efficient chirality transfer from the macrocyclic host to the achiral luminophore gives rise to pronounced circular dichroism (CD) and circularly polarized luminescence (CPL). The resulting polymer exhibits red emission (625 nm) with a luminescence dissymmetry factor of 8.5 × 10⁻³. This work provides an effective strategy for the development of aqueous CPL-active supramolecular polymers through ultrastrong host–guest recognition. Full article

(This article belongs to the Special Issue A Commemorative Issue in Honor of Professor Sir Fraser Stoddart: Functional Coordination Polymers)

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25 pages, 8821 KB

Open AccessArticle

Regulatory Effect of Polyacrylate Emulsion on the NaCl Attack Behavior of Cement-Based Grouting Materials

by Yuxuan Wang, Shengjie Han, Fan Wang, Lei Hu, Jiao Liao, Shijie Zhu, Yangyang Li and Jiehao Wu

Polymers 2026, 18(17), 2039; https://doi.org/10.3390/polym18172039 (registering DOI) - 22 Aug 2026

Abstract

Cement-based grouting materials with a high water-to-cement ratio are susceptible to connected pore development, chloride ingress, and mechanical degradation in chloride-bearing groundwater and marine environments. To improve resistance to NaCl attack, this study compared an unmodified cement-based grouting material (NC) with a polyacrylate-emulsion-modified [...] Read more.

Cement-based grouting materials with a high water-to-cement ratio are susceptible to connected pore development, chloride ingress, and mechanical degradation in chloride-bearing groundwater and marine environments. To improve resistance to NaCl attack, this study compared an unmodified cement-based grouting material (NC) with a polyacrylate-emulsion-modified material (PA). Mechanical properties, surface wettability, pore structure, phase assemblage, thermal behavior, functional groups, and microstructure were investigated under different NaCl concentrations (0%, 5%, 10%, and 15%) and immersion durations (28 and 90 d). This study systematically evaluates the coupled evolution of mechanical strength retention, surface wettability, pore structure, chloride-bearing phases, and microstructure in a bulk PA-emulsion-modified high-water-to-cement-ratio grouting material under graded NaCl exposure. The results showed pronounced concentration- and time-dependent effects. Low NaCl concentrations were associated with continued hydration and reaction-product filling, whereas higher concentrations and prolonged exposure led to pore coarsening and strength loss. PA modification improved the mechanical stability of the material in NaCl environments. After 90 d of immersion in 15% NaCl, the compressive and flexural strengths of the PA group were 23.60% and 22.53% higher than those of the NC group, respectively, while the corresponding strength-retention ratios were higher by 9.06 and 10.40 percentage points. Contact-angle and MIP results showed that PA reduced surface wettability and mercury-accessible porosity. After 15% NaCl exposure, the contact angle of the PA group remained 72.5°, compared with 40.1° for the NC group, while the porosity decreased from 38.11% in the NC group to 30.98% in the PA group. XRD, TG-DTG, and FTIR analyses indicated the formation and evolution of Friedel’s salt or other chloride-bearing AFm phases after NaCl exposure. Combined with SEM observations, the results indicate that PA mitigates NaCl-induced deterioration through reduced surface wettability, refined pore structure, regulated chloride-bearing product distribution, and improved matrix integrity. Overall, the findings establish a coupled surface–pore–phase–microstructure framework for understanding the enhanced NaCl resistance of PA-modified cement-based grouting materials. Full article

(This article belongs to the Special Issue Application of Polymers in Cementitious Materials, 2nd Edition)

41 pages, 7844 KB

Open AccessReview

From Waste to Value-Added Resource: A Strategic Review of Recycling and Regeneration Pathways for Fiber-Reinforced Polymer Waste

by Yi Liu, Yingfang Fan, Lei Wang and Wenjie Qi

Polymers 2026, 18(17), 2038; https://doi.org/10.3390/polym18172038 (registering DOI) - 22 Aug 2026

Abstract

The rapid expansion of fiber-reinforced polymers (FRPs) in wind energy, transportation, and aerospace is generating increasing amounts of accompanied waste, making effective valorization essential to a circular economy. This review compares FRP recovery technologies in terms of recovered-fiber quality, operating conditions, post-treatment, environmental [...] Read more.

The rapid expansion of fiber-reinforced polymers (FRPs) in wind energy, transportation, and aerospace is generating increasing amounts of accompanied waste, making effective valorization essential to a circular economy. This review compares FRP recovery technologies in terms of recovered-fiber quality, operating conditions, post-treatment, environmental impacts, and industrial applicability. Then, it also examines direct reuse, FRP remanufacturing, and reuse in cementitious composites. Quantitative synthesis indicates that high-quality recycled carbon fibers (rCFs) generally retain more than 90% of their original strength, whereas mechanically recovered glass fibers (rGFs) typically retain approximately 70–90%. The preferred pathway depends on the intrinsic value, damage state, morphology, and residual properties. Components with sufficient residual capacity should be directly reused; high-quality fibers are better suited to polymer remanufacturing; and heterogeneous or lower-grade glass-FRP (GFRP) fractions are more compatible with cementitious applications, where mechanically recycled GFRP can provide interfacial bond strengths comparable to conventional engineering macrofibers. Future research should establish quantitative links among recovered material quality, processing, interfacial behavior, and end-use performance, while adopting consistent environmental and economic assessment boundaries. A graded utilization framework is therefore required to support both large-scale and value-added reuse of FRP waste. Full article

(This article belongs to the Special Issue Advanced Fiber-Reinforced Polymer Composites: Design, Manufacturing, Characterization, and Application, 2nd Edition)

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29 pages, 5227 KB

Open AccessReview

Organic and Perovskite Solar Cells with Printed Electrodes

by Kyungsik Kim, Yeong-Ho Kim, Jinho Lee, Soonil Hong and Jong-Hoon Lee

Polymers 2026, 18(17), 2037; https://doi.org/10.3390/polym18172037 (registering DOI) - 22 Aug 2026

Abstract

Organic solar cells (OSCs) and perovskite solar cells (PSCs) are emerging photovoltaic technologies owing to their high efficiency, low-cost processing, and diverse applications ranging from utility-scale power generation to small-scale electronics. A key advantage of OSCs and PSCs over traditional silicon-based solar cells [...] Read more.

Organic solar cells (OSCs) and perovskite solar cells (PSCs) are emerging photovoltaic technologies owing to their high efficiency, low-cost processing, and diverse applications ranging from utility-scale power generation to small-scale electronics. A key advantage of OSCs and PSCs over traditional silicon-based solar cells is their solution-processability, which enables fabrication via cost-effective scalable printing technologies suitable for commercialization. In addition to organic and perovskite photoactive layers, other functional layers, including interfacial layers and electron and hole transport layers, can also be processed using solution-based printing techniques. However, the conventional architecture of these emerging photovoltaics relies on vacuum-based deposition processes for both oxide-based electrodes (e.g., indium tin oxide and fluorine tin oxide) and metallic top electrodes (e.g., Au, Ag, Cu, and Al), which contrasts with printing-based processing. The implementation of printing technologies for electrode fabrication is necessary to achieve low-cost production and flexible photovoltaic applications. Herein, we review printed electrodes—including metal electrodes, conductive polymers, and carbon-based materials—used to fabricate OSCs and PSCs. Full article

(This article belongs to the Special Issue Polymer Films in Photovoltaic Devices: Modification Towards Higher Efficiency and Stability)

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18 pages, 20578 KB

Open AccessArticle

Effect of Copper-Modified ZSM-5 Zeolite Concentration on the Thermomechanical and Antimicrobial Properties of Compatibilized Native Starch/Polylactic Acid Blends

by Karla Garrido-Miranda, Elizabeth Moreno-Bohorquez, Mary Judith Arias-Tapia, Cristian Miranda, Ángelo Oñate, Carlos Lanziotti, Ángel Contreras, Jesús D. Rhenals-Julio, Andrés F. Jaramillo and Manuel F. Melendrez

Polymers 2026, 18(17), 2036; https://doi.org/10.3390/polym18172036 (registering DOI) - 22 Aug 2026

Abstract

The development of multifunctional biodegradable materials with improved structural performance and antimicrobial functionality is essential for advancing sustainable packaging. This study evaluates the effect of copper-modified ZSM-5 zeolite (ZCu) concentration (0, 1, and 5 wt%) on thermoplastic starch/polylactic acid (TPS/PLA) blends. The TPS [...] Read more.

The development of multifunctional biodegradable materials with improved structural performance and antimicrobial functionality is essential for advancing sustainable packaging. This study evaluates the effect of copper-modified ZSM-5 zeolite (ZCu) concentration (0, 1, and 5 wt%) on thermoplastic starch/polylactic acid (TPS/PLA) blends. The TPS was derived from Ipomoea batatas (sweet potato, SP) and Dioscorea rotundata (diamond yam, DY) starches and compatibilized with 1 wt% citric acid. The ZCu response depended on both ZCu loading and the botanical starch source. Structural analyses showed that SP-based composites reached their highest crystallinity at 1 wt% ZCu (13.70%), whereas DY-based systems exhibited an initial decrease at 1 wt% followed by an increase to 12.75% at 5 wt%, reflecting distinct concentration-dependent crystallization trends. Thermal analyses demonstrated a substantial increase in the degradation onset temperature of SP-based composites, from 132.9 °C to 185.1 °C at 1 wt% ZCu, indicating an effective thermal barrier effect. Nanomechanical mapping revealed concentration- and starch-source-dependent changes in local hardness, reduced modulus, and elastic recovery, without evidence of uniform mechanical reinforcement across all formulations. Antibacterial activity was observed exclusively in composites containing 5 wt% ZCu, with inhibition zones of 5.3 mm against Staphylococcus aureus and 1.0 mm against Escherichia coli. These findings highlight how the structural, thermal, nanomechanical and antimicrobial responses of TPS/PLA blends vary with ZCu concentration and the botanical origin of the starch. Full article

(This article belongs to the Special Issue Advances in Bio-Based Polymers for Sustainable Packaging)

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19 pages, 1872 KB

Open AccessArticle

Green Polymeric Nanocomposite (KCl/SiO₂/Xanthan/Origanum vulgare) for Multi-Scale Interfacial Stabilization and Permeability Preservation in Carbonate Petroleum Reservoirs

by Yaser Ahmadi, Mehdi Havasbeigi and David A. Wood

Polymers 2026, 18(16), 2035; https://doi.org/10.3390/polym18162035 (registering DOI) - 21 Aug 2026

Abstract

In carbonate petroleum reservoirs, permeability impairment caused by asphaltene precipitation and deposition remains a major challenge that limits long-term productivity. This study introduces a green polymeric nanocomposite (KCl/SiO₂/Xanthan/Origanum vulgare, NCs) designed to control interfacial dynamics and preserve flow capacity [...] Read more.

In carbonate petroleum reservoirs, permeability impairment caused by asphaltene precipitation and deposition remains a major challenge that limits long-term productivity. This study introduces a green polymeric nanocomposite (KCl/SiO₂/Xanthan/Origanum vulgare, NCs) designed to control interfacial dynamics and preserve flow capacity in carbonate formations. Using a multi-technique approach—interfacial tension (IFT) analysis, atomic force microscopy (AFM), and rock-core, fluid-flooding experiments at simulated subsurface conditions—the NCs’ abilities were evaluated in terms of their potential to modify properties at fluid–fluid and fluid–rock interfaces. The NCs increased the CO₂–brine/oil IFT slope in certain pressure regions by up to 40.77%. These results indicate competitive adsorption that stabilizes interfaces. Adsorption isotherms confirmed a monolayer mechanism with a high capacity of 294.12 mg/g. AFM topographic mapping revealed order-of-magnitude changes in surface roughness (reductions in average roughness by ~75%, root-mean-square by ~83%, peak-to-valley by ~93%). These results directly link nanoscale smoothing to reduced capillary pinning. Core flooding tests demonstrated that NCs treatment decreased formation damage by up to 67.45% at 4000 psi, maintaining a high permeability ratio (k/k_i = 0.87) and preserving porosity (φ/φ_i = 0.887, representing 88.7% porosity retention). These results establish that the studied NCs coherently manipulate fluid physics in relation to molecular adsorption and macroscopic permeability. Consequently, these NCs offer a sustainable, high-performance strategy for flow assurance and formation damage control in geological and geothermal reservoirs. Full article

(This article belongs to the Special Issue Polymer Fluids in Geology and Geotechnical Engineering)

46 pages, 24663 KB

Open AccessReview

From Screening to Optimization: Strategic Implementation of Design of Experiments (DOE) for Robust Nanoparticle Formulation

by Ritu Gupta, Mahua Sarkar and Huan Xie

Polymers 2026, 18(16), 2034; https://doi.org/10.3390/polym18162034 - 21 Aug 2026

Abstract

Design of experiments (DOE) offers a powerful, systematic framework for optimizing nanoparticle (NP) formulations by replacing inefficient one-factor-at-a-time (OFAT) methods. By enabling the simultaneous evaluation of multiple variables, DOE uncovers critical factor interactions and identifies true global optima—critical for quality-by-design approaches. Despite its [...] Read more.

Design of experiments (DOE) offers a powerful, systematic framework for optimizing nanoparticle (NP) formulations by replacing inefficient one-factor-at-a-time (OFAT) methods. By enabling the simultaneous evaluation of multiple variables, DOE uncovers critical factor interactions and identifies true global optima—critical for quality-by-design approaches. Despite its potential for systematic innovation, DOE remains underutilized in nanomedicine due to its perceived complexity; this review provides a practical roadmap to bridge the gap between statistical theory and robust NP optimization. It provides a practical overview of DOE concepts, including factor selection, design choice, graphical interpretation of results (perturbation/contour plots), model validation (regression analysis and ANOVA), and numerical optimization via desirability function (D). Common pitfalls and best-practice strategies are discussed to support reliable model building and decision-making. A practical case study on poly(lactic-co-glycolic acid) (PLGA) NPs illustrates a multistage workflow: utilizing Taguchi screening to isolate key factors, followed by central composite design (CCD), for precise surface mapping. Numerical optimization using Design-Expert^® software maximized EE% (highest importance) within size/zeta ranges, yielding optimal conditions (5 mg drug amount, 4 mL aqueous volume; D = 0.961). Confirmation runs (EE 41.2%, NP size 124 nm, zeta potential −15 mV) validated predictions (EE 47.6%, NP size 133 nm, zeta potential −17.2 mV), confirming model reliability. Ultimately, by bridging conceptual foundations with practical implementation, this review aims to encourage broader adoption of DOE, particularly among emerging formulation scientists, and serves as a roadmap to accelerate scalable NP development, fostering data-driven innovation and improving efficiency in nanomedicine research. Moreover, future integration of artificial intelligence (AI) and artificial neural networks (ANNs) with DOE will drive a predictive, data-driven approach to NP optimization—accelerating robust, scalable, and regulatory-ready nanomedicine development with fewer experiments. Full article

(This article belongs to the Special Issue Polymer Innovations for Advanced Biomedical Applications: Insights and Developments)

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22 pages, 3837 KB

Open AccessArticle

Effect of Ergothioneine on the Stability of Hyaluronic Acid-Based Wound-Healing Materials

by Tianyu Ma, Shuangshuang Qi, Junkai Liu, Dongjiao Li, Xia Li, Shiyue Hu, Fuhua Zheng, Ruiyan Wang, Yang Su, Yunjiao Chi, Xueqi Zhao, Zhen Qin and Hao Wu

Polymers 2026, 18(16), 2033; https://doi.org/10.3390/polym18162033 - 21 Aug 2026

Abstract

Hyaluronic acid (HA)-based hydrogels are widely used as wound-healing materials and topical delivery systems because of their excellent biocompatibility, water retention capacity, and ability to promote cell migration. However, HA is prone to oxidative chain scission, which reduces molecular weight and compromises formulation [...] Read more.

Hyaluronic acid (HA)-based hydrogels are widely used as wound-healing materials and topical delivery systems because of their excellent biocompatibility, water retention capacity, and ability to promote cell migration. However, HA is prone to oxidative chain scission, which reduces molecular weight and compromises formulation stability and functional performance. This study evaluated the feasibility of ergothioneine (EGT) as a candidate antioxidant stabilizing excipient in a model HA-based wound-healing material. CCK-8 assays assessed the biocompatibility of EGT in L929 mouse fibroblasts after 24 h of exposure, and a stress-screening framework including Fenton oxidation, high-temperature/high-humidity treatment, light exposure, and quiescent storage at 4 °C was established. The results showed that Fenton oxidation markedly induced HA degradation, whereas EGT incorporation effectively protected HA structural integrity under oxidative stress. Cell scratch assays further demonstrated that EGT did not interfere with the ability of HA to promote cell migration. EGT may serve as a candidate antioxidant stabilizing excipient for HA-based wound-healing materials, improving HA structural and material stability under oxidative challenge while preserving HA-associated cell-migration function. Full article

(This article belongs to the Section Polymer Applications)

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19 pages, 1982 KB

Open AccessArticle

Pre-Damage Strengthening of Heavy-Duty Steel Crane Girders Using Bonded CFRP Plates for Fatigue Life Enhancement

by Xiaoqing Zhao, Yuzhu Liang, Nan Jin and Zhiwei Liu

Polymers 2026, 18(16), 2032; https://doi.org/10.3390/polym18162032 - 21 Aug 2026

Abstract

In recent years, premature fatigue issues in heavy-duty steel crane girders have occurred frequently, underscoring an urgent need to establish targeted life extension methods. Compared with post-crack repair after macroscopic fatigue cracks have appeared, it is more practical to delay or even prevent [...] Read more.

In recent years, premature fatigue issues in heavy-duty steel crane girders have occurred frequently, underscoring an urgent need to establish targeted life extension methods. Compared with post-crack repair after macroscopic fatigue cracks have appeared, it is more practical to delay or even prevent the formation of such cracks in fatigue-sensitive zones of the crane girder. Extensive research has demonstrated that bonding Carbon Fiber-Reinforced Polymer (CFRP) plates can significantly enhance the fatigue life of defective components. However, most existing studies focus on thin plates with pre-existing macroscopic cracks, with limited attention given to scenarios involving thick plates or intervention before crack initiation. Therefore, this study focuses on the fatigue problem around bolt holes in the lower flange of heavy-duty steel crane girders. It investigates the life extension method of bonding CFRP plates prior to macroscopic crack formation. Through finite element analysis and comparative fatigue tests, the fatigue life enhancement mechanism was preliminarily interpreted. The effectiveness of this method is validated, and a practical CFRP bonding strategy is proposed to significantly improve the fatigue life of the lower flange in heavy-duty steel crane girders. Full article

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

38 pages, 1762 KB

Open AccessReview

Recycling of Flexible Plastic Films: Emergent Technologies

by Jacob S. Licht, Marina Tsianou and Paschalis Alexandridis

Polymers 2026, 18(16), 2031; https://doi.org/10.3390/polym18162031 - 21 Aug 2026

Abstract

Plastic is a valuable material for packaging of food and pharmaceuticals, protective wrappings in construction and agriculture, and fluid storage. Flexible plastic or plastic film waste from packaging, agriculture, and construction applications grows at a rate of at least 92 million metric tons [...] Read more.

Plastic is a valuable material for packaging of food and pharmaceuticals, protective wrappings in construction and agriculture, and fluid storage. Flexible plastic or plastic film waste from packaging, agriculture, and construction applications grows at a rate of at least 92 million metric tons a year, is considered challenging to recycle, and is typically landfilled. In recent years, there have been great advancements in plastic recycling technology in order to deal with the global challenge of plastic waste buildup and support legislation from a local to national level to implement recycling. This work highlights the most recent advancements in plastic film recycling. Plastic films are mono- or multilayered based on what their applications will be, with multilayer multimaterial films being the more challenging feedstock for recycling. Mechanical recycling cannot easily process flexible films. Pyrolysis can use polyolefin-based film as feedstock but is not practiced at scale to match the rate of plastic film waste generation, and incineration can recover energy from film feedstock but is not recycling plastic. This has motivated the development of new recycling technologies designed around plastic films. Better characterization technologies to identify film compositions in municipal waste streams have been key to sorting out film feedstock for mechanical recycling and the baling of flexible plastic waste, but they struggle with multilayer films and black plastic. Compatibilization enables the recycling of mixed plastic waste but requires polymer compositions for selecting specific compatibilizers. Dissolution–precipitation recovers individual types of polymers from multilayer films and, at the same time, can purify polymers from additives or contaminants, but requires intense solvent processing and associated energy. Delamination of multilayer films can separate and recover solid films of polyolefins at relatively low amounts of solvent but requires quality feedstock to be efficient. Both dissolution–precipitation and delamination recycling of films recover the original polymer molecules and maintain their embodied energy, hence support circularity. In the case of PET-containing films, depolymerization to recover PET monomers offers opportunities to recycle challenging film feedstock. Full article

(This article belongs to the Special Issue Advances in Recycling and Reuse of Polymers)

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40 pages, 5340 KB

Open AccessReview

Green Synthesis and Functional Design of Polypyrrole-Based Nanomedicines for Cancer Theranostics: A Critical Review and Sustainability-Guided Perspective

by Jiaqiao Zhong and Yuanzhe Li

Polymers 2026, 18(16), 2030; https://doi.org/10.3390/polym18162030 - 21 Aug 2026

Abstract

Nanomedicine has advanced cancer theranostics via targeted delivery and phototherapy, yet many high-performance systems rely on inorganic or metal-intensive materials synthesized through energy-demanding routes, raising concerns about biocompatibility, environmental accumulation, and sustainability. This review re-evaluates polypyrrole (PPy)-based nanomedicines from a green chemistry perspective, [...] Read more.

Nanomedicine has advanced cancer theranostics via targeted delivery and phototherapy, yet many high-performance systems rely on inorganic or metal-intensive materials synthesized through energy-demanding routes, raising concerns about biocompatibility, environmental accumulation, and sustainability. This review re-evaluates polypyrrole (PPy)-based nanomedicines from a green chemistry perspective, shifting focus from performance-centric optimization to sustainability-guided design. PPy, an organic conductive polymer with near-infrared photothermal activity and structural tunability, offers a promising platform. However, pristine PPy suffers from limited functionality, poor biodegradability, and insufficient reactive oxygen species (ROS) generation. Reported FeCl₃-, CuCl₂-, and Fe²⁺/H₂O₂-mediated routes are compared to examine formulation-specific relationships among synthesis conditions, polymer characteristics, redox behavior, ROS-related function, and process burdens. Because the underlying studies differ in composition, processing, purification, and assay conditions, these comparisons are used to identify evidence-supported trade-offs and data gaps rather than to establish a universal causal hierarchy. Green strategies are critically assessed, including one-step carboxylated copolymerization for backbone degradability and metal–polyphenol networks for catalytic ROS amplification. To organize the heterogeneous evidence, this review introduces a PPy-specific dual-axis evidence map that considers process-related sustainability alongside biofunctional performance. This qualitative tool is intended to identify trade-offs and evidence gaps rather than provide a validated sustainability score. Full article

(This article belongs to the Section Polymer Applications)

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25 pages, 3879 KB

Open AccessReview

Progress in Sol–Gel-Derived Phenolic Aerogels: Control of Network Topology, Drying Technologies, and Functional Modification

by Hongwei Yang, Zongyi Deng, Minxian Shi and Zhixiong Huang

Polymers 2026, 18(16), 2029; https://doi.org/10.3390/polym18162029 - 21 Aug 2026

Abstract

Phenolic aerogels, owing to their low density, high char yield, large specific surface area, and well-defined three-dimensional topological networks, hold considerable promise for applications in extreme thermal protection and multifunctional material systems. The sol–gel process, a cornerstone methodology for constructing the three-dimensional nanoporous [...] Read more.

Phenolic aerogels, owing to their low density, high char yield, large specific surface area, and well-defined three-dimensional topological networks, hold considerable promise for applications in extreme thermal protection and multifunctional material systems. The sol–gel process, a cornerstone methodology for constructing the three-dimensional nanoporous architecture of these materials, critically governs the resulting microstructural topology and macroscopic performance through its reaction kinetics, phase-separation behavior, and drying dynamics. This review systematically surveys recent advances in the sol–gel synthesis of phenolic aerogels, focusing on the polycondensation mechanisms operative under acidic and basic catalytic conditions, nucleation-and-growth kinetics, and strategies for tailoring multiscale pore structures. It further provides a comparative analysis of interfacial regulation mechanisms for capillary-stress elimination across supercritical drying, freeze-drying, and ambient-pressure drying routes. We also dissect the structure–property relationships underpinning Knudsen-effect-mediated gaseous thermal insulation, multi-scale hybrid network toughening, and inorganic phase-transition-induced in situ ceramization for thermal protection, demonstrating the synergistic optimization of thermal insulation, structural load-bearing, and ablation resistance. Finally, we summarise current applications in extreme thermal protection, environmental adsorption, electromagnetic interference shielding, and electrochemical energy storage and highlight future directions towards green, scalable manufacturing and intelligent materials design. Full article

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

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24 pages, 1879 KB

Open AccessReview

Toward In Situ Stabilization of Raw Chinese Lacquer (Toxicodendron vernicifluum): Current Evidence, Processing Strategies, and Research Challenges

by Ziyue Zhang, Baoju Jin, Xiaotong Li, Hanyun Gao and Xinhao Feng

Polymers 2026, 18(16), 2028; https://doi.org/10.3390/polym18162028 - 21 Aug 2026

Abstract

Raw Chinese lacquer, tapped from the sap of Toxicodendron vernicifluum, is a natural water-in-oil microemulsion containing urushiol, polysaccharides, proteins, and laccase. Because this reactive system continues to oxidize and polymerize after harvesting, handling conditions directly determine water content, viscosity, and later film-forming [...] Read more.

Raw Chinese lacquer, tapped from the sap of Toxicodendron vernicifluum, is a natural water-in-oil microemulsion containing urushiol, polysaccharides, proteins, and laccase. Because this reactive system continues to oxidize and polymerize after harvesting, handling conditions directly determine water content, viscosity, and later film-forming performance. This review analyzes potential in situ stabilization routes that couple purification, low-temperature vacuum dehydration, and quality conditioning at, or near, the collection site. Emphasis is placed on how laccase retention, oxygen exposure, and urushiol polymerization are controlled together to limit transport losses and premature crusting. Portable filtration devices, reported centrifugal filtration systems, and proposed vacuum dehydration strategies are compared in terms of throughput, field compatibility, and process control. Physical and bio-based conditioning strategies, including shear adjustment, oxygen management, and natural film-forming aids, are further considered for on-site regulation. Surface-enhanced Raman spectroscopy (SERS) and portable spectroscopic devices are examined as feedback tools for parameter adjustment under field temperatures, humidity, and storage variation; however, these signals are treated as decision-support indicators that still require lacquer-specific calibration after tapping. The central task is to define a field-compatible process window for water removal, laccase retention, viscosity control, drying behavior, and storage stability before downstream coating preparation. The remaining challenges involve miniaturized equipment, standardized evaluation, evidence-level classification, and dynamic control of coupled variables. Full article

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

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