Polymers

37 pages, 2382 KB

Open AccessArticle

Integrated Hydraulic and Mathematical Evaluation of Flat Sheet Polyamide Reverse Osmosis Membranes for Poultry Slaughterhouse Wastewater Treatment

by Andrei Zaharia, Valentin Nedeff, Juan A. López-Ramírez, Dumitra Raducanu, Narcis Barsan and Emilian Mosnegutu

Polymers 2026, 18(16), 1974; https://doi.org/10.3390/polym18161974 - 13 Aug 2026

Abstract

Reuse of industrial wastewater contributes to the conservation of freshwater resources and the implementation of the principles of the circular economy. In this study, the cyclic performance of a flat-sheet polyamide reverse osmosis membrane (PA-RO) for the advanced treatment of wastewater from a [...] Read more.

Reuse of industrial wastewater contributes to the conservation of freshwater resources and the implementation of the principles of the circular economy. In this study, the cyclic performance of a flat-sheet polyamide reverse osmosis membrane (PA-RO) for the advanced treatment of wastewater from a poultry slaughterhouse, pretreated by dissolved air flotation (DAF), was evaluated. The membrane was operated at three recirculation flow rates in successive filtration and chemical cleaning cycles to evaluate its hydraulic behavior, retention efficiency, fouling evolution, and permeate quality. Among the conditions investigated, the recirculation flow rate of 0.5 L/min provided the highest hydraulic stability and flux recovery under the investigated conditions, although hydraulic and microbiological performances were not optimized under the same operating conditions. The progressive deterioration of membrane performance during cyclic operation was associated with the accumulation of reversible and irreversible fouling, evidenced by the increase in hydraulic resistances and the incomplete flux recovery after chemical cleaning. Hierarchical clustering analysis (HCA) and mathematical modeling revealed strong relationships between operating conditions, membrane performance, and fouling evolution, generating predictive models with high coefficients of determination. The results demonstrate the potential of the cyclic operation of the PA-RO membrane to obtain a high-quality permeate intended for industrial reuse and provide a practical framework for optimizing operating conditions and fouling control strategies in membrane wastewater treatment processes. Full article

(This article belongs to the Topic Membrane Separation Technology Research, 2nd Edition)

16 pages, 1236 KB

Open AccessArticle

Impact of Pre-Polymerization Thermal Modification on the Optical Resistance of Anterior Composites Against Thermal Cycling and Coffee Staining: An In Vitro Study

by Yasemin Gün and Hakan Yasin Gönder

Polymers 2026, 18(16), 1973; https://doi.org/10.3390/polym18161973 - 13 Aug 2026

Abstract

Color instability in anterior composite restorations remains a primary cause for clinical replacement. While pre-polymerization thermal modification is increasingly utilized in daily practice, its precise impact on phase-specific and long-term optical resistance against continuous thermal aging and aggressive dietary staining remains unclarified. This [...] Read more.

Color instability in anterior composite restorations remains a primary cause for clinical replacement. While pre-polymerization thermal modification is increasingly utilized in daily practice, its precise impact on phase-specific and long-term optical resistance against continuous thermal aging and aggressive dietary staining remains unclarified. This in vitro study evaluated the impact of pre-polymerization thermal modification (4 °C, 23 °C, and 55 °C) on the phase-specific and cumulative color stability (ΔE₀₀) of four anterior composite resins subjected to sequential thermal aging and prolonged coffee immersion. One hundred twenty specimens (n = 10) were prepared, and ΔE₀₀ was assessed using the CIEDE2000 formula at baseline (T0), post-thermal cycling (T1), and post-coffee immersion (T2). Mixed repeated-measures ANOVA revealed a significant three-way interaction (phase × material × temperature, p < 0.001), demonstrating that thermal conditioning effects vary by material formulation and aging dynamics. During thermal aging (ΔE₀₀ T0–T1), pre-polymerization cooling (4 °C) induced significantly higher discoloration in Estelite Sigma Quick compared to preheated conditions (p < 0.001). Following coffee immersion (ΔE₀₀ T1–T2), refrigeration at 4 °C significantly increased staining in Enamel Plus HRI (p = 0.026) and Estelite Sigma Quick (p = 0.007) compared to room temperature and preheated groups. For cumulative color change (ΔE₀₀ T0–T2), the material type was the primary determinant (p < 0.001), while the independent effect of temperature was not statistically significant (p = 0.395). In conclusion, preheating (55 °C) provides no significant cumulative advantage against staining, whereas refrigeration (4 °C) increases susceptibility to physical and chemical discoloration. The intrinsic chemical composition remains the critical factor driving long-term color stability. Full article

(This article belongs to the Section Polymer Applications)

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26 pages, 25783 KB

Open AccessArticle

CNT Localization and Network Formation in High-Performance PEEK/PEI Blends and Its Effect on Electrical Conductivity

by Behnam Khaledi, Nicole R. Demarquette and Eric David

Polymers 2026, 18(16), 1972; https://doi.org/10.3390/polym18161972 - 13 Aug 2026

Abstract

High-performance thermoplastics are gaining increasing attention for space applications. However, the extreme lunar environment requires multifunctional materials that combine electrical conductivity for electrostatic charge dissipation with low thermal conductivity for thermal insulation. One promising strategy to achieve this balance is through conductive polymer [...] Read more.

High-performance thermoplastics are gaining increasing attention for space applications. However, the extreme lunar environment requires multifunctional materials that combine electrical conductivity for electrostatic charge dissipation with low thermal conductivity for thermal insulation. One promising strategy to achieve this balance is through conductive polymer nanocomposites with controlled morphology. In this study, the localization, migration, and network formation of carbon nanotubes (CNTs) in two-phase blends of polyetheretherketone/polyetherimide (PEEK/PEI) were systematically investigated to establish the relationships between processing, morphology, and the resulting electrical and thermal properties. Despite the strong thermodynamic preference of CNTs for the PEI phase, both PEEK/CNT and PEEK/PEI/CNT nanocomposites exhibit similar electrical percolation thresholds (0.25–0.5 wt.%), attributed to spatial confinement arising from PEEK crystallinity in PEEK/CNT and from phase-selective localization in the blend system, which limits the effective volume available for CNT dispersion. Morphological characterization confirmed co-continuous blend structures and complete CNT migration into the PEI phase in the PEEK/PEI/CNT system, while rheological studies revealed percolated networks forming below the electrical percolation threshold. Processing conditions strongly impacted conductivity: short mixing times preserved interconnected CNT agglomerates and enhanced conductivity, whereas prolonged mixing promoted dispersion but destroyed conductive pathways. Furthermore, thermal annealing induced agglomeration and weakened networks in PEEK/CNT systems but had a negligible effect on PEEK/PEI/CNT composites due to improved CNT–PEI compatibility. Finally, thermal conductivity remained low across all systems, maintaining the material’s insulating performance for the harsh thermal environment of the Moon. Full article

(This article belongs to the Special Issue Recent Advances and Applications of Polymer Nanocomposites)

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16 pages, 1501 KB

Open AccessReview

A Mini Review on CO₂ Capture and Separation Using Nanocellulose-Based Scaffolds

by Priyanka Sharma

Polymers 2026, 18(16), 1971; https://doi.org/10.3390/polym18161971 - 13 Aug 2026

Abstract

Atmospheric carbon dioxide (CO₂) has reached an unprecedented 430 ppm, warming the planet by 50% compared with pre-industrial times and prompting a search for a quick and effective solution to control CO₂ emissions. As a robust, renewable, biodegradable, and sustainable [...] Read more.

Atmospheric carbon dioxide (CO₂) has reached an unprecedented 430 ppm, warming the planet by 50% compared with pre-industrial times and prompting a search for a quick and effective solution to control CO₂ emissions. As a robust, renewable, biodegradable, and sustainable material, nanocellulose can serve as a strong support for many active molecules. Nanocellulose, whether in suspension, aerogel, or membrane form, is not sufficient for efficient CO₂ capture and separation; hence, active molecules, such as silanes, amines, zeolites, and metal–organic frameworks (MOFs), are introduced via chemical modification, such as grafting, or via physical mixing as fillers or additives to make nanocellulose effective for CO₂ capture and separation. Introducing amine or silane molecules into nanocellulose has proven to be an effective strategy for achieving a satisfactory CO₂ absorption capacity exceeding 6 mmol/g. Nanocellulose membranes, when fabricated with MOFs or zeolites and used as a coating with polyvinyl alcohol (PVA) to create a thin-film composite membrane (TFC), can achieve CO₂ permeance of more than 600 GPU for CO₂ separation from flue gas, with CO₂/N₂ selectivity close to 40. This review provides an overview of nanocellulose-based CO₂ capture and separation materials developed over the last 10 years, along with the related challenges that must be overcome to meet current performance and demand. To facilitate readability, the author has provided a brief introduction to the origin, performance, and scale-up developments of nanocellulose at the start of this review. Full article

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

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12 pages, 3548 KB

Open AccessArticle

Homogenization Equivalence Modeling of Honeycomb Bending Considering Regional Deformation Differences

by Wangzi Liu, Guangjie Huang, Xianmo Wang, Yingwei Yu, Zhihui Liu, Haixin Guan, Jingping Zhu and Yu Wang

Polymers 2026, 18(16), 1970; https://doi.org/10.3390/polym18161970 - 13 Aug 2026

Abstract

A Nomex aramid paper honeycomb sandwich structure is the core material of the main load-bearing structures in aviation. Macroscopic full-scale refined modeling faces the problems of large mesh quantity and high calculation cost. Homogenization equivalence is the core path to achieve its efficient [...] Read more.

A Nomex aramid paper honeycomb sandwich structure is the core material of the main load-bearing structures in aviation. Macroscopic full-scale refined modeling faces the problems of large mesh quantity and high calculation cost. Homogenization equivalence is the core path to achieve its efficient simulation design. Most of the existing mature equivalent models are based on the ideal assumption that the honeycomb always remains macroscopically straight, without considering the equivalent performance changes caused by the morphological distortion of micro-cells under bending conditions. Therefore, it is difficult to support a high-precision simulation of large-curvature special-shaped honeycomb sandwich structures. This paper takes the over-stretched rectangular lattice aramid honeycomb as the research object. The mechanical parameters of the matrix are calibrated through experiments, and the reliability of the fine shell finite element model is verified (the maximum error of the end-face strain characteristics between simulation and the DIC test is less than 10%). A customized finite element sample matrix for compression bending is designed, and the angle distribution laws of honeycomb cells under different thicknesses and different bending curvatures are extracted. It is found that the cell angle shows a linear change trend along the wall-thickness direction, which is only strongly correlated with the initial geometric parameters and the bending radius. Finally, a semi-empirical model that can quickly predict the morphology of bent honeycomb cells is obtained through fitting. Verified by the glass compression-molding visualization experiment, the maximum relative error of the predicted cell angle is only 5.05%. This research establishes a rapid characterization method for the deformation of honeycomb cells under bending deformation, providing theoretical support for the microscopic homogenization equivalent modeling of curved honeycomb sandwich structures. Full article

(This article belongs to the Special Issue Multidisciplinary Design of Advanced Polymer Composite Materials and Structures)

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28 pages, 836 KB

Open AccessReview

Recent Advances in PLA Stereocomplexes: Synthesis, Modification, and Applications

by Haowei Cui, Yottha Srithep and John Morris

Polymers 2026, 18(16), 1969; https://doi.org/10.3390/polym18161969 - 13 Aug 2026

Abstract

Stereocomplexes derived from natural polylactides are an important class of renewable plastics. Although neat polylactides generally exhibit low elongation at break and low Young’s modulus, stereocomplex formation significantly enhances their thermal resistance and stiffness (rather than toughness), dimensional stability, and controlled degradability, compared [...] Read more.

Stereocomplexes derived from natural polylactides are an important class of renewable plastics. Although neat polylactides generally exhibit low elongation at break and low Young’s modulus, stereocomplex formation significantly enhances their thermal resistance and stiffness (rather than toughness), dimensional stability, and controlled degradability, compared with simple polylactides. Consequently there has been significant research efforts to discover improved uses of these stereocomplexes—formed when the two enantiomers are combined—reported in many previous reviews. Here, we discuss improvements in them reported in the last five years, including a wide range of applications from simple packaging to biomedical aids, which make use of polylactide biodegradability, and self-assembing micelles, with quite complex structures, that are used for drug delivery and agricultural uses. We also noted that many general claims for degradability in PLA based polymers need to be qualified: the polymers will degrade, but very slowly in normal, low humidity conditions. However, degradation may be accelerated by heat, moisture, and enzymes—and also by fabricating with functional groups. Full article

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

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17 pages, 1667 KB

Open AccessArticle

Triazine-Mediated Zero-Length Crosslinking for Sustainable Leather Tanning

by Valentina Beghetto, Eleonora Fabris, Francesco de Laurentiis, Marco Nogarole, Domenico Santandrea and Dior Tall

Polymers 2026, 18(16), 1968; https://doi.org/10.3390/polym18161968 - 12 Aug 2026

Abstract

The study presents a sustainable, metal-free tanning system based on 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) and N-methylmorpholine (NMM), which stabilizes collagen through a zero-length crosslinking mechanism. Reactive triazine intermediates, generated in situ, selectively activate collagen carboxyl groups, forming active esters that subsequently react with amine [...] Read more.

The study presents a sustainable, metal-free tanning system based on 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) and N-methylmorpholine (NMM), which stabilizes collagen through a zero-length crosslinking mechanism. Reactive triazine intermediates, generated in situ, selectively activate collagen carboxyl groups, forming active esters that subsequently react with amine functionalities to form amide bonds. Unlike conventional tanning systems, no metals or toxic chemicals are incorporated into the tanned leather. Optimization of reagent concentration, temperature, and dosing strategy revealed that the gradual formation of reactive intermediates is essential to balance reaction kinetics and diffusion throughout collagen. Under pickle-free conditions, hydrothermal stability was achieved with only 2.5–3.4 wt% CDMT/NMM, yielding shrinkage temperatures of 81–85 °C that surpass most reported chrome-free tanning systems. The resulting leather displayed a bright white appearance, excellent dyeability, and outstanding physical-mechanical performance, including superior tear resistance and competitive tensile strength. These properties are consistent with the formation of a homogeneous collagen network reinforced by direct covalent amide crosslinks while maintaining fiber flexibility. Furthermore, avoiding pickling significantly reduces chemical consumption and improves wastewater biodegradability, enhancing the environmental sustainability of the process. Overall, CDMT/NMM emerges as a scalable, environmentally friendly tanning technology that combines mechanistically controlled collagen crosslinking with excellent leather performance. Full article

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

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23 pages, 8094 KB

Open AccessArticle

Influence of Technical Parameters of Carbonization on the Physical and Chemical Characteristics of Materials Obtained by Carbonization of Sunflower Husks from the East Kazakhstan Region

by Aigerim Kaiaidarova, Valeryia Bobrova, Andrei Kasperovich, Sergey Lezhnev, Evgeniy Panin, Sergey Nechipurenko and Sergey Efremov

Polymers 2026, 18(16), 1967; https://doi.org/10.3390/polym18161967 - 12 Aug 2026

Abstract

In 2025, the oil and fat industry of the Republic of Kazakhstan showed steady growth, strengthening the country’s position as a major producer and exporter of vegetable oils. However, the production process generates large amounts of waste (up to 100 tons per day), [...] Read more.

In 2025, the oil and fat industry of the Republic of Kazakhstan showed steady growth, strengthening the country’s position as a major producer and exporter of vegetable oils. However, the production process generates large amounts of waste (up to 100 tons per day), and its recycling is an important part of the oil and fat industry’s economy. High-temperature processing of plant waste has proven to be a promising method for creating new materials for various industries. The aim of this study was to determine the influence of various technical parameters of carbonization (processing temperature and process environment) on the physical and chemical characteristics of materials obtained by carbonizing sunflower seed husks from the East Kazakhstan region at temperatures of 300, 400, 500, 600, 700 and 800 °C in an inert argon environment, as well as by processing the husks in an oxidizing environment at a temperature of 650 °C, for further use in elastomer compositions as new ingredients. Increasing the carbonization temperature in an inert environment led to an increase in the amorphous carbon content, surface porosity, and pH of the studied materials. Another parameter that showed a tendency to increase with increasing temperature in an inert environment was the BET specific surface area. In the case of using an oxidizing environment, the highest pH value was observed, and the formation of crystalline mineral phases was also observed. The differences in the phase states of the studied materials may play an important role in shaping the spatial stack of the polymer matrix when used in rubber compound formulations. Full article

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

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43 pages, 13313 KB

Open AccessArticle

Synergistic Impact of Bio-Based and Waste-Derived Contents on the Mechanical and Thermal Performance of Alkali-Activated Slag Mortars

by Hakan Sarıkaya, Gülşah Susurluk and Levent Bostanci

Polymers 2026, 18(16), 1966; https://doi.org/10.3390/polym18161966 - 12 Aug 2026

Abstract

The need to enhance both the mechanical and the thermal insulation performance of alkali-activated mortars has stimulated interest in natural fiber-based reinforcement strategies, particularly for sustainability-driven design and low-carbon construction. This study explores the combined effect of natural kapok fiber, petroleum coke (PC) [...] Read more.

The need to enhance both the mechanical and the thermal insulation performance of alkali-activated mortars has stimulated interest in natural fiber-based reinforcement strategies, particularly for sustainability-driven design and low-carbon construction. This study explores the combined effect of natural kapok fiber, petroleum coke (PC) and waste tire rubber powder (WTRP) on the mechanical, thermal, microstructural, mineralogical, and pore structure characteristics of alkali-activated slag-based mortars. While the beneficial effects of each of these bio-based and waste-derived materials have been widely reported, little attention has been paid to their combined use and the potential for them to work together in a way that is more effective than the sum of their parts. For this purpose, 20 different mortar mixtures were produced, incorporating kapok fibers at ratios of 0%, 0.5%, 0.75% and 1%. The beneficial effect of WTRP was investigated for the case of a 3% cement additive where natural sand was substituted by PC at ratios of 0%, 10% and 20%. The results indicated that the synergistic interaction enabled the development of a sustainable mortar with enhanced thermal insulation performance of up to 37% while maintaining flexural performance compared to the control case. Microstructural, mineralogical, pore structure and thermal analyses revealed that the bio-based and waste-derived contents significantly influenced the pore network, phase evolution and fiber–matrix interactions. Overall, the results highlight the potential of the proposed sustainable material system to produce mortars with enhanced thermal insulation, sufficient mechanical performance, and lowered environmental footprint. Full article

(This article belongs to the Special Issue Application of Polymers in Cementitious Materials)

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18 pages, 4801 KB

Open AccessArticle

Molecular Dynamics Study on the Interfacial Properties of Short Kevlar Fiber Reinforced Polyphenylene Sulfide Composites

by Zebei Mao, Ziping Li, Danyang Liu, Jiqiang Wang and Xingkeng Shen

Polymers 2026, 18(16), 1965; https://doi.org/10.3390/polym18161965 - 12 Aug 2026

Abstract

Polyphenylene sulfide (PPS) is a high-performance thermoplastic engineering material known for its excellent chemical resistance, thermal stability, and flame retardancy. In this work, the interfacial mechanical behavior of short-cut Kevlar fiber-reinforced PPS composites was systematically investigated by all-atom molecular dynamics (MD) simulations. By [...] Read more.

Polyphenylene sulfide (PPS) is a high-performance thermoplastic engineering material known for its excellent chemical resistance, thermal stability, and flame retardancy. In this work, the interfacial mechanical behavior of short-cut Kevlar fiber-reinforced PPS composites was systematically investigated by all-atom molecular dynamics (MD) simulations. By constructing a full-atom interface model between an amorphous PPS matrix and a Kevlar crystal, interfacial normal tension and tangential shear simulations were performed to reveal the mechanisms of load transfer, damage initiation, and damage evolution at the molecular scale. The results show that the interfacial normal tensile strength (approximately 245 MPa) is lower than the bulk tensile strength of pure PPS (approximately 270 MPa), which is attributed to the stiffness mismatch at the interface induced by the high modulus of Kevlar fibers, promoting the preferential initiation and propagation of voids near the geometrical interface. The tangential shear process exhibits pronounced stick-slip characteristics, with the interfacial binding energy fluctuating periodically with shear displacement, corresponding to the alternating establishment and rupture of non-bonded interactions between molecular chains. This study provides a theoretical basis for the micromechanical design of high-performance thermoplastic composite interfaces and identifies molecular-level optimization directions for future interfacial modification strategies of Kevlar/PPS systems. Full article

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

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17 pages, 9856 KB

Open AccessArticle

Electrospun Chitosan/Collagen Fibers Incorporating PLGA and Hydroxyapatite Nanoparticles for In-Vitro 3T3 Fibroblast Migration

by Laila Procel-Badillo, Sarah Briceño, Lenin Ramírez and Gema González

Polymers 2026, 18(16), 1964; https://doi.org/10.3390/polym18161964 - 11 Aug 2026

Abstract

The development of 3D scaffolds that enable the reliable evaluation of cell migration remains a critical challenge in tissue engineering and wound-healing-related research. In this work, 3D scaffolds based on Chitosan/Collagen/Poly(lactic-co-glycolic acid) (PLGA)/Hydroxyapatite (HAp) nanoparticles are presented as a promising approach to studying [...] Read more.

The development of 3D scaffolds that enable the reliable evaluation of cell migration remains a critical challenge in tissue engineering and wound-healing-related research. In this work, 3D scaffolds based on Chitosan/Collagen/Poly(lactic-co-glycolic acid) (PLGA)/Hydroxyapatite (HAp) nanoparticles are presented as a promising approach to studying the migration of the 3T3 cell line. The electrospinning technique was employed to fabricate fibers with an average diameter of 0.2 μm for CH/Coll, 0.69 μm for CH/Coll/PLGA, and 0.14 μm for CH/Coll/HAp. The electrospinning parameters were optimized, and the properties of the scaffolds were further enhanced by incorporating hydroxyapatite (HAp) and PLGA, thereby improving their regenerative potential and tissue-engineering applicability. Preliminary cell proliferation was monitored in the wound area at 4, 12, 24, and 35 h. The highest cell migration was observed in scaffolds with hydroxyapatite nanoparticles. The resulting fiber matrix demonstrated promising effects on fibroblast migration in an in vitro scratch-assay model using NIH 3T3 cells, relevant to skin tissue repair. Full article

(This article belongs to the Special Issue Advances in Polymeric Electrospun Fibers and Functional Composites)

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41 pages, 3833 KB

Open AccessReview

Hydroxypropyl Cellulose Derived from Sugarcane Bagasse as a Tablet Binder and Drug Delivery Matrix: A Structured Narrative Review of Synthesis, Pharmaceutical Performance, and Sustainability Indicators Relative to Commercial Grades

by Yusdan Yulidan Aulia Nisa, Ida Musfiroh, Amirah Mohd Gazzali, Okta Nama Putra, Taufik Muhammad Fakih, Derina Paramitasari, Karjawan Pudjianto and Muchtaridi Muchtaridi

Polymers 2026, 18(16), 1963; https://doi.org/10.3390/polym18161963 - 11 Aug 2026

Abstract

Hydroxypropyl cellulose (HPC) is extensively utilized as a binder and in controlled-release matrices, yet its production predominantly relies on high-purity α-cellulose derived from wood or cotton, which subjects supply chains to sustainability issues and fluctuations in feedstock prices. Annually, sugarcane bagasse, estimated at [...] Read more.

Hydroxypropyl cellulose (HPC) is extensively utilized as a binder and in controlled-release matrices, yet its production predominantly relies on high-purity α-cellulose derived from wood or cotton, which subjects supply chains to sustainability issues and fluctuations in feedstock prices. Annually, sugarcane bagasse, estimated at approximately 490–600 million tons annualy, presents a scalable, residue-based cellulose source for HPC production within circular bioeconomy frameworks. This review compiles findings from 106 peer-reviewed studies on cellulose and HPC derived from bagasse, addressing synthesis methods, structure–property relationships, and pharmaceutical applications. Published studies indicate that HPC derived from bagasse can achieve a degree of substitution (DS 1.87) compared to commonly reported commercial wood-pulp HPC grades (DS 1.8–2.5). Crystallinity reduction relative to commercial HPC has been proposed based on the lower crystallinity of the underlying bagasse cellulose feedstock, but this has not yet been directly measured for the hydroxypropylated product. Beyond performance, bagasse is an agricurtural residue available at negligible feedstock cost, in contrast to the established market prices of purified wood pulp and cotton linter (US$18–25 per kg) used in commercial HPC manufacturing. Life-cycle assessments of bagasse valorization pathways have similarly reported favorable environmental profiles relative to conventional biomass feedstocks. However, no dedicated techno-economic or life-cycle assessment specific to pharmaceutical-grade HPC production from bagasse has been published, and these potential sustainability and cost advantages therefore remain to be formally validated at industrial scale. Key challenges remain in regulatory acceptance, impurity control, batch-to-batch standardization, and scaling up etherification under pharmaceutical good manufacturing practice (GMP) constraints. Overall, the reviewed literature positions sugarcane bagasse (SCB)-derived HPC as a promising candidate for combining excipient performance with potential sustainability and cost benefits, necessitating targeted process optimization and qualification studies to expedite industrial adoption. Full article

(This article belongs to the Special Issue Biodegradable Polymers for Medical Applications–Advances and Expectations)

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15 pages, 2226 KB

Open AccessArticle

Electrochemical Synthesis of Superhydrophobic Polyaniline/Silane Coating Towards Corrosion Protection of Mild Steel

by Yu Chen, Haoyao Zhou and Niteng Fang

Polymers 2026, 18(16), 1962; https://doi.org/10.3390/polym18161962 - 11 Aug 2026

Abstract

In this study, a two-step electrodeposition strategy was proposed to fabricate an eco-friendly superhydrophobic polyaniline (PANI)/silane composite coating on mild steel for corrosion protection. The first step consists of creating a pure PANI adherent coating using a cyclic voltammetry technique and the second [...] Read more.

In this study, a two-step electrodeposition strategy was proposed to fabricate an eco-friendly superhydrophobic polyaniline (PANI)/silane composite coating on mild steel for corrosion protection. The first step consists of creating a pure PANI adherent coating using a cyclic voltammetry technique and the second step consists of realizing superhydrophobic features using electrodeposition in mixed silane monomers at constant potential. The structure and composition characterization results revealed successful modification of the underlying pure PANI layer with superhydrophobic surface silane film. Wettability tests indicated a high contact angle of 155° and a low sliding angle of 4.2°. Electrochemical measurements revealed that the corrosion current density of PANI/silane-coated mild steel decreased by approximately three orders of magnitude compared to the uncoated sample and the corrosion protection efficiency was as high as 99.6%. Moreover, the prepared PANI/silane hybrid coating exhibited good chemical stability and strong adhesion after 10 days of corrosion in 3.5 wt.% NaCl solution. Full article

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

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30 pages, 3611 KB

Open AccessReview

Chemical Recycling of Poly(ethylene terephthalate) to Functional Glycolysates: Overcoming Phase Instability and Secondary Crystallization

by Marek Lewandowski, Przemysław Kosobucki and Jacek Stuczyński

Polymers 2026, 18(16), 1961; https://doi.org/10.3390/polym18161961 - 11 Aug 2026

Abstract

Poly(ethylene terephthalate) (PET) waste management faces challenges as mechanical recycling limitations become apparent under strict EU regulations. This review critically evaluates PET glycolysis as a vital chemical recycling method, focusing on overcoming barriers to industrial implementation. While systematizing knowledge on reaction mechanisms and [...] Read more.

Poly(ethylene terephthalate) (PET) waste management faces challenges as mechanical recycling limitations become apparent under strict EU regulations. This review critically evaluates PET glycolysis as a vital chemical recycling method, focusing on overcoming barriers to industrial implementation. While systematizing knowledge on reaction mechanisms and parameters, a significant research gap is identified: the necessity for utilizing a high initial mass fraction of waste PET in the reaction feed. Specifically, exceeding a critical concentration of PET-derived oligomers in the resulting glycolysis reaction mixture (typically when the initial waste PET input is above 40% by mass) inevitably triggers phase instability and secondary crystallization during storage. This instability at high concentrations is fundamentally driven by the altered oligomer molecular-weight distribution and the thermodynamic supersaturation of rigid aromatic segments upon cooling. Traditional laboratory approaches using a high excess of glycolyzing agent fail to meet industrial stability demands for subsequent polyester polyol synthesis. Currently, preventing crystallization relies on costly branched glycols or modifiers to disrupt molecular symmetry. This article highlights the urgent need for alternative, additive-free methods to achieve phase stability, such as the elimination of released ethylene glycol from the reaction environment. By addressing shortcomings in glycolysate shelf-life studies, this review charts innovative directions for developing technologies that convert high concentrations of waste PET into phase-stable glycolysates. Full article

(This article belongs to the Special Issue Chemical Recycling of Polymers, 2nd Edition)

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24 pages, 4220 KB

Open AccessArticle

Design of Experiments Investigation of Sericin Acetylation Using a Quantitative FTIR Approach

by Rony Aad, Luca Leuzzi, Diletta Ami, Greta Bianchi, Marco Mangiagalli, Antonino Natalello, Laura Cipolla and Simone Vesentini

Polymers 2026, 18(16), 1960; https://doi.org/10.3390/polym18161960 - 11 Aug 2026

Abstract

Sericin, a silk-derived protein recovered as a by-product of the textile industry, is a renewable biomacromolecule with considerable potential for sustainable material development. Chemical modification represents an effective strategy for its valorization. In this study, acetylation using acetyl chloride (AcCl) was selected as [...] Read more.

Sericin, a silk-derived protein recovered as a by-product of the textile industry, is a renewable biomacromolecule with considerable potential for sustainable material development. Chemical modification represents an effective strategy for its valorization. In this study, acetylation using acetyl chloride (AcCl) was selected as a model reaction to systematically investigate the reactivity of sericin in an N,N-dimethylacetamide/lithium chloride (DMA/LiCl) solvent system and to evaluate the influence of reaction parameters on both the extent of functionalization and protein secondary structure. A Design of Experiments (DoE) strategy, comprising an initial full factorial screening followed by Box–Behnken optimization, was employed to investigate the effects of AcCl equivalents, sericin concentration, and LiCl content. A quantitative FTIR workflow based on constrained Gaussian deconvolution was developed to derive functionalization index (FI) and β-sheet index (BI) from both peak areas and peak intensities, enabling the simultaneous evaluation of chemical modification and structural organization. The exploratory screening identified AcCl as the dominant factor governing sericin functionalization. During the optimization phase, the FI models described the general response trends, whereas the BI was successfully represented by robust quadratic models (R² = 0.977–0.978; adjusted R² = 0.936–0.938), revealing significant linear, interaction, and quadratic effects, with LiCl concentration and sericin concentration playing key roles in governing structural organization. The analytical workflow was verified by reproducibility assessment and independent validation experiments. Overall, this study proposes a quantitative DoE–FTIR framework for systematically investigating sericin functionalization and its associated structural evolution, providing support for future studies aimed at sericin industrial valorization. Full article

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

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24 pages, 4925 KB

Open AccessArticle

Tuning the Calcination Temperature of ZnO in Chitosan–Graphene Oxide/Epoxy Coatings for Optimized Corrosion Mitigation of Carbon Steel

by Yasin Albarqouni, Euodia Banius, Farah Alfoudari, Aljoury Alsulaiti, Mohammad R. Thalji and Arman Bin Abdullah

Polymers 2026, 18(16), 1959; https://doi.org/10.3390/polym18161959 - 11 Aug 2026

Abstract

The corrosion-protection performance of zinc oxide-hybrid polymeric coatings is traditionally attributed to the individual contributions of their constituent phases. This study reveals that the calcination temperature of zinc oxide (ZnO) filler is a critical, previously overlooked processing parameter that dictates not only filler [...] Read more.

The corrosion-protection performance of zinc oxide-hybrid polymeric coatings is traditionally attributed to the individual contributions of their constituent phases. This study reveals that the calcination temperature of zinc oxide (ZnO) filler is a critical, previously overlooked processing parameter that dictates not only filler crystallinity but also the collective synergistic failure mechanism of the entire coating system. Herein, we demonstrate that incorporating ZnO calcined at 500 °C yields a ternary chitosan–graphene oxide–zinc oxide/epoxy (CS–GO–ZnO/EP) composite coating with a highly compact, dense morphology, minimal internal porosity, and exceptional filler dispersion, as validated by FTIR, XRD, and SEM analyses. The optimized CS–GO–ZnO/EP coating applied to carbon steel exhibits outstanding dry and wet pull-off adhesion strengths, the highest surface hydrophobicity (102.2°), and superior electrochemical barrier protection. Notably, after a 120-h immersion period in an aggressive 3.5 wt.% NaCl electrolyte, the CS–GO–ZnO/EP (500 °C) maintains excellent coating resistance (R_coat = 1.06 × 10⁵ Ω) and a minimized corrosion rate (CR = 0.074 mm/y). This thermal threshold is a key processing window that improves chemical bonding and compatibility between the different parts of the hybrid matrix without causing the severe nanoparticle sintering, phase aggregation, and micro-cracking that happen at 650 °C. This work offers a significant advancement in the design of eco-friendly, high-performance hybrid coatings, demonstrating that precise control of the inorganic phase’s thermal history provides a direct pathway toward superior durability, hydrophobicity, and electrochemical stability for carbon steel protection in aggressive marine environments. Full article

(This article belongs to the Special Issue Nanotechnology-Enabled Self-Healing Polymeric Coatings)

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30 pages, 12929 KB

Open AccessArticle

Multi-Objective Optimization of FDM Dimensional Accuracy for PLA/TPU Blends Based on Entropy Weight-TOPSIS and Orthogonal Array Design

by Pei Li, Tianlu Wei, Li Yang, Jing Zhao and Shuo Wang

Polymers 2026, 18(16), 1958; https://doi.org/10.3390/polym18161958 - 10 Aug 2026

Abstract

Fused deposition modeling (FDM) of polylactic acid (PLA) is plagued by dimensional inaccuracies—thermal shrinkage, warpage, and geometric distortion—that restrict its application in high-precision manufacturing. Blending thermoplastic polyurethane (TPU) with PLA enhances toughness, yet the coupled effects of blend ratio and printing parameters on [...] Read more.

Fused deposition modeling (FDM) of polylactic acid (PLA) is plagued by dimensional inaccuracies—thermal shrinkage, warpage, and geometric distortion—that restrict its application in high-precision manufacturing. Blending thermoplastic polyurethane (TPU) with PLA enhances toughness, yet the coupled effects of blend ratio and printing parameters on dimensional accuracy remain unclear. This study establishes a multi-objective optimization framework integrating single-factor experiments, orthogonal design, ANOVA, and entropy weight–TOPSIS. Single-factor experiments combined with TOPSIS first identify the optimal PLA/TPU blend ratio, and orthogonal experiments are subsequently conducted on this optimal ratio to determine the best parameter combination. The 70:30 PLA/TPU blend delivers the optimal comprehensive performance (TOPSIS closeness: 0.680), attributed to favorable phase compatibility and robust interfacial adhesion as verified by XRD and SEM. Range analysis and ANOVA on the orthogonal results identify infill rate and layer height as the dominant factors governing dimensional accuracy (p < 0.05). Under the optimized parameter set (60 mm/s, 210 °C, 90% infill, 0.1 mm layer), the total dimensional deviation reaches only 0.256 mm, substantially lower than single-objective counterparts (0.321–0.418 mm). This work offers a validated strategy for precision control in FDM through synergistic optimization of blend formulation and processing parameters. Full article

(This article belongs to the Section Polymer Processing and Engineering)

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15 pages, 15629 KB

Open AccessArticle

Anchorage-Capture Dual Mechanism in a Biomass-Derived Hydrogel Electrolyte for Dendrite-Free Aqueous Zinc Ion Batteries

by Shubing Zhen, Yali Song, Jingyu Xu, Xinhao Li, Jiayuan Luo, Yuyun Xie, Jinxi Ye, Yushi Wu, Guiling Wang, Qian Qu and Tong Zhang

Polymers 2026, 18(16), 1957; https://doi.org/10.3390/polym18161957 - 10 Aug 2026

Abstract

The design of biomass-derived polymer electrolytes with integrated multifunctionality represents a key strategy for sustainable energy storage devices. Here, we report a fully biomass-derived dual-network hydrogel electrolyte fabricated by combining Pectin (PC) and Chitosan (CTS), two naturally abundant polysaccharides. The Pectin/Chitosan dual-network hydrogel [...] Read more.

The design of biomass-derived polymer electrolytes with integrated multifunctionality represents a key strategy for sustainable energy storage devices. Here, we report a fully biomass-derived dual-network hydrogel electrolyte fabricated by combining Pectin (PC) and Chitosan (CTS), two naturally abundant polysaccharides. The Pectin/Chitosan dual-network hydrogel electrolyte (PC/CTS) forms a robust physically crosslinked network through electrostatic interactions between the carboxyl groups of PC and the amino groups of CTS, reinforced by dense hydrogen bonding and amide crosslinks, yielding a tensile strength of 77.76 MPa. The abundant polar functional groups of the dual polymer network serve a synergistic dual function: the amino groups of CTS preferentially adsorb onto the zinc anode surface (adsorption energy: −1.24 eV), forming a dynamic protective interphase, while the carboxyl groups of PC coordinate with Zn²⁺ (binding energy: −0.86 eV), reconstituting the solvation sheath and guiding uniform ion flux. This anchorage-capture mechanism, enabled by the molecular design of the polymer network, effectively suppresses dendrite growth, hydrogen evolution, and parasitic side reactions. Consequently, the PC/CTS electrolyte enables stable Zn//Zn cycling for 3350 h, 99.5% average Coulombic efficiency (CE) over 780 Zn//Cu cycles (at 5 mA cm⁻² and 1 mAh cm⁻²), and 63.8% capacity retention after 500 cycles in Zn//MnO₂ full cells. This work demonstrates that rational engineering of natural polymer networks can simultaneously address electrode stability challenges in aqueous batteries, offering a sustainable materials platform for next-generation energy storage devices. Full article

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

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37 pages, 1331 KB

Open AccessReview

Selective Textile Recycling with Deep Eutectic Solvents: A Mechanistic Framework

by Roderik Plavec, Mária Petková, Slávka Hlaváčiková, Marcela Hricová, Ján Kruželák and Jozef Feranc

Polymers 2026, 18(16), 1956; https://doi.org/10.3390/polym18161956 - 10 Aug 2026

Abstract

Textile waste is no longer dominated by simple single-polymer materials. Most post-consumer textiles contain combinations of natural and synthetic fibres, elastane, dyes, coatings, finishes, and other additives, which makes selective recycling considerably more difficult. Deep eutectic solvents (DES) offer a promising route for [...] Read more.

Textile waste is no longer dominated by simple single-polymer materials. Most post-consumer textiles contain combinations of natural and synthetic fibres, elastane, dyes, coatings, finishes, and other additives, which makes selective recycling considerably more difficult. Deep eutectic solvents (DES) offer a promising route for addressing this complexity because their composition and physicochemical properties can be widely tuned. However, the outcome of DES treatment is often discussed mainly in terms of solvent composition or solvent–polymer affinity, although these factors alone cannot explain why similar DES formulations may lead to different responses in different polymeric or textile systems. In this review, DES-assisted textile recycling is examined from a mechanistic polymer-science perspective. The discussion focuses on how polymer morphology, transport accessibility, supramolecular organization, chemical reactivity, and processing conditions jointly determine whether a material undergoes swelling, molecular dissolution, structural destabilization, or chemical degradation. Particular attention is paid to the distinction between these processes, since changes in sample mass, fibre appearance, or crystallinity do not by themselves prove either true polymer dissolution or chain scission. Evidence from cellulose-based fibres, polyesters, polyamides, polyurethanes, elastane-containing materials, and multicomponent textile systems is used to show how different material outcomes may arise from apparently related DES–polymer interactions. The reviewed studies indicate that selectivity in DES-assisted textile recycling should not be treated as a fixed property of the solvent or of the polymer alone. It is more appropriately understood as the result of a coupled and time-dependent interaction between the DES medium, polymer morphology, textile architecture, and processing conditions. The mechanistic framework proposed here provides a basis for comparing reported DES-based recycling strategies, identifying the experimental evidence needed to support mechanistic claims, and guiding the rational selection of DES composition, process conditions, and recovery pathways for complex textile waste. Full article

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

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