Polymers

16 pages, 2807 KiB

Open AccessReview

Research on the Rapid Curing Mechanism and Technology of Chinese Lacquer

by Jiangyan Hou, Tianyi Wang, Yao Wang, Xinhao Feng and Xinyou Liu

Polymers 2025, 17(12), 1596; https://doi.org/10.3390/polym17121596 (registering DOI) - 7 Jun 2025

Chinese lacquer, a historically significant bio-based coating, has garnered increasing attention in sustainable materials research due to its outstanding corrosion resistance, thermal stability, and environmental friendliness. Its curing process relies on the laccase-catalyzed oxidation and polymerization of urushiol to form a dense lacquer [...] Read more.

Chinese lacquer, a historically significant bio-based coating, has garnered increasing attention in sustainable materials research due to its outstanding corrosion resistance, thermal stability, and environmental friendliness. Its curing process relies on the laccase-catalyzed oxidation and polymerization of urushiol to form a dense lacquer film. However, the stringent temperature and humidity requirements (20–30 °C, 70–80% humidity) and a curing period that can extend over several weeks severely constrain its industrial application. Recent studies have significantly enhanced the curing efficiency through strategies such as pre-polymerization control, metal ion catalysis (e.g., Cu²⁺ reducing drying time to just one day), and nanomaterial modification (e.g., nano-Al₂O₃ increasing film hardness to 6H). Nevertheless, challenges remain, including the sensitivity of laccase activity to environmental fluctuations, the trade-off between accelerated curing and film performance, and issues related to toxic pigments and VOC emissions. Future developments should integrate enzyme engineering (e.g., directed evolution to broaden laccase tolerance), intelligent catalytic systems (e.g., photo-enzyme synergy), and green technologies (e.g., UV curing), complemented by multiscale modeling and circular design strategies, to drive the innovative applications of Chinese lacquer in high-end fields such as aerospace sealing and cultural heritage preservation. Full article

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

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20 pages, 7089 KiB

Open AccessArticle

Tuning Biodegradation and Physicochemical Features of PLA/HAp Biomaterials by Incorporating Nanofibrillated Cellulose Through a Colloidal Processing Route

by Maria Eugenia Juan-Cano, Zoilo Gonzalez, Esther Rincón, Antonio Javier Sanchez-Herencia, Begoña Ferrari and Ana Ferrández-Montero

Polymers 2025, 17(12), 1595; https://doi.org/10.3390/polym17121595 (registering DOI) - 7 Jun 2025

Abstract

Biomaterials play a fundamental role in providing a porous structure that mimics the natural structure of human bone and serves as a support while tissue regenerates. With the use of biodegradable materials, it is possible to avoid unnecessary second surgeries for implant removal. [...] Read more.

Biomaterials play a fundamental role in providing a porous structure that mimics the natural structure of human bone and serves as a support while tissue regenerates. With the use of biodegradable materials, it is possible to avoid unnecessary second surgeries for implant removal. The main objective of this article has been focused on modifying the degradation rate of a biodegradable composite material based on polylactic acid (PLA) reinforced with hydroxyapatite (HAp) by incorporating nanofibrillated cellulose (NFC), capable of tuning the porosity within the matrix. To introduce NFC into the composite material, a colloidal processing approach was chosen to improve and ensure its compatibility with the polymeric matrix. The incorporation of different ratios of NFC generally decreases the mechanical properties, but by adjusting the ratio of HAp/NFC content, this parameter is normalized. The hydrophilicity of the composite is improved by HAp/NFC incorporation, and degradation tests confirm that an increase in the percentage of NFC in the matrix is directly proportional to an increase in the degradation rates of the material. These results represent a significant improvement in personalized medicine, where the design of biodegradable biomaterials with hierarchical and controlled porosity opens new paths in the development of therapies and treatments personalized for each patient. Full article

(This article belongs to the Special Issue Polymer/Ceramic Composites, 2nd Edition)

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22 pages, 1594 KiB

Open AccessArticle

Electrospun Polybenzimidazole Membranes: Fabrication and Fine-Tuning Through Physical and Statistical Approaches

by Emmanuel De Gregorio, Giuseppina Roviello, Valentina Naticchioni, Viviana Cigolotti, Alfonso Pozio, Luis Alexander Hein, Carlo De Luca, Claudio Ferone, Antonio Rinaldi and Oreste Tarallo

Polymers 2025, 17(12), 1594; https://doi.org/10.3390/polym17121594 - 6 Jun 2025

Abstract

Polybenzimidazole (PBI), a high-performance polymer known for its exceptional thermal stability and chemical resistance, was processed by solution electrospinning to manufacture fibrous non-woven membranes. The process was repeated under different conditions by adjusting four main settings: the polymer solution concentration, the flow rate, [...] Read more.

Polybenzimidazole (PBI), a high-performance polymer known for its exceptional thermal stability and chemical resistance, was processed by solution electrospinning to manufacture fibrous non-woven membranes. The process was repeated under different conditions by adjusting four main settings: the polymer solution concentration, the flow rate, the voltage applied between the needle and the collector, and the separating distance. To clarify the interplay between process parameters and material properties, a Design of Experiment (DOE) approach was used to systematically analyze the effects of said parameters on microstructural properties, including fiber diameter, porosity, and air permeability, pointing out that the increase in viscosity improves fiber uniformity, while optimizing the applied voltage and the needle–collector distance enhances jet stability and solvent evaporation, crucial for defect-free fibrous microstructures. Post-processing via calendering further refined the membrane texture and properties, for example by reducing porosity and air permeability without significantly altering the fibrous morphology, particularly at low lamination ratios. Thermal and mechanical evaluations highlighted that the obtained electrospun PBI membranes exhibited enhanced flexibility, but lower tensile strength compared to cast films due to the underlying open pore microstructure. This integrated approach—combining experimental characterization, DOE-guided optimization, and post-processing via calendering—provides a systematic framework for tailoring PBI membranes for specific applications, such as filtration, fuel cells, and molecular sieving. The findings highlight the potential of PBI-based electrospun membranes as versatile materials, offering high thermal stability, chemical resistance, and tunable properties, thereby establishing a foundation for further innovation in advanced polymeric membrane design and applications for energy and sustainability. Full article

(This article belongs to the Special Issue Polymeric Membrane Science and Surface Modification Technologies: 2nd Edition)

19 pages, 6947 KiB

Open AccessArticle

Simulation of the Pyrolysis Process of Cyclohexane-Containing Semi-Aromatic Polyamide Based on ReaxFF-MD

by Xiaotong Zhang, Yuanbo Zheng, Qian Zhang, Kai Wu, Qinwei Yu and Jianming Yang

Polymers 2025, 17(12), 1593; https://doi.org/10.3390/polym17121593 - 6 Jun 2025

Abstract

Cyclohexane-containing semi-aromatic polyamides (c-SaPA) exhibit excellent comprehensive properties. Existing studies predominantly focus on synthesis and modification, while fundamental investigations into pyrolysis mechanisms remain limited, which restricts the development of advanced materials for high-performance applications such as automotive and energy systems. This study employs [...] Read more.

Cyclohexane-containing semi-aromatic polyamides (c-SaPA) exhibit excellent comprehensive properties. Existing studies predominantly focus on synthesis and modification, while fundamental investigations into pyrolysis mechanisms remain limited, which restricts the development of advanced materials for high-performance applications such as automotive and energy systems. This study employs Reactive Force Field Molecular Dynamics (ReaxFF-MD) simulations to establish a pyrolysis model for poly(terephthaloyl-hexahydro-m-xylylenediamine) (PHXDT), systematically probing its pyrolysis kinetics and evolutionary pathways under elevated temperatures. The simulation results reveal an activation energy of 107.55 kJ/mol and a pre-exponential factor of 9.64 × 10¹³ s⁻¹ for the pyrolysis process. The primary decomposition pathway involves three distinct stages. The first is initial backbone scission generating macromolecular fragments, followed by secondary fragmentation that preferentially occurs at short-chain hydrocarbon formation sites alongside radical recombination. Ultimately, the process progresses to deep dehydrogenation, carbonization, and heteroatom elimination through sequential reaction steps. Mechanistic analysis identifies multi-pathway pyrolysis involving carboxyl/amide bond cleavage and radical-mediated transformations (N-C-O, C-C-O, OH· and H·), yielding primary products including H₂, CO, H₂O, CH₃N, C₂H₂, and C₂H₄. Crucially, the cyclohexane structure demonstrates preferential participation in dehydrogenation and hydrogen transfer reactions due to its conformational dynamic instability and low bond dissociation energy, significantly accelerating the rapid generation of small molecules like H₂. Full article

(This article belongs to the Section Polymer Chemistry)

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14 pages, 2552 KiB

Open AccessArticle

Architecting Porosity Through Monomer Engineering: Hypercrosslinked Polymers for Highly Selective CO₂ Capture from CH₄ or N₂

by Lin Liu, Qi Zhang, Xue Leng, Rui Song and Zheng-Bo Han

Polymers 2025, 17(12), 1592; https://doi.org/10.3390/polym17121592 - 6 Jun 2025

Abstract

Natural gas purification and the mitigation of carbon dioxide (CO₂) emissions from flue gases are critical steps in alleviating the greenhouse effect and significantly mitigate multiple environmental challenges associated with global warming. Hypercrosslinked polymers (HCPs) have become a hot topic as [...] Read more.

Natural gas purification and the mitigation of carbon dioxide (CO₂) emissions from flue gases are critical steps in alleviating the greenhouse effect and significantly mitigate multiple environmental challenges associated with global warming. Hypercrosslinked polymers (HCPs) have become a hot topic as prospective adsorbents for gas purification and separation, owing to their low cost and scalability. Hence, TPB-Ben, TPB-Nap, and TPB-Ant were synthesized through a solvent knitting strategy, with the modification in the size of the monomers serving as a distinctive feature. This alteration aimed to explore the impact of phenyl ring quantity on the polymers’ gas adsorption and separation efficiency. All HCPs showed outstanding selective separation capability of CO₂ from CO₂/CH₄ and CO₂/N₂ mixtures, such as TPB-Ben-3-2 (CO₂/CH₄: 10.77; CO₂/N₂: 59.72), TPB-Nap-3-2 (CO₂/CH₄: 9.12; CO₂/N₂: 61.31), and TPB-Ant-3-2 (CO₂/CH₄: 10.00; CO₂/N₂: 62.89), which could be potential candidate adsorbents for natural gas purification and CO₂ capture. Considering the mild reaction conditions, low cost, efficient gas adsorption, and the potential for scalable production, these polymers are considered ideal selective solid adsorbents for capturing CO₂. This further highlights the significance of the solvent knitting strategy. Full article

(This article belongs to the Special Issue Application and Development of Polymer-Based Catalysts)

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19 pages, 7616 KiB

Open AccessReview

Sensitive Chemical and Biological Sensors Based on Phosphorus Dendrimers

by Anne-Marie Caminade

Polymers 2025, 17(12), 1591; https://doi.org/10.3390/polym17121591 - 6 Jun 2025

Abstract

Dendrimers are a special type of ball-shaped hyperbranched polymers consisting of branched monomers organized stepwise around a multifunctional core. They possess many reactive functions, and they are easily accessible as they are located on the surface of the dendrimers. By modifying their terminal [...] Read more.

Dendrimers are a special type of ball-shaped hyperbranched polymers consisting of branched monomers organized stepwise around a multifunctional core. They possess many reactive functions, and they are easily accessible as they are located on the surface of the dendrimers. By modifying their terminal functions, it is possible to change the specificities of dendrimers to give them the desired properties. Dendrimers have been used as catalysts, in diverse fields of nanomedicine, and for the elaboration or modification of materials. The internal structure of dendrimers should be carefully chosen depending on the sought-after properties. Poly(phosphorhydrazone) (PPH) dendrimers possess a relatively rigid and hydrophobic internal structure and an easily functionalized surface, which make them appealing in the field of materials. Indeed, they can be used as a matrix, as glue for stabilizing multilayers, or as multifunctional tools. This review describes the use of PPH dendrimers and dendrons (dendritic wedges) for elaborating sensitive chemical, electrochemical, and biological sensors. Full article

(This article belongs to the Special Issue Development of Applications of Polymer-Based Sensors and Actuators)

19 pages, 8320 KiB

Open AccessArticle

Optimization of Produced Parameters for PA6/PA6GF30 Composite Produced by 3D Printing with Novel Knitting Method

by Selim Hartomacıoğlu, Mustafa Oksuz, Aysun Ekinci and Murat Ates

Polymers 2025, 17(12), 1590; https://doi.org/10.3390/polym17121590 - 6 Jun 2025

Abstract

The additive manufacturing sector is rapidly developing, providing alternatives for mass production in the polymer composite industry. Due to the direction-dependent mechanical properties and high cost of fiber-reinforced polymeric materials, it is necessary to take advantage of alternative multi-materials and production technologies. In [...] Read more.

The additive manufacturing sector is rapidly developing, providing alternatives for mass production in the polymer composite industry. Due to the direction-dependent mechanical properties and high cost of fiber-reinforced polymeric materials, it is necessary to take advantage of alternative multi-materials and production technologies. In this study, a special geometric-shaped knitting technique was investigated using two different materials. The main material was polyamide 6 (PA6), and the inner or second material was PA6 with a 30 wt.% glass fiber addition by weight (PA6GF30). The special geometric shape, layer thickness, nozzle temperature, and post-heat treatment time were measured as process parameters in the production of the PA6/PA6GF30 composites with the fused deposition modeling (FDM) technique. The Taguchi design method and L9 fractional experiment were used in the experimental study. The mechanical behaviors of the PA6/PA6GF30 samples were obtained using tensile and impact tests. In addition, scanning electron microscopy (SEM) analyses were performed on the fracture lines of the PA6/PA6GF30 samples, and damage analyses were carried out in more detail. The experimental results were sorted using grey relational analysis (GRA). Moreover, the optimal experimental conditions and their related plots were obtained. As a result, the highest tensile strength of the PA6GF30 composite was 89.89 MPa with the addition of a special geometric shape. In addition, the maximum impact resistance value of the PA6/PA6GF30 composite was 83 kJ/m². Hence, the developed knitting method presented many advantages when using the FDM technique, and both were successfully used to produce the PA6/PA6GF30 composites. Full article

(This article belongs to the Special Issue 3D Printing of Polymer Composite Materials)

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Graphical abstract

21 pages, 4436 KiB

Open AccessArticle

Alkaline Extraction and Ethanol Precipitation of High-Molecular-Weight Xylan Compounds from Eucalyptus Residues

by María Noel Cabrera, Antonella Rossi, Juan Ignacio Guarino, Fernando Esteban Felissia and María Cristina Area

Polymers 2025, 17(12), 1589; https://doi.org/10.3390/polym17121589 - 6 Jun 2025

Abstract

Alkaline treatment is well suited for extracting high-molecular-weight hemicelluloses, specifically hardwoods xylans, which, due to their polymer structure and chemical characteristics, enable the production of films with desirable mechanical, barrier, and optical properties for packaging applications. Despite its relevance, the optimization of antisolvent [...] Read more.

Alkaline treatment is well suited for extracting high-molecular-weight hemicelluloses, specifically hardwoods xylans, which, due to their polymer structure and chemical characteristics, enable the production of films with desirable mechanical, barrier, and optical properties for packaging applications. Despite its relevance, the optimization of antisolvent addition has received little attention in the literature. This study explores the use of eucalyptus industrial residue as feedstock, utilizing a statistical design to determine the optimal extraction conditions for hemicelluloses while minimizing the lignin content in the recovered liquor. The process uses alkali loads that are compatible with those in conventional Kraft pulp mills. Optimal extraction conditions involve a temperature of 105 °C, 16.7% NaOH charge, and 45 min at maximum temperature. The resulting liquor was subjected to ethanol precipitation under varying pH conditions (initial pH, 9, 7, 5, and 2) and different ethanol-to-liquor ratios (1:1 to 4:1). The acidification was performed using hydrochloric, sulfuric, and acetic acids. Ethanol served as the main antisolvent, while isopropyl alcohol and dioxane were tested for comparison. Results show that 2.3 ± 0.2% of xylans (based on oven-dry biomass) could be extracted, minimizing lignin content in the liquor. This value corresponds to the extraction of 15.6% of the xylans present in the raw material. The highest xylan precipitation yield (78%) was obtained at pH 7, using hydrochloric acid for pH adjustment and an ethanol-to-liquor ratio of 1:1. These findings provide valuable insight into optimizing hemicellulose recovery through antisolvent precipitation, contributing to more efficient biomass valorization strategies within lignocellulosic biorefineries. Full article

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

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18 pages, 4956 KiB

Open AccessArticle

Construction of Fire-Retardant PEO Composite Based on Calcium Sulfate Whiskers Fabricated from Phosphogypsum and DOPO Derivatives

by Jie Zhang, Wei Yan, Weijiang Huang, Kui Wang, Qin Tian, Chunyun Tu, Xingyu Guan, Shaoyuan Wu, Xuan Ba, Chunle Wei, Tong Ye, Jingyu Chen and Yi Zhang

Polymers 2025, 17(12), 1588; https://doi.org/10.3390/polym17121588 - 6 Jun 2025

Abstract

Incorporating a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-based derivative (1,4-bis(diphenoxyphosphoryl)piperazine, DIDOPO) in combination with modified calcium sulfate whiskers (MCSWs) improved the flame retardancy, thermal stability, and rheological properties of a polyethylene oxide (PEO) composite. The synergistic flame-retardant effect of DIDOPO and MCSW on the PEO system was investigated. [...] Read more.

Incorporating a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-based derivative (1,4-bis(diphenoxyphosphoryl)piperazine, DIDOPO) in combination with modified calcium sulfate whiskers (MCSWs) improved the flame retardancy, thermal stability, and rheological properties of a polyethylene oxide (PEO) composite. The synergistic flame-retardant effect of DIDOPO and MCSW on the PEO system was investigated. After introducing 5 wt.% MCSW and 10 wt.% DIDOPO into PEO, the UL-94 rating of the composite reached V-0, and the limiting oxygen index was increased to 26.5%. Additionally, the peak and average heat release rates and total heat release of the PEO/10% DIDOPO/5% MCSW composite decreased by 38.9%, 22%, and 20.07%, respectively. The results of a thermogravimetric analysis (TGA) revealed that PEO/10% DIDOPO/5% MCSW displayed an improved initial thermal stability and rate of char formation compared to those of the PEO matrix. The results of TGA/Fourier transform infrared analysis indicated that the composites exhibited phosphorus-containing groups during thermal degradation, based on the characteristic absorption peaks, and increased amounts of gas-phase volatiles. The morphologies and structures of the residues indicated that the PEO/10% DIDOPO/5% MCSW blend was less stable than PEO during combustion. The MCSW mixture formed a denser, more continuous carbon layer on the composite surface during combustion. The rheological behavior indicated that the high complex viscosity and moduli of PEO/10% DIDOPO/5% MCSW promoted the cross-linking network structure of the condensed phase during combustion. MCSW exhibited an excellent flame retardancy and improved thermal stability, which are potentially promising for use in fire safety applications. Full article

(This article belongs to the Section Polymer Applications)

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25 pages, 11048 KiB

Open AccessArticle

High-Temperature Mechanical and Microstructural Properties of Well Cement Modified with Ethylene-Vinyl Acetate Polymer and Polypropylene Fibers for Geothermal Well Applications

by Shisen Zhao, Kai Qiu and Zhisong Xu

Polymers 2025, 17(12), 1587; https://doi.org/10.3390/polym17121587 - 6 Jun 2025

Abstract

The high-temperature performance of well cement is critical for the construction of deep geothermal wells and high-temperature energy storage wells, where mechanical integrity and pore structure stability govern wellbore reliability. To address the strength degradation and structural deterioration of conventional cements under high [...] Read more.

The high-temperature performance of well cement is critical for the construction of deep geothermal wells and high-temperature energy storage wells, where mechanical integrity and pore structure stability govern wellbore reliability. To address the strength degradation and structural deterioration of conventional cements under high temperature, the G-class cement was modified by ethylene-vinyl acetate (EVA) polymer and polypropylene fibers (PF), and their impact under various temperatures was explored. Results show that at 600 °C, the compressive strength of modified cement remains above 30 MPa. While the cumulative pore area decreases at 500 °C, a significant increase in larger pores and a major restructuring of the pore network occurs at 600 °C, reflecting the dual effects of high temperature on the pore structure. The modified cement retains structural integrity and excellent mechanical performance up to 400 °C with minimal strength loss, uniform strain distribution, and stable pore structure. At 500 °C and above, it still maintains load-bearing capacity and deformation adaptability, meeting the service requirements for geothermal wells and high-temperature energy storage wells. Even at 600 °C, the reinforcing effect of EVA and PF degradation products slow down crack propagation, ensuring durability in extreme conditions. The research findings lay the foundation for the development of well cement for high-temperature service environments. Full article

(This article belongs to the Section Polymer Applications)

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19 pages, 2261 KiB

Open AccessArticle

Impact of Microplastic Contamination on Phosphorus Availability, Alkaline Phosphatase Activity, and Polymer Degradation in Soil

by Efsun Dindar

Polymers 2025, 17(12), 1586; https://doi.org/10.3390/polym17121586 - 6 Jun 2025

Abstract

Microplastics (MPs) are emerging contaminants that can significantly impact soil nutrient dynamics, particularly phosphorus (P) cycling, which is critical for maintaining soil fertility and ecosystem productivity. However, limited information is available on how different microplastic types and concentrations specifically influence phosphorus dynamics and [...] Read more.

Microplastics (MPs) are emerging contaminants that can significantly impact soil nutrient dynamics, particularly phosphorus (P) cycling, which is critical for maintaining soil fertility and ecosystem productivity. However, limited information is available on how different microplastic types and concentrations specifically influence phosphorus dynamics and microbial enzyme activity in soils. Microplastic contamination may alter P cycling by directly supplying phosphorus or indirectly influencing microbial activity and enzyme function through changes in soil structure and aggregation. This study examined the short-term impacts of three widely used microplastic polymers—polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET)—on soil phosphorus forms and alkaline phosphatase activity (APA), a key enzyme in phosphorus transformation. Incubation experiments were conducted at two concentrations (0.5% and 5%) over 30 and 60 days. The results indicated that the impact of microplastics on soil phosphorus dynamics varied according to both polymer type and contamination dose. Microplastics increased available phosphorus (AP) and APA levels compared to control soils, indicating a stimulatory effect on microbial processes. This may be due to the temporary accumulation of phosphorus on MP surfaces, which can stimulate phosphatase activity. Over time, however, both AP and APA levels declined, suggesting that degradation products released from MPs and organic matter may have altered the activity of the microbial communities responsible for P cycling. FTIR analysis revealed clear degradation of microplastics, with PET showing the most pronounced chemical transformation. PP exhibited moderate degradation, while PE demonstrated the highest resistance to environmental breakdown. These degradation processes likely released functional groups (e.g., carboxyl, carbonyl, hydroxyl) and low-molecular-weight compounds into the soil, modifying microbial processes and phosphorus chemistry. Particularly in PET-amended soils, these degradation products may have enhanced phosphate complexation or mobilization, contributing to higher levels of available phosphorus at the end of the incubation time. Understanding the polymer-specific and concentration-dependent effects of microplastics is critical for accurate ecological risk assessment in terrestrial ecosystems. Full article

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

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18 pages, 1809 KiB

Open AccessArticle

A Photo-Crosslinked Casein-Tannic Acid System for Enhanced Hair Protection: A Green Chemistry Approach

by Sujin Kyung, Won-Gun Koh and Hyun Jong Lee

Polymers 2025, 17(12), 1585; https://doi.org/10.3390/polym17121585 - 6 Jun 2025

Abstract

Hair is continuously exposed to various damaging factors in daily life, necessitating effective protective strategies that balance efficacy with environmental sustainability. In this study, we developed an environmentally friendly hair protective coating using casein proteins crosslinked with tannic acid via riboflavin phosphate-mediated photo-initiation. [...] Read more.

Hair is continuously exposed to various damaging factors in daily life, necessitating effective protective strategies that balance efficacy with environmental sustainability. In this study, we developed an environmentally friendly hair protective coating using casein proteins crosslinked with tannic acid via riboflavin phosphate-mediated photo-initiation. Casein solutions containing tannic acid (0.05% w/v) and riboflavin phosphate (0.01–0.1% w/v) were prepared and applied to virgin Asian hair, followed by blue light irradiation to initiate crosslinking. The coating formation mechanism was investigated through rheological characterization, which confirmed successful network formation with optimal mechanical stability at a 0.05% tannic acid concentration. Chemical analysis using FTIR spectroscopy revealed subtle but meaningful interactions between the coating components, while SEM analysis demonstrated the coating’s integration with the hair surface. Mechanical property evaluations showed that the photo-crosslinked coating significantly enhanced hair tensile strength by approximately 21% compared to untreated hair, while maintaining appropriate elasticity. Region-specific analysis of stress–strain behavior indicated that the coating extended the initial Hookean region while preserving natural resistance in the post-yield region, creating a balanced enhancement in mechanical properties. This approach offers a promising alternative to conventional hair treatments by utilizing natural, food-grade components and mild processing conditions, addressing growing demands for sustainable hair care solutions that effectively protect against daily damage. Full article

(This article belongs to the Special Issue Next-Generation Hydrogel Platforms: From Synthesis Strategies to Advanced Applications)

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17 pages, 4594 KiB

Open AccessArticle

Optimizing Mechanical and Microstructural Properties of Sandy Clayey Silt Stabilized with Lignin Fiber and Cement Synergy

by Shuangfeng Guo, Xiaoyi Jiang, Zhihua Zhang, Qingrui Lu, Zhe Wang and Kai Zhao

Polymers 2025, 17(11), 1584; https://doi.org/10.3390/polym17111584 - 5 Jun 2025

Abstract

Soil treatment with natural materials is an effective method to improve the mechanical properties of the original soil for recycling engineering construction. This research aims to evaluate the synergistic effects of lignin fiber and cement on sandy clayey silt stabilization. A factorial experimental [...] Read more.

Soil treatment with natural materials is an effective method to improve the mechanical properties of the original soil for recycling engineering construction. This research aims to evaluate the synergistic effects of lignin fiber and cement on sandy clayey silt stabilization. A factorial experimental design was employed, testing five lignin fiber contents (0%, 2%, 4%, 6%, and 8%) and three cement contents (0%, 2%, and 4%) across four curing periods (1, 7, 14, and 30 days). Unconfined compressive strength (UCS) tests were conducted in triplicate for each combination (total *n* = 180 samples), and failure surfaces were analyzed using Scanning Electron Microscopy with Energy Dispersive X-ray spectroscopy (SEM-EDX). Results indicate a critical lignin fiber threshold of 4%, beyond which UCS decreased by 15–20% due to increased void ratios. Statistical analysis (ANOVA, *p* < 0.05) confirmed significant interactions between lignin fiber, cement content, and curing time. For instance, 4% lignin fiber and 4% cement yielded a 139% UCS increase after 30-day curing compared to untreated soil. SEM-EDX revealed that lignin fiber networks enhance ductility by bridging soil particles, while cement hydration reduced particle detachment. These findings provide a quantitative framework for optimizing lignin fiber-cement stabilization in sustainable geotechnical applications. Full article

(This article belongs to the Special Issue Mechanical Response Characteristics and Performance Evaluation of Polymer Materials)

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29 pages, 3531 KiB

Open AccessArticle

Experimentally and Modeling Assessment of Parameters Affecting Grinding Aid-Containing Cement–PCE Compatibility: CRA, MARS and AOMA-ANN Methods

by Yahya Kaya, Hasan Tahsin Öztürk, Veysel Kobya, Naz Mardani and Ali Mardani

Polymers 2025, 17(11), 1583; https://doi.org/10.3390/polym17111583 - 5 Jun 2025

Abstract

In this study, the compatibility of polycarboxylate ether-based water-reducing admixtures (PCE) with cements produced with different types and dosages of grinding aids (GA) was experimentally and statistically investigated. A total of 203 paste mixtures were prepared using seven different types of GA and [...] Read more.

In this study, the compatibility of polycarboxylate ether-based water-reducing admixtures (PCE) with cements produced with different types and dosages of grinding aids (GA) was experimentally and statistically investigated. A total of 203 paste mixtures were prepared using seven different types of GA and one type of PCE at different dosages. The Marsh funnel flow time and mini-slump values of the mixtures were compared. A modeling study was performed using the experimental data. In this direction, Classical Regression Analysis (CRA), Multivariate Adaptive Regression Splines (MARS), and Artificial Neural Networks (AOMA-ANN) were applied. Innovative approaches, AOMA-ANN (AIP) and AOMA-ANN (ONIP), were introduced. The results showed adverse effects on flow performance with increased GA utilization, except for TEA-based GA. TEA-type GA had the lowest flow performance. AOMA-ANN (ONIP) exhibited the best performance in modeling. Marsh funnel flow-time modeling with AOMA-ANN (ONIP) considered parameters such as sieve residue at 60 microns, the number of molecules per fineness, the density of GA, the pH value of GA, and the PCE dosage. Mini-slump modeling with AOMA-ANN (ONIP) considered parameters such as sieve residue at 60 microns, the density of GA, the pH value of GA, and the PCE dosage. Full article

(This article belongs to the Special Issue Preparation, Structure and Characterization of Polymer/Cement Composites—3rd Edition)

19 pages, 4804 KiB

Open AccessArticle

From Waste to Technological Products: Bioplastics Production from Proteins Extracted from the Black Soldier Fly

by Alessia Di Pasquale, Marina Zoccola, Ashish Mohod, Giulia Dalla Fontana, Anastasia Anceschi and Sara Dalle Vacche

Polymers 2025, 17(11), 1582; https://doi.org/10.3390/polym17111582 - 5 Jun 2025

Abstract

The need to find sustainable solutions to conventional plastics has driven research into alternative materials, including bioplastics, which represent a promising option for reducing pollution and enhancing the value of renewable resources. In this study, bioplastics made from polyvinyl alcohol (PVA) and proteins [...] Read more.

The need to find sustainable solutions to conventional plastics has driven research into alternative materials, including bioplastics, which represent a promising option for reducing pollution and enhancing the value of renewable resources. In this study, bioplastics made from polyvinyl alcohol (PVA) and proteins extracted from the larvae of Black Soldier Fly (BSF), an insect capable of converting organic waste into high-value biomass, were produced and characterized. The proteins were obtained by hydrolysis of defatted BSF larvae with superheated water, avoiding harsh chemical reagents. Next, polymer films were fabricated by mixing PVA and hydrolyzed BSF proteins in different proportions and analyzed for morphological, physical-chemical, mechanical and biodegradability characteristics. The results obtained show that as the BSF protein content increases, the films show a reduction in thermal stability and mechanical properties, and also, they exhibit higher biodegradability, correlated with higher wettability, solubility and ability to absorb moisture. This research highlights the value of using organic waste-fed insects as a resource for bioplastic production, offering an alternative to traditional polymers and contributing to the transition to sustainable materials. Full article

(This article belongs to the Special Issue High-Value Polymer Materials from Waste Recovery and Recycling)

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14 pages, 1694 KiB

Open AccessArticle

An Assessment of Anion Exchange Membranes for CO₂ Capture Processes: A Focus on Fumasep^® and Sustainion^®

by Kseniya Papchenko, Sandra Kentish and Maria Grazia De Angelis

Polymers 2025, 17(11), 1581; https://doi.org/10.3390/polym17111581 - 5 Jun 2025

Abstract

Anion exchange membranes are utilised in cutting-edge energy technologies including electrolysers and fuel cells. Recently, these membranes have also emerged as a promising tool in CO₂ capture techniques, such as moisture-driven direct air capture and the separation of CO₂ from other [...] Read more.

Anion exchange membranes are utilised in cutting-edge energy technologies including electrolysers and fuel cells. Recently, these membranes have also emerged as a promising tool in CO₂ capture techniques, such as moisture-driven direct air capture and the separation of CO₂ from other gases, leveraging the moisture-induced sorption/desorption and diffusion of CO₂ in its ionic forms. In this study, we examine the absorption and permeation of CO₂ and CH₄ in two commercially available anion exchange membranes, Fumasep^® and Sustainion^®, under dry conditions. With the exception of CO₂ sorption in Fumasep^®, these measurements have not been previously reported. These new data points are crucial for evaluating the fundamental separation capabilities of these materials and for devising innovative CO₂ capture strategies, as well as for the simulation of novel combined processes. In a dry state, both materials demonstrate similar CO₂ absorption levels, with a higher value for Sustainion^®. The CO₂ solubility coefficient decreases with pressure, as is typical for glassy polymers. Fumasep^® exhibits higher CO₂/CH₄ ideal solubility selectivity, equal to ~10 at sub-ambient pressures, and higher diffusivity. The CO₂ diffusion coefficient increases with the CO₂ concentration in both membranes due to swelling of the matrix, varying between 0.7 and 2.2 × 10⁻⁸ cm²/s for Fumasep^® and between 1.6 and 9.0 × 10⁻⁹ cm²/s for Sustainion^®. CO₂ permeability exhibits a minimum at a pressure of approximately 2–3 bar. The CO₂ permeability in the dry state is higher in Fumasep^® than in Sustainion^®: 3.43 and 0.72 Barrer at a 2-bar transmembrane pressure, respectively. The estimated perm-selectivity was found to reach values of up to 40 at sub-ambient pressures. The CO₂ permeability and CO₂/CH₄ estimated perm-selectivity in both polymers are of a similar order of magnitude to those measured in fluorinated ion exchange membranes such as Nafion^®. Full article

(This article belongs to the Special Issue Recent Trends in Polymer Membranes: Fabrication Technique, Characterization, Functionalization, and Applications in Environmental Science, 2nd Edition)

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27 pages, 7515 KiB

Open AccessReview

Molecular Design and Role of the Dynamic Hydrogen Bonds and Hydrophobic Interactions in Temperature-Switchable Polymers: From Understanding to Applications

by Yurij Stetsyshyn, Halyna Ohar, Andrzej Budkowski and Giuseppe Lazzara

Polymers 2025, 17(11), 1580; https://doi.org/10.3390/polym17111580 - 5 Jun 2025

Abstract

Temperature-induced transitions in polymer systems, often governed by a phenomenon called critical solution temperatures (CSTs), lie on the basis of various advanced technologies such as tissues detachment, smart windows, enhanced DNA biosensors, etc. Despite this application-oriented progress, the molecular mechanisms of the temperature-induced [...] Read more.

Temperature-induced transitions in polymer systems, often governed by a phenomenon called critical solution temperatures (CSTs), lie on the basis of various advanced technologies such as tissues detachment, smart windows, enhanced DNA biosensors, etc. Despite this application-oriented progress, the molecular mechanisms of the temperature-induced transition based on CSTs remain often underexplored or weakly explained. In this review, we focus on the different molecular mechanisms driving CST-based transitions, systematizing information on homofunctional polymer systems. Understanding these mechanisms is crucial for manipulating temperature-sensitive properties, which offers significant potential for future innovations in smart materials. Full article

(This article belongs to the Section Smart and Functional Polymers)

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Graphical abstract

15 pages, 11557 KiB

Open AccessArticle

Toward Versatile Transient Electronics: Electrospun Biocompatible Silk Fibroin/Carbon Quantum Dot-Based Green-Emission, Water-Soluble Piezoelectric Nanofibers

by Zhipei Xia, Chubao Liu, Juan Li, Biyao Huang, Chu Pan, Yu Lai, Zhu Liu, Dongling Wu, Sen Liang, Xuanlun Wang, Weiqing Yang and Jun Lu

Polymers 2025, 17(11), 1579; https://doi.org/10.3390/polym17111579 - 5 Jun 2025

Abstract

The rapid development of wearable electronics requires multifunctional, transient electronic devices to reduce the ecological footprint and ensure data security. Unfortunately, existing transient electronic materials need to be degraded in chemical solvents or body fluids. Here, we report green luminescent, water-soluble, and biocompatible [...] Read more.

The rapid development of wearable electronics requires multifunctional, transient electronic devices to reduce the ecological footprint and ensure data security. Unfortunately, existing transient electronic materials need to be degraded in chemical solvents or body fluids. Here, we report green luminescent, water-soluble, and biocompatible piezoelectric nanofibers developed by electrospinning green carbon quantum dots (G-CQDs), mulberry silk fibroin (SF), and polyvinyl alcohol (PVA). The introduction of G-CQDs significantly enhances the piezoelectric output of silk fibroin-based fiber materials. Meanwhile, the silk fibroin-based hybrid fibers maintain the photoluminescent response of G-CQDs without sacrificing valuable biocompatibility. Notably, the piezoelectric output of a G-CQD/PVA/SF fiber-based nanogenerator is more than three times higher than that of a PVA/SF fiber-based nanogenerator. This is one of the highest levels of state-of-the-art piezoelectric devices based on biological organic materials. As a proof of concept, in the actual scenario of a rope skipping exercise, the G-CQD/PVA/SF fiber-based nanogenerator is further employed as a self-powered wearable sensor for real-time sensing of athletic motions. It demonstrates high portability, good flexibility, and stable piezoresponse for smart sports applications. This class of water-disposable, piezo/photoactive biological materials could be compelling building blocks for applications in a new generation of versatile, transient, wearable/implantable devices. Full article

(This article belongs to the Special Issue Polymer-Based Wearable Electronics)

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30 pages, 3841 KiB

Open AccessArticle

Eco-Friendly Octylsilane-Modified Amino-Functional Silicone Coatings for a Durable Hybrid Organic–Inorganic Water-Repellent Textile Finish

by Mariam Hadhri, Claudio Colleoni, Agnese D’Agostino, Mohamed Erhaim, Raphael Palucci Rosa, Giuseppe Rosace and Valentina Trovato

Polymers 2025, 17(11), 1578; https://doi.org/10.3390/polym17111578 - 5 Jun 2025

Abstract

The widespread phase-out of long-chain per- and poly-fluoroalkyl substances (PFASs) has created an urgent need for durable, fluorine-free water-repellent finishes that match the performance of legacy chemistries while minimising environmental impact. Here, the performance of an eco-friendly hybrid organic–inorganic treatment obtained by the [...] Read more.

The widespread phase-out of long-chain per- and poly-fluoroalkyl substances (PFASs) has created an urgent need for durable, fluorine-free water-repellent finishes that match the performance of legacy chemistries while minimising environmental impact. Here, the performance of an eco-friendly hybrid organic–inorganic treatment obtained by the in situ hydrolysis–condensation of triethoxy(octyl)silane (OS) in an amino-terminated polydimethylsiloxane (APT-PDMS) aqueous dispersion was investigated. The sol was applied to plain-weave cotton and polyester by a pad-dry-cure process and benchmarked against a commercial fluorinated finish. Morphology and chemistry were characterised by SEM–EDS, ATR-FTIR, and Raman spectroscopy; wettability was assessed by static contact angle, ISO 4920 spray ratings, and AATCC 193 water/alcohol repellence; and durability, handle, and breathability were evaluated through repeated laundering, bending stiffness, and water-vapour transmission rate measurements. The silica/PDMS coating formed a uniform, strongly adherent nanostructured layer conferring static contact angles of 130° on cotton and 145° on polyester. After five ISO 105-C10 wash cycles, the treated fabrics still displayed a spray rating of 5/5 and AATCC 193 grade 7, outperforming or equalling the fluorinated control, while causing ≤5% loss of water-vapour permeability and only a marginal increase in bending stiffness. These results demonstrate that the proposed one-step, water-borne sol–gel process affords a sustainable, industrially scalable route to high-performance, durable, water-repellent finishes for both natural and synthetic textiles, offering a viable alternative to PFAS-based chemistry for outdoor apparel and technical applications. Full article

(This article belongs to the Special Issue Environmentally Friendly Textiles, Fibers and Their Composites)

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