Polymers

16 pages, 4785 KB

Open AccessArticle

Wrinkling Analysis and Process Optimization of the Hydroforming Processes of Uncured Fiber Metal Laminates for Aircraft Fairing Structures

by Yunlong Chen and Shichen Liu

Polymers 2025, 17(16), 2267; https://doi.org/10.3390/polym17162267 - 21 Aug 2025

Viewed by 666

Abstract

Lightweight composite structures like fiber metal laminates (FMLs) are widely used to manufacture aircraft structures and substitute metallic parts. While the superior mechanical performance of FMLs, including their high specific strength and excellent impact and fatigue resistance, has gained the interest of many [...] Read more.

Lightweight composite structures like fiber metal laminates (FMLs) are widely used to manufacture aircraft structures and substitute metallic parts. While the superior mechanical performance of FMLs, including their high specific strength and excellent impact and fatigue resistance, has gained the interest of many researchers in the aerospace manufacturing industry, there are still some challenges that need to be considered. Conventional approaches like lay-up techniques and autoclave molding can achieve the relatively simple FML parts with large radii and profiles required for aircraft fuselages and flat skins. However, these methods are not suitable for forming complex-shaped structural parts due to the limited failure strain of fiber-reinforced materials and complex failure modes of the laminates. This research puts forward a new methodology that combines the hydroforming and subsequent curing process to investigate the feasibility of manufacturing complex aircraft parts like fairings made by FMLs. In this research, wrinkle formations are analyzed under various parameters during the hydroforming process. The geometrical shape of the initial blanks and the parameters, including blank holder force and cavity pressure, have been optimized to avoid flange edge wrinkles, and the addition of local support materials contributes to improving local wrinkling in the sharp corners. A finite element model (FEM) taking material laws, interlayer contacts, and boundary conditions into account is used to predict the dynamic hydroforming process of the fiber metal laminate, and experimental works are carried out for its verification. It is expected that the proposed method will reduce both costs and time, as well as reducing laminate defects. Thus, this method offers great potential for future applications related to manufacturing complex-shaped aerospace parts. Full article

(This article belongs to the Special Issue Polymeric Sandwich Composite Materials)

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14 pages, 4874 KB

Open AccessArticle

Temperature Dependence of Strain-Induced Crystallization in Silica- and Carbon Black-Filled Natural Rubber Compounds

by Gaurav Gupta, André Wehmeier, Rene Sattler, Jens Kiesewetter and Mario Beiner

Polymers 2025, 17(16), 2266; https://doi.org/10.3390/polym17162266 - 21 Aug 2025

Viewed by 335

Abstract

The results of strain-induced crystallization (SIC) studies on natural rubber compounds containing different amounts of carbon black and silica are reported. Two-dimensional wide-angle X-ray diffraction (2D WAXD) experiments were performed to quantify the degree of SIC at ambient and enlarged temperatures. The influence [...] Read more.

The results of strain-induced crystallization (SIC) studies on natural rubber compounds containing different amounts of carbon black and silica are reported. Two-dimensional wide-angle X-ray diffraction (2D WAXD) experiments were performed to quantify the degree of SIC at ambient and enlarged temperatures. The influence of temperature and filler system on the degree of crystallinity of natural rubber was investigated, since the estimated temperatures in truck tire treads are in the range 60–80 °C. Interestingly, the degree of crystallinity for silica-filled natural rubber compounds was commonly at least similar or higher compared to carbon black-filled compounds with identical filler mass fraction. In addition, it was demonstrated that the temperature dependence of natural rubber compounds containing silica and carbon black is also similar. In both cases the SIC disappeared slightly above 100 °C. Hence, it was concluded that the SIC behavior is most likely not the decisive factor for the different abrasion resistance of silica- and carbon black-reinforced natural rubber compounds for truck tire treads. This is an important insight considering the rising demand for sustainable rubber compounds for truck tire treads with low CO₂ emissions as well as reduced abrasion. Full article

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

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25 pages, 8316 KB

Open AccessArticle

Acid-Responsive Self-Healing Waterborne Epoxy Coating: Preparation, Release Behavior, and Anticorrosion Performance Based on Bowl-Shaped Mesoporous Polydopamine Nanocontainer Loaded with 2-MBI Inhibitors

by Xiaohong Ji, Minghui Yang, Huiwen Tian, Jin Hou, Jingqiang Su, Zhen Wang, Zixue Zhang, Yuefeng Tian, Liangliang Zhou, Guanghua Hu, Yunfei Yang, Jizhou Duan and Baorong Hou

Polymers 2025, 17(16), 2265; https://doi.org/10.3390/polym17162265 - 21 Aug 2025

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Abstract

We present a straightforward emulsion-induced interfacial anisotropic assembly method for in- situ synthesis of bowl-shaped, self-encapsulated mesoporous polydopamine (BMPDA) nanocontainers (M-M@P) loaded with 2-mercaptobenzimidazole (2-MBI). Results showed that the loading capacity of the bowl-shaped mesoporous polydopamine reaches 24 wt.%. The M-M@P exhibits a [...] Read more.

We present a straightforward emulsion-induced interfacial anisotropic assembly method for in- situ synthesis of bowl-shaped, self-encapsulated mesoporous polydopamine (BMPDA) nanocontainers (M-M@P) loaded with 2-mercaptobenzimidazole (2-MBI). Results showed that the loading capacity of the bowl-shaped mesoporous polydopamine reaches 24 wt.%. The M-M@P exhibits a cumulative MBI release of 91.61% after immersion in a 3.5 wt.% NaCl solution at pH = 2 for 24 h, accompanied by a corrosion inhibition efficiency of 95.54%. Additionally, the acid-responsive M-M@P not only enables controlled release of MBI but also synergistically promotes the formation of a protective film on the carbon steel substrate via the chelation of PDA-Fe³⁺, thereby enhancing the self-healing performance of waterborne epoxy coatings. Full article

(This article belongs to the Section Polymer Applications)

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17 pages, 3908 KB

Open AccessArticle

Structure, Mechanical Properties, and Rheological Characteristics of Poly(Butylene Adipate-co-Terephthalate)–Polylactic Acid Blends Modified via In Situ Maleic Anhydride Grafting

by Min Jin, Bei Qi, Kang Chen, Lijun Cao, Pengrui Chen, Ce Sun, Jianfeng Zhan, Zhuofeng Shao, Haiyan Tan and Yanhua Zhang

Polymers 2025, 17(16), 2264; https://doi.org/10.3390/polym17162264 - 21 Aug 2025

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Abstract

Polylactic acid (PLA) materials face inherent limitations in many applications due to their low toughness. To address this challenge, this study employed a reactive melt-grafting method to prepare maleic anhydride (MA)-grafted poly(butylene adipate-co-terephthalate) (PBAT–MA), providing an effective approach to improve the interfacial compatibility [...] Read more.

Polylactic acid (PLA) materials face inherent limitations in many applications due to their low toughness. To address this challenge, this study employed a reactive melt-grafting method to prepare maleic anhydride (MA)-grafted poly(butylene adipate-co-terephthalate) (PBAT–MA), providing an effective approach to improve the interfacial compatibility between PLA and PBAT, thereby significantly enhancing the toughness and impact resistance of PLA and expanding its application scope. The grafting reaction process of PBAT–MA was investigated, as well as its toughening mechanism and effect on PLA. The results showed that at a maleic anhydride concentration of 2 wt%, the obtained PLA–PBAT–MA composite material exhibited the best performance, with a fracture elongation of 358.1%, 450.4% higher than that of the unmodified composite material. The impact strength was 333.9 kJ/m², 917.3% higher than that of the unmodified composite material. This enhanced effect is attributed to the optimal MA concentration preserving the tough structure of PBAT while effectively bridging the interface between PLA and PBAT, promoting efficient stress transfer between the two phases, and ultimately achieving exceptional toughness. Full article

(This article belongs to the Section Polymer Chemistry)

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36 pages, 2136 KB

Open AccessReview

Valorization of Agro-Industrial Lignin as a Functional Polymer for Sustainable Wastewater Treatment

by Elena Ungureanu, Bogdan-Marian Tofanica, Eugen Ulea, Ovidiu C. Ungureanu, Maria E. Fortună, Răzvan Rotaru, Irina Volf and Valentin I. Popa

Polymers 2025, 17(16), 2263; https://doi.org/10.3390/polym17162263 - 21 Aug 2025

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Abstract

The rational design of functional and sustainable polymers is central to addressing global environmental challenges. In this context, unmodified lignin derived from Sarkanda grass (Tripidium bengalense), an abundant agro-industrial lignocellulosic byproduct, was systematically investigated as a natural polymeric adsorbent for the [...] Read more.

The rational design of functional and sustainable polymers is central to addressing global environmental challenges. In this context, unmodified lignin derived from Sarkanda grass (Tripidium bengalense), an abundant agro-industrial lignocellulosic byproduct, was systematically investigated as a natural polymeric adsorbent for the remediation of aqueous media contaminated with heavy metals. The study evaluates lignin’s behavior toward nine metal(loid) ions: arsenic, cadmium, chromium, cobalt, copper, iron, nickel, lead, and zinc. Adsorption performance was systematically investigated under static batch conditions, optimizing key parameters, with equilibrium and kinetic data modeled using established isotherms and rate equations. Surface characterization and seed germination bioassays provided supporting evidence. Unmodified Sarkanda grass lignin demonstrated effective adsorption, exhibiting a clear preference for Cu(II) followed by other divalent cations, with lower capacities for As(III) and Cr(VI). Adsorption kinetics consistently followed a pseudo-second-order model, indicating chemisorption as the dominant mechanism. Thermodynamic studies revealed spontaneous and endothermic processes. Bioassays confirmed significant reduction in aqueous toxicity and strong metal sequestration. This work positions unmodified Sarkanda grass lignin as a bio-based, low-cost polymer platform for emerging water treatment technologies, contributing to circular bioeconomy goals and highlighting the potential of natural polymers in sustainable materials design. Full article

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

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12 pages, 1108 KB

Open AccessArticle

Hydrogen Permeation Resistance of PVDF–Graphene Nanocomposite Coatings for Metallic Pipelines

by Mohammed M. Aman, Bashar S. Mohammed and Ahmad Mahamad Al-Yacouby

Polymers 2025, 17(16), 2262; https://doi.org/10.3390/polym17162262 - 21 Aug 2025

Viewed by 714

Abstract

Hydrogen-induced steel embrittlement imposes a technical difficulty in facilitating effective and safe hydrogen transportation via pipelines. This investigative study assesses the potency of polyvinylidene fluoride (PVDF)–graphene-based composite coatings in the inhibition of hydrogen permeation. Spin coating was the method selected for this study, [...] Read more.

Hydrogen-induced steel embrittlement imposes a technical difficulty in facilitating effective and safe hydrogen transportation via pipelines. This investigative study assesses the potency of polyvinylidene fluoride (PVDF)–graphene-based composite coatings in the inhibition of hydrogen permeation. Spin coating was the method selected for this study, and varying graphene concentrations ranging from 0.1 to 1wt% were selected and applied to 306 stainless steel substrates. A membrane permeation cell was used in the evaluation of hydrogen permeability, while the impact of graphene loading on coating performance was analyzed using the response surface methodology (RSM). The outcomes showed an inversely proportional relationship between the graphene concentration and hydrogen ingress. The permeation coefficient for pure PVDF was recorded as 16.74, which decreased to 14.23, 12.10, and 11.46 for 0.3, 0.5, and 1.0 wt% PVDF-G, respectively, with the maximum reduction of 31.6% observed at 1.0 wt%. ANOVA established statistical significance, along with indications of strong projection dependability. However, the inhibition reduction stabilized with increasing graphene concentrations, likely caused by nanoparticle agglomeration. The results support the notion of PVDF–graphene’s potential as a suitable coating for the transformation of pipelines for hydrogen transport infrastructure. This research will aid in the establishment of suitable contemporary barrier coating materials, which will enable the safe utilization of hydrogen energy in the current energy transportation grid. Full article

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

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17 pages, 2407 KB

Open AccessArticle

Chitosan Films Loaded with Alginate Nanoparticles for Gentamicin Release on Demand

by Cecilia Zorzi Bueno, Helton José Wiggers, Pascale Chevallier, Francesco Copes and Diego Mantovani

Polymers 2025, 17(16), 2261; https://doi.org/10.3390/polym17162261 - 21 Aug 2025

Viewed by 870

Abstract

If untreated, skin wounds can lead to severe complications. Depending on the type of injury, long-term antibiotic administration is often required, and this decreases patient compliance. This limitation could be addressed by applying dressings capable of preventing infections by controlling drug release to [...] Read more.

If untreated, skin wounds can lead to severe complications. Depending on the type of injury, long-term antibiotic administration is often required, and this decreases patient compliance. This limitation could be addressed by applying dressings capable of preventing infections by controlling drug release to the wound site. In this research, biodegradable wound dressings were investigated, based on natural polymers chitosan and alginate and incorporating the broad-spectrum gentamicin as antibiotic. Specifically, gentamicin was loaded into alginate nanoparticles, which were then loaded into chitosan-based films. This approach aimed at obtaining a system capable of modulating antibiotic release. The obtained nanoparticles had an average diameter of 86 nm and polydispersity index of 0.15. Antibiotic loading was around 600 µg/mg, with loading efficiency close to 100%. Films incorporating nanoparticles were compared to control films, which contained only gentamicin. Results showed that nanoparticles incorporation decreased film’s swelling in phosphate buffer saline, thus leading to a decrease in burst release while cytocompatibility for human dermal fibroblasts was maintained. Antibacterial activity was confirmed against both gram-positive and gram-negative bacteria. Moreover, the antibiotic was released as a function of pH, with distinct behavior at pHs ranging from 7.4 to 5.5. This indicates that alginate nanoparticles dispersed in chitosan films effectively release gentamicin on demand. Full article

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

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7 pages, 169 KB

Open AccessEditorial

Development and Application of Polymer Scaffolds

by Wang Guo

Polymers 2025, 17(16), 2260; https://doi.org/10.3390/polym17162260 - 21 Aug 2025

Viewed by 375

Abstract

It is with great pleasure that we introduce this Special Issue of Polymers, entitled “Development and Application of Polymer Scaffolds” (https://www [...] Full article

(This article belongs to the Special Issue Development and Application of Polymer Scaffolds)

19 pages, 3447 KB

Open AccessArticle

The Effect of Longan Peel and Seed on Wheat Starch and the Quality of Longan Cake

by Yi-Shan Chen, Yang Xiao, Heng-Yu Liang, Nan Chen, Hao-Xiang Gao and Wei-Cai Zeng

Polymers 2025, 17(16), 2259; https://doi.org/10.3390/polym17162259 - 21 Aug 2025

Viewed by 451

Abstract

In the present study, the effects of longan peel and seed on the quality of longan cake were determined, and the effects of longan peel extract (LPE) and longan seed extract (LSE) on the physicochemical properties of wheat starch were also measured. Furthermore, [...] Read more.

In the present study, the effects of longan peel and seed on the quality of longan cake were determined, and the effects of longan peel extract (LPE) and longan seed extract (LSE) on the physicochemical properties of wheat starch were also measured. Furthermore, the phenolic profile and antioxidant activities of these extracts were observed. The results showed that both longan peel and seed could improve the color, texture, and volatile flavor compounds of longan cake. In addition, the properties of wheat starch, including gelatinization characteristics, thermogravimetric analysis, rheological properties, solubility, swelling power, water/oil-holding capacity and iodine binding ability, were all affected by LPE and LSE significantly. Both LPE and LSE had high contents of total phenols (LPE: 71.05 ± 2.57 mg/g, LSE: 78.49 ± 5.21 mg/g) and total flavonoids (LPE: 286.27 ± 6.04 mg/g, LSE: 423.21 ± 7.69 mg/g). Gallic acid, ellagic acid, and ellagic acid 4-O-α-l-arabinofuranoside were identified as the main phenolic compounds of LPE, while those of LSE were gallic acid, ellagic acid, ellagic acid 4-O-α-l-arabinofuranoside and (-)-epicatechin. Furthermore, LPE and LSE both exhibited good antioxidant activities to scavenge free radicals and showed high reducing power. All results suggest that longan peel and seed are rich in phenols and can improve the properties of starch so as to enhance the quality of starch product, which shows their potential application in food and chemical industries. Full article

(This article belongs to the Special Issue Advanced Polymers in Food Science)

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22 pages, 4847 KB

Open AccessArticle

Advanced Cellulose Triacetate-Based Mixed Matrix Membranes Enhanced by Bimetallic Ni-Cu-BTC MOFs for CO₂/CH₄ Separation

by Esha Asad, Ayesha Raza, Amna Safdar, Muhammad Nouman Aslam Khan and Humais Roafi

Polymers 2025, 17(16), 2258; https://doi.org/10.3390/polym17162258 - 21 Aug 2025

Viewed by 631

Abstract

Cu-BTC (HKUST-1) metal–organic framework (MOF) is widely recognized for its carbon capture capability due to its unsaturated copper sites, high surface area, and well-defined porous structure. This study developed mixed matrix membranes (MMMs) using cellulose triacetate (CTA), incorporating bimetallic Ni-Cu-BTC MOFs for CO [...] Read more.

Cu-BTC (HKUST-1) metal–organic framework (MOF) is widely recognized for its carbon capture capability due to its unsaturated copper sites, high surface area, and well-defined porous structure. This study developed mixed matrix membranes (MMMs) using cellulose triacetate (CTA), incorporating bimetallic Ni-Cu-BTC MOFs for CO₂/CH₄ separation, and benchmarked them against membranes fabricated with monometallic Cu-BTC. CTA was selected for its biodegradability, membrane-forming properties, and cost-effectiveness. The optimized membrane with 10 wt.% Ni-Cu-BTC achieved a CO₂ permeability of 22.9 Barrer at 25 °C and 5 bar—more than twice that of pristine CTA—with a CO₂/CH₄ selectivity of 33.8. This improvement stems from a 51.66% increase in fractional free volume, a 49.30% rise in the solubility coefficient, and a 51.94% boost in the diffusivity coefficient. Dual-sorption model analysis further confirmed enhanced solubility and adsorption mechanisms. These findings establish CTA/Ni-Cu-BTC membranes as promising candidates for high-performance CO₂ separation in natural gas purification and related industrial processes. Full article

(This article belongs to the Special Issue Polymer-Based Membranes: Innovation in Separation Technology)

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21 pages, 3238 KB

Open AccessArticle

Development and Characterization of a Novel Erucyl Ultra-Long-Chain Gemini Surfactant

by Guiqiang Fei and Banghua Liu

Polymers 2025, 17(16), 2257; https://doi.org/10.3390/polym17162257 - 21 Aug 2025

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Abstract

To stimulate the progress of clean fracturing fluid systems, an innovative erucyl ultra-long-chain gemini surfactant (EUCGS) was devised and manufactured during the course of this study. The target product was successfully prepared via a two-step reaction involving erucyl primary amine, 3-bromopropionyl chloride, and [...] Read more.

To stimulate the progress of clean fracturing fluid systems, an innovative erucyl ultra-long-chain gemini surfactant (EUCGS) was devised and manufactured during the course of this study. The target product was successfully prepared via a two-step reaction involving erucyl primary amine, 3-bromopropionyl chloride, and 1,3-bis(dimethylamino)propanediol, with an overall yield of 78.6%. FT-IR and ¹H NMR characterization confirmed the presence of C₂₂ ultra-long chains, cis double bonds, amide bonds, and quaternary ammonium headgroups in the product structure. Performance tests showed that EUCGS exhibited an extremely low critical micelle concentration (CMC = 0.018 mmol/L) and excellent ability to reduce surface tension (γCMC = 30.0 mN/m). Rheological property studies indicated that EUCGS solutions gradually exhibited significant non-Newtonian fluid characteristics with increasing concentration, and wormlike micelles with a network structure could self-assemble at a concentration of 1.0 mmol/L. Dynamic rheological tests revealed that the solutions showed typical Maxwell fluid behavior and significant shear-thinning properties, which originated from the orientation and disruption of the wormlike micelle network structure under shear stress. In the presence of 225 mmol/L NaCl, the apparent viscosity of a 20 mmol/L EUCGS solution increased from 86 mPa·s to 256 mPa·s. A temperature resistance evaluation showed that EUCGS solutions had a good temperature resistance at high shear rates and 100 °C. The performance evaluation of fracturing fluids indicates that the proppant settling rate (0.25 cm/min) of the EUCGS-FFS system at 90 °C is significantly superior to that of the conventional system. It features the low dosage and high efficiency of the breaker, with the final core damage rate being only 0.9%. The results demonstrate that the EUCGS achieves a synergistic optimization of high-efficiency interfacial activity, controllable rheological properties, and excellent thermal–salt stability through precise molecular structure design, providing a new material choice for the development of intelligent responsive clean fracturing fluids. Full article

(This article belongs to the Special Issue Polymer Science in Petroleum Engineering: Latest Trends and Developments)

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13 pages, 1556 KB

Open AccessArticle

3,4-Dihydroxybenzenesulfonyl-Functionalized Polyethyleneimine for Uranium Chelation

by Kai Liang, Sifan Liu, Fan Zhang, Wenjin Cui, Ying Tian, Shuchen Liu and Lin Wang

Polymers 2025, 17(16), 2256; https://doi.org/10.3390/polym17162256 - 21 Aug 2025

Viewed by 514

Abstract

3,4-dihydroxybenzenesulfonyl-functionalized polyethyleneimine (PS), a novel polymeric chelator, was synthesized by conjugating 3,4-dihydroxybenzenesulfonyl (CAM) groups with branched polyethyleneimine (BPEI, MW = 600 Da) via N-acylation. PS demonstrated a high uranium adsorption capacity of 78.08% at a concentration of 4 mg/mL, accompanied by significant selectivity [...] Read more.

3,4-dihydroxybenzenesulfonyl-functionalized polyethyleneimine (PS), a novel polymeric chelator, was synthesized by conjugating 3,4-dihydroxybenzenesulfonyl (CAM) groups with branched polyethyleneimine (BPEI, MW = 600 Da) via N-acylation. PS demonstrated a high uranium adsorption capacity of 78.08% at a concentration of 4 mg/mL, accompanied by significant selectivity over competing ions such as Ca²⁺, Zn²⁺, and Cu²⁺. Notably, in competitive adsorption experiments, PS exhibited a uranium adsorption rate of 59.49%, which was 3.95 times higher than that of calcium (15.06%) in the Ca²⁺ system. Cytotoxicity assays revealed enhanced biocompatibility (IC₅₀ = 86.98 μg/mL), surpassing CaNa₃-DTPA 3.7-fold. In a uranium exposure model (200 μg/mL), PS significantly improved cell survival rates and reduced intracellular uranium levels by 77.37% (immediate administration) and 64.18% (delayed administration). These findings establish PS as a potent and safe polymeric chelator for uranium decorporation, offering a promising strategy for mitigating the hazards of radioactive materials. Full article

(This article belongs to the Section Polymer Chemistry)

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40 pages, 2346 KB

Open AccessReview

Towards Enhanced Electrospinning of Alginate—Can Recent Strategies Overcome Limitations? A Review

by Paulina Wróbel, Julia Zwolińska, Daniel Szopa and Anna Witek-Krowiak

Polymers 2025, 17(16), 2255; https://doi.org/10.3390/polym17162255 - 20 Aug 2025

Viewed by 636

Abstract

Electrospun alginate nanofibers are emerging as versatile materials for biomedical, environmental, and packaging applications due to their biocompatibility, biodegradability, and functional tunability. However, the direct electrospinning of alginate remains a significant challenge, mainly due to its polyelectrolytic nature, rigid chain structure, and limited [...] Read more.

Electrospun alginate nanofibers are emerging as versatile materials for biomedical, environmental, and packaging applications due to their biocompatibility, biodegradability, and functional tunability. However, the direct electrospinning of alginate remains a significant challenge, mainly due to its polyelectrolytic nature, rigid chain structure, and limited chain entanglement. This review provides a comprehensive analysis of recent strategies developed to overcome these limitations, including polymer blending, chemical modification, the addition of surfactants, multi-fluid techniques, and process optimization. We systematically discuss the integration of nanofibers with functional agents such as microorganisms, bioactive compounds, plant extracts, and nanoparticles, highlighting their potential in wound healing, active packaging, bioremediation, and controlled release systems. This review also examines the scalability of alginate electrospinning, summarizing recent patents, industrial solutions, and challenges related to the standardization of the process. Key knowledge gaps are identified, including the need for long-term stability studies, structure–function correlations, green processing approaches, and expansion into novel application domains beyond healthcare. Addressing these research directions will be crucial to unlocking the full potential of alginate nanofibers as sustainable, high-performance materials for industrial use. Full article

(This article belongs to the Special Issue Natural Polymeric Materials: Polysaccharides and Carbohydrate Polymers, 2nd Edition)

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52 pages, 4676 KB

Open AccessReview

Aramid Fiber-Reinforced Plastics (AFRPs) in Aerospace: A Review of Recent Advancements and Future Perspectives

by Xinning Xu, Yanbing Guo, Zhikang Shen, Boyang Liu, Fei Yan and Ning Zhong

Polymers 2025, 17(16), 2254; https://doi.org/10.3390/polym17162254 - 20 Aug 2025

Viewed by 524

Abstract

This review examines the application of aramid fiber-reinforced plastics (AFRPs) in the aerospace industry, highlighting their significance in enhancing aircraft performance. Aramid fibers, such as Kevlar^® and Twaron^®, have emerged as key materials due to their exceptional tensile strength, low [...] Read more.

This review examines the application of aramid fiber-reinforced plastics (AFRPs) in the aerospace industry, highlighting their significance in enhancing aircraft performance. Aramid fibers, such as Kevlar^® and Twaron^®, have emerged as key materials due to their exceptional tensile strength, low density, and thermal stability. However, challenges persist in manufacturing, durability, and multifunctionality. This paper evaluates the latest advancements in AFRP, focusing on how molecular structure, interfacial engineering, and manufacturing innovations influence performance. It addresses questions on improving adhesion, efficient manufacturing methods, enhancing durability under extreme conditions, and developing multifunctional AFRP. By analyzing breakthroughs from 2020 to 2025 and proposing targeted solutions, this review aims to help AFRP meet the demands of future aerospace systems. Full article

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

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14 pages, 13989 KB

Open AccessArticle

Facile Preparation of a Cellulose-Based Thermoresponsive Gel for Rapid Water Harvesting from the Atmosphere

by Xiaoyu Wang, Hui Zhang, Xinxin Liu, Jie Du and Yingguang Xu

Polymers 2025, 17(16), 2253; https://doi.org/10.3390/polym17162253 - 20 Aug 2025

Viewed by 455

Abstract

Atmospheric water harvesting, as an emerging water collection technology, is expected to mitigate water resource crises. Adsorption-based atmospheric water harvesting technology offers distinct advantages, including geographical independence and reduced reliance on ambient humidity levels. Herein, a thermoresponsive gel (PNIPAM/TO-CNF) integrated with lithium chloride [...] Read more.

Atmospheric water harvesting, as an emerging water collection technology, is expected to mitigate water resource crises. Adsorption-based atmospheric water harvesting technology offers distinct advantages, including geographical independence and reduced reliance on ambient humidity levels. Herein, a thermoresponsive gel (PNIPAM/TO-CNF) integrated with lithium chloride was constructed to achieve accelerated moisture sorption and rapid desorption capabilities. In the designated PNIPAM/TO-CNF/LiCl gel, PNIPAM provided a temperature-responsive hydrophilic–hydrophobic transition network; the hydrophilicity and structural strength were enhanced by TO-CNF, the moisture absorption capacity was dramatically elevated by hygroscopic salt LiCl, and pore-forming agent polyethylene glycol created a favorable porous structure. This synergistic design endows the gel with an optimized hydrophilic network, temperature-responsive behavior, and a porous architecture conducive to water vapor transportation, thereby achieving rapid moisture absorption and desorption. Under 60% relative humidity, the gel exhibited a water vapor adsorption capacity of 144% within 1 h, reaching its maximum absorption capacity of 178% after 140 min. The gel exhibited an even more superior desorption performance: when heated to 70 °C, its moisture content rapidly decreased to 16% of its initial weight within 1 h, corresponding to the desorption of 91% of the total absorbed water. A simplified pore-forming methodology that enables the integration of temperature-responsive properties with efficient moisture transfer channels was reported in this paper, providing a viable design pathway for achieving accelerated adsorption–desorption cycles in atmospheric water harvesting. Full article

(This article belongs to the Special Issue Advances in Lignocellulose: Cellulose, Hemicellulose and Lignin)

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12 pages, 1767 KB

Open AccessArticle

Thioxanthone Skeleton-Based One-Component Macro-Photoinitiator Reduces Oxygen Inhibition and Migration Through Cooperative Effect

by Yiyun Du, Jingyan Zhang, Tianyi Han and Yi Zhu

Polymers 2025, 17(16), 2252; https://doi.org/10.3390/polym17162252 - 20 Aug 2025

Viewed by 389

Abstract

The oxygen inhibition and migration of micromolecules which stem from photoinitiators (PIs) remain two critical challenges to address in radical photocuring. In this work, we reported a one-step ternary copolymerization strategy to construct a one-component macromolecular photoinitiator (PPI) using polymerizable thioxanthone (TX), amine [...] Read more.

The oxygen inhibition and migration of micromolecules which stem from photoinitiators (PIs) remain two critical challenges to address in radical photocuring. In this work, we reported a one-step ternary copolymerization strategy to construct a one-component macromolecular photoinitiator (PPI) using polymerizable thioxanthone (TX), amine (N), and fluorinated alkane (F) as monomers. Then, we utilize the low surface energy of F unit and macromolecular skeleton to reduce oxygen inhibition and migration. Compared to micromolecule TX, PPI also exhibits a broad absorption in the 250–430 nm range, and a higher molar extinction coefficient. The effects of the TX, N, and F component ratios on the photoinitiation efficiency of PPI were systematically investigated, and the photopolymerization kinetics revealed that the increased content of F unit can eliminate the oxygen inhibition of PPI. As a result, PPI demonstrates the more superior photoinitiation efficiency compared to the traditional TX/N two-component macromolecule photoinitiation system. Migration experiments indicated that there is a 60% reduction in the migration rate for PPI compared to the TX/N photoinitiation system. This work provides an effective strategy to address oxygen inhibition and micromolecule migration issues in radical photocuring, showing potential applications in food and pharmaceutical packaging fields. Full article

(This article belongs to the Special Issue Recent Advances in Polymer-Based Organic Coatings)

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23 pages, 2612 KB

Open AccessReview

From Lignocellulosic Residues to Protein Sources: Insights into Biomass Pre-Treatments and Conversion

by Isabela Vera dos Anjos, Natacha Coelho, Hugo Duarte, Diogo Neves Proença, Maria F. Duarte, Raul Barros, Sara Raposo, Sandra Gonçalves, Anabela Romano and Bruno Medronho

Polymers 2025, 17(16), 2251; https://doi.org/10.3390/polym17162251 - 20 Aug 2025

Viewed by 509

Abstract

With the global population steadily rising, the demand for sustainable protein sources has become increasingly urgent. Traditional animal- and plant-based proteins face challenges related to scalability, resource efficiency, and environmental impact. In this context, single-cell protein has emerged as a promising alternative. Derived [...] Read more.

With the global population steadily rising, the demand for sustainable protein sources has become increasingly urgent. Traditional animal- and plant-based proteins face challenges related to scalability, resource efficiency, and environmental impact. In this context, single-cell protein has emerged as a promising alternative. Derived from microorganisms such as algae, bacteria, fungi, and yeast, single-cell protein offers a high nutritional profile- including all essential amino acids and vitamins—while enabling rapid production, minimal land and water requirements, and no generation of greenhouse gas emissions. A particularly compelling advantage of single-cell protein is its ability to be produced from agro-industrial waste, converting low-cost residues into valuable nutritional resources and contributing to environmental sustainability. Among these waste streams, lignocellulosic biomass from agricultural and forestry residues stands out as a renewable, biodegradable, and abundant feedstock. This review explores the potential of lignocellulosic waste as a substrate for single-cell protein production, emphasizing both its environmental advantages and nutritional value. It highlights the single-cell protein role as a sustainable and scalable alternative to conventional protein sources. The review also identifies key scientific, economic, and regulatory challenges, and recognizes the importance of targeted investments, particularly in policy development, public awareness, and technological innovation, to enable the broader adoption and acceptance of single-cell protein -based products. Full article

(This article belongs to the Special Issue Valorization of Biopolymer from Renewable Biomass)

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17 pages, 8493 KB

Open AccessArticle

Effect of Surface-Modified Mica in Hybrid Filler Systems on the Curing and Mechanical Behavior of Ethylene–Propylene–Diene Monomer (EPDM)/Butadiene Rubber (BR) Blend

by Won-Young Jung, Seong-Woo Cho and Keon-Soo Jang

Polymers 2025, 17(16), 2250; https://doi.org/10.3390/polym17162250 - 20 Aug 2025

Viewed by 375

Abstract

This study investigates the influence of hybrid filler systems comprising carbon black (CB), mica, and surface-modified mica (SM) on the properties of ethylene–propylene–diene monomer (EPDM)/butadiene rubber (PB) composites. To reduce the environmental issues associated with CB, mica was incorporated as a partial substitute, [...] Read more.

This study investigates the influence of hybrid filler systems comprising carbon black (CB), mica, and surface-modified mica (SM) on the properties of ethylene–propylene–diene monomer (EPDM)/butadiene rubber (PB) composites. To reduce the environmental issues associated with CB, mica was incorporated as a partial substitute, and its compatibility with the rubber matrix was enhanced through surface modification using ureidopropyltrimethoxysilane (URE). The composites with hybrid filler systems and surface modification were evaluated in terms of curing behavior, crosslink density, mechanical and elastic properties, and dynamic viscoelasticity. Rheological analysis revealed that high mica loadings delayed vulcanization due to reduced thermal conductivity and accelerator adsorption, whereas SM composites maintained comparable curing performance. Swelling tests showed a reduction in crosslink density with increased unmodified mica content, while SM-filled samples improved the network density, confirming enhanced interfacial interaction. Mechanical testing demonstrated that the rubber compounds containing SM exhibited average improvements of 17% in tensile strength and 20% in toughness. In particular, the CB20/SM10 formulation achieved a well-balanced enhancement in tensile strength, elongation at break, and toughness, surpassing the performance of the CB-only system. Furthermore, rebound resilience and Tan δ analyses showed that low SM content reduced energy dissipation and improved elasticity, whereas excessive filler loadings led to increased hysteresis. The compression set results supported the thermal stability and recovery capacity of the SM-containing systems. Overall, the results demonstrated that the hybrid filler system incorporating URE-modified mica significantly enhanced filler dispersion and rubber–filler interaction, offering a sustainable and high-performance solution for elastomer composite applications. Full article

(This article belongs to the Special Issue Mechanical and Dynamic Characterization of Polymeric Composites, 3rd Edition)

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12 pages, 3386 KB

Open AccessArticle

Poly(Vinyl Alcohol)–Carbon Nanotube Self−Adhesive Hydrogels for Wearable Strain Sensors

by Guofan Zeng, Nuozhou Yi, Qiaohang Guo, Fei Han and Mingcen Weng

Polymers 2025, 17(16), 2249; https://doi.org/10.3390/polym17162249 - 20 Aug 2025

Viewed by 449

Abstract

Wearable conductive hydrogel sensors, which are highly convenient, have attracted attention for their great potential in human motion monitoring and smart healthcare. However, the self−adhesive properties, sensing performance, and stability of traditional hydrogels are not ideal, which seriously hinders their use in monitoring [...] Read more.

Wearable conductive hydrogel sensors, which are highly convenient, have attracted attention for their great potential in human motion monitoring and smart healthcare. However, the self−adhesive properties, sensing performance, and stability of traditional hydrogels are not ideal, which seriously hinders their use in monitoring and diagnosing joints throughout the human body. Here, CaCl₂ is used to crosslink PVA to improve its self−adhesive properties, and it is then combined with a CNT conductive network. Next, a cyclic freeze–thaw strategy is utilized to fabricate a wearable PVA−Ca−CNT hydrogel with excellent self-adhesive properties and stability. PVA−Ca−CNT hydrogels can adhere to various substrates, with a maximum self-adhesion strength of 398 kPa and a unit adhesion energy of as high as 305 μJ cm⁻². Furthermore, the CNT three−dimensional network enhances the tensile strength to 110 kPa, with almost no hysteresis. Based on resistance changes, PVA−Ca−CNT hydrogel exhibits a sensitivity of up to 11.11 as a strain sensor as well as a response to strain stimuli within 180 ms. When PVA−Ca−CNT hydrogel is adhered to the surface of human skin, it operates as a sensor for monitoring human movement. Not only can it accurately monitor the movement positions of major joints in the human body, it can also accurately identify tiny movements of the fingers and be used as a finger Morse code output device, which demonstrates the enormous potential of human motion monitoring systems based on self−adhesive hydrogel sensors in practical applications. Full article

(This article belongs to the Special Issue Polymeric Composite for Biosensor Applications)

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25 pages, 7378 KB

Open AccessArticle

Additive Manufacturing of Biobased Material Used in Electrical Insulation: Comparative Studies on Various Printing Technologies

by Robert Sekula, Alexander Leis, Anne Wassong, Annsophie Preuss, Hermann Hanning, Jan Kemnitzer, Marco Wimmer, Maciej Kuniewski and Pawel Mikrut

Polymers 2025, 17(16), 2248; https://doi.org/10.3390/polym17162248 - 20 Aug 2025

Viewed by 460

Abstract

In the power industry, various electrically insulating materials are used to ensure proper mechanical, thermal, and dielectric performance over decades of equipment operation. In power transformers, cellulose is the predominant material in manufacturing various insulation components. Most of these products are manufactured by [...] Read more.

In the power industry, various electrically insulating materials are used to ensure proper mechanical, thermal, and dielectric performance over decades of equipment operation. In power transformers, cellulose is the predominant material in manufacturing various insulation components. Most of these products are manufactured by wet-molding technology. However, this process is long, labor-intensive, and highly energy-demanding. Under the frame of an EU-funded grant, a new kind of insulation material and manufacturing process were developed. Fully bio-based material (produced in the form of pellets) can be processed using additive manufacturing, allowing for much shorter manufacturing times for insulation products, with considerably less scrap and energy consumption (due to the elimination of the drying stage). The focus of the project was extrusion additive manufacturing technology, but at a later stage, a biomaterial powder was developed, making it possible to print with other technologies. In the paper, comparative studies on various additive manufacturing techniques of newly developed biopolymers have been presented, including extrusion, High Speed Sintering (HSS), and Selective Laser Sintering (SLS). The applicability of such material in power transformers required extensive testing of various properties. These results are discussed in the paper and include: oil compatibility, volume resistivity measurements, permittivity and dissipation factor measurements, determination of partial discharge inception voltage, partial discharges measurement, and breakdown voltage measurements. Although mechanical properties remain below industrial targets, the pioneering results provide a promising route for unique directions toward more sustainable manufacturing of high-voltage cellulose insulation and ideas for improving the material properties during the printing process. Full article

(This article belongs to the Special Issue Polymer Materials for Application in Additive Manufacturing)

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6 pages, 186 KB

Open AccessEditorial

Advances in Functional Rubber and Elastomer Composites II

by Vineet Kumar and Md Najib Alam

Polymers 2025, 17(16), 2247; https://doi.org/10.3390/polym17162247 - 20 Aug 2025

Viewed by 562

Abstract

Recently, rubber and elastomer materials have expanded their applications from traditional mechanical uses to advanced mechanical, electrical, and sensor applications [...] Full article

(This article belongs to the Special Issue Advances in Functional Rubber and Elastomer Composites II)

20 pages, 2635 KB

Open AccessArticle

Polyethylene Terephthalate Glycolysis: Kinetic Modeling and Validation

by Maja Gabrič, Žan Lavrič, Martin Schwiderski, Laureline Marc, Erik Temmel, Miha Grilc and Blaž Likozar

Polymers 2025, 17(16), 2246; https://doi.org/10.3390/polym17162246 - 20 Aug 2025

Viewed by 499

Abstract

In this study, a comprehensive investigation of PET glycolysis has been performed. The research included the development of analytical techniques, experiments with different reactor systems, and the development of mathematical models to understand the kinetics of the process. Quantitative HPLC analysis was adopted [...] Read more.

In this study, a comprehensive investigation of PET glycolysis has been performed. The research included the development of analytical techniques, experiments with different reactor systems, and the development of mathematical models to understand the kinetics of the process. Quantitative HPLC analysis was adopted and optimized for the detection of BHET, while the size-exclusion chromatography method was developed to determine the molecular weight distribution of solid PET residues. Over 33 experiments were performed with magnetically coupled shaft-stirred Amar reactors, resulting in more than 300 experimentally determined BHET concentration points at various reaction times, temperatures, catalyst concentrations, and ethylene glycol-to-PET ratios. Afterwards, a kinetic model was developed to describe the observed phenomena with a validation step. Full article

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

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16 pages, 2789 KB

Open AccessArticle

A Numerical Study on Lightning Damages and Residual Strength of CFRP Laminates Considering Delamination Induced by Thermal Stress

by Qian-Zhi Yin, Jiapeng Bian and Yin Fan

Polymers 2025, 17(16), 2245; https://doi.org/10.3390/polym17162245 - 19 Aug 2025

Viewed by 453

Abstract

Most numerical studies on carbon fiber-reinforced polymer (CFRP) lightning damages fail to account for delamination, a factor that plays a significant role in the subsequent analysis of residual strength. This study establishes an electro-thermo-mechanical coupled numerical model incorporating delamination effects to predict lightning-induced [...] Read more.

Most numerical studies on carbon fiber-reinforced polymer (CFRP) lightning damages fail to account for delamination, a factor that plays a significant role in the subsequent analysis of residual strength. This study establishes an electro-thermo-mechanical coupled numerical model incorporating delamination effects to predict lightning-induced damage in carbon fiber-reinforced plastic (CFRP) composites. Subsequently, parametric investigations evaluate the influence of varying input loads and stacking sequences on interlaminar pyrolysis and delamination damage, with damage assessment quantitatively conducted based on simulated post-strike uniaxial ultimate compressive loads. Post-strike uniaxial compressive strength reduction with cohesive elements is 28.91%, demonstrating closer alignment with experimental reduction (36.72%) than the 21.12% reduction predicted by the interlaminar-effect-neglecting model. Under combined thermal expansion and shockwave overpressure, the 28.91% compressive strength reduction demonstrates closer alignment with the experimental 36.72% reduction than the 25.13% reduction observed under isolated shockwave overpressure. The results highlight the critical role of thermal delamination in compressive strength reduction, with distinct waveform-dependent mechanisms: under C-waveform lightning currents, arc thermal effects cannot be neglected; D-waveform strikes exhibit predominant contributions from impact loading to delamination damage, with thermally driven delamination likewise pronounced. Increased current amplitude correlates with amplified mechanical damage severity, while premature symmetry in ply stacking sequences exacerbates compressive performance degradation. This work enhances multi-physics modeling fidelity by bridging thermal delamination and mechanical degradation pathways, offering foundational insights for optimizing lightning strike resistance in advanced aerospace composite systems. Full article

(This article belongs to the Special Issue Fibre-Reinforced Polymer Laminates: Structure and Properties)

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37 pages, 5147 KB

Open AccessReview

Next-Generation Wound Healing Materials: Role of Biopolymers and Their Composites

by Jonghyuk Park and Ranjit De

Polymers 2025, 17(16), 2244; https://doi.org/10.3390/polym17162244 - 19 Aug 2025

Viewed by 752

Abstract

The progress in biopolymers and their composites as advanced materials for wound healing has revolutionized therapeutic approaches for skin regeneration. These materials can effectively integrate their inherent biocompatibility and biodegradability with the enhanced mechanical strength and customizable properties of polymers and functional additives. [...] Read more.

The progress in biopolymers and their composites as advanced materials for wound healing has revolutionized therapeutic approaches for skin regeneration. These materials can effectively integrate their inherent biocompatibility and biodegradability with the enhanced mechanical strength and customizable properties of polymers and functional additives. This review presents a detailed investigation of the design principles, classifications, and biomedical applications of biopolymeric composites, focusing on their capabilities to promote angiogenesis, exhibit antimicrobial activities, and facilitate controlled drug delivery. By overcoming the challenges of conventional wound dressings, such as inadequate exudate management, mechanical fragility, and cytotoxicity, these composites provide dynamic, stimuli-responsive platforms that can adapt to the wound microenvironment. This study further highlights innovative advances in nanoparticle-assisted reinforcement, fiber-based scaffolds, and multi-stimuli responsive smart delivery systems. Finally, the future perspective illustrates how the challenges related to long-term physiological stability, scalable manufacturing, and clinical implementation can be addressed. Overall, this article delivers a comprehensive framework for understanding the transformative impact of biopolymeric composites in next-generation wound care. Full article

(This article belongs to the Special Issue Advanced Polymeric Composite for Drug Delivery Application)

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43 pages, 71331 KB

Open AccessReview

Polymeric and Polymer-Functionalized Drug Delivery Vectors: From Molecular Architecture and Elasticity to Cellular Uptake

by Thorsten Auth

Polymers 2025, 17(16), 2243; https://doi.org/10.3390/polym17162243 - 19 Aug 2025

Viewed by 466

Abstract

Polymers and polymer composites offer versatile possibilities for engineering the physico-chemical properties of materials on micro- and macroscopic scales. This review provides an overview of polymeric and polymer-decorated particles that can serve as drug-delivery vectors: linear polymers, star polymers, diblock-copolymer micelles, polymer-grafted nanoparticles, [...] Read more.

Polymers and polymer composites offer versatile possibilities for engineering the physico-chemical properties of materials on micro- and macroscopic scales. This review provides an overview of polymeric and polymer-decorated particles that can serve as drug-delivery vectors: linear polymers, star polymers, diblock-copolymer micelles, polymer-grafted nanoparticles, polymersomes, stealth liposomes, microgels, and biomolecular condensates. The physico-chemical interactions between the delivery vectors and biological cells range from chemical interactions on the molecular scale to deformation energies on the particle scale. The focus of this review is on the structure and elastic properties of these particles, as well as their circulation in blood and cellular uptake. Furthermore, the effects of polymer decoration in vivo (e.g., of glycosylated plasma membranes, cortical cytoskeletal networks, and naturally occurring condensates) on drug delivery are discussed. Full article

(This article belongs to the Special Issue Advanced Polymeric Composite for Drug Delivery Application)

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10 pages, 247 KB

Open AccessEditorial

Editorial to the Special Issue “Theoretical and Computational Polymer Science: Physics, Chemistry, and Biology”

by Hector Eduardo Roman

Polymers 2025, 17(16), 2242; https://doi.org/10.3390/polym17162242 - 19 Aug 2025

Viewed by 454

Abstract

This Editorial provides a concise review of the contributions featured in this Special Issue (SI), which is dedicated to the theoretical aspects of polymers in physics, chemistry, and biology, covering both their structural and dynamical properties [...] Full article

(This article belongs to the Special Issue Theoretical and Computational Polymers Science: Physics, Chemistry and Biology)

19 pages, 5241 KB

Open AccessArticle

Photodegradation Behavior of Nanosilica-Filled PMMA Composite: Cooperative Effect of Mixed Solvents and Interfacial Functional Groups

by Zhiping Xu, Liangchen Li, Ying Liu and Rui Yang

Polymers 2025, 17(16), 2241; https://doi.org/10.3390/polym17162241 - 19 Aug 2025

Viewed by 448

Abstract

Poly(methyl methacrylate) (PMMA) and its composites are widely used in industrial applications; therefore, their durability is of great concern. In this study, the photooxidative degradation behavior of nanosilica-filled PMMA composite films and the cooperative effect of mixed solvents containing tetrahydrofuran (THF) and chloroform [...] Read more.

Poly(methyl methacrylate) (PMMA) and its composites are widely used in industrial applications; therefore, their durability is of great concern. In this study, the photooxidative degradation behavior of nanosilica-filled PMMA composite films and the cooperative effect of mixed solvents containing tetrahydrofuran (THF) and chloroform (TCM), as well as interfacial functional groups, was investigated. The surface functional groups of nanosilica fillers, such as polar, aryl, and alkyl moieties, significantly affect the photodegradation kinetics and pathways for PMMA. The key process lies in the modulation of solvent–solvent reaction selectivity at the polymer–filler interface. Functional groups that selectively promote the chlorination reaction between THF and TCM accelerate PMMA photodepolymerization, while those that suppress this reaction hinder degradation. This interfacial effect is validated by trends in molecular weight loss, volatile product profiles, and MMA yields during aging. Our findings reveal that the photodegradation behavior of PMMA composites is not only governed by environmental conditions but also critically influenced by interfacial chemistry. In this way, this study provides novel insight into the interfacial aging process for polymer nanocomposites, as well as guidance for the rational design of PMMA-based materials with improved durability. Full article

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

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14 pages, 2974 KB

Open AccessArticle

Processibility, Thermo-Mechanical Properties, and Radiation Hardness of Polyurethane and Silicone Resins

by Christian Scheuerlein, Melanie Albeck, Roland Piccin, Federico Ravotti and Giuseppe Pezzullo

Polymers 2025, 17(16), 2240; https://doi.org/10.3390/polym17162240 - 18 Aug 2025

Viewed by 457

Abstract

Different polyurethanes (PURs) and silicone for potential use in particle accelerators and detectors have been characterized in the uncured state, after curing, and after exposure to ionizing irradiation in ambient air and in liquid helium. The viscosity evolution during processing was measured with [...] Read more.

Different polyurethanes (PURs) and silicone for potential use in particle accelerators and detectors have been characterized in the uncured state, after curing, and after exposure to ionizing irradiation in ambient air and in liquid helium. The viscosity evolution during processing was measured with a rheometer. Dynamic mechanical analysis (DMA) and Shore A hardness measurements were applied to detect irradiation-induced crosslinking and chain scission effects. Uniaxial tensile and flexural tests under ambient and cryogenic conditions have been performed to assess changes in mechanical strength, elongation at break, and elastic properties. The initial viscosity of 550 cP at 25 °C of the uncured PUR RE700-4 polyol and RE106 isocyanate system for protective encapsulation is sufficiently low for impregnation of small magnet coils, but the pot life of about 30 min is too short for impregnation of large magnet coils. The cured RE700-4 system has outstanding mechanical properties at 77 K (flexural strength, impact strength, and fracture toughness). When RE700-4 is exposed to ionizing radiation, chain scission and cross-linking occur at a similar rate. In the other casting systems, irradiation-induced changes are cross-linking dominated, as manifested by an increase of the rubbery shear modulus (G’_rubbery), the ambient temperature Young’s modulus (E_RT), and the Shore A hardness. Cross-linking rates are strongly reduced when irradiation occurs in liquid helium. The irradiation effect on mechanical properties can be strongly dependent on the testing temperature. The RT mechanical strength and strain at fracture of the cross-linking silicone is drastically decreased after 1.6 MGy, whereas its 77 K strain at fracture has almost doubled. In addition, 77 K elastic moduli are similar for all pure resins and only slightly affected by irradiation. Full article

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

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21 pages, 6478 KB

Open AccessArticle

Localized Combination Therapy Using Collagen–Hydroxyapatite Bone Grafts for Simultaneous Bone Cancer Inhibition and Tissue Regeneration

by Alina Florentina Vladu, Madalina Georgiana Albu Kaya, Anton Ficai, Denisa Ficai, Raluca Tutuianu, Ludmila Motelica, Vasile Adrian Surdu, Ovidiu-Cristian Oprea, Roxana Doina Truşcă and Irina Titorencu

Polymers 2025, 17(16), 2239; https://doi.org/10.3390/polym17162239 - 18 Aug 2025

Viewed by 569

Abstract

The global burden of cancer continues to grow, with bone cancer—though rare—posing serious challenges in terms of treatment and post-surgical reconstruction. Autologous bone grafting remains the gold standard, yet limitations such as donor site morbidity drive the search for alternative solutions. Tissue engineering, [...] Read more.

The global burden of cancer continues to grow, with bone cancer—though rare—posing serious challenges in terms of treatment and post-surgical reconstruction. Autologous bone grafting remains the gold standard, yet limitations such as donor site morbidity drive the search for alternative solutions. Tissue engineering, combining biomaterials and therapeutic agents, offers promising avenues. This study focuses on the development of multifunctional scaffolds based on collagen and hydroxyapatite obtained by the freeze-drying technique and incorporating both synthetic (doxorubicin) and natural (caffeic acid) compounds for osteosarcoma treatment. These scaffolds aim to combine tumor inhibition with bone regeneration, addressing the dual need for local drug delivery and structural repair in bone cancer therapy. The characterization of these composite materials revealed that a spongious structure with interconnected pores and a homogeneous pore distribution, with pore sizes between 20 and 250 μm suitable for osteoblasts infiltration. The Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis-differential scanning calorimetry (TG-DSC) and X-ray diffraction (XRD) analyses confirmed the formation of hydroxyapatite inside the collagen matrix. LDH and XTT assays confirmed that the antitumoral scaffolds possess great potential for osteosarcoma treatment, showing that after 3 days of culturing, the extracts containing doxorubicin-7A, both alone and in combination with caffeic acid-9A, significantly reduced the viability of cell lines to below 7% and 20%, respectively. Full article

(This article belongs to the Special Issue Smart and Bio-Medical Polymers: 3rd Edition)

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17 pages, 4237 KB

Open AccessArticle

Controlled Release of D-Limonene from Biodegradable Films with Enzymatic Treatment

by Viktor Nakonechnyi, Viktoriia Havryliak and Vira Lubenets

Polymers 2025, 17(16), 2238; https://doi.org/10.3390/polym17162238 - 17 Aug 2025

Viewed by 537

Abstract

The instability of many volatile organic compounds (VOCs) limits their usage in different fragrance carriers and products. In scratch-and-sniff applications, VOCs are bound so strongly that release cannot happen without an external trigger. On the other hand, other fixatives like cyclodextrins release unstable [...] Read more.

The instability of many volatile organic compounds (VOCs) limits their usage in different fragrance carriers and products. In scratch-and-sniff applications, VOCs are bound so strongly that release cannot happen without an external trigger. On the other hand, other fixatives like cyclodextrins release unstable volatile molecules too rapidly. We engineered biodegradable gelatin films whose release profile can be tuned by glycerol plasticization and alkaline protease degradation. Digitalized VOC release profiles acquired with the described near-real-time analysis toolkit are digital twins that replicate the behavior of the evaluated films in silico. Seven formulations were cast from 10% gelatin containing D-limonene, glycerol (5%, 20%), protease-C 30 kU mL⁻¹, and samples with additional water to establish a higher hydromodule for protease catalytic activity. Release profiles were monitored for nine days at 23 ± 2 °C in parallel by metal-oxide semiconductor (MOS) e-noses, gravimetric weight loss, and near-infrared measurements (NIR). These continuous measurements were cross-checked with gel electrophoresis, FTIR spectroscopy, hardness tests, and sensory intensity ratings. Results showed acceleration of VOC release by enzymatic treatment during the first days, as well as overall impact on the release profile. Differences in low and high glycerol films were observed, and principal component analysis of NIR spectra separated low and high glycerol groups, mirroring the MOS and FTIR data. Usability of MOS data was explored in comparison to more biased and subjective intensity results from sensory panel evaluation. Overall, the created toolkit showed good cross-checked results and enabled the possibility for close to real-time analysis for bio-based VOC carriers. Full article

(This article belongs to the Special Issue Polymer Thin Films and Their Applications)

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Polymers, Volume 17, Issue 16 (August-2 2025) – 104 articles

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