Polymers

30 pages, 6910 KB

Open AccessReview

Polymers as the Primary Fabrication Material for Soft Robotic Grippers: A Concise Review

by Maryna Yeromina, Ján Duplák, Samuel Mikuláško and Rastislav Kaščák

Polymers 2025, 17(18), 2464; https://doi.org/10.3390/polym17182464 - 11 Sep 2025

Each component implemented in a robotic system requires a priority on low weight, flexibility, and durability. These key parameters for creating a stable yet flexible device can be achieved by applying polymer materials in the construction, not only in the static parts of [...] Read more.

Each component implemented in a robotic system requires a priority on low weight, flexibility, and durability. These key parameters for creating a stable yet flexible device can be achieved by applying polymer materials in the construction, not only in the static parts of the skeleton but also in the design and production of robotic grippers. This concise review highlights the possibilities of using polymers as the primary fabrication material for the specific area of “soft grippers” used in dental production. The main part of the article is devoted to analyzing polymer materials—specifically SMPs—their modifications, the characteristics of their primary properties, and the specifics of their use in robotic grippers. The article also provides information on the current state of research conducted over the last decade, through a brief overview obtained from the renowned Web of Science and Scopus databases. As part of the overview, we used basic keywords relevant to the analyzed issue: soft, gripper, and polymer. The review results indicate continuous growth in the number of publications, with the highest increase recorded in 2016 compared to 2016, showing more than a fourfold increase. The lowest increase was recorded in 2020 compared to 2019, where the publication rate was stagnant. The most frequently published documents are Articles, comprising 80.1% to 68.3% (more than 5000 publications). The most popular categories in which documents were published are Engineering 27.1%, (more than 4500 publications) and Materials Science Multidisciplinary 45.2% (more than 180 publications). Based on this review, the importance and need for research into this issue and its analysis can be confirmed, not only in practical applications but also within theoretical reviews and summaries. Full article

(This article belongs to the Special Issue New Possibilities of Obtaining and Applications of Polymers in Industry and Medicine)

16 pages, 2496 KB

Open AccessArticle

Surface Properties of Recombinant Pea Vicilin and Cupin-1.2 Solutions in 8M Urea

by Nikolay Isakov, Dmitry Angel, Mikhail Belousov, Giuseppe Loglio, Reinhard Miller, Anton Nizhnikov and Boris Noskov

Polymers 2025, 17(18), 2463; https://doi.org/10.3390/polym17182463 - 11 Sep 2025

Abstract

The kinetic dependencies of the surface pressure, the dilational dynamic surface elasticity and ellipsometric angles of cupin-1.2 and vicilin solutions in 8M urea were measured at different concentrations. The analysis of these kinetics dependencies and the obtained master curves allowed us to determine [...] Read more.

The kinetic dependencies of the surface pressure, the dilational dynamic surface elasticity and ellipsometric angles of cupin-1.2 and vicilin solutions in 8M urea were measured at different concentrations. The analysis of these kinetics dependencies and the obtained master curves allowed us to determine a few adsorption steps in the investigated systems and showed that the master curves are individual characteristics of the protein for a given solvent. At the same time, the shape of these curves can be different for adsorbed and spread layers of plant proteins indicating different structures of these layers. The dependencies of the dynamic surface elasticity on surface pressure are non-monotonic, unlike the corresponding results for most of the solutions of the investigated plant proteins. The extremums of these dependencies can be connected to the formation of the distal region of the surface layer in agreement with the theory for the surface viscoelasticity of polymer solutions. Full article

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

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17 pages, 1664 KB

Open AccessArticle

Enhanced Ablative Performance of Additively Manufactured Thermoplastic Composites for Lightweight Thermal Protection Systems (TPS)

by Teodor Adrian Badea, Lucia Raluca Maier and Alexa-Andreea Crisan

Polymers 2025, 17(18), 2462; https://doi.org/10.3390/polym17182462 - 11 Sep 2025

Abstract

The research investigated the potential of five novel additively manufactured (AM) fiber-reinforced thermoplastic composite (FRTPC) configurations as alternatives for ablative thermal protection system (TPS) applications. The thermal stability and ablative behavior of ten samples developed via fused deposition modeling (FDM) three-dimensional (3D) printing [...] Read more.

The research investigated the potential of five novel additively manufactured (AM) fiber-reinforced thermoplastic composite (FRTPC) configurations as alternatives for ablative thermal protection system (TPS) applications. The thermal stability and ablative behavior of ten samples developed via fused deposition modeling (FDM) three-dimensional (3D) printing out of fire-retardant thermoplastics were investigated using an in-house oxyacetylene torch bench. All samples featured an innovative internal thermal management architecture with three air chambers. Furthermore, the enhancement of thermal benefits was achieved through several approaches: ceramic coating, mechanical hybridization, or continuous fiber reinforcement. For each configuration, two samples were exposed to flame at 1450 ± 50 °C for 30 s and 60 s, respectively, with the front surface subjected to direct exposure at a distance of 100 mm during the ablation tests. Internal temperatures recorded at two back-side contact points remained below 50 °C, well under the 180 °C maximum allowable back-face temperature for TPS during testing. Continuous reinforced configurations 4 and 5 displayed higher thermal stability the lowest values in terms of thickness, mass loss, and recession rates. Both configurations showed half of the weight losses measured for the other tested configurations, ranging from approximately 5% (30 s) to 10–12% (60 s), confirming the trend observed in the thickness loss measurements. However, continuous glass-reinforced configuration 5 exhibited the lowest weight loss values for both exposure durations, benefiting from its non-combustible nature, low thermal conductivity, and high abrasion resistance intrinsic characteristics. In particular, the Al₂O₃ surface coated configuration 1 showed a mass loss comparable to reinforced configurations, indicating that an enhanced surface coat adhesion could provide a potential benefit. A key outcome of the study was the synergistic effect of the novel air chamber architecture, which reduces thermal conductivity by forming small internal air pockets, combined with the continuous front-wall fiber reinforcement functioning as a thermal and abrasion barrier. This remains a central focus for future research and optimization. Full article

(This article belongs to the Section Polymer Applications)

22 pages, 6744 KB

Open AccessArticle

Research on the Blast Mitigation Performance of Polyurea–Steel Composite Plates Based on Constrained Layer Damping Structures

by Rui Zhang, Qi Dong, Zhiqiang Fang, Yongjun Deng, Pengcheng Li, Hao Xu and Weibo Huang

Polymers 2025, 17(18), 2461; https://doi.org/10.3390/polym17182461 - 11 Sep 2025

Abstract

To address the challenge of balancing the damping performance with mechanical strength in conventional polyurea materials for blast mitigation, this study develops a constrained layer damping coating structure using Q413t viscoelastic polyurea (Q413t) as the damping layer and FPU-1 flexible polyurea (FPU-1) as [...] Read more.

To address the challenge of balancing the damping performance with mechanical strength in conventional polyurea materials for blast mitigation, this study develops a constrained layer damping coating structure using Q413t viscoelastic polyurea (Q413t) as the damping layer and FPU-1 flexible polyurea (FPU-1) as the constraining layer. The mechanical behaviors of both types of polyurea were characterized through tensile testing at varying loading speeds, while dynamic thermomechanical analysis was utilized to evaluate their damping properties. A 75 g TNT contact explosion test and finite element simulation were employed to explore the protective mechanism. The results show that Q413t demonstrates significant strain-rate sensitivity under intermediate-strain-rate conditions, whereas FPU-1 exhibits minimal variation in mechanical strength. Q413t demonstrates a superior damping performance over a frequency range of 0–10⁴ Hz. FPU-1 achieved a loss factor of 0.3 when the loading frequency reached 10⁴–10⁵ Hz. Under the 75 g TNT contact explosion load, the configuration with a 1 mm damping layer and a 3 mm constraint layer achieved a maximum displacement reduction of 35.26%. In the constrained layer damping coating, the damping layer contributes to blast protection through energy dissipation and load distribution, while the constraining layer reduces structural deformation by limiting displacement. Relative motion between the layers further enhances the overall damping performance. The constrained layer damping coating provides optimal blast protection when the damping-to-constraining layer thickness ratio is 1:3. The constrained layer damping coating enables the synergistic optimization of mechanical strength and energy dissipation, effectively mitigating structural deformation induced by blast loading and demonstrating promising engineering application potential. Full article

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

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20 pages, 4092 KB

Open AccessArticle

Thermo-Compression of Thermoplastic Chitosan Films Reinforced with Microcrystalline Cellulose for Antibacterial Food Packaging Application

by Prasong Srihanam, Theeraphol Phromsopha, Aphidech Sangdee, Nuanchai Khotsaeng, Pham Ngoc Lan and Yodthong Baimark

Polymers 2025, 17(18), 2460; https://doi.org/10.3390/polym17182460 - 11 Sep 2025

Abstract

Thermoplastic chitosan/microcrystalline cellulose (TPC/MCC) composite films were prepared by thermo-compression and are reported here for the first time. L-lactic acid (LLA) was used as a plasticizer in the formation of TPC. TPC films with varying LLA contents and the TPC/MCC composite films with [...] Read more.

Thermoplastic chitosan/microcrystalline cellulose (TPC/MCC) composite films were prepared by thermo-compression and are reported here for the first time. L-lactic acid (LLA) was used as a plasticizer in the formation of TPC. TPC films with varying LLA contents and the TPC/MCC composite films with different MCC contents were produced for evaluation. The physicochemical, mechanical, and antibacterial properties of the thermo-compressed TPC and TPC/MCC films were characterized. LLA enhanced thermal stability and crystallinity, improved film flexibility, and reduced the water solubility of the chitosan matrix. Incorporation of MCC further improved mechanical properties and decreased water dissolution. Tensile testing showed that the addition of 5 wt% MCC increased maximum tensile strength by 82% and Young’s modulus by 124%. All TPC and TPC/MCC films exhibited antibacterial activities against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Antibacterial efficacy decreased as MCC content increased to 20 wt%. These thermo-compressed TPC/MCC films can be tailored to display a range of properties by adjusting the contents of LLA and MCC, making them well suited for antibacterial food-packaging applications. Full article

(This article belongs to the Special Issue Sustainable Polymers for Value Added and Functional Packaging)

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20 pages, 10734 KB

Open AccessArticle

Viscoelastic Foams with Enhanced Fire Resistance Using Additive and Reactive Flame Retardants

by Grzegorz Węgrzyk, Dominik Grzęda, Milena Leszczyńska, Anna Bryśkiewicz, Katarzyna Bulanda, Mariusz Oleksy and Joanna Ryszkowska

Polymers 2025, 17(18), 2459; https://doi.org/10.3390/polym17182459 - 11 Sep 2025

Abstract

The influence of non-halogenated additive flame retardants, expandable graphite (EG) and ammonium polyphosphate (APP)—as well as a reactive phosphorus-containing polyol, on the flammability, thermal stability, physico-mechanical performance, and morphology of viscoelastic polyurethane foams (VEFs) was investigated. For this purpose, a series of polyurethane [...] Read more.

The influence of non-halogenated additive flame retardants, expandable graphite (EG) and ammonium polyphosphate (APP)—as well as a reactive phosphorus-containing polyol, on the flammability, thermal stability, physico-mechanical performance, and morphology of viscoelastic polyurethane foams (VEFs) was investigated. For this purpose, a series of polyurethane foams incorporating both additive and reactive flame retardants was synthesized and analyzed. The incorporation of flame retardants led to a substantial enhancement of fire resistance, as evidenced by an increase in the limiting oxygen index (LOI) to 28–31%, achievement of the UL-94 V₀ flammability rating, and a 92% reduction in peak heat release rate (pHRR) compared to the unmodified reference foam. Alterations in mechanical performance were correlated with structural changes both at the microscopic and molecular level, confirmed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Full article

(This article belongs to the Special Issue Advances in Polyurethane Synthesis and Applications)

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14 pages, 1701 KB

Open AccessArticle

Synthesis of Linear and Branched Polycarbonate Polyols via Double Metal Cyanide-Catalyzed Ring-Opening (Co)polymerization of Epoxides

by Won Seok Jae, Ha-Kyung Choi, Han Su Lee, Chinh Hoang Tran, Chi Le Hoang Tran, Khoa Anh Trinh and Il Kim

Polymers 2025, 17(18), 2458; https://doi.org/10.3390/polym17182458 - 11 Sep 2025

Abstract

A series of polyether and poly(ether carbonate) polyols have been synthesized via Zn(II)-Co(III) double metal cyanide (DMC)-catalyzed ring-opening (co)polymerization of various epoxides, such as propylene oxide, 1,2-epoxybutane, epichlorohydrin, styrene oxide, and glycidol, with and without CO₂. The resulting polyether polyols exhibit [...] Read more.

A series of polyether and poly(ether carbonate) polyols have been synthesized via Zn(II)-Co(III) double metal cyanide (DMC)-catalyzed ring-opening (co)polymerization of various epoxides, such as propylene oxide, 1,2-epoxybutane, epichlorohydrin, styrene oxide, and glycidol, with and without CO₂. The resulting polyether polyols exhibit linear and branched architectures (degrees of branching, DB = 0.27), high catalytic activities with turnover frequencies up to 461 min⁻¹, narrow dispersities (1.15–1.25), and low levels of unsaturation (0.004 meq g⁻¹). The DMC catalysts also enable the efficient synthesis of poly(propylene carbonate) polyol with carbonate contents up to 40% and yields reaching 63%. Additionally, branched poly(ether carbonate) polyols with tunable DB values (0.14–0.21), yields up to 70%, and carbonate contents up to 33% are synthesized via CO₂ fixation to glycidol. The synthesized polyols hold strong potential for industrial applications in polyurethanes and other advanced materials, offering versatile performance for use in coatings, adhesives, sealants, and elastomers. Overall, this study highlights the effectiveness of DMC catalysts in producing high-performance polyols, contributing to the development of sustainable materials with precise architectural control. Full article

(This article belongs to the Section Polymer Chemistry)

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19 pages, 4799 KB

Open AccessArticle

Durability of Basalt- and Glass Fiber-Reinforced Polymers: Influence of Internal Stresses, Mass Loss Modeling, and Mechanical/Thermomechanical Properties Under Extreme Cold Climate Exposure

by Anatoly K. Kychkin, Oleg V. Startsev, Mikhail P. Lebedev, Anatoly S. Krotov, Aisen A. Kychkin and Anna A. Gavrilieva

Polymers 2025, 17(18), 2457; https://doi.org/10.3390/polym17182457 - 11 Sep 2025

Abstract

The durability of basalt fiber-reinforced polymer (BFRP) and glass fiber-reinforced polymer (GFRP) composites was evaluated under extreme cold conditions in Yakutsk (

- 54

to

+ 36

°C. Laminates (18 layers, epoxy CYD-128) were exposed outdoors for three years. Mechanical testing showed tensile [...] Read more.

The durability of basalt fiber-reinforced polymer (BFRP) and glass fiber-reinforced polymer (GFRP) composites was evaluated under extreme cold conditions in Yakutsk (

- 54

to

+ 36

°C. Laminates (18 layers, epoxy CYD-128) were exposed outdoors for three years. Mechanical testing showed tensile strength and modulus reductions of 22–32% for GFRP, compared with only 6–12% for BFRP. Dynamic mechanical analysis indicated that the glass transition temperature decreased by 11–14 °C in GFRP and 4–6 °C in BFRP. Mass loss kinetics were studied on specimens of different sizes (10 × 10, 20 × 20, and 40 × 40 mm) over 405 days. Seasonal sorption ranged between 0.01–0.19%, while long-term degradation followed a Fickian law with diffusion coefficients of degradation products from

1 \times 10^{- 4}

to

0.29 {mm}^{2} / day

. A diffusion-based model was proposed, where total mass change is represented as the superposition of reversible sorption and irreversible degradation. The model accurately reproduced experimental trends, highlighting the higher resistance of BFRP. Surface morphology analysis revealed matrix erosion and microcracking on exposed surfaces, with average roughness increasing from 1.61–5.61 µm to 5.86–11.73 µm. Thermomechanical analysis confirmed that BFRP maintained more stable coefficients of linear thermal expansion (

- 60

to

100

°C) than GFRP, reducing thermally induced stresses during seasonal cycles. These findings demonstrate the superior stability of BFRP compared with GFRP under cold-climate exposure. Comparison of experimental results with mathematical modeling demonstrated that the primary cause of polymer matrix degradation is the action of abrupt internal stresses arising during thermal cycling under extreme cold climate conditions. Full article

(This article belongs to the Special Issue Degradation and Stability of Polymer-Based Systems: 2nd Edition)

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28 pages, 3889 KB

Open AccessArticle

PVA-Cellulose Fibers Composites Impregnated with Antimicrobial Particles: The Solvent Effect

by Anca Giorgiana Grigoras, Irina Popescu, Luiza Madalina Gradinaru, Gabriela Mihalache, Florin Daniel Lipsa, Simona Luminita Nica and Vasile Cristian Grigoras

Polymers 2025, 17(18), 2456; https://doi.org/10.3390/polym17182456 - 10 Sep 2025

Abstract

Nowadays, utilizing biodegradable and bio-inspired substances and combining them in innovative ways is a prerequisite for obtaining new and useful materials. In this paper, we designed and characterized eco-friendly materials as alternatives for packaging and medical applications. Thus, cellulose fibers of medical gauze [...] Read more.

Nowadays, utilizing biodegradable and bio-inspired substances and combining them in innovative ways is a prerequisite for obtaining new and useful materials. In this paper, we designed and characterized eco-friendly materials as alternatives for packaging and medical applications. Thus, cellulose fibers of medical gauze or filter paper were coated with a mixed solution containing poly(vinyl alcohol) (PVA), plant-based synthesized silver particles (AgPs), and magnetite (MG). The composites and their components were studied using UV-Vis, FTIR, and Energy-Dispersive X-ray (EDX) spectroscopy, Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM) to evidence the presence, size, surface charge, morphology, and chemical composition of particles in the composites, as well as particle interactions. Their proven hydrophobic and antibacterial character could recommend them for the design of antifouling medical coatings and food packaging. Full article

(This article belongs to the Special Issue New Advances in Cellulose and Wood Fibers)

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28 pages, 4294 KB

Open AccessArticle

Engineering Poly(L-Lactic Acid)/Hydroxyapatite Scaffolds via Melt-Electrowriting: Enhancement of Osteochondral Cell Response in Human Nasal Chondrocytes

by Valentina Basoli, Vittorio Barbano, Cecilia Bärtschi, Cosimo Loffreda, Matteo Zanocco, Alfredo Rondinella, Alex Lanzutti, Wenliang Zhu, Stefania Specchia, Andrea Barbero, Florian Markus Thieringer, Huaizhong Xu and Elia Marin

Polymers 2025, 17(18), 2455; https://doi.org/10.3390/polym17182455 - 10 Sep 2025

Abstract

Osteochondral repair remains challenging due to cartilage’s limited self-healing capacity and the structural complexity of the osteochondral interface, particularly the hypertrophic layer anchoring cartilage to bone. We fabricated melt electrowritten (MEW) poly(L-lactic acid) (PLLA) scaffolds incorporating 1%, 5%, and 10% hydroxyapatite (HAp) to [...] Read more.

Osteochondral repair remains challenging due to cartilage’s limited self-healing capacity and the structural complexity of the osteochondral interface, particularly the hypertrophic layer anchoring cartilage to bone. We fabricated melt electrowritten (MEW) poly(L-lactic acid) (PLLA) scaffolds incorporating 1%, 5%, and 10% hydroxyapatite (HAp) to provide a precise fiber architecture (~200 μm pores) and bone-mimetic biochemical cues. Human nasal chondrocytes (hNCs), currently in clinical trials for knee cartilage repair, were selected for their phenotypic plasticity and established safety profile, facilitating translational potential. HAp–PLLA scaffolds, especially at higher HAp contents, enhanced hNC adhesion, proliferation, mineralization, and maintenance of cartilage-specific ECM compared to PLLA alone. This work demonstrates the first high-HAp MEW-printed PLLA scaffold for osteochondral repair, integrating architectural precision with bioactivity in a clinically relevant cell–material system. Full article

(This article belongs to the Special Issue Functional Polymer-Modified Nanocomposites for Tissue Engineering and Biomedical Applications)

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25 pages, 5754 KB

Open AccessArticle

Evaluation of Thermomechanical Properties of Polymer Blends Intended for Additive Manufacturing Processing: Comparative Study of Poly(Lactic Acid) and Poly(Lactic Acid)/Polyhydroxyalkanoate Blends

by Jacek Andrzejewski, Katarzyna Skórczewska and Mateusz Barczewski

Polymers 2025, 17(18), 2454; https://doi.org/10.3390/polym17182454 - 10 Sep 2025

Abstract

The following article presents the results of research on the assessment of the effect of FDM printing process conditions on the properties of the obtained products. During the research, unmodified PLA and a PLA/PHA mixture were subjected to comparative analysis. Both materials exhibit [...] Read more.

The following article presents the results of research on the assessment of the effect of FDM printing process conditions on the properties of the obtained products. During the research, unmodified PLA and a PLA/PHA mixture were subjected to comparative analysis. Both materials exhibit excellent processability under standard FDM process conditions; however, the PLA/PHA blend is gaining attention due to its potential as a more thermally resistant and less brittle alternative to unmodified PLA. The printing procedure conducted at high bed platform temperature confirmed that for standard PLA varieties and the PLA/PHA blend, it is possible to obtain improved thermomechanical properties only by modifying the machine parameters of the printing process. The increase in the Vicat softening temperature value was about 80 °C, reaching above 130 °C. Interestingly, for materials based on pure PLA, most mechanical properties exhibit noticeable improvement, with the improvement in impact strength being particularly beneficial. For most materials, the measurements revealed significant anisotropy of properties within the tested samples, which was particularly due to the use of different bed platform temperatures. The apparent effect of this was the change in the thermal conditions of the PLA phase crystallization process, with crystallinity levels ranging from 17 to 33% for selected samples. The obtained results confirm that PLA/PHA blends are an interesting alternative for the PLA-based material; however, further research is needed to improve the application potential further. Full article

(This article belongs to the Special Issue Natural Polymers: Design, Characterization and Applications)

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29 pages, 5212 KB

Open AccessArticle

Multi-Objective Optimization of an Injection Molding Process for an Alvarez Freeform Lens Using an Integrated Optical System and Mold Flow Analyses

by Po-Yu Yen, Chao-Ming Lin and I-Hsiu Chang Chien

Polymers 2025, 17(18), 2453; https://doi.org/10.3390/polym17182453 - 10 Sep 2025

Abstract

This study optimizes the design and fabrication of an injection-molded Alvarez freeform lens using Moldex3D mold flow analysis and CODE V optical design simulations. The dual-software approach facilitates the transition between the manufacturing simulations and the optical design/verification process, thereby addressing the conversion [...] Read more.

This study optimizes the design and fabrication of an injection-molded Alvarez freeform lens using Moldex3D mold flow analysis and CODE V optical design simulations. The dual-software approach facilitates the transition between the manufacturing simulations and the optical design/verification process, thereby addressing the conversion issues between the two analysis modules. The optical quality of the designed lens is evaluated using spot diagram, distortion, and modulation transfer function (MTF) simulations. The Taguchi design methodology is first employed to identify the individual effects of the key injection molding parameters on the quality of the fabricated lens. The quality is then further improved by utilizing two multi-objective optimization methods, namely Gray Relational Analysis (GRA) and Robust Multi-Criteria Optimization (RMCO), to determine the optimal combination of the injection molding parameters. The results demonstrate that RMCO outperforms GRA, showing more substantial improvements in the optical quality of the lens. Overall, the proposed integrated method, incorporating Moldex3D, CODE V, Taguchi robust design, and RMCO analyses, provides an effective approach for optimizing the injection molding of Alvarez freeform lenses, thereby enhancing their quality. Future research could extend this methodology to other optical components and more complex optical systems. Full article

(This article belongs to the Special Issue Advances in Polymer Molding and Processing)

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17 pages, 6012 KB

Open AccessArticle

Relaxation of Shear-Induced Orientation and Textures in Semi-Dilute DNA Solutions

by Scarlett Elizabeth López-Alvarez, François Caton, Denis C. D. Roux, Félix Armando Soltero Martínez, Florian Scholkopf, Frédéric Nallet, Guillermo Toriz, Arnaud Saint-Jalmes, Marguerite Rinaudo and Lourdes Mónica Bravo-Anaya

Polymers 2025, 17(18), 2452; https://doi.org/10.3390/polym17182452 - 10 Sep 2025

Abstract

Recent studies on semi-dilute Calf-Thymus DNA (CT-DNA) solutions have revealed the presence of birefringence and small-scale textures influenced by shear and ionic strength. In this study, we investigate these phenomena on the same solutions to elucidate the underlying shear-induced supramolecular organization and relaxation [...] Read more.

Recent studies on semi-dilute Calf-Thymus DNA (CT-DNA) solutions have revealed the presence of birefringence and small-scale textures influenced by shear and ionic strength. In this study, we investigate these phenomena on the same solutions to elucidate the underlying shear-induced supramolecular organization and relaxation dynamics using rheo-birefringence, rheology, and rheo-SAXS (small-angle X-ray scattering). Static SAXS confirmed concentration-dependent inter-chain correlations in the 15–25 nm range, while rheology revealed a slipping yield-stress behavior. Oscillatory strain sweep and steady state rheo-birefringence experiments correlated the appearance of textures with the onset of flow and a stress plateau observed over a shear rate range from approximately 1 to 1000 s⁻¹. Transient rheo-birefringence and rheo-SAXS revealed two distinct relaxation mechanisms on well-separated time scales: a fast process lasting a few seconds, inversely proportional to the shear rate, consistent with the orientational relaxation of DNA segments on a ~20 nm scale; and a slower relaxation over tens of seconds, independent of the shear rate, associated with the disappearance of textures, and attributed to a diffusive process. These findings provide significant insights into the mechanisms governing DNA organization and dynamics in semi-dilute solutions under flow and highlight the need for temporally resolved start-up rheo-SAXS and rheo-birefringence measurements, as well as theoretical models describing these processes across various spatial and temporal scales. Full article

(This article belongs to the Special Issue Biobased Polymers and Their Structure-Property Relationships)

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25 pages, 9053 KB

Open AccessArticle

Enhanced Mechanical Robustness of Sprayed Cellulose Nanofibril Coatings Through Internal Crosslinking with Boric Acid

by Pieter Samyn, Patrick Cosemans, Erik V. Van der Eycken and Guglielmo A. Coppola

Polymers 2025, 17(18), 2451; https://doi.org/10.3390/polym17182451 - 10 Sep 2025

Abstract

The enhanced mechanical durability of sprayed nanocellulose coatings at the macroscopic level is primarily required to promote their application in demanding industrial applications with frequently exposed surfaces. In this study, different coating configurations are designed by spraying aqueous cellulose nanofiber (CNF) suspensions in [...] Read more.

The enhanced mechanical durability of sprayed nanocellulose coatings at the macroscopic level is primarily required to promote their application in demanding industrial applications with frequently exposed surfaces. In this study, different coating configurations are designed by spraying aqueous cellulose nanofiber (CNF) suspensions in combination with boric acid (BA) as an internal crosslinker and polydopamine (PDA) as an adhesive interlayer onto glass substrates. Multilayer coatings (CNF/BA) or mixed-layer coatings (CNF + BA) with various concentrations of BA and numbers of sprayed layers are evaluated for maximized mechanical performance based on tape tests, rub tests, cross-cut tests, and scratching tests. Good adhesive strength was realized with an interlayer of PDA/BA (high-concentration BA = 10 mM). The highest cohesive strength was observed for a mixed CNF + BA coating (high-concentration BA = 10 mM) with a scratch resistance of 9 N, and a multilayer CNF/BA coating (gradient layers with ultra-high BA concentration = 100 mM) with a scratch resistance of 8 N. The coatings with the highest density did not uniquely introduce the best mechanical resistance when comparing CNF/BA and CNF + BA coatings, as the formation of BA crystals in multilayer coatings might negatively affect the mechanical properties through embrittlement. Alternatively, the mixed CNF + BA coatings with high BA concentrations provide high density and the best mechanical resistance. The favorable crosslinking corresponds to stabilized water contact angles and reduced spreading of the water as a function of time, while a decrease in coating density causes a reduction in transparency. The chemical interactions between CNF and BA are illustrated by infrared spectroscopy, confirming a reduction in free hydroxyl groups upon crosslinking. Full article

(This article belongs to the Special Issue Preparation and Application of Cellulose-Based and Chitosan-Based Materials)

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20 pages, 5353 KB

Open AccessArticle

Aging Mechanisms and Performance Degradation of XLPE Submarine Cable Insulation Under Marine Major Anion Effects

by Liang Zou, Zheng Liu, Zhiyun Han, Shoushui Han, Guochang Li and Qingsong Liu

Polymers 2025, 17(18), 2450; https://doi.org/10.3390/polym17182450 - 10 Sep 2025

Abstract

When the outer sheath of submarine cables is damaged, the degradation of cross-linked polyethylene (XLPE) insulation by anions in seawater becomes a critical factor affecting cable service life. This study investigates 500 kV three-core XLPE insulation and systematically reveals the differential and synergistic [...] Read more.

When the outer sheath of submarine cables is damaged, the degradation of cross-linked polyethylene (XLPE) insulation by anions in seawater becomes a critical factor affecting cable service life. This study investigates 500 kV three-core XLPE insulation and systematically reveals the differential and synergistic degradation mechanisms of major seawater anions (Cl⁻, SO₄²⁻, HCO₃⁻). Accelerated aging tests at 90 °C were conducted using solution systems simulating both single-ion and composite environments, combined with electrical performance evaluation, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Results show that seawater causes significantly greater deterioration of resistivity, breakdown strength, and molecular structure than any single-ion solution. Mechanistic analysis demonstrates that Cl⁻ induces nucleophilic substitution, SO₄²⁻ promotes oxidative chain scission, and HCO₃⁻ facilitates hydrolysis via pH regulation, while their coexistence produces nonlinear synergistic effects through oxidative reactions, electrochemical coupling, and ion transport. This work provides the first systematic comparison of individual and combined anion effects on XLPE, offering new mechanistic insights and quantitative evidence for understanding multi-ion degradation, with implications for insulation material design, protective strategies, and service life prediction of submarine cables. Full article

(This article belongs to the Special Issue Advanced Polymeric Materials for Electrical Insulation and High-Voltage Applications)

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17 pages, 4495 KB

Open AccessArticle

Rheological and Chemical Effects of Waste Tire Pyrolytic Oil and Its Encapsulation as Rejuvenators on Asphalt Binders

by Rodrigo Delgadillo, Araceli González, Ixa Marzal, Jose L. Concha, Cristina Segura, Luis E. Arteaga-Pérez and Jose Norambuena-Contreras

Polymers 2025, 17(18), 2449; https://doi.org/10.3390/polym17182449 - 10 Sep 2025

Abstract

This study investigates the rheological and chemical effects of waste tire pyrolytic oil (TPO) and its encapsulation (POC) as rejuvenators for asphalt binders. Driven by the need for sustainable and effective strategies to Recycle Reclaimed Asphalt Pavement (RAP), we investigated the use of [...] Read more.

This study investigates the rheological and chemical effects of waste tire pyrolytic oil (TPO) and its encapsulation (POC) as rejuvenators for asphalt binders. Driven by the need for sustainable and effective strategies to Recycle Reclaimed Asphalt Pavement (RAP), we investigated the use of TPO in two forms: as a liquid additive and as polymer capsules. The capsules, made in a 1:5 mass ratio (one part polymer, five parts TPO), were assessed through two methods: rheological tests (dynamic modulus and phase angles) and chemical composition analysis (carbonyl and sulfoxide indices). The binders underwent three aging levels: unaged, primary aging (RTFO), and secondary aging (PAV). Five liquid TPO dosages (1%, 2%, 4%, 6%, 9% by weight) and three encapsulated TPO dosages (6%, 9%, 12% by weight) were tested. Results show that TPO reduces stiffness, increases viscous response, and lowers aging indices, with higher dosages enhancing the effect. Quantitatively, 9% liquid TPO restores PAV-aged binder to near-unaged conditions, suitable for RAP recycling, while 4% release from POCs achieves rejuvenation comparable to RTFO-aged binders, enabling self-healing applications. The estimated release of TPO from POCs during mixing was 20–40%, ensuring a gradual softening effect. These findings highlight the potential of TPO and POC in enhancing asphalt durability and recycling. Full article

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

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22 pages, 5572 KB

Open AccessArticle

Design of Vitrimers with Simultaneous Degradable and Dynamic Crosslinkers: Mechanical and Thermal Behavior Based on Transesterification Reactions Between β-Amino Esters and Hydroxylated Acrylate/Methacrylate Monomers

by Naroa Ayensa, Felipe Reviriego, Helmut Reinecke, Alberto Gallardo, Carlos Elvira and Juan Rodríguez-Hernández

Polymers 2025, 17(18), 2448; https://doi.org/10.3390/polym17182448 - 10 Sep 2025

Abstract

In recent years, efforts have focused on developing repairable, malleable, and recyclable thermoset materials to reduce the growing volume of polymer waste and extend the lifetime of existing polymeric materials. Specifically, associative covalent adaptable networks (CANs), also known as vitrimers, have received considerable [...] Read more.

In recent years, efforts have focused on developing repairable, malleable, and recyclable thermoset materials to reduce the growing volume of polymer waste and extend the lifetime of existing polymeric materials. Specifically, associative covalent adaptable networks (CANs), also known as vitrimers, have received considerable attention. In this work, photopolymerizable vitrimers were prepared by combining crosslinkers containing β-amino esters in their structure with hydroxylated acrylate or methacrylate monomers, with the aim of reprocessing these materials through the activation of transesterification reactions. The network design and photopolymerization conditions were optimized to ensure the successful formation of the vitrimers. Tunable mechanical and thermal properties were achieved by varying their chemical composition. Furthermore, the reprocessing ability of these materials was confirmed through thermal treatments. Additionally, these vitrimers exhibited the ability to undergo hydrolysis in basic aqueous media, providing an alternative pathway for recycling. Full article

(This article belongs to the Special Issue Latest Progress on Polymer Synthesis with Multifunctional Monomers)

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23 pages, 1426 KB

Open AccessReview

Chitosan-Based Materials as Effective Materials to Remove Pollutants

by Anathi Dambuza, Pennie P. Mokolokolo, Mamookho E. Makhatha and Motshabi A. Sibeko

Polymers 2025, 17(18), 2447; https://doi.org/10.3390/polym17182447 - 10 Sep 2025

Abstract

Chitosan is a natural polymer derived from chitin through the deacetylation process. It has emerged as a key ingredient in sustainable wastewater treatment, due to its biodegradability, non-toxicity, and low cost. This biopolymer possesses abundant functional groups, such as -NH₂ and -OH, [...] Read more.

Chitosan is a natural polymer derived from chitin through the deacetylation process. It has emerged as a key ingredient in sustainable wastewater treatment, due to its biodegradability, non-toxicity, and low cost. This biopolymer possesses abundant functional groups, such as -NH₂ and -OH, that efficiently interact with pollutants. This review offers a comprehensive evaluation of pollutant separation techniques involving chitosan-based materials, including adsorption, membrane filtration, flocculation, and photocatalysis. It further examines the underlying adsorption mechanisms, emphasizing how pollutants interact with chitosan and its derivatives at the molecular level. Special focus is given to various modifications of chitosan, alongside a comparative assessment of different chitosan-based adsorbents (hydrogels, nanoparticles, nanocomposites, microspheres, nanofibers, etc.), highlighting their performance in removing heavy metals, dyes, and emerging organic pollutants. The reviewed performance of these polymeric materials from 2015–2025 not only gives an insight about the recent advancement but also points the need for the design of high-performing chitosan-based adsorbents with applications in real water matrices. Full article

(This article belongs to the Special Issue Advanced Study on Natural Polymers and Their Applications)

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17 pages, 9667 KB

Open AccessArticle

Influences of Strain Rates on Tensile and Shear Performances of CF/PP and GF/PP Thermoplastic Composites

by Changye Liu, Juncheng Lv, Yixin Chen, Xinyue Miao, Qinghao Liu, Zhen Wang, Guohua Zhu and Kai Song

Polymers 2025, 17(18), 2446; https://doi.org/10.3390/polym17182446 - 10 Sep 2025

Abstract

This study aims to investigate the influences of strain rates on tensile and shear performances of carbon fiber-reinforced polypropylene (CF/PP) and glass fiber-reinforced polypropylene (GF/PP) thermoplastics. First, the differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests were conducted on the polypropylene to [...] Read more.

This study aims to investigate the influences of strain rates on tensile and shear performances of carbon fiber-reinforced polypropylene (CF/PP) and glass fiber-reinforced polypropylene (GF/PP) thermoplastics. First, the differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests were conducted on the polypropylene to determine its melting and decomposition temperatures, identified as approximately 166 °C and 450 °C, respectively. Subsequently, CF/PP and GF/PP specimens were fabricated through the thermo-compression molding process, and subjected to the uniaxial tension and bias extension tests across six strain rates (1.7 × 10⁻⁶ s⁻¹, 0.5 s⁻¹, 5 s⁻¹, 50 s⁻¹, 250 s⁻¹, and 500 s⁻¹). The results indicated that the tensile modulus/strength and shear modulus/strength of both CF/PP and GF/PP specimens improved with the increase in strain rates, whereas the shear failure strain exhibited a decreasing trend due to the transition of polypropylene from ductile to brittle behaviors. At 500 s⁻¹, CF/PP exhibited 53.08%/53.6% and 52.5%/52.4% increases in tensile/shear modulus and tensile/shear strength compared to 1.7 × 10⁻⁶ s⁻¹, while GF/PP showed 54.6%/113.4% and 71.5%/92.3% improvements, respectively. Furthermore, fracture surfaces exhibited progressive roughening with increasing strain rates. The dynamic increase factor (

D I F

) quantitatively characterized the strain rate dependencies of elastic and strength properties, establishing an analytical model for developing rate-dependent constitutive models in future research. Full article

(This article belongs to the Special Issue Material-Process-Structure Integrated Design for Advanced Polymeric Composites)

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18 pages, 5657 KB

Open AccessArticle

Design and Interlaminar Stress Analysis of Composite Fan Blade Shank

by Yongjun Wu, Yukun Zhang, Zijian Wang, Lu Jin, Xu Tang, Xuyang Li and Yong Chen

Polymers 2025, 17(18), 2445; https://doi.org/10.3390/polym17182445 - 9 Sep 2025

Abstract

The fan blade shank serves as a critical transition structure connecting the airfoil and dovetail, with its geometric design significantly influencing the blade’s structural integrity. This study investigates the geometric configuration and static strength of the laminated composite fan blade shank, with emphasis [...] Read more.

The fan blade shank serves as a critical transition structure connecting the airfoil and dovetail, with its geometric design significantly influencing the blade’s structural integrity. This study investigates the geometric configuration and static strength of the laminated composite fan blade shank, with emphasis on design methodology and analytical approaches. Utilizing Bézier spline curve techniques, two shank configurations—thickened and thinned—were developed for the laminated composite fan blade shank, followed by ply design and static strength analysis. The results demonstrate that high-stress regions in the laminated composite fan blade are predominantly located at the junction between the shank section and the leading edge of the dovetail. Furthermore, the thickened shank configuration effectively reduces the peak σ₃₃ by approximately 15% and simultaneously alleviates the interlaminar shear stress σ₁₃, without introducing adverse ply drop angles, which exhibits superior interlaminar stress resistance under tensile loading conditions. Full article

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

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25 pages, 8096 KB

Open AccessReview

Liquid Crystalline Block Copolymers for Advanced Applications: A Review

by Maryam Safari and Jules A. W. Harings

Polymers 2025, 17(18), 2444; https://doi.org/10.3390/polym17182444 - 9 Sep 2025

Abstract

Liquid crystalline block copolymers (LCBCPs) have emerged as an adaptable hybrid class at the intersection of self-assembling block copolymers and liquid crystalline ordering, producing multi-tiered architectures that can be finely programmed for multifunctional performance. This review surveys recent advances in their structure–property relationships [...] Read more.

Liquid crystalline block copolymers (LCBCPs) have emerged as an adaptable hybrid class at the intersection of self-assembling block copolymers and liquid crystalline ordering, producing multi-tiered architectures that can be finely programmed for multifunctional performance. This review surveys recent advances in their structure–property relationships and highlights applications spanning nanotechnology, biomedical systems, flexible photonics, stimuli-responsive, energy storage, and soft robotics. Particular emphasis is placed on how molecular design enables precise tuning of structural, optical, mechanical, and stimuli-responsive functions, positioning LCBCPs as strong candidates for next-generation functional materials. We also discuss current challenges, including scalability, phase control, and advanced characterization, and outline promising research directions to accelerate their translation from laboratory concepts to real-world technologies. Full article

(This article belongs to the Special Issue Advances in Block Copolymers: Synthesis, Characterization and Applications)

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18 pages, 6073 KB

Open AccessArticle

Harnessing Polyaminal Porous Networks for Sustainable Environmental Applications Using Ultrafine Silver Nanoparticles

by Bedour Almalki, Maymounah A. Alrayyani, Effat A. Bahaidarah, Maha M. Alotaibi, Shaista Taimur, Dalal Alezi, Fatmah M. Alshareef and Nazeeha S. Alkayal

Polymers 2025, 17(18), 2443; https://doi.org/10.3390/polym17182443 - 9 Sep 2025

Abstract

Environmental contamination is a critical global concern, primarily due to detrimental greenhouse gas (GHG) emissions, especially carbon dioxide (CO₂), which significantly contribute to climate change. Moreover, the presence of harmful heavy metals like Ni, Cd, Cu, Hg, and Pb in soil [...] Read more.

Environmental contamination is a critical global concern, primarily due to detrimental greenhouse gas (GHG) emissions, especially carbon dioxide (CO₂), which significantly contribute to climate change. Moreover, the presence of harmful heavy metals like Ni, Cd, Cu, Hg, and Pb in soil and water ecosystems has led to poor water quality. Noble metal nanoparticles (MNPs), for instance, Pd, Ag, Pt, and Au, have emerged as promising solutions for addressing environmental pollution. However, the practical utilization of MNPs faces challenges as they tend to aggregate and lose stability. To overcome this issue, the reverse double-solvent method (RDSM) was utilized to synthesis melamine-based porous polyaminals (POPs) as a supportive material for the in situ growing of silver nanoparticles (Ag NPs). The porous structure of melamine-based porous polyaminals, featuring aminal-linked (-HN-C-NH-) and triazine groups, provides excellent binding sites for capturing Ag⁺ ions, thereby improving the dispersion and stability of the nanoparticles. The resulting material exhibited ultrafine particle sizes for Ag NPs, and the incorporation of Ag NPs within the porous polyaminals demonstrated a high surface area (~279 m²/g) and total pore volume (1.21 cm³/g), encompassing micropores and mesopores. Additionally, the Ag NPs@POPs showcased significant capacity for CO₂ capture (2.99 mmol/g at 273 K and 1 bar) and effectively removed Cu (II), with a remarkable removal efficiency of 99.04%. The nitrogen-rich porous polyaminals offer promising prospects for immobilizing and encapsulating Ag nanoparticles, making them outstanding adsorbents for selectively capturing carbon dioxide and removing metal ions. Pursuing this approach holds immense potential for various environmental applications. Full article

(This article belongs to the Collection Progress in Polymer Composites and Nanocomposites)

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19 pages, 3859 KB

Open AccessArticle

PP-Based Blends with PVP-I Additive: Mechanical, Thermal, and Barrier Properties for Packaging of Iodophor Pharmaceutical Formulations

by Melania Leanza, Domenico Carmelo Carbone, Giovanna Poggi, Marco Rapisarda, Marilena Baiamonte, Emanuela Teresa Agata Spina, David Chelazzi, Piero Baglioni, Francesco Paolo La Mantia and Paola Rizzarelli

Polymers 2025, 17(18), 2442; https://doi.org/10.3390/polym17182442 - 9 Sep 2025

Abstract

The influence of minor components on leaching molecular iodine (I₂) through polypropylene (PP)-based packaging from a povidone iodine-based (PVP-I) formulation, simulating an ophthalmic application, was evaluated. I₂ is a cheap, broad-spectrum, and multi-target antiseptic. Nevertheless, it is volatile, and the [...] Read more.

The influence of minor components on leaching molecular iodine (I₂) through polypropylene (PP)-based packaging from a povidone iodine-based (PVP-I) formulation, simulating an ophthalmic application, was evaluated. I₂ is a cheap, broad-spectrum, and multi-target antiseptic. Nevertheless, it is volatile, and the prolonged storage of I₂-based formulations is demanding in plastic packaging because of transmission through the material. Therefore, we explored the possibility of moderating the loss of I₂ from an iodophor formulation by introducing small amounts of molecular iodine into the polymer material commonly used in eyedropper caps, i.e., PP. Thus, PP was blended via an extrusion process with a polymeric complex containing iodine (such as PVP-I) or with a second polymeric component able to complex the I₂ released from an iodophor solution. The aim of this work was to introduce I₂ into PP-based polymer matrices without using organic solvents and indirectly, i.e., through the addition of components that could generate molecular iodine or complex it in the solid phase, as I₂ is heat-sensitive. To increase the miscibility between PP and PVP-I, poly(N-vinylpyrrolidone) (PVP) or a vinyl pyrrolidone vinyl acetate copolymer 55/45 (Sokalan) were added as compatibilizers. The PP-based binary and ternary blends, in granular or sheet form, were characterized thermally (Differential Scanning Calorimetry, DSC, and Thermogravimetric analysis, TGA), mechanically (tensile tests), morphologically (scanning electron microscopy (SEM)), and chemically (attenuated total reflectance Fourier transform infrared (ATR-FTIR)). Additionally, the variation in wettability induced by the introduction of the hydrophilic minority components was determined by static contact angle measurements (static contact angle (SCA)), and tests were carried out to determine the barrier properties against oxygen (oxygen transmission rate (OTR)) and molecular iodine. The I₂ leaching of the different blends was compared with that of PP by monitoring the I₂ retention in a buffered PVP-I solution via UV-vis spectroscopy. Overall, the experimental data showed the capability of the minority components in the blends to increase thermal stability as well as act as a barrier to oxygen. Additionally, the PP blend with PVP-I induced a reduction in molecular iodine leaching in comparison with PP. Full article

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

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19 pages, 4701 KB

Open AccessArticle

Finite Element Analysis and Experimental Investigation on the Machinability of PMMA/CNT Composites via Nanosectioning

by Guoyu Fu, Jia Ge, Hao Li, Fengzhen Sun and Weizhou Wu

Polymers 2025, 17(18), 2441; https://doi.org/10.3390/polym17182441 - 9 Sep 2025

Abstract

In this study, an innovative modeling approach has been proposed to demonstrate the removal mechanisms of Polymethyl Methacrylate (PMMA) reinforced with randomly distributed carbon nanotubes (CNTs) during nanosectioning. The viscoplastic behavior of the matrix polymer was described using the Mulliken–Boyce model and the [...] Read more.

In this study, an innovative modeling approach has been proposed to demonstrate the removal mechanisms of Polymethyl Methacrylate (PMMA) reinforced with randomly distributed carbon nanotubes (CNTs) during nanosectioning. The viscoplastic behavior of the matrix polymer was described using the Mulliken–Boyce model and the distribution of the CNTs in the matrix was modeled using the random sequential adsorption (RSA) method. The effects of cutting thickness and CNT loading on the machinability of the nanocomposites are explored. Subsequent experiments were conducted to validate the modeling. It reveals that the addition of CNT increases the resistance to cutting, compared to the malleable matrix. Although the primary strain distribution for both plain PMMA and PMMA/CNT composites aligns closely, discernible disparities between the two materials emerge. A force augmentation is anticipated whenever a nanotube interacts with the cutting tool, which causes surface protrusions and sub-surface damage. The addition of CNT with a loading lower than 1.0 wt% does not change the mechanisms of chip formation, but the addition of 1.0 wt% CNTs increases cutting force by approximately 32%. This work provides a feasible approach and framework to numerically model the nanosectioning of CNT-reinforced thermoplastics. Full article

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

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21 pages, 3250 KB

Open AccessArticle

Modification of Rigid Polyurethane Foams with Straw Additive: Influence of Chemical Treatment and Content on Performance Properties

by Anna Strąkowska, Justyna Miedzianowska-Masłowska and Sylwia Makowska

Polymers 2025, 17(18), 2440; https://doi.org/10.3390/polym17182440 - 9 Sep 2025

Abstract

This work aimed to synthesize rigid polyurethane foams with improved functional properties through modification with the addition of cellulose in the form of straw: unmodified, silanized, and silanized with the addition of fumed silica. The prepared rigid polyurethane foams contained 0.5; 1; and [...] Read more.

This work aimed to synthesize rigid polyurethane foams with improved functional properties through modification with the addition of cellulose in the form of straw: unmodified, silanized, and silanized with the addition of fumed silica. The prepared rigid polyurethane foams contained 0.5; 1; and 3 parts by weight of the modifier about the weight of the polyol used. As part of the work, a number of tests were carried out to determine the impact of the modifiers used on the reaction kinetics and on the functional properties of rigid polyurethane foams. Silanization improved thermal stability and interfacial compatibility, while silica further enhanced porosity and surface activity. The optimal properties were obtained at low loadings: 0.5 wt.% provided the best mechanical strength, and 1 wt.% yielded the most uniform cell morphology and density. Higher contents increased porosity, reduced strength, and lowered water resistance. Dynamic mechanical analysis confirmed predominantly elastic behavior, with silica-modified fillers offering the most stable thermomechanical response. Overall, even small amounts of modified straw enhanced mechanical, structural, and water-resistant properties, demonstrating its potential as a sustainable and cost-effective biofiller for eco-friendly polyurethane foams. Full article

(This article belongs to the Special Issue Thermoplastic Foams: Processing, Manufacturing, and Characterization)

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27 pages, 3120 KB

Open AccessArticle

Reprocessing of Simulated Industrial PLA Waste for Food Contact Applications

by Javiera Sepúlveda-Carter, Simón Faba, Marcos Sánchez Rodríguez and Marina P. Arrieta

Polymers 2025, 17(18), 2439; https://doi.org/10.3390/polym17182439 - 9 Sep 2025

Abstract

This study explores reusing discarded industrial polylactic acid (PLA), such as defective parts, scraps and burrs, for food contact applications. Reprocessing of PLA (PLA-RP) was simulated via melt extrusion, and the obtained pellets were characterized in terms of viscosity average molecular weight (M [...] Read more.

This study explores reusing discarded industrial polylactic acid (PLA), such as defective parts, scraps and burrs, for food contact applications. Reprocessing of PLA (PLA-RP) was simulated via melt extrusion, and the obtained pellets were characterized in terms of viscosity average molecular weight (M_v), melt flow index (MFI), the presence of non-intentionally added substances (NIASs) and the absence of metals to ensure that no substances exceeded the specific migration limits (SMLs). A slight reduction in the M_v, accompanied by an increase in the MFI, was observed in PLA-RP. In virgin PLA, fewer compounds were detected, likely related to residual additives. A higher variety and concentration of volatile and non-listed compounds were observed in reprocessed PLA (PLA-RP), with three exceeding their assigned Cramer class thresholds, requiring further evaluation. Most identified substances were typically linked to thermal degradation or potential additives for reprocessing. In both the virgin and reprocessed materials, all substances with SMLs remained below applicable thresholds, including trace metals. The PLA-RP was further processed into films by means of a compression moulding process. The structure, mechanical behaviour, thermal stability and water vapor transmission rate were comparable to those of virgin PLA, indicating no significant changes. The overall migration level tested in a fatty food simulant remained below regulatory limits. The materials fully disintegrated under laboratory-scale composting conditions in less than 3 weeks. Thus, reprocessed PLA shows great potential as a non-migrating material of interest in the sustainable food packaging field. Full article

(This article belongs to the Special Issue Advances in Biopolymer Research: Sustainability and Applications)

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20 pages, 3579 KB

Open AccessArticle

Evolution of the Structure of EDPM Crosslinking Networks and Its Influence on the Rheological Properties of the Injection Molding Process

by Salvador Gomez-Jimenez, Carlos Guerrero Mendez, Daniela Lopez-Betancur, Antonio Robles-Guerrero, David Navarro-Solis, Luis Silva-Acosta, Enrique A. Lopez-Baltazar, Jennifer Ortiz-Letechipia and Ada Rebeca Contreras-Rodríguez

Polymers 2025, 17(18), 2438; https://doi.org/10.3390/polym17182438 - 9 Sep 2025

Abstract

The rubber industry is evolving by incorporating innovative tools to improve production processes. A proper manufacturing process determines the behavior and service life of the resulting products. In this research, molecular dynamics simulations were used to study the effect of temperature in the [...] Read more.

The rubber industry is evolving by incorporating innovative tools to improve production processes. A proper manufacturing process determines the behavior and service life of the resulting products. In this research, molecular dynamics simulations were used to study the effect of temperature in the cured structure on the resulting mechanical properties of EPDM. The results of the simulations at different temperatures of the crosslinked ethylene–propylene–diene monomer (EPDM) were then compared in terms of the radius of gyration, free volume, root mean square displacement, stress curves, viscosity, and gel point. Then, using the superposition principle, viscosity and tensile stress were evaluated. The molecular dynamics superposition results could reasonably predict the mechanical behavior of EPDM during and after the injection process. The results provide new insights into the molecular-level crosslinking mechanisms of amorphous polymers and their influence on mechanical behavior, which facilitates the design of the injection process for rubber component applications. The results show an increase in viscosity and a decrease in the critical gel point with increasing temperature. The hardness tests performed on an automotive component demonstrate that this has an impact on the resulting properties. Full article

(This article belongs to the Special Issue Applications of Process Simulation in Polymer-Based Products Injection Molding)

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17 pages, 2379 KB

Open AccessArticle

Effect of Application of a Homogeneous Magnetic Field During Chemical Crosslinking of Magnetic Collagen-Based Hydrogels with Genipin on Their Essential Properties

by Adriana Gilarska, Wojciech Horak, Agnieszka Radziszewska, Damian Rybicki and Czesław Kapusta

Polymers 2025, 17(18), 2437; https://doi.org/10.3390/polym17182437 - 9 Sep 2025

Abstract

The aim of this study was to investigate the effect of a static, homogeneous magnetic field on the physicochemical properties of magnetic hydrogels based on collagen and superparamagnetic iron oxide nanoparticles (SPIONs), chemically crosslinked with genipin. The crosslinking process was initiated in the [...] Read more.

The aim of this study was to investigate the effect of a static, homogeneous magnetic field on the physicochemical properties of magnetic hydrogels based on collagen and superparamagnetic iron oxide nanoparticles (SPIONs), chemically crosslinked with genipin. The crosslinking process was initiated in the presence of a magnetic field with three different induction values (100, 250 and 500 mT), generated in specially designed experimental systems. It was demonstrated that the applied field did not noticeably affect the crosslinking efficiency, and stable hydrogels with a high gel fraction in the range of 87–94% were obtained. STEM image analysis revealed that in the highest magnetic field, the nanoparticles tended to form larger clusters, while at lower fields and in the material crosslinked at zero field, smaller clusters and chains of nanoparticles were observed mainly. This observation was reflected in the magnetic susceptibility, which showed a weaker response to the magnetic field of the material obtained by crosslinking in the presence of the 500 mT field compared to the material crosslinked without the field—larger clusters of nanoparticles may hinder the alignment of the magnetic moments of their constituent nanoparticles. Studies of the physicochemical properties of the hydrogels obtained indicate that the presence of larger clusters can cause a local decrease in the crosslinking density, resulting in a slight decrease in the storage modulus and increased initial swelling and degradation rates. The results obtained show that the application of a homogeneous magnetic field with moderate induction values during the crosslinking process can be used as a tool for modification of the microstructure of magnetic collagen-based hydrogels. The possibility of such structural modifications may be useful in designing biomaterials with properties tailored to their target application. Full article

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

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19 pages, 8443 KB

Open AccessArticle

A Carboxylated Nitrile Butadiene Rubber Latex Film with Synergistically Enhanced Water-Based Lubricity and Tensile Strength: Fabrication and Characterization

by Jinting Zhai and Mingsheng Wu

Polymers 2025, 17(18), 2436; https://doi.org/10.3390/polym17182436 - 9 Sep 2025

Abstract

To address the inherent trade-off between high wet friction and poor mechanical properties in carboxylated nitrile butadiene rubber (XNBR) films, this study introduces a layered silicate (bentonite) as a dual-functional lubricating-reinforcing additive. Unlike the conventional linear polymer anionic polyacrylamide (APAM), which has limited [...] Read more.

To address the inherent trade-off between high wet friction and poor mechanical properties in carboxylated nitrile butadiene rubber (XNBR) films, this study introduces a layered silicate (bentonite) as a dual-functional lubricating-reinforcing additive. Unlike the conventional linear polymer anionic polyacrylamide (APAM), which has limited efficacy, bentonite exhibits superior performance attributed to its unique two-dimensional (2D) nanosheet structure. The mechanism is twofold: under shear stress, the hydrated nanosheets align to form a highly efficient, low-friction interface; simultaneously, these rigid nanosheets act as a reinforcing filler within the matrix, enhancing mechanical strength through stress dissipation and microcrack inhibition. Consequently, the bulk incorporation of bentonite resulted in a remarkable 38% increase in tensile strength, coupled with a significant 48% reduction in the wet coefficient of friction. This work elucidates an effective mechanism for synergistically improving both surface and bulk properties of a polymer using inorganic nanosheets, offering a new strategy for the design of advanced functional composites. Full article

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

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23 pages, 30393 KB

Open AccessArticle

An Acid-Cleavable Lamellar Block Copolymer for Sub-30-nm Line Spacing Patterning via Graphoepitaxial Directed Self-Assembly and Direct Wet Etching

by Jianghao Zhan, Caiwei Shang, Muqiao Niu, Jiacheng Luo, Shengguang Gao, Zhiyong Wu, Shengru Niu, Yiming Xu, Xingmiao Zhang, Zili Li and Shisheng Xiong

Polymers 2025, 17(18), 2435; https://doi.org/10.3390/polym17182435 - 9 Sep 2025

Abstract

Graphoepitaxial directed self-assembly (DSA) of block copolymers (BCPs) has emerged as a promising strategy for sub-30 nm line spacing patterning in semiconductor nanofabrication. Among the available BCP systems, polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA) has been extensively utilized due to its well-characterized phase [...] Read more.

Graphoepitaxial directed self-assembly (DSA) of block copolymers (BCPs) has emerged as a promising strategy for sub-30 nm line spacing patterning in semiconductor nanofabrication. Among the available BCP systems, polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA) has been extensively utilized due to its well-characterized phase behavior and compatibility with standard lithographic processes. However, achieving a high-fidelity pattern with PS-b-PMMA remains challenging, owing to its limited etch contrast and reliance on UV-assisted degradation for PMMA removal. In this study, we report the synthesis of an acid-cleavable lamellar BCP, PS-N=CH-PMMA, incorporating a dynamic Schiff base (-N=CH-) linkage at the junction. This functional design enables UV-free wet etching, allowing selective removal of PMMA domains using glacial acetic acid. The synthesized copolymers retain the self-assembly characteristics of PS-b-PMMA and form vertically aligned lamellar nanostructures, with domain spacings tunable from 36.1 to 40.2 nm by varying the PMMA block length. When confined within 193i-defined trench templates with a critical dimension (CD) of 55 nm (trench width), these materials produced well-ordered one-space-per-trench patterns with interline spacings tunable from 15 to 25 nm, demonstrating significant line spacing shrinkage relative to the original template CD. SEM and FIB-TEM analyses confirmed that PS-N=CH-PMMA exhibits markedly improved vertical etch profiles and reduced PMMA residue compared to PS-b-PMMA, even without UV exposure. Furthermore, Ohta–Kawasaki simulations revealed that trench sidewall angle critically influences PS distribution and residual morphology. Collectively, this work demonstrates the potential of dynamic covalent chemistry to enhance the wet development fidelity of BCP lithography and offers a thermally compatible, UV-free strategy for sub-30 nm nanopatterning. Full article

(This article belongs to the Special Issue Advances in Self-Assembly of Block Copolymers: Synthesis and Applications)

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