Polymers

15 pages, 6782 KB

Open AccessArticle

Biocompatibility Assessment of Polydimethylsiloxane for Vitreous Substitution Application in Relation to Physicochemical Properties

by Diba Grace Auliya, Mutiara Septiani and Risdiana Risdiana

Polymers 2026, 18(13), 1597; https://doi.org/10.3390/polym18131597 (registering DOI) - 26 Jun 2026

Abstract

Polydimethylsiloxane (PDMS) has long been utilized as a vitreous humour substitute in the treatment of retinal detachment. To address increasing clinical demands, PDMS synthesis has been explored, yielding a range of viscosities of PDMS with favourable properties for this application. While various formulations [...] Read more.

Polydimethylsiloxane (PDMS) has long been utilized as a vitreous humour substitute in the treatment of retinal detachment. To address increasing clinical demands, PDMS synthesis has been explored, yielding a range of viscosities of PDMS with favourable properties for this application. While various formulations and synthesis routes for developed PDMS have been reported in previous studies, an evaluation of their biocompatibility and relationship to physical properties has not yet been reported. However, the biocompatibility of this biomaterial is a critical determinant of its long-term performance. Accordingly, this study aims to evaluate the biocompatibility of PDMS and its relationship with physical properties through a comprehensive assessment that correlates polymer synthesis parameters, physicochemical properties, storage stability, emulsification resistance, and cytotoxicity. The samples tend to be stable during a five-month storage period. No signs of emulsification were observed when the samples were exposed to the emulsifiers. All samples exhibited no cytotoxic effect through the resazurin assay. Collectively, these findings suggest that synthesized PDMS possesses favourable biocompatibility and physicochemical stability, supporting its potential as a vitreous humour substitute. Full article

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

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39 pages, 4376 KB

Open AccessArticle

Transient Electroosmotic Flow of Maxwell Fluids Through Soft Channels with High Surface Potentials

by Clara G. Hernández, Juan P. Escandón, Edson M. Jimenez, Juan R. Gómez, René O. Vargas, David A. Torres and Nicolas Ratkovich

Polymers 2026, 18(13), 1596; https://doi.org/10.3390/polym18131596 (registering DOI) - 26 Jun 2026

Abstract

This study analyzes the combined effects of non-Newtonian rheology and electrostatics on the transient electroosmotic flow of Maxwell fluids in soft channels. The walls of the rigid channels are hydrophobic, ionically charged, and coated with a polyelectrolyte layer (PEL). This design is intended [...] Read more.

This study analyzes the combined effects of non-Newtonian rheology and electrostatics on the transient electroosmotic flow of Maxwell fluids in soft channels. The walls of the rigid channels are hydrophobic, ionically charged, and coated with a polyelectrolyte layer (PEL). This design is intended to regulate both the surface electric potential and the flow velocity. The mathematical model is based on modified Poisson–Boltzmann and momentum equations, which are solved numerically using a one-dimensional (1D) approach. The results indicate that high potentials, exceeding the Debye–Hückel limit, are achieved under conditions of thick polyelectrolyte layers, high surface charge density, and a higher concentration of fixed charges compared to the electrolyte ionic concentration. In this regime, steric effects increase the electric potential; however, this potential increase is limited by the formation of a Donnan potential. The hydrodynamic analysis demonstrates that the velocity magnitude is influenced not only by the wall potential but also by the spatial distribution of free charge density and electroosmotic force, which, in turn, are affected by steric effects. Additionally, changing the polarity and concentration of fixed charge in the PEL produces asymmetric flows, and while hydrodynamic slip enhances velocity, the drag parameter reduces it. Finally, the dimensionless parameters that control the time required to dampen the oscillatory flow induced by viscoelastic effects and reach steady-state are mainly the relaxation time, the drag parameter, the PEL thickness, and the electrokinetic parameter of the PEL, while the surface charge density and the external pressure gradient exert a comparatively minor influence. Full article

(This article belongs to the Special Issue Polymers at Surfaces and Interfaces)

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12 pages, 1915 KB

Open AccessArticle

Achieving Low Dielectric Loss and High Humidity Stability Polyimide Through the Synergistic Effect of Copolymer Monomer Optimization and Aggregation State Regulation

by Xing Kang, Chenyu Liu, Hongkui Wu, Runxin Bei, Siwei Liu and Yi Zhang

Polymers 2026, 18(13), 1595; https://doi.org/10.3390/polym18131595 (registering DOI) - 26 Jun 2026

Abstract

Polyimide (PI) has excellent comprehensive performance and a wide range of applications, but its high molecular chain rigidity, poor flexibility, and difficulty in processing and molding limit its further applications. Introducing flexible groups, fluorinated groups, and copolymer modification are effective methods to improve [...] Read more.

Polyimide (PI) has excellent comprehensive performance and a wide range of applications, but its high molecular chain rigidity, poor flexibility, and difficulty in processing and molding limit its further applications. Introducing flexible groups, fluorinated groups, and copolymer modification are effective methods to improve PI performance. Among them, ether bonds can enhance the mobility of molecular chains and optimize processing performance, trifluoromethyl groups can improve material crystallinity and high-frequency dielectric properties, and copolymer modification can achieve the regulation of aggregated structures. In this study, the rigid TFMB-BPDA polyimide system was used as the matrix, and various ether-bond-containing diamine monomers were introduced through copolymerization, to explore the effects of different types of ether-bond-containing diamines and the soft-to-hard segment ratios on the aggregated structure and high-frequency dielectric properties of PI films. The goal is to optimize the comprehensive performance of PI materials through molecular structure design. Full article

(This article belongs to the Section Polymer Chemistry)

38 pages, 37093 KB

Open AccessArticle

Mechanical Performance of Gravelly Soil Stabilized with Recycled Polypropylene Fiber and Polyurethane

by Pei Zuan, Jiali Feng, Pingcuo Langjia and Xinghong Liu

Polymers 2026, 18(13), 1594; https://doi.org/10.3390/polym18131594 (registering DOI) - 26 Jun 2026

Abstract

Gravel soil used as backfill behind rockfall barriers in mountainous roads can extend structural service life and support sustainable resource utilization. However, rainfall-induced erosion may cause soil loss and reduce its buffering capacity. The fibers are short discrete fibers with a length of [...] Read more.

Gravel soil used as backfill behind rockfall barriers in mountainous roads can extend structural service life and support sustainable resource utilization. However, rainfall-induced erosion may cause soil loss and reduce its buffering capacity. The fibers are short discrete fibers with a length of approximately 12 mm and an average diameter of 32.7 μm, corresponding to an aspect ratio of approximately 367. Reinforcement is achieved through fiber–soil interaction mechanisms, including particle bridging, interfacial friction, and pull-out resistance. The effects of polyurethane and fiber contents on compressive strength, shear strength, and impact resistance were evaluated using response surface methodology. Scanning electron microscopy was used to examine the microstructural features associated with the reinforcement mechanisms, and engineering-scale model tests were conducted to assess erosion and impact resistance under representative service conditions. The results show that polyurethane and fibers produce significant nonlinear enhancement effects on the mechanical properties of gravel soil, mainly through their individual contributions, whereas their interaction is limited. Multi-objective optimization indicates that the optimal mixture contains 6.8% polyurethane and 0.19% fiber, with prediction errors below 5%. The unconfined compressive strength of the gravelly soil increased from 107.6 kPa to 931.5 kPa, representing a 765.7% increase. Cohesion increased from 23.4 kPa to 83.44 kPa, representing a 256.4% increase. The internal friction angle increased from 43.4° to 61.23°, corresponding to a 41.08% increase. Under 1 h of intense rainfall erosion, the stabilized soil exhibited only slight surface particle detachment and maintained overall integrity. In impact tests, the velocity attenuation rate reached 65.6–71.4%. The proposed material provides a sustainable solution for improving buffer layers in rockfall barriers. Full article

(This article belongs to the Topic Advances in Fiber-Reinforced Composites)

12 pages, 2196 KB

Open AccessArticle

Comparative Study on the Properties of Smoke Sheet Rubber Produced by Different Solidification Methods

by Linguang Ruan, Lin Yan, Dandan Yao, Bingguo Liu, Shenghui Guo and Jiawang Yin

Polymers 2026, 18(13), 1593; https://doi.org/10.3390/polym18131593 (registering DOI) - 26 Jun 2026

Abstract

To investigate the effects of coagulation methods on the structure and properties of sheet rubber, this study prepared natural rubber using different coagulation systems, including acetic acid, formic acid, biological coagulants, and pineapple juice, and systematically analyzed their non-rubber components, gel content, molecular [...] Read more.

To investigate the effects of coagulation methods on the structure and properties of sheet rubber, this study prepared natural rubber using different coagulation systems, including acetic acid, formic acid, biological coagulants, and pineapple juice, and systematically analyzed their non-rubber components, gel content, molecular weight distribution, rheological behavior, and mechanical properties of the vulcanized rubber. The results indicate that the type of coagulant significantly affects the protein, phospholipid, and gel content. Among these, the pineapple juice gel exhibited the lowest residual protein content, suggesting that the proteases, organic acids, and active components it contains promote the degradation and removal of non-rubber components. GPC and rheological results show that pineapple juice gel and bio-gel samples possess a broad molecular weight distribution and exhibit a more pronounced viscoelastic response at high temperatures. After uniform vulcanization, the differences in hardness, tensile strength, and tear resistance among the various samples were minimal, indicating that the vulcanized network determines the final mechanical properties, while the coagulation method primarily regulates microstructure and processing behavior. This study provides a theoretical basis for the application of bio-coagulants in the processing of green shikigai gum. Full article

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

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17 pages, 1897 KB

Open AccessArticle

Constitutive Modeling of the Nonlinear Tensile Response of High-Strength Nanofiber Yarns Under Monotonic Loading

by Qingqing Shao, Jingyu Hu, Qiyu Wei, Jiqiang Cao, Yuanshu Xiao, Xiang Liu, Bo Xing and Xiakeer Saitaer

Polymers 2026, 18(13), 1592; https://doi.org/10.3390/polym18131592 (registering DOI) - 26 Jun 2026

Abstract

High-strength nanofiber yarns exhibit pronounced nonlinear tensile responses arising from their hierarchical fibrous architecture, yet compact constitutive descriptions remain limited. Here, high-strength polyacrylonitrile nanofiber yarns were prepared by post-drawing as-spun yarns above the glass transition temperature, and their aligned, stacked morphology was confirmed [...] Read more.

High-strength nanofiber yarns exhibit pronounced nonlinear tensile responses arising from their hierarchical fibrous architecture, yet compact constitutive descriptions remain limited. Here, high-strength polyacrylonitrile nanofiber yarns were prepared by post-drawing as-spun yarns above the glass transition temperature, and their aligned, stacked morphology was confirmed by scanning electron microscopy. Monotonic tensile tests at different loading rates were used to quantify the rate-dependent stress–strain response. The tangent modulus derived from the tensile curve varied strongly with strain, confirming clear deviation from linear viscoelasticity. To capture this behavior, two effective models were established: a modified nonlinear three-element model and a structural four-element model incorporating a nonlinear elastic contribution. Closed-form stress–strain expressions were derived for constant strain-rate loading and fitted to experimental data using nonlinear regression. Both models reproduced the measured tensile curves with high accuracy over the investigated loading-rate range, with correlation coefficients close to unity and low fitting errors. The identified parameters were highly consistent between formulations, indicating functional equivalence for the present monotonic tensile dataset. These results provide a compact framework for characterizing and designing hierarchical polymer nanofiber yarns. Full article

(This article belongs to the Section Polymer Fibers)

26 pages, 11657 KB

Open AccessArticle

Structure–Property Relationships of Hot-Pressed Wood–Polymer Composite Boards from Recycled ABS Edge-Banding Waste and Wood Fibers

by Viktor Savov, Petar Antov, Alexandrina Kostadinova-Slaveva, Ekaterina Todorova, Matei Botev, Georgi Ivanov, Viktoria Dudeva, Martina Todorova, Konstantinos Ninikas, Stoyko Petrin and Anton Kuzmin

Polymers 2026, 18(13), 1591; https://doi.org/10.3390/polym18131591 (registering DOI) - 26 Jun 2026

Abstract

Recycled thermoplastics offer a promising route for valorizing industrial residues and developing thermoplastic-bonded wood-based panels without added formaldehyde-based resins. In this study, experimental wood–polymer composite boards were produced from recycled acrylonitrile–butadiene–styrene (ABS) edge-banding waste used as the polymer matrix and industrial wood fibers [...] Read more.

Recycled thermoplastics offer a promising route for valorizing industrial residues and developing thermoplastic-bonded wood-based panels without added formaldehyde-based resins. In this study, experimental wood–polymer composite boards were produced from recycled acrylonitrile–butadiene–styrene (ABS) edge-banding waste used as the polymer matrix and industrial wood fibers used as the lignocellulosic reinforcement. The boards were manufactured at target densities of 800–1200 kg·m⁻³ and wood fiber contents of 10–30%, followed by the evaluation of selected physical and mechanical properties, including water absorption, thickness swelling, modulus of elasticity and bending strength. Thermogravimetric analysis of the recycled ABS edge-banding material and qualitative optical microscopy of the board surfaces were used to support, but not independently prove, the interpretation of the composite structure. The recycled ABS waste enabled the formation of compact boards, with density exerting the strongest influence on water resistance and bending performance. The regression models indicated a balanced region at 21.84 wt.% wood fibers and 1134 kg·m⁻³, corresponding to predicted water absorption of 1.62%, thickness swelling of 3.22%, modulus of elasticity of 2931 N·mm⁻² and bending strength of 22.20 N·mm⁻². Optical microscopy suggested a more continuous ABS-rich surface in the most homogeneous specimens, whereas local accumulations of fine particles and areas of limited polymer coverage were observed on the opposite surface. These findings demonstrate the potential of recycled ABS edge-banding waste for wood–polymer board production, while indicating that additional feedstock cleaning and sieving should be investigated in subsequent work to improve furnish uniformity and structural homogeneity. Full article

(This article belongs to the Special Issue Advances in Wood and Wood Polymer Composites, 2nd Edition)

26 pages, 4086 KB

Open AccessArticle

Research on the Similarity Law of the Fragmentation Effect of a Reactive Inner Core PELE Penetrating a Steel Plate

by Yongjin Lu, Bo Tan, Shixi Yang, Shiyan Sun, Gangwei Liu and Da Deng

Polymers 2026, 18(13), 1590; https://doi.org/10.3390/polym18131590 (registering DOI) - 26 Jun 2026

Abstract

This study explores the similarity of the fragmentation effect of a reactive inner core PELE (RIC-PELE) when penetrating a steel plate by measuring the broken length of the jacket after perforating the steel plate and the dispersion radius of the jacket fragments behind [...] Read more.

This study explores the similarity of the fragmentation effect of a reactive inner core PELE (RIC-PELE) when penetrating a steel plate by measuring the broken length of the jacket after perforating the steel plate and the dispersion radius of the jacket fragments behind the steel plate. Based on the dimensional theory, the dimensionless functions of these two physical quantities were analyzed and established. On the basis of verifying the validity of numerical simulation, the penetration and deflagration damage effects of five scale models were simulated on the ANSYS/Autodyn 17.0 software platform, and the dimensional analysis was verified. In the obtained dimensionless functions, the independent variables are all geometric dimensionless quantities. The simulation results reveal that, within the impact velocity range of 900–1900 m/s, the dimensionless broken length of the jacket and the dimensionless dispersion radius of jacket fragments behind the target are approximately equal in different scale models at the same velocity; these values fall within error margins of ±7% and ±9% of the reference model, respectively, and both dimensionless quantities exhibit an approximately linear positive relationship with impact velocity. This indicates that when ignoring the size effect caused by the strain rate effect of the materials, the geometric similarity law of the fragmentation effect of a RIC-PELE penetrating a steel plate essentially holds, thereby verifying the correctness of the dimensional analysis. Full article

(This article belongs to the Section Polymer Applications)

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28 pages, 9452 KB

Open AccessReview

Polydimethylsiloxane in Optics

by Sergio Calixto, Roberto Zitzumbo and Mariana Alfaro-Gomez

Polymers 2026, 18(13), 1589; https://doi.org/10.3390/polym18131589 (registering DOI) - 26 Jun 2026

Abstract

Optics is the science of light, which supports disciplines like biology, medicine, engineering, materials science, chemistry, physics and more. Optics helps to improve diagnostic speed, portable and user-friendly devices, cost efficiency, and sensitivity. Through time, optical components have been made with hard and [...] Read more.

Optics is the science of light, which supports disciplines like biology, medicine, engineering, materials science, chemistry, physics and more. Optics helps to improve diagnostic speed, portable and user-friendly devices, cost efficiency, and sensitivity. Through time, optical components have been made with hard and non-deformable materials. However, traditional optical elements can no longer meet the needs of the market, and new optical elements are needed, such as materials with higher degrees of freedom. A candidate that has been proposed to replace traditional optical materials is polydimethylsiloxane (PDMS or silicone) because it presents suitable characteristics like biocompatibility, nontoxicity, flexibility, non-biodegradability, high transparency in the UV–visible range, low scattering and absorption, easy fabrication, cost-effective relation and more. Many articles have reported the fabrication of optical components with silicone and the use of these components in optical devices. Unfortunately, there is no review that comprehensively covers the field of optics in relation to the application of silicone. The present work is intended as a descriptive overview to provide a clear and accessible review of the topic, rather than a comparative analysis. Articles describing the use of silicone in the fabrication of optical components during the past 20 years were reviewed. Full article

(This article belongs to the Section Polymer Applications)

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Graphical abstract

22 pages, 6652 KB

Open AccessArticle

Numerical Simulation Study on Residual Stress and Strain in the Curing and Molding of HTPB Two-Stage Solid Propellant

by Jinpeng Chang, Chunguang Xu and Yingjun Dai

Polymers 2026, 18(13), 1588; https://doi.org/10.3390/polym18131588 (registering DOI) - 26 Jun 2026

Abstract

Understanding the curing and molding process of HTPB two-stage solid propellants and their stress and strain distributions is essential for the efficient manufacturing, long-term storage, safe transportation, and reliable operation of solid rocket motors. In this study, the residual stress and strain generated [...] Read more.

Understanding the curing and molding process of HTPB two-stage solid propellants and their stress and strain distributions is essential for the efficient manufacturing, long-term storage, safe transportation, and reliable operation of solid rocket motors. In this study, the residual stress and strain generated during the curing and molding of HTPB two-stage solid propellants were numerically investigated. The mechanisms responsible for residual stress and strain were analyzed, the relaxation modulus was characterized using a Prony series and the WLF time–temperature superposition equation, and the curing and cooling processes of a two-stage solid propellant grain were simulated. Furthermore, the effects of the modulus m and length-to-diameter ratio n on the residual stress and strain fields were investigated. The results show that at the end of the curing and cooling of the grains, there are high stress and strain zones on the sides close to the core mold and the shell. At the connection point between the first-stage and second-stage grains, due to the different materials, there is a sudden change in stress and strain. The curing stage accounts for 32.1% of the total residual stress and 32.6% of the total residual strain. As the modulus m increases, the overall stress and strain of the grain increase. As the length-to-diameter ratio n increases, the overall stress and strain of the grain decrease. This work provides a basis for the dimensional design of two-stage solid propellant grains and the selection of critical regions for structural safety evaluation. Full article

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

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25 pages, 2942 KB

Open AccessArticle

Research on the Mechanical Durability Performance and Action Mechanism of Basalt Fiber-Reinforced Concrete for Ship Lock Wall

by Benkun Lu, Jie Chen, Shuncheng Xiang, Zhe Peng, Changyu Liu, Haotian Yu and Yasi Ye

Polymers 2026, 18(13), 1587; https://doi.org/10.3390/polym18131587 (registering DOI) - 26 Jun 2026

Abstract

To address early-age cracking in concrete walls of hydraulic structures such as ship locks, basalt fibers (BFs) were incorporated as a reinforcement strategy. The effects of varying BF dosages and lengths on the workability, mechanical strength, and crack resistance of concrete were systematically [...] Read more.

To address early-age cracking in concrete walls of hydraulic structures such as ship locks, basalt fibers (BFs) were incorporated as a reinforcement strategy. The effects of varying BF dosages and lengths on the workability, mechanical strength, and crack resistance of concrete were systematically evaluated. Furthermore, the internal microstructure was examined using scanning electron microscopy (SEM), and the durability performance, including impermeability, freeze–thaw resistance, and abrasion resistance, was assessed. The results indicate that workability decreased with increasing fiber content and length. The highest mechanical performance among tested mixes was achieved with 0.1% BF of 9 mm length, increasing 7-day and 28-day compressive strength by 17.47% and 22.59%, respectively, compared to plain concrete. The greatest crack resistance was observed with 0.2% BF of 18 mm length, delaying cracking by 150% and reducing crack width by 85%. Durability tests showed that a 0.2%-18 mm BF mix reduced water permeability depth by 47.37% and a 0.3% BF content optimized abrasion resistance. Freeze–thaw cycles indicated that a 0.3% fiber content effectively maintained the relative dynamic elastic modulus. SEM analysis revealed that BFs act as micro-bridges within the matrix, optimizing pore structure, inhibiting micro-crack propagation, and enhancing concrete density. This study evaluates BF-reinforced concrete and provides a practical reference for improving crack resistance and long-term durability in ship lock structures. Full article

(This article belongs to the Special Issue Advances in the Preparation, Properties and Application of Polyurethane, Cellulose and Their Composites (3rd Edition))

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9 pages, 3620 KB

Open AccessArticle

The Promoting Effect of Reactive Comb Compatibilizer on the Formation of Co-Continuous Structure in PVDF/PLLA Blends

by Yufei Dong, Fei Li, Jiayao Wang, Yongjin Li, Guipeng Yu and Jichun You

Polymers 2026, 18(13), 1586; https://doi.org/10.3390/polym18131586 (registering DOI) - 26 Jun 2026

Abstract

While many kinds of reactive compatibilizers (RCs) have been artificially created for reducing interfacial tension in immiscible polymer blends, the effect of RCs on co-continuity formation (preferred in application) remains controversial. In this work, we selected the previously reported poly(vinylene fluoride)/poly(L-lactic acid)/reactive comb [...] Read more.

While many kinds of reactive compatibilizers (RCs) have been artificially created for reducing interfacial tension in immiscible polymer blends, the effect of RCs on co-continuity formation (preferred in application) remains controversial. In this work, we selected the previously reported poly(vinylene fluoride)/poly(L-lactic acid)/reactive comb compatibilizer (PVDF/PLLA/RCC) blend system as the model system, in which the reaction between epoxy groups in RCC and terminal carboxyl groups in PLLA upon blending can produce glycidyl methacrylate (GMA)-PLLA side chains located at the PVDF/PLLA interface. By manipulating PVDF/PLLA composition ratio and RCC content, a half-U-shaped co-continuous phase diagram with an upward opening was obtained, suggesting a promoting effect of RCC on PVDF/PLLA co-continuity. This can be attributed to both the high viscosity of PLLA/RCC and the inhibited PVDF phase coalescence. On the one hand, owing to the significantly increased viscosity of PLLA/RCC relative to neat PLLA, the decreased viscosity ratio of PVDF to PLLA(/RCC) can lower the co-continuous PVDF/PLLA composition ratio. On the other hand, the coalescence of PVDF phase in PVDF/PLLA/20%RCC can be effectively inhibited due to the addition of RCC, opposite to the inclined PLLA phase coalescence in the neat PVDF/PLLA blend with high PVDF fraction (e.g., 80%). Our results provide guidance for evaluating and selecting RCs for a specific immiscible polymer blend in practical application. Full article

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16 pages, 1453 KB

Open AccessArticle

Marine Bacterial Biopolymers, Cyanobacteria and Seaweed Biomasses as Soil Amendments to Enhance Soil Wetting Properties and Water Retention

by Waqas Ali, Elio Coppola, Rossana Marzaioli, Vincenzo Zammuto, Luigi Marfella, Marina Morabito, Concetta Gugliandolo, Giulia Maisto and Flora Angela Rutigliano

Polymers 2026, 18(13), 1585; https://doi.org/10.3390/polym18131585 (registering DOI) - 26 Jun 2026

Abstract

Soil water retention is a key factor in ecological processes regulating ecosystem stability and resilience under environmental stress. In this regard, marine-derived additives may provide sustainable strategies to enhance soil water dynamics. Here, novel biopolymers derived from thermophilic bacteria, including six exopolysaccharides (EPS1–EPS6) [...] Read more.

Soil water retention is a key factor in ecological processes regulating ecosystem stability and resilience under environmental stress. In this regard, marine-derived additives may provide sustainable strategies to enhance soil water dynamics. Here, novel biopolymers derived from thermophilic bacteria, including six exopolysaccharides (EPS1–EPS6) and four biosurfactants (BS1-BS4), and biomasses from seaweed (BM1–BM4) and marine cyanobacteria (BC1–BC2), were investigated for their wetting properties and soil water retention. Wetting properties, including reduction in contact angle (RCA) and atmospheric-air moisture uptake (AMU), were monitored for 36 h at constant temperature (30 °C). The effect on soil water retention was evaluated in terms of water loss of soil samples treated with two different concentrations (0.5 and 1% w/w) of either biopolymers or biomasses in a microcosm consisting of 10 g of soil and 10 mL of water, kept at a stable temperature of 22 °C for 200 h (until complete evaporation occurred). BC2 derived from Leptolyngbya sp. 43.3 was the best wetting agent (RCA = 39.44%), while the EPS4 produced by Bacillus horneckiae SBP3 was the best humectant agent (AMU = 179.63%). Soils amended with bacterial biopolymers (EPS4, EPS5, EPS6, BS1 and BS3), as well as biomasses derived from cyanobacteria BC2 and seaweed BM1–BM4, produced better improvement in soil water retention, with marked effects at the concentration of 1% w/w. The lipopeptide BS1 was the most effective in water loss reduction over a specific time of 96–125 h at both concentrations. These findings highlight the potential of these materials as nature-based solutions to improve soil-mediated ecosystem resilience to drought under climate change. Full article

(This article belongs to the Special Issue Advances in Biopolymers and Biobased Polymers: Engineering Innovations and Applications)

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16 pages, 1465 KB

Open AccessArticle

Topology-Dependent Compression and Energy Absorption of 3D-Printed Resin Scaffolds Filled with Polyurethane Foam

by Yi Jie, Yongcheng Hong and Yajiu Zhang

Polymers 2026, 18(13), 1584; https://doi.org/10.3390/polym18131584 (registering DOI) - 25 Jun 2026

Abstract

Lightweight resin lattice structures are prone to instability and failure under compressive loading, which leads to limited load bearing capacity and energy absorption performance. In this study, tough resin triply periodic minimal surface (TPMS) lattice scaffolds were fabricated using stereolithography-based 3D printing, and [...] Read more.

Lightweight resin lattice structures are prone to instability and failure under compressive loading, which leads to limited load bearing capacity and energy absorption performance. In this study, tough resin triply periodic minimal surface (TPMS) lattice scaffolds were fabricated using stereolithography-based 3D printing, and polyurethane foam (PUF) was subsequently infiltrated into three representative topologies, namely Schwarz Primitive (P), I-Wrapped Package (IWP), and Gyroid (G), to form interpenetrating phase composites (IPC). Quasi-static compression results show that PUF infiltration significantly improves the compressive response of all IPC architectures. The stress level in the plateau region is increased, while the magnitude of local stress drops is reduced, leading to a more stable progressive compression behavior. By comparing the stress–strain responses of IPC with the linear superposition of the pure resin scaffold and PUF phases, it is found that the actual energy absorption of IPC exceeds the predicted additive response, indicating a pronounced synergistic effect between the two phases. Among them, the IWP-based IPC achieves a specific energy absorption of 11.72 J/g. These results demonstrate that interpenetrating phase architectures can maintain lightweight characteristics while enhancing load bearing stability and energy absorption efficiency, providing useful guidance for topology selection and lightweight design of TPMS-based energy absorbing composite structures. Full article

(This article belongs to the Topic Manufacturing and Mechanics of Materials)

25 pages, 4368 KB

Open AccessArticle

Interfacial Compatibility and Performance Evaluation of Waste Plastic Aggregate in SBS-Modified Asphalt Mixtures Using Liquid Anti-Stripping Agents

by Joohan Eom, Kyungnam Kim, Jaehyun Lee and Tri Ho Minh Le

Polymers 2026, 18(13), 1583; https://doi.org/10.3390/polym18131583 (registering DOI) - 25 Jun 2026

Abstract

Waste plastic aggregate (WPA) is a promising recycled material for asphalt mixtures, but its polymeric surface can weaken binder adhesion and increase moisture-related damage, even in SBS-modified systems. Therefore, a clear need exists to identify anti-stripping agents that are compatible with WPA, rather [...] Read more.

Waste plastic aggregate (WPA) is a promising recycled material for asphalt mixtures, but its polymeric surface can weaken binder adhesion and increase moisture-related damage, even in SBS-modified systems. Therefore, a clear need exists to identify anti-stripping agents that are compatible with WPA, rather than simply increasing WPA content in asphalt mixtures. This study evaluates the interfacial and mixture-scale performance of SBS-modified asphalt mixtures containing two WPA types, namely coarse WPA and fine WPA, treated with three liquid anti-stripping agents: amine-based agent (AS-Am), organosilane coupling-type adhesion promoter (AS-OS), and ester/surfactant-based wetting agent (AS-Es). The novelty of this study lies in selecting the anti-stripping system based on WPA–binder adhesion compatibility and validating it through moisture, rutting, rheological, and fracture performance. Binder bond strength, tensile bond strength, shear bond strength, indirect tensile strength/tensile strength ratio (ITS/TSR), Hamburg wheel tracking (HWT), multiple stress creep recovery (MSCR), and semi-circular bending (SCB) tests were conducted. AS-OS showed the best overall performance. It increased binder bond strength (BBS) by 52.8% for coarse WPA and 61.5% for fine WPA, while the optimum 0.5% dosage improved tensile bond strength by 81.0% and 97.2%, respectively. AS-OS also increased shear strength by 58.8–68.3% and improved TSR to 89.0% and 86.2%. In HWT, C-OS and F-OS reduced final rut depth by 44.0% and 45.8%, respectively. SCB results further showed higher fracture work, especially for F-OS. The findings indicate that proper anti-stripping chemistry is essential for durable WPA–SBS asphalt mixtures. Full article

(This article belongs to the Section Polymer Chemistry)

19 pages, 2244 KB

Open AccessArticle

Optimized Polyurethane/CNTs Composite for Stress-Free Two-Way Shape Memory via Training Enhancement

by Yutong Guo, Kangkang Shi, Yujie Chen, Qunfu Fan, Dongsheng Li and Hezhou Liu

Polymers 2026, 18(13), 1582; https://doi.org/10.3390/polym18131582 (registering DOI) - 25 Jun 2026

Abstract

Thermally responsive shape memory polymer materials are the most widely used type of intelligent materials and have found applications in numerous fields. However, their practical utility is often limited by poor heat conduction. Carbon nanotubes (CNTs), renowned for their exceptional thermo-conductive and photothermal [...] Read more.

Thermally responsive shape memory polymer materials are the most widely used type of intelligent materials and have found applications in numerous fields. However, their practical utility is often limited by poor heat conduction. Carbon nanotubes (CNTs), renowned for their exceptional thermo-conductive and photothermal properties, provide a promising solution. In this study, CNTs were integrated into polyurethane prepared by stepwise polymerization method, using hydroxyl terminated polycaprolactone (PCL-diOH), poly(ethylene glycol) (PEG) and hexamethylene diisocyanate (HDI). The resulting polyurethane composite material exhibits remarkable mechanical strength, enhanced thermal conductivity, and superior shape memory performance. Notably, it demonstrates a form of training enhancement phenomenon, which shows higher mechanical properties. And the composite could achieve stress-free two-way shape memory behavior after cyclic stretching process. Additionally, this composite material can exhibit “vitrimer” material properties at higher temperatures (110 °C), allowing for shape reprogramming. The carbon nanotube-reinforced composite material can achieve remote and precise manipulation under light stimulation. By combining the composite material with a metal thermally conductive layer, a multi-layer structure with shape memory properties can be prepared, which can achieve two-way shape memory behavior under electrical and light stimulation, further expanding the application potential of the composite material in the real world. Full article

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

17 pages, 5298 KB

Open AccessArticle

Rheological Evolution and Viscoelastic Transition of Ambient-Curing Epoxy–Urethane Reactive Polymer Composites

by Xinmei Zhang, Yan Shi, Dongliang Wang, Biao Ma, Jianmin Liao and Tao Chen

Polymers 2026, 18(13), 1581; https://doi.org/10.3390/polym18131581 (registering DOI) - 25 Jun 2026

Abstract

Ambient-curing epoxy–urethane reactive polymer composites require a balance between initial flowability and subsequent structure buildup. In this study, epoxy–urethane reactive polymer composites containing precipitated calcium carbonate were prepared and referred to as EUPC formulations. Their rheological evolution was characterized by flow sweep, temperature [...] Read more.

Ambient-curing epoxy–urethane reactive polymer composites require a balance between initial flowability and subsequent structure buildup. In this study, epoxy–urethane reactive polymer composites containing precipitated calcium carbonate were prepared and referred to as EUPC formulations. Their rheological evolution was characterized by flow sweep, temperature sweep, time sweep, three-interval thixotropy tests (3ITT), amplitude sweep, and oscillatory time sweep. The formulations exhibited distinct initial flow resistance and strong temperature sensitivity, with apparent viscosity decreasing as temperature increased. During ambient curing, viscosity increased continuously, indicating progressive rheological buildup under the selected testing conditions. The 3ITT results showed high-shear-induced apparent viscosity reduction followed by recovery-stage viscosity evolution after returning to the low-shear condition, indicating that the recovery index should be interpreted as an apparent post-shear recovery index rather than a purely thixotropic recovery parameter. Oscillatory measurements revealed a gradual transition from viscous-dominated to more elastic-dominated behavior, and the apparent gel time followed the sequence EUPC-2 < EUPC-4 < EUPC-1 < EUPC-3 < EUPC-5 < EUPC-6. These results indicate that EUPC processability and structure buildup should be evaluated by integrating initial viscosity, temperature sensitivity, post-shear response, and operational viscous-to-elastic transition. Full article

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

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15 pages, 9022 KB

Open AccessArticle

Electrospinning CaCO₃/Porous PLA Nanofibers for Daytime Radiative Cooling

by Yangyang Sun, Changnai Yang, Mengge Li, Xiaomin Zeng, Dengkun Su, Shiyi Pan, Yu Zhang, Qiong Jiang and Shizhe Lin

Polymers 2026, 18(13), 1580; https://doi.org/10.3390/polym18131580 (registering DOI) - 25 Jun 2026

Abstract

To develop high-performance and eco-friendly passive daytime radiative cooling (PDRC) materials, calcium carbonate (CaCO₃)/porous polylactic acid (PLA) nanofibers were fabricated via electrospinning. This fabrication utilized PLA as the matrix and 40 nm CaCO₃ nanoparticles as fillers, with ambient humidity controlled [...] Read more.

To develop high-performance and eco-friendly passive daytime radiative cooling (PDRC) materials, calcium carbonate (CaCO₃)/porous polylactic acid (PLA) nanofibers were fabricated via electrospinning. This fabrication utilized PLA as the matrix and 40 nm CaCO₃ nanoparticles as fillers, with ambient humidity controlled above 85%RH during electrospinning. The resulting nanofibers possessed numerous CaCO₃/PLA interfaces and porous surface structures. Experimental results demonstrated that the CaCO₃/porous PLA nanofibers achieved a solar reflectivity of ~92.3%, significantly exceeding that of PLA (~72.1%), CaCO₃/PLA (~86.0%), and porous PLA (~79.6%) nanofibers. During outdoor testing, CaCO₃/porous PLA nanofibers exhibited optimal PDRC performance with a temperature reduction of ~10.3 °C, representing a 6.1 °C improvement compared to PLA nanofibers. This enhancement is attributed to synergistic light-scattering sites generated by surface porosity and CaCO₃/PLA interfaces, which collectively strengthen solar spectrum scattering. Furthermore, significant morphological degradation was observed after 80-day soil burial, confirming biodegradability. This study proposes a facile strategy for developing high-performance eco-friendly PDRC materials. Full article

(This article belongs to the Special Issue Polymer Composites for Smart and Eco-Friendly Systems)

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24 pages, 8997 KB

Open AccessArticle

Self-Standing Cutin Isolate Films

by Nevena Hromiš, Sandra Bučko, Zorica Stojanović, Senka Popović, Biljana Pajin, Milica Stožinić, Di Zhang, Nejra Omerović and Jaroslav Katona

Polymers 2026, 18(13), 1579; https://doi.org/10.3390/polym18131579 (registering DOI) - 25 Jun 2026

Abstract

Cutin, a natural polyester, has attracted attention as a precursor for bio-based materials mimicking plant cuticles, particularly in food packaging. Most studies focus on polycondensation of hydrolyzed cutin fractions or combining cutin hydrolysates with other components; however, cutin precipitation, conditions affecting it, and [...] Read more.

Cutin, a natural polyester, has attracted attention as a precursor for bio-based materials mimicking plant cuticles, particularly in food packaging. Most studies focus on polycondensation of hydrolyzed cutin fractions or combining cutin hydrolysates with other components; however, cutin precipitation, conditions affecting it, and cutin isolate film properties, without addition of other filmogenic material, remain insufficiently understood. Owing to the pH-dependent solubility of cutin, which progressively decreases as pH is lowered from strongly alkaline to acidic conditions, this study investigates the influence of pH on cutin dispersion formation and characteristics, and evaluates the impact of these dispersion properties on the formation and performance of self-assembled cutin isolate films, with a view to developing films with improved water-barrier and moisture-resistance properties. The influence of three plasticizers, glycerol, propylene glycol, and polyethylene glycol 400, at two concentrations was also evaluated. Results demonstrated that pH is the primary factor influencing cutin isolate dispersion characteristics and film performance, with decreasing pH promoting cutin precipitation and particle aggregation, thereby inducing changes in film structure. The strongest effects were observed for swelling, solubility, and tensile strength, followed by water vapor permeability, elongation at break, and thickness. Plasticizer type mainly affected moisture content and significantly influenced permeability and thickness, while concentration of plasticizer primarily impacted permeability. Interactions between pH and plasticizer significantly influenced most properties. Films prepared from cutin dispersions at pH 6.5 and pH 5 with polyethylene glycol (10%) showed the best balance of mechanical and barrier properties. Additionally, films prepared from the cutin solutions at pH 12 with glycerol (20%) exhibited good mechanical performance and high solubility, suitable for specific applications. Full article

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

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