Polymers

20 pages, 2759 KB

Open AccessArticle

Selective Gold Ion Sorption from Iron-Containing Solution Using an Interpolymer System of Industrial Ion Exchangers

by Gulnur Dyussembayeva, Talkybek Jumadilov, Juozas Gražulevicius, Zhazira Mukatayeva, Khuangul Khimersen and Bakytgul Totkhuskyzy

Polymers 2025, 17(20), 2808; https://doi.org/10.3390/polym17202808 - 21 Oct 2025

Viewed by 440

Abstract

The escalating demand for precious metals in high-tech industries and jewelry, combined with the depletion of their reserves, underscores the need for efficient methods of gold recovery from industrial effluents. An interpolymer system comprising industrial ion exchangers KU-2-8 (in H⁺ form) and [...] Read more.

The escalating demand for precious metals in high-tech industries and jewelry, combined with the depletion of their reserves, underscores the need for efficient methods of gold recovery from industrial effluents. An interpolymer system comprising industrial ion exchangers KU-2-8 (in H⁺ form) and AV-17-8 (in OH⁻ form) demonstrated strong selective sorption capacity for Au(I) ions from a simulated Au(I)/Fe(II) mixed solution. The optimal KU-2-8:AV-17-8 (3:3) system achieved a sorption efficiency of 97.0% for Au(I) ions after 48 h with a desorption efficiency of 98.0% using a thiourea/sulfuric acid solution. The distribution coefficient (K_d) for Au(I) ions reached a maximum of 3233.3 mL/g at the 3:3 ratio, with a separation coefficient (β) of 40.62, indicating exceptional selectivity over Fe(II) ions. Fourier-transform infrared (FTIR) spectroscopy revealed structural changes post-sorption, including shifts in absorption bands (e.g., from 1273.5 cm⁻¹ to 1292.9 cm⁻¹) and the appearance of new bands (e.g., at 3171.1 cm⁻¹), confirming stable ion interactions. Thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) demonstrated enhanced thermal stability post-sorption, with reduced mass loss up to 100 °C. These findings highlight the KU-2-8:AV-17-8 (3:3) interpolymer system’s high selectivity, robust sorption capacity, and efficient desorption, presenting a sustainable solution for gold recovery in hydrometallurgical applications. Full article

(This article belongs to the Collection Progress in Polymer Applications)

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23 pages, 5872 KB

Open AccessArticle

Room-Temperature Self-Healing Polyurethanes Containing Halloysite Clay with Enhanced Mechanical Properties

by Eva Dauder-Bosch and José Miguel Martín-Martínez

Polymers 2025, 17(20), 2807; https://doi.org/10.3390/polym17202807 - 21 Oct 2025

Viewed by 358

Abstract

Room-temperature self-healing polyurethanes (PUs) generally show limited mechanical properties. In order to improve the mechanical properties of PUs without sacrificing their self-healing ability, in this study, different amounts of halloysite clay filler were added. Thus, intrinsically self-healing PUs were synthesized using polycarbonate diol [...] Read more.

Room-temperature self-healing polyurethanes (PUs) generally show limited mechanical properties. In order to improve the mechanical properties of PUs without sacrificing their self-healing ability, in this study, different amounts of halloysite clay filler were added. Thus, intrinsically self-healing PUs were synthesized using polycarbonate diol polyol, aliphatic diisocyanate, 1,4-butanediol, and different amounts (0.5–10 wt.%) of thermally treated halloysite. During synthesis, the halloysite clay was added to the polyol. The structural, thermal, viscoelastic, and mechanical properties of the resulting halloysite-filled PUs were evaluated. All halloysite-filled PUs retained their room-temperature self-healing capability while exhibiting improved mechanical strength. The PU with 0.5 wt.% halloysite (E0.5) showed the most balanced performance, with well-dispersed halloysite nanotubes intercalated within the soft segments, enhancing chain mobility and soft segment ordering. Higher halloysite loadings (1–3 wt.%) led to increased mechanical properties but also some round clay particle agglomeration and surface migration, leading to limited halloysite–polyurethane interactions. The addition of more than 3 wt.% halloysite did not result in further improvements in mechanical properties. The findings of this study provide new insight into the filler–polymer interaction mechanism and establish a foundation for the design of multifunctional PUs with both autonomous self-repair and enhanced mechanical performance. Full article

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

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23 pages, 1771 KB

Open AccessArticle

An Integrated Biorefinery Proof of Concept: The Synthesis of Fully Bio-Based, Functional Lignin Polyester Copolymers of Cyclic Anhydrides and Epoxides Towards Polyol Applications and Tunable Bio-Derived Materials

by Oliver J. Driscoll, Daniel J. van de Pas, Kirk M. Torr, Hayden P. Thomas, Richard Vendamme and Elias Feghali

Polymers 2025, 17(20), 2806; https://doi.org/10.3390/polym17202806 - 21 Oct 2025

Viewed by 439

Abstract

A versatile, sustainable feedstock pathway to bio-based polymeric materials was developed utilizing lignin biomass and the ring-opening copolymerization (ROCOP) of cyclic anhydrides and epoxides to synthesize functional, lignin-derived, fully bio-based polyester polyols. The initial goal was to make the ROCOP reaction more applicable [...] Read more.

A versatile, sustainable feedstock pathway to bio-based polymeric materials was developed utilizing lignin biomass and the ring-opening copolymerization (ROCOP) of cyclic anhydrides and epoxides to synthesize functional, lignin-derived, fully bio-based polyester polyols. The initial goal was to make the ROCOP reaction more applicable to bio-derived starting materials and more attractive to commercialization by conducting the polymerization under less constrained and industrially relevant conditions in air and without the extensive purification of reagents, catalysts, or solvents, typically used in the literature. A refined ROCOP system was applied as a powerful tool in lignin valorization by successfully synthesizing the lignin-derived copolyester prepolymers from lignin models and depolymerized native lignin sourced from the reductive catalytic fractionation of Pinus radiata wood biomass. After mechanistic studies based on NMR characterization, an alternative ROCOP-style mechanism was proposed. This was found to be (1) contributing to the acceleration of the observed reaction rates with added [PPNCl] organo-catalyst and (2) ‘self-initiation/self-promoted’ ROCOP without any added external [PPNCl] catalyst, likely due to the presence of inherent [OH] groups/ species in the lignin-derived glycidyl ether monomer promoting reactivity. As a final goal, the potential of these lignin-derived polyesters as intermediate polyols was demonstrated by applying them in the synthesis of polyurethane (PU) film materials with a high biomass content of 75–79%. A dramatic range of thermomechanical properties was observed for the resulting materials, demonstrating how the ROCOP reaction can be used to tailor the properties of the functional polyester and PU material based on the nature of the epoxide and anhydride substrates used. These findings help endeavors towards predicting the relationship between chemical structure and material thermomechanical properties and performance, relevant for industrial applications. Overall, this study demonstrated the proof of concept that PU materials can be prepared from lignocellulosic biomass utilizing industrially feasible ROCOP of bio-derived cyclic anhydrides and epoxides. Full article

(This article belongs to the Special Issue Recent Progress on Lignocellulosic-Based Polymeric Materials)

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27 pages, 8920 KB

Open AccessArticle

Thermal Stability and Decomposition Mechanisms of PVA/PEGDA–PEGMA IPN-Hydrogels: A Multimethod Kinetic Approach

by Akmaral Zh. Sarsenbekova, Ulygbek B. Tuleuov, Akerke T. Kazhmuratova, Abylaikhan N. Bolatbay, Lyazzat Zh. Zhaparova and Yerkeblan M. Tazhbayev

Polymers 2025, 17(20), 2805; https://doi.org/10.3390/polym17202805 - 21 Oct 2025

Viewed by 484

Abstract

This paper presents a comprehensive analysis of the thermal stability and decomposition mechanisms of IPN hydrogels based on polyvinyl alcohol (PVA) and a copolymer network of poly(ethylene glycol) diacrylate–poly(ethylene glycol) methacrylate (PEGDA–PEGMA). Using thermogravimetric analysis (TGA/DTG) and multi-approach kinetic analysis (Friedman and Ozawa–Flynn–Wall [...] Read more.

This paper presents a comprehensive analysis of the thermal stability and decomposition mechanisms of IPN hydrogels based on polyvinyl alcohol (PVA) and a copolymer network of poly(ethylene glycol) diacrylate–poly(ethylene glycol) methacrylate (PEGDA–PEGMA). Using thermogravimetric analysis (TGA/DTG) and multi-approach kinetic analysis (Friedman and Ozawa–Flynn–Wall isoconversion methods, nonparametric kinetics, Shestaka-Berggren model), the influence of composition on the processes of dehydration, thermal destruction, and the distribution of activation energy by degrees of conversion was investigated. The constructed three-dimensional kinetic “landscapes” made it possible to identify characteristic features of the behavior of various samples, including differences in the rate and mechanisms of destruction. It was found that an increase in the content of PVA enhances moisture binding and shifts the T_max of dehydration to higher temperatures, while an increase in the concentration of PEGDA forms a denser network that limits moisture retention and accelerates thermal decomposition. Calculation of diffusion coefficients using the Fick model showed a decrease in D with an increase in network density, which reflects an increase in resistance to moisture mass transfer. The combination of the data obtained demonstrates the multistage nature of thermal destruction and allows for the targeted selection of hydrogel compositions for biomedical, environmental, and materials science applications, including drug delivery systems, sorbents and heat-resistant coatings. Full article

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

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13 pages, 4309 KB

Open AccessReview

Accuracy and Powder Removal Limits in Multi Jet Fusion 3D Printing

by Karel Raz, Zdenek Chval and Petra Faitova

Polymers 2025, 17(20), 2804; https://doi.org/10.3390/polym17202804 - 21 Oct 2025

Viewed by 488

Abstract

Multi Jet Fusion (MJF) is a leading technology for producing functional polymer parts. However, it still faces challenges with dimensional accuracy and removing unfused powder from complex internal geometries. First, dimensional accuracy was mapped by producing 45 identical PA12 specimens on an HP [...] Read more.

Multi Jet Fusion (MJF) is a leading technology for producing functional polymer parts. However, it still faces challenges with dimensional accuracy and removing unfused powder from complex internal geometries. First, dimensional accuracy was mapped by producing 45 identical PA12 specimens on an HP MJF 4200 printer in a 5 × 9 layout across five vertical layers. The analysis revealed a consistent pattern: parts located in the central positions of the build volume exhibited the poorest accuracy, while those near the perimeter were the most precise, regardless of their vertical height. This spatial variation is attributed to non-uniform thermal control from the printer’s adaptive lamp–thermal camera system. Second, the limits of powder removal from closed body-centered cubic (BCC) lattice structures were quantified. Using sandblasting and X-ray inspection, a strong inverse relationship was found between a lattice’s relative density and the maximum thickness that could be thoroughly cleaned of powder. For example, low-density structures (ρ = 0.07) could be cleaned up to five layers deep, whereas high-density structures (ρ = 0.39–0.47) were limited to only 1.5–1.7 layers. These findings offer actionable guidelines for optimizing part placement and designing internal lattice structures for MJF technology. The key findings are the spatial variation in dimensional accuracy in MJF printing, where the central parts are the least accurate and perimeter parts are the most precise, and the inverse relationship between a lattice’s relative density (ρ) and cleanable thickness. Specifically, low-density structures (ρ = 0.07) could be thoroughly cleaned up to five layers, while high-density ones (ρ = 0.39–0.47) were limited to approximately 1.5–1.7 layers. The layer thickness was a pre-designed parameter (2, 3, 4, and 5 layers), and powder removal was supported by using automated sandblasting followed by verification via industrial X-ray imaging. Full article

(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)

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18 pages, 3117 KB

Open AccessArticle

Structural and Functional Enhancement of Halal Gelatin Capsules Reinforced with Corn Husk Cellulose

by Flora Elvistia Firdaus and Aurelia Kinanti

Polymers 2025, 17(20), 2803; https://doi.org/10.3390/polym17202803 - 21 Oct 2025

Viewed by 437

Abstract

Corn husk-derived cellulose (CHC) was incorporated into gelatin–cassava starch (CS) capsule formulations to evaluate its effectiveness as a sustainable reinforcing agent. The addition of CHC enhanced the structural cohesion of the films and improved their resistance to storage-related temperature–humidity stress, while maintaining desirable [...] Read more.

Corn husk-derived cellulose (CHC) was incorporated into gelatin–cassava starch (CS) capsule formulations to evaluate its effectiveness as a sustainable reinforcing agent. The addition of CHC enhanced the structural cohesion of the films and improved their resistance to storage-related temperature–humidity stress, while maintaining desirable flexibility. Consistent with this, the films retained mechanical performance and appearance under ICH-aligned storage conditions, indicating better endurance during storage and processing. Disintegration performance remained within pharmacopeial requirements in both acidic and neutral media, confirming the suitability of the capsules for oral delivery applications. Surface assessment revealed more uniform morphology and fewer irregularities in the capsule matrix when CHC was present, suggesting strong compatibility among the cellulose, gelatin, and starch components. Collectively, these findings demonstrate that CHC is an effective plant-based reinforcement capable of strengthening gelatin capsules without compromising functional performance. The use of corn husk, an abundant agricultural residue, also highlights a sustainable pathway for the development of halal-compliant capsule shells and contributes to the broader advancement of eco-friendly biopolymer systems in pharmaceutical applications. Full article

(This article belongs to the Special Issue Advances in Cellulose-Based Polymers and Composites, 2nd Edition)

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22 pages, 564 KB

Open AccessReview

Electrospinning PLLA/PCL Blend Fibre-Based Materials and Their Biomedical Application: A Mini Review

by Chen Meng

Polymers 2025, 17(20), 2802; https://doi.org/10.3390/polym17202802 - 20 Oct 2025

Viewed by 572

Abstract

Fibres play a crucial role in diverse biomedical applications, ranging from tissue engineering to drug delivery. Electrospinning has emerged as a simple and versatile technique for producing ultrafine fibres at micro- to nanoscale dimensions. Synthetic biopolymers are effective cues to replace damaged tissue [...] Read more.

Fibres play a crucial role in diverse biomedical applications, ranging from tissue engineering to drug delivery. Electrospinning has emerged as a simple and versatile technique for producing ultrafine fibres at micro- to nanoscale dimensions. Synthetic biopolymers are effective cues to replace damaged tissue in the biomedical field, both in vitro and in vivo applications. Among them, poly (L-lactic acid) (PLLA) is a renewable, environmentally friendly biopolymer material. Polycaprolactone (PCL) is a synthetic polymer with good biocompatibility and biodegradation characteristics. However, both electrospun PLLA and PCL fibres have their limitations. To overcome these shortcomings, electrospinning PLLA/PCL blend fibres has been the subject of many studies. This review discusses the different parameters for the electrospinning of PLLA/PCL-based fibres for biomedical applications. Furthermore, we also discuss how electrospun PLLA/PCL-based scaffolds can be modified or combined with other biomaterials, such as natural polymers and bioceramics, and examine their in vitro and in vivo applications in various tissue repair strategies. Full article

(This article belongs to the Special Issue Polymer Composites for Biomedical Applications)

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69 pages, 84358 KB

Open AccessReview

Advances and Prospects of Lignin-Derived Hard Carbons for Next-Generation Sodium-Ion Batteries

by Narasimharao Kitchamsetti and Sungwook Mhin

Polymers 2025, 17(20), 2801; https://doi.org/10.3390/polym17202801 - 20 Oct 2025

Viewed by 718

Abstract

Lignin-derived hard carbon (LHC) has emerged as a highly promising anode material for sodium-ion batteries (SIBs), owing to its renewable nature, structural tunability, and notable electrochemical properties. Although considerable advancements have been made in the development of LHCs in recent years, the absence [...] Read more.

Lignin-derived hard carbon (LHC) has emerged as a highly promising anode material for sodium-ion batteries (SIBs), owing to its renewable nature, structural tunability, and notable electrochemical properties. Although considerable advancements have been made in the development of LHCs in recent years, the absence of a comprehensive and critical review continues to impede further innovation in the field. To address this deficiency, the present review begins by examining the intrinsic characteristics of lignin and hard carbon (HC) to elucidate the underlying mechanisms of LHC microstructure formation. It then systematically categorizes the synthesis strategies, structural attributes, and performance influences of various LHCs, focusing particularly on how feedstock characteristics and fabrication parameters dictate final material behavior. Furthermore, optimization methodologies such as feedstock pretreatment, controlled processing, and post-synthesis modifications are explored in detail to provide a practical framework for performance enhancement. Finally, informed recommendations and future research directions are proposed to facilitate the integration of LHCs into next-generation SIB systems. This review aspires to deepen scientific understanding and guide rational design for improved LHC applications in energy storage. Full article

(This article belongs to the Special Issue Advances in Polymer Applied in Batteries and Capacitors, 2nd Edition)

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28 pages, 1278 KB

Open AccessReview

Polymeric Frontiers in Next-Generation Energy Storage: Bridging Molecular Design, Multifunctionality, and Device Applications Across Batteries, Supercapacitors, Solid-State Systems, and Beyond

by Akhil Sharma, Sonu Sharma, Monu Sharma, Vikas Sharma, Shivika Sharma and Iyyakkannu Sivanesan

Polymers 2025, 17(20), 2800; https://doi.org/10.3390/polym17202800 - 20 Oct 2025

Viewed by 641

Abstract

Polymer materials have become promising candidates for next-generation energy storage, with structural tunability, multifunctionality, and compatibility with a variety of device platforms. They have a molecular design capable of customizing ion and electron transport routes, integrating redox-active species, and enhancing interfacial stability, surpassing [...] Read more.

Polymer materials have become promising candidates for next-generation energy storage, with structural tunability, multifunctionality, and compatibility with a variety of device platforms. They have a molecular design capable of customizing ion and electron transport routes, integrating redox-active species, and enhancing interfacial stability, surpassing the drawbacks of traditional inorganic systems. New developments have been made in multifunctional polymers that have the ability to combine conductivity, mechanical properties, thermal stability, and self-healing into a single scaffold system, which is useful in battery, supercapacitor, and solid-state applications. By incorporating polymers with carbon nanostructures, ceramics, or two-dimensional materials, hybrid polymer nanocomposites improve electrochemical performance, durability, and mechanical compliance, and the solid polymer electrolytes, as well as artificial solid electrolyte interphases, resolve dendrite growth and safety issues. The multifunctionality also extends to flexibility, stretchability, and miniaturization, which implies that polymers are suitable for use in wearable devices and biomedical devices. At the same time, sustainable polymer innovation focuses on bio-based feedstocks, which can be recycled, and green synthesis pathways. Polymer discovery using artificial intelligence and machine learning is faster than standard methods, predicts structure–property–performance relationships, and can be rationally engineered. Although there are difficulties in stability during long periods, scalability, and trade-offs between indeedness and mechanical endurance, polymers are a promising avenue with regard to dependable, safe, and sustainable power storage. This review presents the molecular strategies, multifunctional uses, and prospects, where polymers are at the center of the next-generation energy technologies. Full article

(This article belongs to the Special Issue Polymeric Materials for Next-Generation Energy Storage)

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18 pages, 7564 KB

Open AccessArticle

Ultrasensitive and Selective Fluorescent Sensor for 5-Hydroxymethylfurfural Based on a Molecularly Imprinted Polymeric Nanocomposite

by Fatih Pekdemir and İzzet Koçak

Polymers 2025, 17(20), 2799; https://doi.org/10.3390/polym17202799 - 20 Oct 2025

Viewed by 395

Abstract

A fluorescence sensor was designed based on nitrogen-doped graphene quantum dots confined in a metal–organic framework and molecularly imprinted polymer for the selective determination of 5-hydroxymethylfurfural (HMF). Morphological, structural, and spectroscopic characterizations, such as SEM, STEM, BET, FT-IR, and XRD, verified successful synthesis [...] Read more.

A fluorescence sensor was designed based on nitrogen-doped graphene quantum dots confined in a metal–organic framework and molecularly imprinted polymer for the selective determination of 5-hydroxymethylfurfural (HMF). Morphological, structural, and spectroscopic characterizations, such as SEM, STEM, BET, FT-IR, and XRD, verified successful synthesis and imprinting with enhanced surface area and structural durability. The sensor demonstrated intense fluorescence at around 420 nm, which was quenched through photoinduced electron transfer (PET) by HMF, exhibiting a linear relationship up to 35 µmol L⁻¹ and a detection limit of 30 nmol L⁻¹. It offered high imprinting efficiency, selectivity, and stability. The sensing platform also displayed efficient anti-interference performance toward interference species and presented excellent recovery in actual food samples such as honey, juice, and coffee, thus revealing the applicability of the sensing device for real-world HMF measurement in complicated matrices. Full article

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

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33 pages, 23229 KB

Open AccessArticle

Synthesis and Comparative Study of the Structure and Antibacterial Activity of Polygalacturonate Complexes with Ionic and Nanoparticulate Silver

by Andrey V. Nemtarev, Elena V. Kuznetsova, Abdulla A. Yergeshov, Darya S. Eflova, Rezeda A. Ishkaeva, Inna R. Valiullina, Vladimir F. Mironov, Diana V. Salakhieva and Timur I. Abdullin

Polymers 2025, 17(20), 2798; https://doi.org/10.3390/polym17202798 - 20 Oct 2025

Viewed by 482

Abstract

A series of silver-polygalacturonate complexes with improved structure and activity against bacterial infections was developed. Pure sodium polygalacturonate was obtained by saponification of a pectin precursor and identified by NMR as predominantly homogalacturonan (uronide content 95%). Polygalacturonate complexes with ionic and borohydride-reduced silver [...] Read more.

A series of silver-polygalacturonate complexes with improved structure and activity against bacterial infections was developed. Pure sodium polygalacturonate was obtained by saponification of a pectin precursor and identified by NMR as predominantly homogalacturonan (uronide content 95%). Polygalacturonate complexes with ionic and borohydride-reduced silver with a controllable metallic component were synthesized; the role of spontaneous Ag⁺ reduction was revealed. The presence of uniform 5 nm nanoparticles and negligible particulate by-products in the reduced complexes was verified. The complexes showed similar silver-normalized activity against non-resistant bacteria, irrespective of complex stoichiometry/silver state. Pharmaceutical silver proteinate with a similar nanoparticle profile exhibited the same silver-normalized activity, indicating the lack of a ligand effect. The Ag⁺ complex was more effective against some hospital drug-resistant strains. The cytotoxicity of the complexes depended on fibroblast type, silver state, ligand type, exposure time, presumably in association with cellular availability and glutathione depletion. The complexes were administered to rats with excisional wounds persistently infected with S. aureus. Swab/histological analyses of the treated wounds revealed decreased bacterial burden/tissue damage, along with promotion of wound contraction/closure and matrix formation. The nanoparticle complexes that were compared had similar antibacterial/regenerative effects, while the Ag⁺ complex demonstrated higher efficacy in vivo. These results encourage the use of the developed silver-polygalacturonate complexes as antibacterial substances. Full article

(This article belongs to the Special Issue Bioactive Polymer Materials with Antibacterial Properties, 2nd Edition)

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21 pages, 6164 KB

Open AccessArticle

Development and Feasibility Assessment of a Sequential Antenna Deployment System Based on Fiber-Reinforced Shape Memory Polymer Composites

by Marylen T. De la Cruz, Riana Gabrielle P. Gamboa, Jon Dewitt E. Dalisay, Ricky Kristan M. Raguindin and Eduardo R. Magdaluyo, Jr.

Polymers 2025, 17(20), 2797; https://doi.org/10.3390/polym17202797 - 20 Oct 2025

Cited by 1 | Viewed by 462

Abstract

With the growing demand for reliable, low-impact deployment systems in small satellite missions, this work introduces an antenna deployment mechanism using fiber-reinforced shape memory polymer composites (SMPC). The mechanism utilized thermally activated SMPCs for stowage and release, configured with different glass transition temperatures [...] Read more.

With the growing demand for reliable, low-impact deployment systems in small satellite missions, this work introduces an antenna deployment mechanism using fiber-reinforced shape memory polymer composites (SMPC). The mechanism utilized thermally activated SMPCs for stowage and release, configured with different glass transition temperatures (T_g), tuned through the addition of poly(ethylene glycol) (PEG-600), for sequential actuation. The deployment mechanism consisted of three SMPC components with varying PEG concentrations: SMPC-P (0 wt%), SMPC-5 (5 wt%), and SMPC-10 (10 wt%). For component design, three bending angle configurations (BAC) of 20°, 30°, and 40° were tested. The samples exhibited the highest fixity ratio (93.58%, 95.76%, and 96.52% for SMPC-P, SMPC-5, and SMPC-10, respectively) when conformed to the 20° BAC. All samples achieved full recovery within 2 min, with PEG-incorporated composites exhibiting more uniform behavior across cycles, while recovery rates varied by material and BAC. Deployment testing confirmed the antenna was released successfully across all BACs. The 20° BAC exhibited the fastest response, completing deployment 24 s and 30 s ahead of the 30° and 40° BACs, respectively. The proposed mechanism exhibits promising potential for integration in future CubeSat missions. However, further testing under simulated space conditions is necessary to comprehensively assess and validate its performance. Full article

(This article belongs to the Special Issue Multifunctional Polymer Composite Materials, 2nd Edition)

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15 pages, 4787 KB

Open AccessArticle

Formation of Nanocompounds of TiO₂ Using PVA-HAp Nanofibers by Sol-Gel Technique

by Marvin Elco Estrada Macias, Humberto Alejandro Monreal Romero, Guillermo Martínez Mata, Rosaura Pacheco Santiesteban, Claudia López Meléndez, Héctor Alfredo López Aguilar, Oscar Chávez Acosta, Carlos A. Martínez-Pérez, Caleb Carreño-Gallardo and José Guadalupe Chacón-Nava

Polymers 2025, 17(20), 2796; https://doi.org/10.3390/polym17202796 - 19 Oct 2025

Viewed by 472

Abstract

The use of hydroxyapatite (HAp) nanofibers in combination with titanium dioxide (TiO₂) emerges as a method for the design and improvement of materials at the biomedical, architectonic, and industrial levels. In this research, TiO₂ nanocomposites were developed using HAp nanofibers [...] Read more.

The use of hydroxyapatite (HAp) nanofibers in combination with titanium dioxide (TiO₂) emerges as a method for the design and improvement of materials at the biomedical, architectonic, and industrial levels. In this research, TiO₂ nanocomposites were developed using HAp nanofibers through the sol-gel technique. The molecular assembly strategy reveals the formation of nanocomposites with sizes of 100–500 nm at 700 °C. EDS analysis shows the presence of Ca and P, indicating that HAp nanofibers have been integrated into the nanocomposites. The crystalline phases corresponding to rutile and anatase were detected by X-ray spectroscopy analysis. The morphology of the composites was analyzed by surface segmentation analysis, scanning electron microscope, and scanning tunneling microscope. Full article

(This article belongs to the Section Polymer Fibers)

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22 pages, 4424 KB

Open AccessArticle

Research into the Influence of Volume Fraction on the Bending Properties of Selected Thermoplastic Cellular Structures from a Mechanical and Energy Absorption Perspective

by Katarina Monkova, Peter Pavol Monka, Damir Godec and Monika Torokova

Polymers 2025, 17(20), 2795; https://doi.org/10.3390/polym17202795 - 19 Oct 2025

Viewed by 298

Abstract

The aim of the manuscript is to study the effect of volume fraction on the bending properties of selected thermoplastic cellular structures (Primitive, Diamond, and Gyroid) from a mechanical and energy absorption perspective, with a view to their promising prospects and use not [...] Read more.

The aim of the manuscript is to study the effect of volume fraction on the bending properties of selected thermoplastic cellular structures (Primitive, Diamond, and Gyroid) from a mechanical and energy absorption perspective, with a view to their promising prospects and use not only for bumpers, but also for various vehicle and aircraft components, or other applications. Samples belonging to the group of so-called complex structures with Triply Periodic Minimal Surfaces, dimensions of 20 × 20 × 250 mm, and volume fractions of 30, 35, 40, 45, and 55%, were prepared by PTC Creo 10.0 software and produced using the Fused Filament Fabrication technique from Nylon CF12 material, while the basic cell size of 10 × 10 × 10 mm was maintained for all samples and the volume fraction was controlled by the wall thickness of the structure. Experimental bending tests were performed on a Zwick 1456 machine and based on recorded data; in addition to the maximum forces, the stiffness, yield strength, and effective modulus of elasticity in bending were evaluated for individual structures and volume fractions. Furthermore, the amount of energy absorbed until reaching the maximum force and until failure was compared, as well as the ductility indices μ_d and μ_U (derived from deformation and absorbed energy, respectively), as an important dissipation factor in absorbers, based on which it is also possible to predict which of the structures will have better damping. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage, 2nd Edition)

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19 pages, 10606 KB

Open AccessArticle

Experimental Study on Flexural Performance of SFCB-Reinforced ECC-Concrete Composite Beams

by Yu Ling, Shuo Xu, Chaohao Bi, Zile Feng, Dian Liang and Yongjian Cai

Polymers 2025, 17(20), 2794; https://doi.org/10.3390/polym17202794 - 19 Oct 2025

Viewed by 432

Abstract

Engineered Cementitious Composite (ECC) exhibits superior tensile strain-hardening behavior and enhanced crack control due to its distinctive multiple cracking characteristic. In contrast, Steel–Glass Fiber Reinforced Polymer (GFRP) Composite Bars (SFCBs) combine the ductility of steel with the corrosion resistance of GFRP. To investigate [...] Read more.

Engineered Cementitious Composite (ECC) exhibits superior tensile strain-hardening behavior and enhanced crack control due to its distinctive multiple cracking characteristic. In contrast, Steel–Glass Fiber Reinforced Polymer (GFRP) Composite Bars (SFCBs) combine the ductility of steel with the corrosion resistance of GFRP. To investigate the synergistic mechanisms for optimizing the performance of concrete structures, this study designed eight SFCB-reinforced ECC-concrete composite beams. Four-point bending tests were conducted to examine the influence of the ECC replacement height in the tension zone (hE/h = 0%, 16.67%, 33.33%, 50%) and the steel ratio in the bottom longitudinal reinforcement (As/Ab = 0%, 9%, 25%, 49%, 100%) on the flexural performance. The experimental results demonstrated the following: (1) Increasing the ECC replacement significantly improved both the ultimate bending capacity and ductility, while exerting a limited effect on flexural stiffness. Specifically, when increased from 0% to 50%, the ultimate bending strength and ductility index increased by 4.79% and 8.09%, respectively. (2) The steel ratio predominantly governed the yield behavior and crack development. Higher steel ratios resulted in increased flexural stiffness prior to yield, higher yield moments, improved ductility at failure, and superior crack control capability before yielding. (3) The synergistic mechanisms were identified: the ECC layer optimizes crack control by distributing crack-induced strains through multiple cracking, while the steel ratio within the SFCB regulates the ductile response. The findings of this study provide valuable theoretical guidance for enhancing the capacity and ductility of building structures. Full article

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17 pages, 8198 KB

Open AccessArticle

Determination of Optimal Reinforcement Ratios for Injection Molded Engineering Components: A Numerical Simulation

by Fuat Tan and Oğuz Veli Satı

Polymers 2025, 17(20), 2793; https://doi.org/10.3390/polym17202793 - 19 Oct 2025

Viewed by 431

Abstract

In this work, the influence of glass fibers on the performance of the injection molding process for a PA6-based AR15/M4 grip was investigated numerically. The process was realistically modeled using Autodesk Moldflow Insight for different glass fiber percentages (0 wt%, 15 wt%, 30 [...] Read more.

In this work, the influence of glass fibers on the performance of the injection molding process for a PA6-based AR15/M4 grip was investigated numerically. The process was realistically modeled using Autodesk Moldflow Insight for different glass fiber percentages (0 wt%, 15 wt%, 30 wt%, 45 wt%). The simulation results were evaluated, including the temperature distribution, flow time, pressure drop, pumping power, volumetric shrinkage and warpage displacement. The findings indicate that, with 15 wt% glass fibers, the material exhibits the shortest fill period (0.62 s) and the lowest pressure drop (0.0061 MPa) and power consumption (0.000433 kW), indicating maximum flow efficiency. On the other hand, a 30 wt% GF setup exhibited the largest volumetric shrinkage (17.76% at most) and warpage (Y: 1.213 mm), even though it had better thermal conductivity. The 45 wt% GF material exhibited the lowest amount of shrinkage and distortion but led to a greater energy consumption compared to 30 wt% GF. Overall, the 15 wt% GF grade provided the highest average process efficiency and dimensional accuracy; therefore, it is the most appropriate grade for precision molded firearm components. Full article

(This article belongs to the Special Issue Advances in Polymer Processing Technologies: Injection Molding)

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16 pages, 2135 KB

Open AccessArticle

Biodegradable PVA–Alginate Bio-Based Polymers Incorporating Cardanol-Based Polyols for Antibacterial Applications

by Da Hae Lee, Hee Ju Ahn, Jaekyoung Lee and Hee Chul Woo

Polymers 2025, 17(20), 2792; https://doi.org/10.3390/polym17202792 - 18 Oct 2025

Viewed by 502

Abstract

The extensive use of petroleum-based plastics has caused serious environmental concerns; thus, the need for biodegradable alternatives is essential. Here, we present eco-friendly bio-based polymers prepared by crosslinking poly(vinyl alcohol) (PVA) and alginate (ALG) with glutaraldehyde, while incorporating cardanol-derived polyols (PCD) to add [...] Read more.

The extensive use of petroleum-based plastics has caused serious environmental concerns; thus, the need for biodegradable alternatives is essential. Here, we present eco-friendly bio-based polymers prepared by crosslinking poly(vinyl alcohol) (PVA) and alginate (ALG) with glutaraldehyde, while incorporating cardanol-derived polyols (PCD) to add antibacterial functionality. The synthesized bio-based polymers were characterized by FT-IR, XRD, and TGA. FT-IR confirmed sufficient crosslinking between PVA and ALG, whereas XRD revealed a minor decrease in crystallinity. Thermogravimetric analysis showed enhanced thermal stability with increasing ALG contents, as the residual mass increased from 8 wt% (PVA only) to 19–31% (PVA:ALG = 80:20–60:40). Swelling behavior was strongly governed by ALG, with higher ratios promoting water uptake up to 130%, whereas PCD reduced swelling due to increased hydrophobicity. Antibacterial assays indicated complete inactivation of Escherichia coli and Staphylococcus aureus within 10–60 min depending on the polymer composition. These results demonstrate that tuning the PVA:ALG ratio and PCD content allows precise control of physicochemical properties. Overall, the developed PVA–ALG/PCD bio-based polymers represent a versatile and sustainable platform for eco-friendly packaging, biomedical, and water treatment applications. Full article

(This article belongs to the Special Issue Advanced Environmentally Friendly Polymeric Materials and Their Applications, 2nd Edition)

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20 pages, 1943 KB

Open AccessArticle

Experimental and Machine Learning Modelling of Ni(II) Ion Adsorption onto Guar Gum: Artificial Neural Network (ANN) and K-Nearest Neighbor (KNN) Comparative Study

by Ismat H. Ali, Malak F. Alqahtani, Nasma D. Eljack, Sawsan B. Eltahir, Makka Hashim Ahmed and Abubakr Elkhaleefa

Polymers 2025, 17(20), 2791; https://doi.org/10.3390/polym17202791 - 18 Oct 2025

Viewed by 413

Abstract

In this study, a guar gum-based adsorbent was developed and evaluated for the removal of Ni(II) ions from aqueous solutions through a combined experimental and machine learning (ML) approach. The adsorbent was characterized using FTIR, SEM, XRD, TGA, and BET analyses to confirm [...] Read more.

In this study, a guar gum-based adsorbent was developed and evaluated for the removal of Ni(II) ions from aqueous solutions through a combined experimental and machine learning (ML) approach. The adsorbent was characterized using FTIR, SEM, XRD, TGA, and BET analyses to confirm surface functionality and porous morphology suitable for metal binding. Batch adsorption experiments were conducted to optimize the effects of pH, adsorbent dosage, contact time, temperature, and initial metal concentration. The adsorption efficiency increased with higher pH and adsorbent dosage, achieving a maximum Ni(II) removal of 97% (qₘ = 86.0 mg g⁻¹) under optimal conditions (pH 6.0, dosage 1.0 g L⁻¹, contact time 60 min, and initial concentration 50 mg L⁻¹). The process followed the pseudo-second-order kinetic and Langmuir isotherm models. Thermodynamic results revealed the spontaneous, endothermic, and physical nature of the adsorption process. To complement the experimental findings, artificial neural network (ANN) and k-nearest neighbor (KNN) models were developed to predict Ni(II) removal efficiency based on process parameters. The ANN model yielded a higher prediction accuracy (R² = 0.97) compared to KNN (R² = 0.95), validating the strong correlation between experimental and predicted outcomes. The convergence of experimental optimization and ML prediction demonstrates a robust framework for designing eco-friendly, biopolymer-based adsorbents for heavy metal remediation. Full article

(This article belongs to the Special Issue Application of Natural-Based Polymers in Water Treatment)

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15 pages, 5244 KB

Open AccessArticle

Eco-Friendly Membrane Separators Based on Furanoate Polymers for Li-Ion Batteries

by Sofia Santi, Luca Bargnesi, Giulia Fredi, Michelina Soccio, Nadia Lotti, Catia Arbizzani and Andrea Dorigato

Polymers 2025, 17(20), 2790; https://doi.org/10.3390/polym17202790 - 18 Oct 2025

Viewed by 350

Abstract

Conventional lithium-ion battery separators made from petroleum-based polymers pose environmental concerns due to their non-renewable origin and energy-intensive production. Novel bio-based alternatives, such as poly(alkylene 2,5-furanoate)s (PAFs), offer improved sustainability and favorable thermomechanical properties. This work investigated electrospun mats of poly(butylene 2,5-furandicarboxylate) (PBF) [...] Read more.

Conventional lithium-ion battery separators made from petroleum-based polymers pose environmental concerns due to their non-renewable origin and energy-intensive production. Novel bio-based alternatives, such as poly(alkylene 2,5-furanoate)s (PAFs), offer improved sustainability and favorable thermomechanical properties. This work investigated electrospun mats of poly(butylene 2,5-furandicarboxylate) (PBF) and poly(pentamethylene 2,5-furandicarboxylate) (PPeF), which, despite structural similarity, exhibit distinct behaviors. PBF mats demonstrated superior performance with fiber diameters of about 1.0 µm and porosity of 53.6% with high thermal stability (T_g = 25 °C, T_m = 170 °C, 18.8% crystallinity). The semicrystalline PBF showed higher electrolyte uptake (531–658 wt%) and had a lower MacMullin number (N_M = 3–10) than commercial Celgard separators (N_M = 15), indicating enhanced ionic conductivity. Electrochemical testing revealed stability up to 5 V and successful cycling performance with specific capacity of 135 mAh/g after 100 cycles and coulombic efficiency near 100%. In contrast, PPeF’s amorphous nature (T_g = 14 °C) resulted in temperature-sensitive pore closure that enhanced safety by reducing short-circuit risk, although its solubility in carbonate electrolytes limited its application to aqueous systems. These findings highlight the potential of PAF-based separators to improve both the environmental impact and performance of batteries, supporting the development of safer and more sustainable energy storage systems. Full article

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

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15 pages, 3412 KB

Open AccessArticle

Wet-Spun Disulphide LCE Fibres for Continuous Production of Fibrous Artificial Muscles

by Joshua C. Ince, Alan R. Duffy and Nisa V. Salim

Polymers 2025, 17(20), 2789; https://doi.org/10.3390/polym17202789 - 18 Oct 2025

Viewed by 351

Abstract

Liquid Crystalline Elastomers (LCEs) are a class of shape-changing polymers with exceptional mechanical properties and potential as artificial muscles/polymer actuators. Much work has been dedicated to expanding the methods available for processing LCEs into various forms using different manufacturing techniques such as 3D [...] Read more.

Liquid Crystalline Elastomers (LCEs) are a class of shape-changing polymers with exceptional mechanical properties and potential as artificial muscles/polymer actuators. Much work has been dedicated to expanding the methods available for processing LCEs into various forms using different manufacturing techniques such as 3D printing, film casting, and microfluidic processing. Recently, several works have reported processing LCEs into long fibres and have highlighted the advantages that fibrous LCEs boast over LCE films. However, the development of alternative methods to produce fibrous LCEs is warranted to fully expedite this field of research. In this study, a method for continuous production of disulphide crosslinked LCE fibres via the technique of wet spinning is explored and reported on. Furthermore, the results show that the mechanical properties, actuation force, and actuation strain can be tuned by adjusting how much crosslinker is incorporated into the wet-spinning dope solution. Depending on the given formulation, the reported fibres could repeatedly actuate in response to thermal energy with actuation forces ranging from 0.002 to 0.02 N per fibre and actuation strains ranging from 9.7 to 33%. Full article

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

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18 pages, 1162 KB

Open AccessReview

Ferulic Acid and Polyferulic Acid in Polymers: Synthesis, Properties, and Applications

by Mateusz Leszczyński, Mariusz Ł. Mamiński and Paweł G. Parzuchowski

Polymers 2025, 17(20), 2788; https://doi.org/10.3390/polym17202788 - 17 Oct 2025

Viewed by 551

Abstract

Ferulic acid (FA), together with its polymers and derivatives, has been attracting growing attention as a building block for advanced sustainable polymeric materials due to its renewable origin, intrinsic antioxidant activity, and potential for biodegradability. This review aims to provide a comprehensive overview [...] Read more.

Ferulic acid (FA), together with its polymers and derivatives, has been attracting growing attention as a building block for advanced sustainable polymeric materials due to its renewable origin, intrinsic antioxidant activity, and potential for biodegradability. This review aims to provide a comprehensive overview of recent progress in the synthesis and functionalization of FA-based polymers, covering polymerization strategies, enzymatic modifications, and grafting approaches. The physicochemical characteristics of these materials are discussed, with particular emphasis on thermal stability, antioxidant performance, controlled release of active agents, and their impact on the mechanical and barrier properties of polymer matrices. Furthermore, key application domains—including biomedicine, food packaging, and environmental engineering—are examined, highlighting both the advantages and current limitations associated with FA utilization. Finally, perspectives are outlined regarding the necessity for further research to enhance bioavailability, stability, and synthetic efficiency, as well as the potential of FA-derived polymers in the development of next-generation, functional, and environmentally sustainable materials. Full article

(This article belongs to the Special Issue Cellulose and Wood-Based Materials in Polymer Systems and Materials Engineering)

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23 pages, 14755 KB

Open AccessArticle

Ethylene-Vinyl Acetate Copolymer as a Polyfunctional Modifier for Low-Viscosity Photosensitive Compositions

by Dmitriy A. Bazhanov, Uliana V. Nikulova, Ramil R. Khasbiullin, Nikita Yu. Budylin, Elizaveta V. Ermakova and Aleksey V. Shapagin

Polymers 2025, 17(20), 2787; https://doi.org/10.3390/polym17202787 - 17 Oct 2025

Viewed by 406

Abstract

The article presents the results of a study of the possibility of using heat-treated ethylene-vinyl acetate copolymer (EVA) as a thermoplastic modifier in a photosensitive composition based on tert-butyl acrylate (tBA). The use of such a modifier in 3D printing compositions is important [...] Read more.

The article presents the results of a study of the possibility of using heat-treated ethylene-vinyl acetate copolymer (EVA) as a thermoplastic modifier in a photosensitive composition based on tert-butyl acrylate (tBA). The use of such a modifier in 3D printing compositions is important for improving their physical and mechanical properties at low temperatures. An attempt was also made to use EVA as a polymer chain brancher. The molecular structure of the components and their compositions, rheology, curing kinetics, and phase organization of photocured systems were studied using FTIR and NMR spectroscopy, spectrophotometry, rheometry, Photo-DSC, and scanning electron microscopy. It was found that heat treatment of EVA allows the formation of single C=C bonds in macromolecules, which are necessary for a potential crosslinking agent with tBA. It was shown that EVA effectively functions as a thickener and modifier: with an increase in the modifier concentration, the nature of the composition flow changes from Newtonian to pseudoplastic, the rate of the photochemical polymerization reaction decreases, and the degree of conversion of the system decreases. However, the formation of a heterogeneous phase structure and the absence of a continuous spatial network of chemical bonds prevent the use of EVA simultaneously as a functional additive and crosslinking agent. Full article

(This article belongs to the Special Issue Process–Structure–Properties Relationships in Polymers and Polymer Composites)

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20 pages, 2917 KB

Open AccessArticle

Multi-Objective Optimization and Reliability Assessment of Date Palm Fiber/Sheep Wool Hybrid Polyester Composites Using RSM and Weibull Analysis

by Mohammed Y. Abdellah, Ahmed H. Backar, Mohamed K. Hassan, Miltiadis Kourmpetis, Ahmed Mellouli and Ahmed F. Mohamed

Polymers 2025, 17(20), 2786; https://doi.org/10.3390/polym17202786 - 17 Oct 2025

Viewed by 306

Abstract

This study investigates date palm fiber (DPF) and sheep wool hybrid polyester composites with fiber loadings of 0%, 10%, 20%, and 30% by weight, fabricated by compression molding, to develop a sustainable and reliable material system. Experimental data from prior work were modeled [...] Read more.

This study investigates date palm fiber (DPF) and sheep wool hybrid polyester composites with fiber loadings of 0%, 10%, 20%, and 30% by weight, fabricated by compression molding, to develop a sustainable and reliable material system. Experimental data from prior work were modeled using Weibull analysis for reliability evaluation and response surface methodology (RSM) for multi-objective optimization. Weibull statistics fitted a two-parameter distribution to tensile strength and fracture toughness, extracting shape (η) and scale (

β

) parameters to quantify variability and failure probability. The analysis showed that 20% hybrid content achieved the highest scale values (

β

= 28.85 MPa for tensile strength and

β

= 15.03

M P a \sqrt{m}

for fracture toughness) and comparatively low scatter (η = 10.39 and 9.2, respectively), indicating superior reliability. RSM quadratic models were developed for tensile strength, fracture toughness, thermal conductivity, acoustic attenuation, and water absorption, and were combined using desirability functions. The RSM optimization was found at 18.97% fiber content with a desirability index of 0.673, predicting 25.89 MPa tensile strength, 14.23

M P a \sqrt{m}

fracture toughness, 0.08 W/m·K thermal conductivity, 20.49 dB acoustic attenuation, and 5.11% water absorption. Overlaying Weibull cumulative distribution functions with RSM desirability surfaces linked probabilistic reliability zones (90–95% survival) to the deterministic optimization peak. This integration establishes a unified framework for designing natural fiber composites by embedding reliability into multi-property optimization. Full article

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

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25 pages, 6090 KB

Open AccessArticle

Comparative Study of AlSi10Mg and 304 Stainless-Steel Fillers in PA12 Composites Manufactured Using Injection Moulding Process for Liners and Sleeve-Based Applications: Microstructure, Mechanical Properties, Thermal Stability, and Wear Behaviour

by Nabeel Maqsood, Bilal Islam, Karolis Stravinskas, Oleksandr Kapustynskyi, Romuald Petkevič, Alireza Shahidi and Genrik Mordas

Polymers 2025, 17(20), 2785; https://doi.org/10.3390/polym17202785 - 17 Oct 2025

Cited by 1 | Viewed by 329

Abstract

This study presents a comparative evaluation of injection-moulded PA12 composites reinforced with AlSi10Mg and 304 SS fillers, with emphasis on microstructure–property correlations linking powder morphology, mechanical performance, thermal stability, and tribological behaviour. Powder characterization revealed distinct morphologies—fine spherical AlSi10Mg particles (D50 ≈ 32 [...] Read more.

This study presents a comparative evaluation of injection-moulded PA12 composites reinforced with AlSi10Mg and 304 SS fillers, with emphasis on microstructure–property correlations linking powder morphology, mechanical performance, thermal stability, and tribological behaviour. Powder characterization revealed distinct morphologies—fine spherical AlSi10Mg particles (D50 ≈ 32 µm) dispersed uniformly in the matrix—while SS particles (D50 ≈ 245 µm) tended to agglomerate, leading to interfacial voids. Tensile testing showed that the elastic modulus of neat PA12 (0.95 GPa) increased by 20% and 28% with 20 wt% AlSi10Mg and SS, respectively. However, tensile strength decreased from 35.04 MPa (PA12) to 32.18 MPa (20 wt% AlSi10Mg) and 31.03 MPa (20 wt% 304 SS), consistent with stress concentrations around particle clusters. Hardness values remained nearly unchanged at 96–98 Shore D across all composites. Thermal analysis indicated that AlSi10Mg promoted crystallization, increasing crystallinity from 31% (PA12) to 34% and raising Tm by 2 °C. In contrast, 304 SS reduced crystallinity to 28% but significantly improved thermal stability, shifting Tonset from 405 °C (PA12) to 426 °C at 20 wt%. Tribological tests demonstrated substantial improvements: the coefficient of friction decreased from 0.42 (PA12) to 0.34 (AlSi10Mg) and 0.29 (304 SS), while wear rates dropped by 40% and 55%, respectively. SEM confirmed smoother worn surfaces in AlSi10Mg composites and abrasive grooves in 304 SS composites. The findings show that AlSi10Mg is advantageous for smoother surfaces and improved crystallinity, while SS enhances stiffness, wear resistance, and thermal endurance, providing design guidelines for PA12 composites in aerospace, automotive, and engineering applications. Full article

(This article belongs to the Special Issue Multifunctional Polymer Composite Materials, 2nd Edition)

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17 pages, 4000 KB

Open AccessArticle

Development and Characterization of Near-Infrared Detectable Twin Dye Patterns on Polyester Packaging for Smart Optical Tagging

by Silvio Plehati, Aleksandra Bernašek Petrinec, Tomislav Bogović and Jana Žiljak Gršić

Polymers 2025, 17(20), 2784; https://doi.org/10.3390/polym17202784 - 17 Oct 2025

Viewed by 377

Abstract

Smart polyester materials with embedded near-infrared (NIR) functionalities offer a promising pathway for low-cost, covert tagging, and object identification. In this study we present the development and characterization of polyester packaging surfaces printed with spectrally matched twin dyes that are invisible under visible [...] Read more.

Smart polyester materials with embedded near-infrared (NIR) functionalities offer a promising pathway for low-cost, covert tagging, and object identification. In this study we present the development and characterization of polyester packaging surfaces printed with spectrally matched twin dyes that are invisible under visible light but selectively absorbed in the NIR region. The dye patterns were applied using a Direct-to-Film transfer (DTF) method onto polyester substrates. To validate their optical behavior, we applied a dual measurement approach. Laboratory grade NIR absorbance spectroscopy was used to characterize the spectral profiles of the twin dyes in the 400–900 nm range. A custom photodiode-based detection system was constructed to evaluate the feasibility of low-cost, embedded NIR absorbance sensing. Results from both methods show correlation in absorbance contrast between the dye pairs, confirming their suitability for spectral tagging. The developed materials were evaluated in a real-world detection scenario using commercially available NIR cameras. Under dark field conditions with edge illuminated planar lighting, the twin dye patterns were successfully recognized through custom software, enabling non-contact identification and spatial localization of the NIR codes. This work presents a low-cost, scalable approach for smart packaging applications based on optical detection of actively illuminated twin dyes using accessible NIR imaging systems. Full article

(This article belongs to the Special Issue Polymer Packaging: Sustainable Innovations and Alternatives to Fossil-Based Materials)

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15 pages, 1610 KB

Open AccessArticle

Utilization of Hydrolyzed Agro-Industrial Waste from Arti-Chokes to Obtain Structurally Functional Bacterial Cellulose by Komagataeibacter rhaeticus QK23

by Claudio Eduardo Quiñones-Cerna, Gabriela Barraza-Jáuregui, José Alfredo Cruz-Monzón, Fernando Hurtado-Butrón, Bertha Soledad Soriano-Bernilla, Diego Miguel Gutiérrez-Rodríguez, Johnny Huanes-Carranza, Wilmer Ugarte-López, Juan Carlos Rodríguez-Soto, Heber Max Robles-Castillo, Eulalio López-Quiroz and Magaly De La Cruz-Noriega

Polymers 2025, 17(20), 2783; https://doi.org/10.3390/polym17202783 - 17 Oct 2025

Viewed by 398

Abstract

Bacterial cellulose (BC) is a pure, crystalline biopolymer with broad applications, though large-scale production remains limited by the high cost of culture media. This study evaluated the use of artichoke bract waste as an alternative substrate for BC production by Komagataeibacter rhaeticus QK23, [...] Read more.

Bacterial cellulose (BC) is a pure, crystalline biopolymer with broad applications, though large-scale production remains limited by the high cost of culture media. This study evaluated the use of artichoke bract waste as an alternative substrate for BC production by Komagataeibacter rhaeticus QK23, focusing on culture optimization and physicochemical characterization of the resulting biopolymer. Infrared spectroscopy revealed functional groups characteristic of cellulose, hemicellulose, lignin, and inulin, along with structural sugars (glucose 24%, xylose 5.07%, arabinose 4.96%, galactose 8.81%, and mannose 1.75%). After hydrolysis with H₂SO₄, up to 11.81 g/L of reducing sugars were released and incorporated into Hestrin–Schramm medium lacking glucose. Using a central composite design, inoculum dose (10–20%) and incubation time (7–14 days) were optimized under static conditions at 30 °C. The highest yield (1.57 g/L) was obtained with 20% inoculum after 14 days. The product corresponded to type I cellulose with a crystallinity index of 81.87%, and AFM analysis revealed a surface roughness of 32.96 nm. The results demonstrate that artichoke hydrolysates are a viable and sustainable source for BC production, promoting agricultural waste valorization and cost reduction in industrial biotechnology. Full article

(This article belongs to the Special Issue Recent Progress on Lignocellulosic-Based Polymeric Materials)

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26 pages, 2233 KB

Open AccessArticle

Rheology for Wood Plastic Composite Extrusion—Part 1: Laboratory vs. On-Line Rheometry

by Krzysztof J. Wilczyński, Kamila Buziak, Adrian Lewandowski and Krzysztof Wilczyński

Polymers 2025, 17(20), 2782; https://doi.org/10.3390/polym17202782 - 17 Oct 2025

Viewed by 429

Abstract

Common polymeric materials (neat polymers) are quite well known, and their properties are often available in appropriate material databases. However, material data, e.g., rheological data, for materials such as polymer blends, polymer composites (including wood plastic composites), and filled plastics are simply lacking [...] Read more.

Common polymeric materials (neat polymers) are quite well known, and their properties are often available in appropriate material databases. However, material data, e.g., rheological data, for materials such as polymer blends, polymer composites (including wood plastic composites), and filled plastics are simply lacking in material databases. This paper addresses the problem of determining viscosity curves for one of the most widely used advanced polymeric materials: wood plastic composites. Studies were conducted in laboratory and production settings, i.e., on-line. Laboratory tests were conducted in two ways: on the basis of classical rheometric measurements, i.e., High-Pressure Capillary Rheometry (HPCR), and on the basis of Melt Flow Index (MFI) measurements, also including tests based on a limited number of measurement points. Tests in production conditions, i.e., on-line, were conducted during the extrusion process using the measurement of the process output (material flow rate) and pressure in a specialized extrusion die. The test results (viscosity curves) obtained from Melt Flow Index (MFI) measurements and on-line measurements were presented and evaluated against the background of the results (viscosity curves) obtained from classical capillary rheometry measurements (HPCR). Due to the lack of rheological data of wood plastic composites in available databases, in-house research methods based on the two-point viscosity curve determination in the plastometric (MFI) tests and the tests under production conditions, that is, on-line, have been proposed. The two-point method, based on the power law model, is quick and easy to implement, and allows for solving many polymer processing issues analytically. On-line tests have the significant advantage of being conducted under the actual flow conditions of the tested material, rather than under laboratory conditions, as is the case with rheometric and plastometric tests, which do not take into account the processing history of the tested material. The issues of rheology and modeling of wood plastic composite processing, e.g., extrusion and injection molding, which have not yet been resolved and require practical solutions, were also discussed. The results of this part of the study (viscosity curves and models) will be used in the second part of the study to evaluate the impact of rheological testing methods and rheological models on the accuracy of process modeling (extrusion). Full article

(This article belongs to the Special Issue Advances in Wood and Wood Polymer Composites)

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15 pages, 4121 KB

Open AccessArticle

The Effects of Soft-Segment Molecular Weight on the Structure and Properties of Poly(trimethylene terephthalate)-block-poly(tetramethylene glycol) Copolymers

by Hailiang Dong, Yuchuang Tian, Junyu Li, Jiyou Shi, Jun Kuang, Wenle Zhou and Ye Chen

Polymers 2025, 17(20), 2781; https://doi.org/10.3390/polym17202781 - 17 Oct 2025

Viewed by 403

Abstract

A series of PTT-b-PTMG copolyesters was synthesized via direct esterification followed by melt polycondensation using purified terephthalic acid (PTA), bio-based 1,3-propanediol (PDO), and poly(tetramethylene glycol) (PTMG) of varying molecular weights (650–3000 g/mol). The resulting materials were comprehensively characterized in terms of [...] Read more.

A series of PTT-b-PTMG copolyesters was synthesized via direct esterification followed by melt polycondensation using purified terephthalic acid (PTA), bio-based 1,3-propanediol (PDO), and poly(tetramethylene glycol) (PTMG) of varying molecular weights (650–3000 g/mol). The resulting materials were comprehensively characterized in terms of chemical structure, molecular weight, thermal behavior, phase morphology, crystalline architecture, and mechanical performance using a range of analytical techniques: Fourier-transform infrared spectroscopy (FTIR), ¹H-NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), dynamic mechanical thermal analysis (DMA), tensile testing, and other standard physical methods. FTIR, ¹H-NMR, and GPC data confirmed the successful incorporation of both PTT-hard and PTMG-soft segments into the copolymer backbone. As the PTMG molecular weight increased, the average sequence length of the PTT-hard segments (L_n,T) also increased, leading to higher melting (T_m) and crystallization (T_c) temperatures, albeit with a slight reduction in overall crystallinity. DMA results indicated enhanced microphase separation between hard and soft domains with increasing PTMG molecular weight. WAXS and SAXS analyses further revealed that the crystalline structure and long-range ordering were strongly dependent on the copolymer composition and block architecture. Mechanical testing showed that tensile strength at break remained relatively constant across the series, while Young’s modulus increased significantly with higher PTMG molecular weight—concurrently accompanied by a decrease in elongation at break. Furthermore, the elastic deformability and recovery behavior of PTT-b-PTMG block copolymers were evaluated through cyclic tensile testing. TGA confirmed that all copolyesters exhibited excellent thermal stability. This study demonstrates that the physical and mechanical properties of bio-based PTT-b-PTMG elastomers can be effectively tailored by adjusting the molecular weight of the PTMG-soft segment, offering valuable insights for the rational design of sustainable thermoplastic elastomers with tunable performance. Full article

(This article belongs to the Section Polymer Chemistry)

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20 pages, 1365 KB

Open AccessArticle

Incorporating Carbamate Functionalities in Multifunctional Monomer System Enhances Mechanical Properties of Methacrylate Dental Adhesives

by Burak Korkmaz, Erhan Demirel, Anil Misra, Candan Tamerler and Paulette Spencer

Polymers 2025, 17(20), 2780; https://doi.org/10.3390/polym17202780 - 17 Oct 2025

Viewed by 481

Abstract

Although resin-based composite is the most popular direct restoration material in the U.S., composite restorations can fail shortly after placement. The leading cause of failure is recurrent marginal decay. The adhesive that bonds the composite to the tooth is intended to seal the [...] Read more.

Although resin-based composite is the most popular direct restoration material in the U.S., composite restorations can fail shortly after placement. The leading cause of failure is recurrent marginal decay. The adhesive that bonds the composite to the tooth is intended to seal the margin, but the degradation of the adhesive seal to dentin leads to gaps that are infiltrated by cariogenic bacteria. The development of strategies to mitigate adhesive degradation is an area of intense interest. Recent studies focus on exploiting hydrogen–bond interactions to enhance polymer network stability. This paper presents the preparation and characterization of model adhesives that capitalize on carbamate-functionalized long-chain silane monomers to enhance polymer stability and mechanical properties in wet environments. The adhesive composition is HEMA/BisGMA, 3-component photoinitiator system, carbamate-functionalized long-chain silane monomers, e.g., commercial SHEtMA (Cb1) and newly synthesized SHEMA (Cb2). Polymerization behavior, water sorption, leachates, and dynamic mechanical properties were investigated. The properties of Cb1 and Cb2 were compared to previously studied middle- (SC4) and short-chain (SC5) silane monomers. Cb1- and Cb2-formulations exhibit greater resilience under wet conditions as compared to middle-chain silane monomers. Dental adhesives containing the carbamate-functionalized long-chain silane monomers exhibit reduced flexibility in water-submersed conditions and enhanced stability as a result of increased hydrogen–bond interactions. The results emphasize the critical role of hydrogen bonding in maintaining structural integrity of dental adhesive formulations under conditions that simulate the wet, oral environment. Full article

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

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20 pages, 6325 KB

Open AccessArticle

Activation of Inflammatory and Apoptosis Pathways on Human Gingival Fibroblasts Exposed to Dental Resin Composites

by Francesco De Angelis, Edoardo Sorrentino, Antonella Mazzone, Ylenia Della Rocca, Jacopo Pizzicannella, Oriana Trubiani, Giovanna Iezzi, Camillo D’Arcangelo, Guya Diletta Marconi and Francesca Diomede

Polymers 2025, 17(20), 2779; https://doi.org/10.3390/polym17202779 - 17 Oct 2025

Viewed by 415

Abstract

The use of dental composite resins has significantly increased over recent years, thanks to their esthetics and mechanical features, despite some doubts being raised about their biocompatibility. Residual methacrylate can be eluted from bulk composites, and its amount may significantly increase over time, [...] Read more.

The use of dental composite resins has significantly increased over recent years, thanks to their esthetics and mechanical features, despite some doubts being raised about their biocompatibility. Residual methacrylate can be eluted from bulk composites, and its amount may significantly increase over time, leading to cytotoxic effects that can involve several inflammatory patterns. The aim of this in vitro study was to evaluate the activation of the inflammatory pathway NFκB p65/MyD88/NALP3 and the apoptosis pathway of BCL-2/BAX/Caspase-3 (CASP-3) expression on human gingival fibroblasts (hGFs) after 24 h and 1-week exposure to the eluates of three heat-cured dental composite resins: GrandioSO, VOCO (GR); Enamel Plus HRi Biofunction, Micerium (BF); and Filtek universal restorative, 3M (FU). The results highlighted that NFκB p65/MyD88/NALP3 was activated after resin exposure in a time-dependent manner. Moreover, immunofluorescence and gene expression analyses showed that pro-apoptotic markers CASP-3 and BAX were elevated, while anti-apoptotic protein BCL-2 was suppressed in hGFs after dental resin exposure. The present in vitro study analyzed mechanisms related to cytotoxicity and apoptosis, suggesting ways to limit composite cytotoxicity through advancements in material technology. The activation of inflammation and apoptotic pathways appeared to be material-dependent, and was less pronounced with BF and FU, which could hypothetically indicate them being a safer clinical choice to preserve periodontal health in daily dental practice. Full article

(This article belongs to the Special Issue Advanced Polymeric Materials for Dental Applications III)

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Polymers, Volume 17, Issue 20 (October-2 2025) – 92 articles

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