Polymers

21 pages, 4078 KiB

Open AccessArticle

Wet Chemical-Synthesized Low-Loss Dielectric Composite Material Based on CuCl-Cu₇S₄ Nanoparticles and PVDF Copolymer

by Alexander A. Maltsev, Andrey A. Vodyashkin, Evgenia L. Buryanskaya, Olga Yu. Koval, Alexander V. Syuy, Sergei B. Bibikov, Irina E. Maltseva, Bogdan A. Parshin, Anastasia M. Stoynova, Pavel A. Mikhalev and Mstislav O. Makeev

Polymers 2025, 17(13), 1845; https://doi.org/10.3390/polym17131845 - 30 Jun 2025

Abstract

Polymer composites with high dielectric permittivity (>10) and low dielectric loss are critical for energy storage and microelectronic applications. This study reports on a semi-transparent composite of a PVDF copolymer filled with Cu₇S₄ nanoparticles synthesized via a wet chemical route. [...] Read more.

Polymer composites with high dielectric permittivity (>10) and low dielectric loss are critical for energy storage and microelectronic applications. This study reports on a semi-transparent composite of a PVDF copolymer filled with Cu₇S₄ nanoparticles synthesized via a wet chemical route. Only a small content (6%) of copper sulfide increases the dielectric permittivity of the material from 10.4 to 15.9 (1 kHz), maintaining a low dielectric loss coefficient (less than 0.1). The incorporated nanoparticles affect the morphology of the composite film surface and crystalline phases in the whole volume, which was studied with FTIR spectroscopy, differential scanning calorimetry and scanning probe microscopy. Full article

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

19 pages, 1034 KiB

Open AccessArticle

Preparation of Glass Fiber Reinforced Polypropylene Bending Plate and Its Long-Term Performance Exposed in Alkaline Solution Environment

by Zhan Peng, Anji Wang, Chen Wang and Chenggao Li

Polymers 2025, 17(13), 1844; https://doi.org/10.3390/polym17131844 - 30 Jun 2025

Abstract

Glass fiber reinforced polypropylene composite plates have gradually attracted more attention because of their repeated molding, higher toughness, higher durability, and fatigue resistance compared to glass fiber reinforced thermosetting composites. In practical engineering applications, composite plates have to undergo bending effect at different [...] Read more.

Glass fiber reinforced polypropylene composite plates have gradually attracted more attention because of their repeated molding, higher toughness, higher durability, and fatigue resistance compared to glass fiber reinforced thermosetting composites. In practical engineering applications, composite plates have to undergo bending effect at different angles in corrosive environment of concrete, including bending bars from 0~90°, and stirrups of 90°, which may lead to long-term performance degradation. Therefore, it is important to evaluate the long-term performance of glass fiber reinforced polypropylene composite bending plates in an alkali environment. In the current paper, a new bending device is developed to prepare glass fiber reinforced polypropylene bending plates with the bending angles of 60° and 90°. It should be pointed out that the above two bending angles are simulated typical bending bars and stirrups, respectively. The plate is immersed in the alkali solution environment for up to 90 days for long-term exposure. Mechanical properties (tensile properties and shear properties), thermal properties (dynamic mechanical properties and thermogravimetric analysis) and micro-morphology analysis (surface morphology analysis) were systematically designed to evaluate the influence mechanism of bending angle and alkali solution immersion on the long-term mechanical properties. The results show the bending effect leads to the continuous failure of fibers, and the outer fibers break under tension, and the inner fibers buckle under compression, resulting in debonding of the fiber–matrix interface. Alkali solution (OH− ions) corrode the surface of glass fiber to form soluble silicate, which is proved by the mass fraction of glass fiber decreased obviously from 79.9% to 73.65% from thermogravimetric analysis. This contributes to the highest degradation ratio of tensile strength was 71.6% (60° bending) and 65.6% (90° bending), respectively, compared to the plate with bending angles of 0°. A high curvature bending angle (such as 90°) leads to local buckling of fibers and plastic deformation of the matrix, forming microcracks and fiber–resin interface bonding at the bending area, which accelerates the chemical erosion and debonding process in the interface area, bringing about an additional maximum 10.56% degradation rate of the shear strength. In addition, the alkali immersion leads to the obvious degradation of storage modulus and thermal decomposition temperature of composite plate. Compared with the other works on the long-term mechanical properties of glass fiber reinforced polypropylene, it can be found that the long-term performance of glass fiber reinforced polypropylene composites is controlled by the corrosive media type, bending angle and immersion time. The research results will provide durability data for glass fiber reinforced polypropylene composites used in concrete as stirrups. Full article

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

20 pages, 2378 KiB

Open AccessArticle

Design and Synthesis Optimization of Fluorescent Acrylate-Based and Silicate-Based Materials for Carbonyl Adsorption

by Laura Carballido, Thomas Karbowiak and Elias Bou-Maroun

Polymers 2025, 17(13), 1843; https://doi.org/10.3390/polym17131843 - 30 Jun 2025

Abstract

For their use as chemical sensors, the optimization of the performance of polymeric materials is a critical step in their development for the desired application. The main objective of this work was to identify the best-suited materials to develop a sensor for carbonyl [...] Read more.

For their use as chemical sensors, the optimization of the performance of polymeric materials is a critical step in their development for the desired application. The main objective of this work was to identify the best-suited materials to develop a sensor for carbonyl monitoring based on fluorescence. Two categories of materials were compared: acrylate-based materials, obtained by radical polymerization, and silicate-based materials, obtained by sol-gel synthesis. The performances of these materials in terms of yield of polymerization, carbonyl adsorption capacity and fluorescence property were compared. More precisely, the influence of various synthesis parameters such as polymerization type, radical polymerization initiation method, the nature of the functional monomer and the molar ratio of the different reactants was assessed. On the first hand, among acrylate-based materials, the one based on 4-vinylaniline showed better adsorption capacity compared to those based on 3-vinylaniline and 2-vinylaniline. Moreover, materials obtained by UV-polymerization showed a better adsorption capacity compared to those obtained by thermally initiated polymerization. On the other hand, the silicate-based material provided a better synthesis reproducibility, a higher adsorption capacity and a higher fluorescence intensity compared to its acrylate-based counterparts. Finally, contrary to the acrylate-based materials tested, the adsorption capacity and fluorescence properties of silicate-based materials were stable over time. Full article

(This article belongs to the Section Polymer Chemistry)

20 pages, 2287 KiB

Open AccessArticle

Stability of TPU/PP Blends Exposed to UV Radiation for Industrial Applications

by Carlos Vargas-Isaza, Jose A. Tamayo, Libia M. Baena, Juan Felipe Santa Marin and Adrian José Benitez-Lozano

Polymers 2025, 17(13), 1842; https://doi.org/10.3390/polym17131842 - 30 Jun 2025

Abstract

Thermoplastic polyurethanes (TPUs) have found diverse applications across different industries, which expose the material to various environmental conditions. Among these, UV radiation stands out as one of the most aggressive, leading to significant degradation in polymers. Considering this, this study explores the use [...] Read more.

Thermoplastic polyurethanes (TPUs) have found diverse applications across different industries, which expose the material to various environmental conditions. Among these, UV radiation stands out as one of the most aggressive, leading to significant degradation in polymers. Considering this, this study explores the use of commercial additives, such as polyethylene masterbatches (MB), and their effectiveness as inhibitors of UV radiation-induced degradation. In addition, it investigates the possibility of blending high-performance polymers, such as TPU, with commodity polymers, such as polypropylenes. The prepared blends were evaluated via thermogravimetric analysis, infrared and electron microscopy, hardness and tensile strength assessments, and scanning electron microscopy before and after 320 h of exposure to accelerated aging. The findings suggest that the adequate incorporation of additives in blends can help to reduce the harmful effects caused by UV radiation on the polymeric materials. Full article

(This article belongs to the Section Polymer Applications)

19 pages, 6258 KiB

Open AccessArticle

Experimental Study on Crack Evolution Characteristics in Guar Gum-Modified Silty Clay

by Xiyan Jiang, Wanxin Hou, Dongning Zhang, Zhibao Guo, Dameng Wang and Xu Wang

Polymers 2025, 17(13), 1841; https://doi.org/10.3390/polym17131841 - 30 Jun 2025

Abstract

The formation of soil cracks in soil slopes can compromise structural integrity. Guar gum, as a natural high-molecular-weight biopolymer, offers environmental and economic advantages in soil stabilizers due to its biodegradability, strong binding properties, and ability to form a three-dimensional network structure. To [...] Read more.

The formation of soil cracks in soil slopes can compromise structural integrity. Guar gum, as a natural high-molecular-weight biopolymer, offers environmental and economic advantages in soil stabilizers due to its biodegradability, strong binding properties, and ability to form a three-dimensional network structure. To investigate its improvement effects, outdoor dry shrinkage cracking tests were conducted on silt loam using different guar gum dosages. Image preprocessing was performed using Photoshop software, and Python algorithms combined with the PCAS system were employed to quantitatively analyze the development process of cracks, revealing the evolution patterns of basic crack parameters, fractal dimensions, and probability entropy. The results indicate the following: (1) the addition of guar gum improves the water retention capacity of the soil, with the average moisture content of the samples decreasing as the guar gum content increases; (2) as the guar gum content increased, the total length, total area, and surface crack ratio of the cracks all increased, but the average crack width decreased significantly, with the maximum decrease reaching 9.8%, indicating that guar gum can effectively suppress the expansion of crack width and slow down the infiltration rate of rainwater; (3) the fractal dimension of crack area is less affected by guar gum content, while the fractal dimension of crack length is significantly influenced by guar gum content. Combining both parameters can effectively characterize crack morphology and distribution. The final fractal dimension of crack length generally ranges from 1.2 to 1.3, while the fractal dimension of the crack area remains stable between 1.55 and 1.65; (4) the addition of guar gum has a minor effect on the probability entropy of cracks, with a change of less than 3%, indicating that it does not significantly influence the randomness of cracks. Therefore, this study confirms that guar gum has a significant effect in controlling crack width and optimizing the uniformity of the crack network. Through its mechanisms of binding soil particles and delaying drying shrinkage, it provides an important reference for the ecological protection of cohesive soil slopes. Full article

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

22 pages, 2810 KiB

Open AccessArticle

Molecular Engineering of Carboxylated Polysulfone Membranes for Enhancing Salt Rejection

by Zhuonan Chen and Moris S. Eisen

Polymers 2025, 17(13), 1840; https://doi.org/10.3390/polym17131840 - 30 Jun 2025

Abstract

Abstracts [...] Full article

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

22 pages, 3140 KiB

Open AccessArticle

Study of PVP and PLA Systems and Fibers Obtained by Solution Blow Spinning for Chlorhexidine Release

by Oliver Rosas, Manuel Acevedo and Itziar Vélaz

Polymers 2025, 17(13), 1839; https://doi.org/10.3390/polym17131839 - 30 Jun 2025

Abstract

Antimicrobial resistance arises from treatment non-adherence and ineffective delivery systems. Optimal wound dressings combine localized drug release, exudate management, and bacterial encapsulation through hydrogel-forming nanofibers for enhanced therapy. In this work, polylactic acid (PLA) and polyvinylpyrrolidone (PVP) fibers loaded with chlorhexidine (CHX) were [...] Read more.

Antimicrobial resistance arises from treatment non-adherence and ineffective delivery systems. Optimal wound dressings combine localized drug release, exudate management, and bacterial encapsulation through hydrogel-forming nanofibers for enhanced therapy. In this work, polylactic acid (PLA) and polyvinylpyrrolidone (PVP) fibers loaded with chlorhexidine (CHX) were developed using Solution Blow Spinning (SBS), a scalable electrospinning alternative that enables in situ deposition. Molecular interactions between CHX and polymers in solution (by UV-Vis and fluorescence spectroscopy) and in solid state (by FTIR, XRD and thermal analysis) were studied. The morphology of the polymeric fibers was determined by optical microscopy, showing that PVP fibers are thinner (1625 nm) and more uniform than those of PLA (2237 nm). Finally, drug release from single-polymer fibers discs, overlapping fibers discs (PLA/PVP/PLA and PVP/PLA/PVP), and solid dispersions was determined by UV-Vis spectrometry. PVP-based fibers exhibited faster CHX release due to their hydrophilic nature, while PLA fibers proved sustained release, attributed to their hydrophobic matrix. This study highlights the potential of PLA/PVP-CHX fibers made from SBS as advanced wound dressings, combining biocompatibility and personalized drug delivery, offering a promising platform for localized and controlled antibiotic delivery. Full article

(This article belongs to the Special Issue Development of Bio-Based Materials: Synthesis, Characterization, and Applications, 3rd Edition)

24 pages, 1765 KiB

Open AccessArticle

Enhancing 3D Printing of Gelatin/Siloxane-Based Cellular Scaffolds Using a Computational Model

by Marcos B. Valenzuela-Reyes, Esmeralda S. Zuñiga-Aguilar, Christian Chapa-González, Javier S. Castro-Carmona, Luis C. Méndez-González, R. Álvarez-López, Humberto Monreal-Romero and Carlos A. Martínez-Pérez

Polymers 2025, 17(13), 1838; https://doi.org/10.3390/polym17131838 - 30 Jun 2025

Abstract

In recent years, there has been a surge in the extrusion-based 3D printing of materials for various biomedical applications. This work presents a novel methodology for optimizing extrusion-based 3D bioprinting of a gelatin/siloxane hybrid material for biomedical applications. A systematic approach integrating rheological [...] Read more.

In recent years, there has been a surge in the extrusion-based 3D printing of materials for various biomedical applications. This work presents a novel methodology for optimizing extrusion-based 3D bioprinting of a gelatin/siloxane hybrid material for biomedical applications. A systematic approach integrating rheological characterization, computational fluid dynamics simulation (CFD), and machine-learning-based image analysis, was employed. Rheological tests revealed a shear stress of 50 Pa, a maximum viscosity of 3 × 10⁵ Pa*s, a minimum viscosity of 0.089 Pa*s, and a shear rate of 15 rad/s (27G nozzle, 180 kPa pressure, 32 °C temperature, 30 mm/s velocity) for a BIO X bioprinter. While these parameters yielded constructs with 54.5% similarity to the CAD design, a multi-faceted optimization strategy was implemented to enhance fidelity, computational fluid dynamics simulations in SolidWorks, coupled with a custom-develop a binary classifier convolutional neuronal network for post-printing image analysis, facilitated targeted parameter refinement. Subsequent printing optimized parameters (25G nozzle, 170 kPa, 32 °C, 20 mm/s) achieved a significantly improved similarity of 92.35% CAD, demonstrating efficacy. The synergistic combination of simulation and machine learning ultimately enabled the fabrication of complex 3D constructs with a high fidelity of 94.13% CAD similarity, demonstrating the efficacy and potential of this integrated approach for advanced biofabrication. Full article

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

31 pages, 3860 KiB

Open AccessArticle

Extraction and Characterization of Tannins from the Barks of Four Tropical Wood Species and Formulation of Bioresins for Potential Industrial Applications

by Liliane Nga, Benoit Ndiwe, Achille Bernard Biwole, Jean Jalin Eyinga Biwole, Mewoli Armel, Joseph Zobo Mfomo, Anélie Petrissans, Antonio Pizzi and Antonios N. Papadopoulos

Polymers 2025, 17(13), 1837; https://doi.org/10.3390/polym17131837 - 30 Jun 2025

Abstract

The use of renewable plant resources for the formulation of adhesives is increasingly promising, thanks to their availability at an affordable price and their high content of biomolecules such as polyphenols. The study of tannins therefore remains an active and ongoing area of [...] Read more.

The use of renewable plant resources for the formulation of adhesives is increasingly promising, thanks to their availability at an affordable price and their high content of biomolecules such as polyphenols. The study of tannins therefore remains an active and ongoing area of research. This article presents a recent characterization of tannins extracted from the barks of four types of tropical trees (Entandophragma candolei, Entandophragma cylindricum, Afzelia africana and Dacryodes klaineana) and their application in the development of bioresins. Tannin extraction with hot water yielded between 25% and 40%. Tannin from Entandophragma candolei produced the highest yield. Chemical analysis confirmed the high presence of condensed tannins, with the identification of several new monomers in each tannin type, underlining their uniqueness. The most chemically stable tannins, Dacryodes klaineana and Afzelia africana, demonstrated their ability to withstand temperatures of 525 °C and 375 °C, respectively, with carbon residues of 45.05% and 43.18%. As for the resins, Entandophragma candolei tannin resin stood out for its thermal properties, notably a degradation temperature of 500 °C and a carbon residue rate of 36.72%. As for E. cylindricum resin, it boasted the highest modulus of elasticity (5268 MPa). Characterized tannins can be exploited in the technological sector. Full article

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

16 pages, 2740 KiB

Open AccessArticle

Tailoring Dialdehyde Bacterial Cellulose Synthesis for Versatile Applications

by Krittanan Kadsanit, Malinee Sriariyanun, Muenduen Phisalaphong and Suchata Kirdponpattara

Polymers 2025, 17(13), 1836; https://doi.org/10.3390/polym17131836 - 30 Jun 2025

Abstract

Dialdehyde bacterial cellulose (DBC) has been implemented in versatile applications. DBC was prepared from bacterial cellulose (BC) through periodate oxidation with varying parameters, including the mole ratio of BC and NaOI₄, temperature, and reaction time. The relationship between the degree of [...] Read more.

Dialdehyde bacterial cellulose (DBC) has been implemented in versatile applications. DBC was prepared from bacterial cellulose (BC) through periodate oxidation with varying parameters, including the mole ratio of BC and NaOI₄, temperature, and reaction time. The relationship between the degree of oxidation (DO)/aldehyde content and these parameters was proposed as a quadratic equation to predict the oxidation conditions needed to achieve a specific DO using Response Surface Methodology (RSM). The chemical structure and morphology of DBC were influenced by DO. DBC with different DO levels was used as a crosslinker and a reinforcing agent for gelatin sponge fabrication. Results indicated that a high DO of DBC could enhance the tensile strength and structural stability of the gelatin matrix. Selecting the proper DO level could control the morphological structure of the gelatin sponge, which is crucial for biomedical applications. Full article

(This article belongs to the Special Issue Polysaccharide-Based Materials: Developments and Properties)

23 pages, 4608 KiB

Open AccessArticle

Step-by-Step Analysis of a Copper-Mediated Surface-Initiated Atom-Transfer Radical Polymerization Process for Polyacrylamide Brush Synthesis Through Infrared Spectroscopy and Contact Angle Measurements

by Leonardo A. Beneditt-Jimenez, Isidro Cruz-Cruz, Nicolás A. Ulloa-Castillo and Alan O. Sustaita-Narváez

Polymers 2025, 17(13), 1835; https://doi.org/10.3390/polym17131835 - 30 Jun 2025

Abstract

Polymer brushes (PBs) are transformative surface-modifying nanostructures, yet their synthesis via controlled methods like copper-mediated surface-initiated atom-transfer radical polymerization (Cu⁰-SI-ATRP) faces reproducibility challenges due to a lack of understanding of parameter interdependencies. This study systematically evaluates the Cu⁰-SI-ATRP process [...] Read more.

Polymer brushes (PBs) are transformative surface-modifying nanostructures, yet their synthesis via controlled methods like copper-mediated surface-initiated atom-transfer radical polymerization (Cu⁰-SI-ATRP) faces reproducibility challenges due to a lack of understanding of parameter interdependencies. This study systematically evaluates the Cu⁰-SI-ATRP process for polyacrylamide brushes (PAM-PBs), aiming to clarify key parameters that influence the synthesis process. This evaluation followed a step-by-step characterization that tracked molecular changes through infrared spectroscopy (IR) and surface development by contact angle (CA) through two different mixing methods: ultrasonic mixing and process simplification (Method A) and following literature-based parameters (Method B). Both methods, consisting of surface activation, 3-aminopropyltriethoxysilane (APTES) deposition, bromoisobutyryl bromide (BiBB) anchoring, and polymerization, were analyzed by varying parameters like concentration, temperature, and time. Results showed ultrasonication during surface activation enhanced siloxane (1139→1115 cm⁻¹) and amine (1531 cm⁻¹) group availability while reducing APTES concentration to 1 Vol% without drying sufficed for BiBB anchoring. BiBB exhibited insensitivity to concentration but benefited from premixing, evidenced by sharp C–Br (~1170 cm⁻¹) and methyl (3000–2800 cm⁻¹) bands. Additionally, it was observed that PAM-PBs improved with Method A, which had reduced variance in polymer fingerprint regions compared to Method B. Adding to the above, CA measurements gave complementary step-by-step information along the modifications of the surface, revealing distinct wettability behaviors between bulk PAM and synthesized PAM-PBs (from 51° to 37°). As such, this work identifies key parameter influence (e.g., mixing, BiBB concentration), simplifies steps (drying omission, lower APTES concentration), and demonstrates a step-by-step, systematic parameter decoupling that reduces variability. In essence, this detailed parameter analysis addresses the PAM-PBs synthesis process with better reproducibility than the previously reported synthesis method and achieves the identification of characteristic behaviors across the step-by-step process without the imperative need for higher-cost characterizations. Full article

(This article belongs to the Special Issue State-of-the-Art Polymer Science and Technology in Mexico)

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19 pages, 1174 KiB

Open AccessArticle

Computational Study of Catalytic Poisoning Mechanisms in Polypropylene Polymerization: The Impact of Dimethylamine and Diethylamine on the Deactivation of Ziegler–Natta Catalysts and Co-Catalysts

by Joaquín Alejandro Hernández Fernández, Katherine Liset Ortiz Paternina and Heidis Cano-Cuadro

Polymers 2025, 17(13), 1834; https://doi.org/10.3390/polym17131834 - 30 Jun 2025

Abstract

In this study, density functional theory (DFT) was used to analyze the processes that govern the interactions among triethylaluminum (TEAL), the Ziegler–Natta (ZN) catalyst, and the inhibitory compounds dimethylamine (DMA) and diethylamine (DEA) during olefin polymerization. The structural and charge characteristics of these [...] Read more.

In this study, density functional theory (DFT) was used to analyze the processes that govern the interactions among triethylaluminum (TEAL), the Ziegler–Natta (ZN) catalyst, and the inhibitory compounds dimethylamine (DMA) and diethylamine (DEA) during olefin polymerization. The structural and charge characteristics of these inhibitors were examined through steric maps and DFT calculations. Combined DFT calculations (D3-B3LYP/6-311++G(d,p)) and IR spectroscopic analysis show that the most efficient way to deactivate the ZN catalyst is via the initial formation of the TEAL·DMA complex. This step has a kinetic barrier of only 27 kcal mol⁻¹ and a negative ΔG, in stark contrast to the >120 kcal mol⁻¹ required to form TEAL·DEA. Once generated, TEAL·DMA adsorbs onto the TiCl₄/MgCl₂ cluster with adsorption energies of −22.9 kcal mol⁻¹ in the gas phase and −25.4 kcal mol⁻¹ in n-hexane (SMD model), values 5–10 kcal mol⁻¹ more favorable than those for TEAL·DEA. This explains why, although dimethylamine is present at only 140 ppm, its impact on productivity (−19.6%) is practically identical to that produced by 170 ppm of diethylamine (−20%). The persistence of the ν(Al–N) band at ~615 cm⁻¹, along with a >30% decrease in the Al–C/Ti–C bands between 500 and 900 cm⁻¹, the downward shift of the N–H stretch from ~3300 to 3200 cm⁻¹, and the +15 cm⁻¹ increase in ν(C–N) confirm Al←N coordination and blockage of alkyl transfer, establishing the TEAL·DMA → ZN pathway as the dominant catalytic poisoning mechanism. Full article

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

18 pages, 3268 KiB

Open AccessArticle

Transfer Learning-Enhanced Prediction of Glass Transition Temperature in Bismaleimide-Based Polyimides

by Ziqi Wang, Yu Liu, Xintong Xu, Jiale Zhang, Zhen Li, Lei Zheng and Peng Kang

Polymers 2025, 17(13), 1833; https://doi.org/10.3390/polym17131833 - 30 Jun 2025

Abstract

The glass transition temperature (T_g) was a pivotal parameter governing the thermal and mechanical properties of bismaleimide-based polyimide (BMI) resins. However, limited experimental data for BMI systems posed significant challenges for predictive modeling. To address this gap, this study introduced a [...] Read more.

The glass transition temperature (T_g) was a pivotal parameter governing the thermal and mechanical properties of bismaleimide-based polyimide (BMI) resins. However, limited experimental data for BMI systems posed significant challenges for predictive modeling. To address this gap, this study introduced a hybrid modeling framework leveraging transfer learning. Specifically, a multilayer perceptron (MLP) deep neural network was pre-trained on a large-scale polymer database and subsequently fine-tuned on a small-sample BMI dataset. Complementing this approach, six interpretable machine learning algorithms—random forest, ridge regression, k-nearest neighbors, Bayesian regression, support vector regression, and extreme gradient boosting—were employed to construct transparent predictive models. SHapley Additive exPlanations (SHAP) analysis was further utilized to quantify the relative contributions of molecular descriptors to T_g. Results demonstrated that the transfer learning strategy achieved superior predictive accuracy in data-scarce scenarios compared to direct training on the BMI dataset. SHAP analysis identified charge distribution inhomogeneity, molecular topology, and molecular surface area properties as the major influences on T_g. This integrated framework not only improved the prediction performance but also provided feasible insights into molecular structure design, laying a solid foundation for the rational engineering of high-performance BMI resins. Full article

(This article belongs to the Section Artificial Intelligence in Polymer Science)

34 pages, 5490 KiB

Open AccessArticle

Effectiveness of Acidic Chitosan Solutions for Total Organic Carbon Removal in Drinking Water Treatment

by Josefine Molina-Pinna and Félix R. Román-Velázquez

Polymers 2025, 17(13), 1832; https://doi.org/10.3390/polym17131832 - 30 Jun 2025

Abstract

Natural organic matter (NOM) in surface waters is a major challenge for drinking water treatment due to its role in the formation of disinfection byproducts (DBPs) during chlorination. This study evaluated the performance of chitosan, a biodegradable coagulant, dissolved in acetic, lactic, and [...] Read more.

Natural organic matter (NOM) in surface waters is a major challenge for drinking water treatment due to its role in the formation of disinfection byproducts (DBPs) during chlorination. This study evaluated the performance of chitosan, a biodegradable coagulant, dissolved in acetic, lactic, and L-ascorbic acids for NOM removal under three turbidity levels (403, 1220, and 5038 NTU). Jar tests were conducted using raw water from the Río Grande de Añasco (Puerto Rico), and TOC, DOC, and UV₂₅₄ were measured at multiple time points. TOC removal ranged from 39.8% to 74.3%, with the highest performance observed in high-turbidity water treated with chitosan–L-ascorbic acid. DOC and UV₂₅₄ reductions followed similar trends, with maximum removals of 76.4% and 76.2%, respectively. Estimated THM formation potential (THMFP) was reduced by up to 81.6%. Across all acids, flocculation efficiencies exceeded 95%. Compared to conventional aluminum-based coagulants, chitosan demonstrated comparable performance, while offering environmental benefits. These results confirm the potential of chitosan–acid systems for effective organic matter removal and DBP control, supporting their application as sustainable alternatives in drinking water treatment. Full article

(This article belongs to the Special Issue Recent Advances in Chitosan-Based Materials: Characterization and Applications)

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32 pages, 2072 KiB

Open AccessArticle

Near-Infrared and Sono-Enhanced Photodynamic Therapy of Prostate Cancer Cells Using Phyto-Second Harmonic Generation Nanoconjugates

by Efrat Hochma, Michael A. Firer and Refael Minnes

Polymers 2025, 17(13), 1831; https://doi.org/10.3390/polym17131831 - 30 Jun 2025

Abstract

This study investigates near‑infrared (NIR)-induced, Phyto-enhanced, second harmonic generation-mediated photodynamic therapy (Phyto-SHG-PDT) using barium titanate (BT)/rhein/polyethylene glycol 100 (PEG100) and BT/Yemenite “Etrog” leaf extract/PEG100 nanoconjugates. We compare continuous-wave (CW), multi-line Argon-ion laser illumination in the NIR range with high-peak-power femtosecond (fs) 800 nm [...] Read more.

This study investigates near‑infrared (NIR)-induced, Phyto-enhanced, second harmonic generation-mediated photodynamic therapy (Phyto-SHG-PDT) using barium titanate (BT)/rhein/polyethylene glycol 100 (PEG100) and BT/Yemenite “Etrog” leaf extract/PEG100 nanoconjugates. We compare continuous-wave (CW), multi-line Argon-ion laser illumination in the NIR range with high-peak-power femtosecond (fs) 800 nm pulses. Under CW NIR light, BT/rhein nanoconjugates reduced PC3 prostate cancer cell viability by 18% versus non‑irradiated controls (p < 0.05), while BT/extract nanoconjugates exhibited 15% dark toxicity. The observed SHG signal matched theoretical predictions and previous CW laser studies. Reactive Oxygen Species (ROS) scavenger 1,3-diphenyl-isobenzofuran (DPBF) showed reduced absorbance at 410 nm upon NIR illumination, indirectly supporting SHG emission at 400 nm from nanoconjugates. Under fs-pulsed laser exposure, pronounced two-photon absorption (TPA) and SHG effects were observed in both nanoconjugate types. Our results demonstrate the effectiveness of BT/rhein nanoconjugates under both laser conditions, while the BT/extract nanoconjugates benefited from high-power pulsed excitation. These results highlight the potential of BT-based Phyto-SHG-PDT nanoconjugates for NIR and blue light applications, leveraging nonlinear optical effects for advanced photochemical cancer therapies. Full article

(This article belongs to the Special Issue Functional and Biocompatible Nanostructured Polymer Scaffolds for Therapeutic Applications)

24 pages, 3504 KiB

Open AccessArticle

Polymethyl Methacrylate-like Photopolymer Resin with Titanium Metal Nanoparticles Is a Promising Material for Biomedical Applications

by Dmitriy E. Burmistrov, Dmitriy A. Serov, Ilya V. Baimler, Ann V. Gritsaeva, Pavel Chapala, Aleksandr V. Simakin, Maxim E. Astashev, Ekaterina E. Karmanova, Mikhail V. Dubinin, Guliya R. Nizameeva, Shamil Z. Validov, Fatikh M. Yanbaev, Oleg G. Synyashin and Sergey V. Gudkov

Polymers 2025, 17(13), 1830; https://doi.org/10.3390/polym17131830 - 30 Jun 2025

Abstract

New materials for additive manufacturing are currently being actively studied, which both have the necessary physicochemical properties and are safe for the environment and living organisms. We have proposed a simple process for the production of composite materials based on a transparent polymethyl [...] Read more.

New materials for additive manufacturing are currently being actively studied, which both have the necessary physicochemical properties and are safe for the environment and living organisms. We have proposed a simple process for the production of composite materials based on a transparent polymethyl methacrylate-like photopolymer resin modified with metallic titanium nanoparticles. Standardized plate samples were printed from the obtained modified photopolymer resins using mask stereolithography with an LED light source array (MSLA), and their mechanical properties were evaluated. Plates were also printed, for which the surface topology, distribution of nanoparticles in the polymer matrix, chemical structure, optical properties, chemical structure, and optical properties were characterized. In the context of the impact on biological systems, the ability of materials to enhance the formation of ROS and affect the main biomacromolecules was demonstrated. At the same time, the developed composite materials inhibit the growth of E. coli bacterial cells, and the bactericidal effect of the surfaces of the obtained materials was shown. Despite the significant antibacterial properties of the synthesized materials, no negative impact on the growth and development of adhesive cultures of eukaryotic cells in vitro was detected. Full article

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

22 pages, 3160 KiB

Open AccessArticle

Assessing Flight Angle and Rotor Speed Effects on Drying Efficiency and Power Consumption of the Centrifugal Dryer of Pelletizing Systems

by Mohammadreza Aali, Bernhard Löw-Baselli, Jovan Zecevic and Gerald Berger-Weber

Polymers 2025, 17(13), 1829; https://doi.org/10.3390/polym17131829 - 30 Jun 2025

Abstract

This study used the Discrete Element Method (DEM) coupled with the Moving Particle Semi-implicit (MPS) method to investigate the process of drying in the centrifugal unit of a pelletizing system in polymer processing. The effects of various flight angles (10°, 45°, and 70°) [...] Read more.

This study used the Discrete Element Method (DEM) coupled with the Moving Particle Semi-implicit (MPS) method to investigate the process of drying in the centrifugal unit of a pelletizing system in polymer processing. The effects of various flight angles (10°, 45°, and 70°) and rotor speeds (1280, 1600, and 1920 rpm) on drying efficiency, polymer pellet transport, polymer pellet accumulation, and power consumption were examined. The results showed that the flight angle significantly influenced drying performance. At 1600 rpm, the 10° flight angle configuration required the least power (10.94 kW) but resulted in inefficient water separation, which led to an increase in water droplets (i.e., higher moisture content) in the upper part of the centrifugal unit and near the outlet. With a 70° flight angle, water removal was most effective, but polymer pellet transport efficiency was lower due to centrifugal forces becoming dominant. A 45° flight angle provided the best balance between drying efficiency and power consumption, requiring 16.42 kW while achieving the most efficient polymer pellet transport. Rotor speed also played a crucial role: lower speeds enhanced water removal and reduced power demand but limited throughput, whereas higher speeds facilitated centrifugal separation at the cost of increased power consumption. The optimal combination of the rotor speed and flight angle was found to be 45° at 1280 rpm, which offered an effective trade-off between drying performance and power efficiency. Full article

(This article belongs to the Special Issue New Progress of Polymeric Materials in Advanced Manufacturing, 2nd Edition)

30 pages, 3996 KiB

Open AccessArticle

Investigating the Impact of Seasonal Input Stream Fluctuations on Post-Consumer High-Density Polyethylene Composition and Processing

by Pia Fischer, Elena Berg, Christian Hopmann and Rainer Dahlmann

Polymers 2025, 17(13), 1828; https://doi.org/10.3390/polym17131828 - 30 Jun 2025

Abstract

The recycling of plastics collected from household waste to produce post-consumer recycled (PCR) materials is a critical step of sustainable waste management. However, the processing of PCR materials presents unique challenges, particularly in the context of seasonal input stream fluctuations and resulting PCR [...] Read more.

The recycling of plastics collected from household waste to produce post-consumer recycled (PCR) materials is a critical step of sustainable waste management. However, the processing of PCR materials presents unique challenges, particularly in the context of seasonal input stream fluctuations and resulting PCR material composition variations. Within this paper, the influence of batch-to-batch fluctuations on the processing stability and product properties of high-density polyethylene (HDPE) PCR from the German municipal waste system is analysed. It examines how variations in batch composition affect key parameters such as processing data (injection pressure, torque), mechanical properties (tensile strength, E-modulus, impact strength), and product quality (gel formation, part dimensions, part weight). Therefore, six consecutive household HDPE PCR material batches are analysed regarding their composition, contaminations, and rheological characteristics through ashing, differential scanning calorimetry, high-temperature gel permeation chromatography, and high-pressure capillary rheometry. The batches are then processed using blown- and cast-film extrusion as well as injection moulding, and the resulting process stability and product quality are analysed. The results show a strong correlation between thermal properties, such as crystallisation enthalpy, molecular weight, polypropylene (PP) content, varying batch viscosities, and changes in processing data as well as the resulting product properties. Full article

(This article belongs to the Special Issue Polymers for Circular Packaging Materials)

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17 pages, 3303 KiB

Open AccessArticle

Research on High-Performance Underwater-Curing Polymer Composites for Offshore Oil Riser Pipes

by Xuan Zhao, Jun Wan, Xuefeng Qv, Yajun Yu and Huiyan Zhao

Polymers 2025, 17(13), 1827; https://doi.org/10.3390/polym17131827 - 30 Jun 2025

Abstract

In offshore oil and gas extraction, riser pipes serve as the first isolation barrier for wellbore integrity, playing a crucial role in ensuring operational safety. Protective coatings represent an effective measure for corrosion prevention in riser pipes. To address issues such as electrochemical [...] Read more.

In offshore oil and gas extraction, riser pipes serve as the first isolation barrier for wellbore integrity, playing a crucial role in ensuring operational safety. Protective coatings represent an effective measure for corrosion prevention in riser pipes. To address issues such as electrochemical corrosion and poor adhesion of existing coatings, this study developed an underwater-curing composite material based on a polyisobutylene (PIB) and butyl rubber (IIR) blend system. The material simultaneously exhibits high peel strength, low water absorption, and stability across a wide temperature range. First, the contradiction between material elasticity and strength was overcome through the synergistic effect of medium molecular weight PIB internal plasticization and IIR crosslinking networks. Second, stable peel strength across a wide temperature range (−45 °C to 80 °C) was achieved by utilizing the interfacial effects of nano-fillers. Subsequently, an innovative solvent-free two-component epoxy system was developed, combining medium molecular weight PIB internal plasticization, nano-silica hydrogen bond reinforcement, and latent curing agent regulation. This system achieves rapid surface drying within 30 min underwater and pull-off strength exceeding 3.5 MPa. Through systematic laboratory testing and field application experiments on offshore oil and gas well risers, the material’s fundamental properties and operational performance were determined. Results indicate that the material exhibits a peel strength of 5 N/cm on offshore oil risers, significantly extending the service life of the riser pipes. This research provides theoretical foundation and technical support for improving the efficiency and reliability of repair processes for offshore oil riser pipes. Full article

(This article belongs to the Special Issue Advances in Functional Polymers and Composites: 2nd Edition)

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