Polymers

16 pages, 856 KiB

Open AccessArticle

Study on Differences in Structure and Anti-Inflammatory Activity of Polysaccharides in Five Species of Dendrobium

by Hua Zhu, Hui-Wen Zhang, Jia-Hao Fan, Si-Si Jia, Xin Yi, Zi-Wei Han, Ren-Lei Wang, Hong-Wei Qiu and Guang-Ping Lv

Polymers 2025, 17(9), 1164; https://doi.org/10.3390/polym17091164 - 24 Apr 2025

Abstract

Dendrobium is a famous edible and medicinal plants, and polysaccharides are their main bioactive components. Polysaccharides from five species, namely, DO (Dendrobium officinale Kimura et Migo), DH (Dendrobium huoshanense C. Z. Tang et S. J. Cheng), DNL (Dendrobium nobile Lindl.), [...] Read more.

Dendrobium is a famous edible and medicinal plants, and polysaccharides are their main bioactive components. Polysaccharides from five species, namely, DO (Dendrobium officinale Kimura et Migo), DH (Dendrobium huoshanense C. Z. Tang et S. J. Cheng), DNL (Dendrobium nobile Lindl.), DFH (Dendrobium fimbriatum Hook.), and DCL (Dendrobium chrysanthum Lindl.), were compared based on molecular weight (Mw), monosaccharide composition, and glycosidic bond types. The results showed that Dendrobium polysaccharides (DPs) contain relatively simple compositional monosaccharides and mainly consist of mannose (Man) and glucose (Glc), along with small amounts of arabinose (Ara), xylose (Xyl), and galactose (Gal). The Am/Ag (the ratio of Man to Glc) values in DO, DH, and DNL polysaccharides were 3.23, 3.81, and 3.88, while those in DFH and DCL were 0.45 and 0.81. DPs are mainly composed of →4)Manp(1→ and →4)Glcp(1→, but their molar ratios were different. →4)Manp(1→ and →4)Glcp(1→ ratios were 2.85, 2.92, 1.50, 1.45, and 1.05 in DO, DH, DNL, DFH, and DCL, respectively. Hierarchical cluster analysis (HCA) showed that there were significant differences in structural information, especially in glycosidic bond types and proportions. DH, DO, and DCL were clustered into different groups based on glycosidic bond types and proportions, respectively. Moreover, the five species of Dendrobium could significantly inhibit NO production and apoptosis induced by LPS in RAW 264.7, especially DH. The results of a correlation analysis of structure and anti-inflammatory activity showed that polysaccharides with a high →4)Manp(1→/→4)Glcp(1→ ratio and a molecular weight distribution between 3.343 × 10⁵ Da and 13.540 × 10⁵ Da had better anti-inflammatory activity. The results indicated that the quality evaluation of Dendrobium in clinical applications should investigate molecular weight and the composition of the glycoside bond types and proportions to ensure the consistency of curative effects. Full article

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

29 pages, 4161 KiB

Open AccessArticle

Three-Dimensional Bioprinted Gelatin—Genipin Hydrogels Enriched with hUCMSC-Derived Small Extracellular Vesicles for Regenerative Wound Dressings

by Manal Hussein Taghdi, Maimonah Eissa Al-Masawa, Barathan Muttiah, Mh Busra Fauzi, Jia Xian Law, Ani Amelia Zainuddin and Yogeswaran Lokanathan

Polymers 2025, 17(9), 1163; https://doi.org/10.3390/polym17091163 - 24 Apr 2025

Abstract

Mesenchymal stromal cell-derived small extracellular vesicles (MSC-sEVs) have shown great promise in promoting tissue repair, including skin wound healing, but challenges like rapid degradation and short retention have limited their clinical application. Hydrogels have emerged as effective carriers for sustained EV release. Three-dimensional [...] Read more.

Mesenchymal stromal cell-derived small extracellular vesicles (MSC-sEVs) have shown great promise in promoting tissue repair, including skin wound healing, but challenges like rapid degradation and short retention have limited their clinical application. Hydrogels have emerged as effective carriers for sustained EV release. Three-dimensional printing enables the development of personalized skin substitutes tailored to the wound size and shape. This study aimed to develop 3D bioprinted gelatin–genipin hydrogels incorporating human umbilical cord MSC-sEVs (hUCMSC-sEVs) for future skin wound healing applications. Gelatin hydrogels (8% and 10% w/v) were crosslinked with 0.3% genipin (GECL) to improve stability. The hydrogels were evaluated for their suitability for extrusion-based 3D bioprinting and physicochemical properties, such as the swelling ratio, hydrophilicity, enzymatic degradation, and water vapor transmission rate (WVTR). Chemical characterization was performed using EDX, XRD, and FTIR. The hUCMSC-sEVs were isolated via centrifugation and tangential flow filtration (TFF) and characterized. The crosslinked hydrogels were successfully 3D bioprinted and demonstrated superior properties, including high hydrophilicity, a swelling ratio of ~500%, slower degradation, and optimal WVTR. hUCMSC-sEVs, ranging from 50 to 200 nm, were positive for surface and cytosolic markers. Adding 75 μg/mL of hUCMSC-EVs into 10% GECL hydrogels significantly improved the biocompatibility. These hydrogels offer ideal properties for 3D bioprinting and wound healing, demonstrating their potential as biomaterial scaffolds for skin tissue regeneration applications. Full article

(This article belongs to the Special Issue Smart and Bio-Medical Polymers: 2nd Edition)

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17 pages, 2983 KiB

Open AccessArticle

A Green Method for Bacterial Cellulose Electrospinning Using 1-Butyl-3-Methylimidazolium Acetate and γ-Valerolactone

by Elona Vasili, Bahareh Azimi, Mahendra P. Raut, David A. Gregory, Andrea Mele, Boyang Liu, Katrin Römhild, Marcus Krieg, Frederik Claeyssens, Patrizia Cinelli, Ipsita Roy, Maurizia Seggiani and Serena Danti

Polymers 2025, 17(9), 1162; https://doi.org/10.3390/polym17091162 - 24 Apr 2025

Abstract

Bacterial cellulose (BC) is a highly pure and crystalline cellulose produced via bacterial fermentation. However, due to its chemical structure made of strong hydrogen bonds and its high molecular weight, BC can neither be melted nor dissolved by common solvents. Therefore, processing BC [...] Read more.

Bacterial cellulose (BC) is a highly pure and crystalline cellulose produced via bacterial fermentation. However, due to its chemical structure made of strong hydrogen bonds and its high molecular weight, BC can neither be melted nor dissolved by common solvents. Therefore, processing BC implies the use of very strong, often toxic and dangerous chemicals. In this study, we proved a green method to produce electrospun BC fibers by testing different ionic liquids (ILs), namely, 1-butyl-3-methylimidazolium acetate (BmimAc), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmimTFSI) and 1-ethyl-3-methylimidazolium dicyanamide (EmimDCA), either individually or as binary mixtures. Moreover, γ-valerolactone (GVL) was tested as a co-solvent derived from renewable sources to replace dimethyl sulfoxide (DMSO), aimed at making the viscosity of the cellulose solutions suitable for electrospinning. A BmimAc and BmimAc/EmimTFSI (1:1 w/w) mixture could dissolve BC up to 3 w%. GVL was successfully applied in combination with BmimAc as an alternative to DMSO. By optimizing the electrospinning parameters, meshes of continuous BC fibers, with average diameters ~0.5 μm, were produced, showing well-defined pore structures and higher water absorption capacity than pristine BC. The results demonstrated that BC could be dissolved and electrospun via a BmimAc/GVL solvent system, obtaining ultrafine fibers with defined morphology, thus suggesting possible greener methods for cellulose processing. Full article

(This article belongs to the Special Issue Polymer-Based Electrospun Fibers: Advancements, Applications, and Future Prospects)

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26 pages, 8732 KiB

Open AccessArticle

Impact of CuSn10 Powder on Mechanical Properties and Tribological Performance of Novel Basalt Fiber-Reinforced Hybrid Composites

by Corina Birleanu, Bere Paul, Razvan Udroiu, Mircea Cioaza and Marius Pustan

Polymers 2025, 17(9), 1161; https://doi.org/10.3390/polym17091161 - 24 Apr 2025

Abstract

Hybrid composite materials reinforced with both fibers and particulate fillers are increasingly used in engineering due to their favorable balance of mechanical strength, reduced weight, and enhanced tribological performance. This study investigated the effect of CuSn10 bronze powder additions (5%, 10%, and 15% [...] Read more.

Hybrid composite materials reinforced with both fibers and particulate fillers are increasingly used in engineering due to their favorable balance of mechanical strength, reduced weight, and enhanced tribological performance. This study investigated the effect of CuSn10 bronze powder additions (5%, 10%, and 15% by weight) on the mechanical and tribological properties of novel basalt fiber-reinforced polymer (BFRP) composites. The composites were fabricated via vacuum-assisted processing and tested under dry sliding conditions with varying loads (10, 20, and 30 N) and sliding speeds (0.1, 0.25, and 0.36 m/s). The results show that the optimal tensile strength (440.6 MPa) was achieved at 10 wt% CuSn10, while the best tribological performance was observed at 15 wt% CuSn10, under a 10 N load and 0.25 m/s sliding speed, where the coefficient of friction decreased by up to 38% and the specific wear rate was reduced by more than 50% compared to the unreinforced BFRP composite. These enhancements are attributed to the formation of a stable oxide-based tribolayer (CuO, SnO₂) and improved load transfer at the fiber–matrix interface. Statistical analysis (GLM) confirmed that CuSn10 content had the most significant influence on tribological parameters. The findings provide valuable insight into the design of high-performance hybrid composites for structural and tribological applications. Full article

(This article belongs to the Special Issue Fiber Reinforced Polymeric Composites)

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12 pages, 4996 KiB

Open AccessArticle

Fabrication of Poly(s-triazine-co-o-aminophenol) Conducting Polymer via Electropolymerization and Its Application in Aqueous Charge Storage

by Xueting Bai, Bo Lan, Xinyang Li, Xinlan Yi, Shaotong Pei and Chao Wang

Polymers 2025, 17(9), 1160; https://doi.org/10.3390/polym17091160 - 24 Apr 2025

Abstract

Designing conducting polymers with novel structures is essential for electrochemical energy storage devices. Here, copolymers of s-triazine and o-aminophenol are electropolymerized from an aqueous solution onto a carbon cloth substrate using the galvanostatic method. The poly(s-triazine-co-o-aminophenol) (PT-co-oAP) [...] Read more.

Designing conducting polymers with novel structures is essential for electrochemical energy storage devices. Here, copolymers of s-triazine and o-aminophenol are electropolymerized from an aqueous solution onto a carbon cloth substrate using the galvanostatic method. The poly(s-triazine-co-o-aminophenol) (PT-co-oAP) is characterized, and its charge storage properties are investigated in 1 M H₂SO₄ and in 1 M ZnSO₄. At 1 A g⁻¹, the specific capacities of PT-co-oAP reach 101.3 mAh g⁻¹ and 84.4 mAh g⁻¹ in 1 M H₂SO₄ and in 1 M ZnSO₄, respectively. The specific capacity of PT-co-oAP maintains 90.3% of its initial value after cycling at 10 A g⁻¹ for 2000 cycles in 1 M H₂SO₄. The high specific capacity achieved originates from abundant surface active sites, facile ion diffusion, with optimized active site structure achieved by forming copolymer. The charge storage mechanism involves the redox processes of amino/imino groups and hydroxyl/carbonyl groups in the copolymer, together with the insertion of cations. Two electrode devices using two PT-co-oAP and aqueous 1 M H₂SO₄ are assembled, and the maximum energy density reaches 63 Wh kg⁻¹ at 0.5 A g⁻¹ with a power density of 540 W kg⁻¹. The capacity retention of the device after 3000 cycles at 10 A g⁻¹ reaches 81.2%. Full article

(This article belongs to the Special Issue Polymer-Based Flexible Materials, 3rd Edition)

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14 pages, 1776 KiB

Open AccessArticle

Chestnut Tannin/Furfuryl Alcohol Copolymers for Beech Wood Chemical Modification

by João Vitor Dorini Falavinha, Philippe Gérardin, Pedro Henrique Gonzales De Cademartori and Christine Gérardin-Charbonnier

Polymers 2025, 17(9), 1159; https://doi.org/10.3390/polym17091159 - 24 Apr 2025

Abstract

Tannins, present in all plants, are the most abundant polyphenols in the world. Their potential as a raw material for modifying wood alongside furfuryl alcohol (FA) has already been demonstrated in previous studies. This study focused on using large quantities of hydrolysable tannins [...] Read more.

Tannins, present in all plants, are the most abundant polyphenols in the world. Their potential as a raw material for modifying wood alongside furfuryl alcohol (FA) has already been demonstrated in previous studies. This study focused on using large quantities of hydrolysable tannins from chestnut (Castanea sativa) to replace as much FA as possible to chemically modify beech wood (Fagus sylvatica L.). Impregnation was carried out using different concentrations and ratios of both FA and tannins and tartaric acid as catalysts through a vacuum/atmospheric pressure cycle. Copolymerization was carried out for 24 h at 120 °C. Properties such as weight percent gain (WPG), leachability, anti-swelling efficiency (ASE), thermal stability, wettability and durability against brown rot (Coniophora puteana) and white rot (Coriolus versicolor) were analyzed and compared to a furfurylation treatment without the addition of tannins. These treatments were also chemically characterized using FTIR spectroscopy. The results showed that replacing 50% of FA mass by tannins largely increased WPG and demonstrated similar leachability and dimensional stability to standard furfurylation. Above all, the new treatment showed to have better resistance to wood-degrading fungi, in addition to improved wettability and thermal stability. Full article

(This article belongs to the Special Issue State-of-the-Art Polymer Science and Technology in France: 2nd Edition)

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19 pages, 9330 KiB

Open AccessArticle

Preparation of Polypyrrole/Montmorillonite/Polypropylene Composite Membranes and Investigation of Their Adsorption Performance for Methyl Orange and Pb²⁺

by Baoxin Wang, Binbin Xu, Gaofeng Chen, Chaozhong Wang, Yang Liu, Yang Bai, Mengge Li and Longgui Peng

Polymers 2025, 17(9), 1158; https://doi.org/10.3390/polym17091158 - 24 Apr 2025

Abstract

This study investigates the efficient and recyclable use of polymer-based membrane materials in wastewater treatment, focusing on calcium-based montmorillonite (Ca-MMT), pyrrole (Py), and polypropylene (PP). Through sodium activation, organic modification, pyrrole intercalation, and in situ polymerization, polypyrrole/montmorillonite (PPy/MMT) was synthesized. A polypyrrole/montmorillonite/polypropylene composite [...] Read more.

This study investigates the efficient and recyclable use of polymer-based membrane materials in wastewater treatment, focusing on calcium-based montmorillonite (Ca-MMT), pyrrole (Py), and polypropylene (PP). Through sodium activation, organic modification, pyrrole intercalation, and in situ polymerization, polypyrrole/montmorillonite (PPy/MMT) was synthesized. A polypyrrole/montmorillonite/polypropylene composite membrane (PPy/MMT/PP) was then fabricated using melt compression and coating techniques for pollutant adsorption. The modification of montmorillonite by PPy was examined, alongside the morphology, composition, and structure of PPy/MMT/PP. The membrane’s adsorption performance for methyl orange and Pb²⁺ was evaluated, with a focus on cyclic adsorption. The results showed that PPy increased the interlayer spacing of montmorillonite from 1.23 nm to 1.74 nm and enhanced its specific surface area by 99.424 m²/g. The composite membrane exhibited improved wettability and adsorption capacity, achieving removal rates of 95.98% for methyl orange and 88.48% for Pb²⁺, following pseudo-second-order kinetics. The membrane demonstrated recyclability, maintaining efficient adsorption/desorption over three cycles. This work provides valuable insights and technical support for sustainable wastewater treatment using polymer-based membranes. Full article

(This article belongs to the Special Issue Functional Polymers and Novel Applications)

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18 pages, 11929 KiB

Open AccessArticle

Poly(3-hydroxybutyrate)/Clay/Essential Oils Bionanocomposites Incorporating Biochar: Thermo-Mechanical and Antioxidant Properties

by Karla A. Garrido-Miranda, María Eugenia Gonzalez, Jacobo Hernandez-Montelongo, Andrés Jaramillo, Angelo Oñate, César Burgos-Díaz and Miguel Manso-Silvan

Polymers 2025, 17(9), 1157; https://doi.org/10.3390/polym17091157 - 24 Apr 2025

Abstract

The use of biodegradable active materials is being explored as a strategy to reduce food loss and waste. The aim is to extend the shelf life of food and to ensure biodegradation when these materials are discarded. The utilization of biodegradable polymers remains [...] Read more.

The use of biodegradable active materials is being explored as a strategy to reduce food loss and waste. The aim is to extend the shelf life of food and to ensure biodegradation when these materials are discarded. The utilization of biodegradable polymers remains limited due to their inherent properties and cost-effectiveness. An alternative approach involves the fabrication of bionanocomposites, which offer a potential solution to address these challenges. Therefore, this study investigates the production of a polyhydroxybutyrate/biochar/clay/essential oil (Tepa:Eugenol) bionanocomposite with antioxidant and antimicrobial properties. The morphological, physicochemical, and antioxidant properties of the materials were evaluated in comparison to those of the original PHB. The materials obtained showed a porous surface with cavities, associated with the presence of biochar. It was also determined that it presented an intercalated–exfoliated morphology by XRD. Thermal properties showed minor improvements over those of PHB, indicating that the components did not substantially influence properties such as crystallization temperature, decomposition temperature, or degree of crystallinity; the melting temperature decreased up to 11%. In addition, the PHB/biochar_7/MMT-OM_3/EO_3 bionanocomposites showed a tendency toward hydrophobicity and the highest elastic modulus with respect to PHB. Finally, all essential-oil-loaded bionanocomposites exhibited excellent antioxidant properties against DPPH and ABTS radicals. The results highlight the potential of these bionanocomposites for the development of antioxidant active packaging. Full article

(This article belongs to the Special Issue Application and Characterization of Polymer Nanocomposite)

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16 pages, 5756 KiB

Open AccessArticle

High-Energy Milling as a Pre-Treatment Alternative for Lignocellulosic Fibers Derived from Brewer’s Spent Grain

by Erik Gomez-Hernandez, Ernesto Hernández-Hernández, Javier Castro-Rosas, Rosa A. Vázquez-García, Arturo Cadena-Ramírez, Brenda E. Jiménez-Villeda and Carlos A. Gomez-Aldapa

Polymers 2025, 17(9), 1156; https://doi.org/10.3390/polym17091156 - 24 Apr 2025

Abstract

The objective of this study was to evaluate how high-energy milling affects the structural, thermal, and morphological properties of brewer’s spent grain fibers over time. The researchers determined the chemical composition of the samples using TAPPI techniques, particle size analysis, Fourier-transform infrared spectroscopy [...] Read more.

The objective of this study was to evaluate how high-energy milling affects the structural, thermal, and morphological properties of brewer’s spent grain fibers over time. The researchers determined the chemical composition of the samples using TAPPI techniques, particle size analysis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The samples displayed distinct morphologies and particle sizes depending on the treatment duration. The sample treated for 120 min (T120) showed the smallest particle size (19.4 µm). FTIR spectra revealed that the mechanical treatment strongly disrupted the structure of hemicellulose. The thermal stability of the samples decreased because of the applied treatment. Mechanical milling also fully eliminated the crystalline structure of cellulose in the samples. These findings indicate that high-energy milling holds strong potential as a pre-treatment method for the valorization of lignocellulosic residues. Full article

(This article belongs to the Special Issue State-of-the-Art Cellulose and Renewable Materials)

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30 pages, 7964 KiB

Open AccessArticle

Fabrication and Performance of PVAc-Incorporated Porous Self-Standing Zeolite-Based Geopolymer Membranes for Lead (Pb(II)) Removal in Water Treatment

by Samar Amari, Mariam Darestani, Graeme Millar and Bob Boshrouyeh

Polymers 2025, 17(9), 1155; https://doi.org/10.3390/polym17091155 - 24 Apr 2025

Abstract

This study explores the fabrication, structural characteristics, and performance of an innovative porous geopolymer membrane made from waste natural zeolite powder for Pb(II) removal, with potential applications in wastewater treatment. A hybrid geopolymer membrane incorporating polyvinyl acetate (PVAc) (10, 20, and 30 wt.%) [...] Read more.

This study explores the fabrication, structural characteristics, and performance of an innovative porous geopolymer membrane made from waste natural zeolite powder for Pb(II) removal, with potential applications in wastewater treatment. A hybrid geopolymer membrane incorporating polyvinyl acetate (PVAc) (10, 20, and 30 wt.%) was synthesized and thermally treated at 300 °C to achieve a controlled porous architecture. Characterization techniques, including Fourier-transform infrared spectroscopy (FTIR), revealed the disappearance of characteristic C=O and C-H stretching bands (~1730 cm⁻¹ and ~2900 cm⁻¹, respectively), confirming the full degradation of PVAc. Thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) indicated a total mass loss of approximately 14.5% for the sample with PVAc 20 wt.%, corresponding to PVAc decomposition and water loss. Energy-dispersive spectroscopy (EDS) elemental mapping showed the absence of carbon residues post-annealing, further validating complete PVAc removal. X-ray diffraction (XRD) provided insight into the crystalline phases of the raw zeolite and geopolymer structure. Once PVAc removal was confirmed, the second phase of characterization assessed the membrane’s mechanical properties and filtration performance. The thermally treated membrane, with a thickness of 2.27 mm, exhibited enhanced mechanical properties, measured with a nano-indenter, showing a hardness of 1.8 GPa and an elastic modulus of 46.7 GPa, indicating improved structural integrity. Scanning electron microscopy (SEM) revealed a well-defined porous network. Filtration performance was evaluated using a laboratory-scale dead-end setup for Pb(II) removal. The optimal PVAc concentration was determined to be 20 wt.%, resulting in a permeation rate of 78.5 L/(m²·h) and an 87% rejection rate at an initial Pb(II) concentration of 50 ppm. With increasing Pb(II) concentrations, the flux rates declined across all membranes, while maximum rejection was achieved at 200 ppm. FTIR and EDS analyses confirmed Pb(II) adsorption onto the zeolite-based geopolymer matrix, with elemental mapping showing a uniform Pb(II) distribution across the membrane surface. The next step is to evaluate the membrane’s performance in a multi-cation water treatment environment, assessing the sorption kinetics and its selectivity and efficiency in removing various heavy metal contaminants from complex wastewater systems. Full article

(This article belongs to the Special Issue Innovative Polymers and Technology for Membrane Fabrication)

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18 pages, 8239 KiB

Open AccessArticle

Enhanced Mechanical Properties of 3D-Printed Glass Fibre-Reinforced Polyethylene Composites

by Jan Sezemský, Gregor Primc, Taťana Vacková, Zdeňka Jeníková, Miran Mozetič and Petr Špatenka

Polymers 2025, 17(9), 1154; https://doi.org/10.3390/polym17091154 - 24 Apr 2025

Abstract

Optimisation of the tensile strength of thermoplastic polymer-matrix composites remains a scientific as well as technological challenge for 3D printing technology due to the mass application of composite materials. Inadequate mechanical properties are due to the mismatch in the surface energies of the [...] Read more.

Optimisation of the tensile strength of thermoplastic polymer-matrix composites remains a scientific as well as technological challenge for 3D printing technology due to the mass application of composite materials. Inadequate mechanical properties are due to the mismatch in the surface energies of the polymer and fillers. In this study, an additively manufactured composite was 3D-printed and tested. The composite consisted of a linear low-density polyethylene matrix filled with glass fibres. Composite filaments were extruded from neat and plasma-treated polymer powders. Plasma was sustained in oxygen at 100 Pa by a pulsed microwave discharge, and 250 g of polymer powder of average diameter 150 µm was placed into a dish and stirred during the plasma treatment. The O-atom density at the position of the dish containing polymer powder was about 2 × 10²¹ m⁻³, and the treatment time was varied up to 30 min. A gradual improvement in the composites’ tensile and flexural strength was observed at the plasma treatment time up to about 10 min, and the mechanical properties remained unchanged with prolonged treatment time. The tensile strength of composites prepared from plasma-treated polymer increased by one-third compared to those based on untreated powder. However, reinforcing the modified polyethylene with plasma-treated glass fibres did not result in further significant mechanical improvement compared to untreated fibres. In contrast, strength values doubled using glass fibres with silane sizing in combination with plasma-modified matrix. The results were explained by the increased surface energy of the polymer powder due to functionalisation with polar functional groups during plasma treatment. Full article

(This article belongs to the Section Polymer Chemistry)

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17 pages, 5072 KiB

Open AccessArticle

Numerical Simulations for Damage and Failure of a Polymer Material Subjected to Thermal Fatigue Loading

by Jun Koyanagi, Takumu Sugiyama, M. J. Mohammad Fikry, Yutong Li and Takuhei Tsukada

Polymers 2025, 17(9), 1153; https://doi.org/10.3390/polym17091153 - 23 Apr 2025

Abstract

This study proposes a novel numerical approach to simulate damage accumulation and failure in polymer materials under thermal fatigue, using an entropy-based damage criterion. Unlike the many experimental studies in this area, few numerical simulations exist due to the complexity of modeling thermal [...] Read more.

This study proposes a novel numerical approach to simulate damage accumulation and failure in polymer materials under thermal fatigue, using an entropy-based damage criterion. Unlike the many experimental studies in this area, few numerical simulations exist due to the complexity of modeling thermal fatigue. In our method, thermal and mechanical stresses arising from thermal expansion mismatches and temperature gradients are modeled through a coupled simulation approach. A viscoelastic constitutive equation is implemented in ABAQUS via a user-defined subroutine to capture damage progression. The method includes surface and internal thermal conduction, thermal deformation, and time–temperature superposition using reduced viscosity, enabling accurate simulation under varying thermal conditions. The results show that localized thermal stresses induced by temperature gradients lead to progressive damage and failure. This study demonstrates the first successful numerical simulation of thermal fatigue-induced damage in polymer materials. The proposed framework reduces the need for extensive experiments and offers insights into residual stress prediction and durability evaluation, contributing to polymer design and application in high-performance environments. Full article

(This article belongs to the Special Issue Mechanical and Dynamic Characteristics of Polymers and Polymer Composites)

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19 pages, 6702 KiB

Open AccessArticle

Synthesis and Electrochromic Properties of Triphenylamine-Based Aromatic Poly(amide-imide)s

by Sheng-Huei Hsiao and Zong-De Ni

Polymers 2025, 17(9), 1152; https://doi.org/10.3390/polym17091152 - 23 Apr 2025

Abstract

Three new amide-preformed triphenylamine-diamine monomers, namely 4,4′-bis(p-aminobenzamido)triphenylamine (4), 4,4′-bis(p-aminobenzamido)-4″-methoxytriphenylamine (MeO-4), and 4,4′-bis(p-aminobenzamido)-4″-tert-butyltriphenylamine (t-Bu-4), were synthesized and subsequently used to produce three series of electroactive aromatic poly(amide-imide)s (PAIs) via [...] Read more.

Three new amide-preformed triphenylamine-diamine monomers, namely 4,4′-bis(p-aminobenzamido)triphenylamine (4), 4,4′-bis(p-aminobenzamido)-4″-methoxytriphenylamine (MeO-4), and 4,4′-bis(p-aminobenzamido)-4″-tert-butyltriphenylamine (t-Bu-4), were synthesized and subsequently used to produce three series of electroactive aromatic poly(amide-imide)s (PAIs) via two-step polycondensation reactions with commercially available tetracarboxylic dianhydrides. Strong and flexible PAI films could be obtained by solution casting of the poly(amic acid) films followed by thermal imidization or direct solution casting from the organosoluble PAI samples. The PAIs had high glass-transition temperatures of 296–355 °C and showed no significant decomposition below 500 °C. The PAIs based on diamines MeO-4 and t-Bu-4 showed high electrochemical redox stability and strong color changes upon oxidation. For the PAIs derived from diamine 4, the TPA radical cation formed in situ during the electro-oxidative process could dimerize to a tetraphenylbenzidine structure, resulting in an additional oxidation state and color change. These PAIs exhibited increased solubility, lowered oxidation potentials, and enhanced redox stability compared to their polyimide analogs. Full article

(This article belongs to the Section Polymer Chemistry)

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20 pages, 2492 KiB

Open AccessReview

Advances in PBT Binder and Its Application in Propellants

by Ning Zhang, Xifei Gao, Yunjun Luo, Weihai Zhang, Yanping Xin, Kai Zhang, Chen Xue, Han Zhang, Jiao Wei and Hui Wang

Polymers 2025, 17(9), 1151; https://doi.org/10.3390/polym17091151 - 23 Apr 2025

Abstract

3,3-Bis (azide methyl) oxy-butyl ring (BAMO)-tetrahydrofuran (THF) copolyethers (PBT) are some of the most promising energetic binders. In this paper, the methods of synthesis of PBT binders are reviewed, and the research progress in PBT binders and PBT-based solid propellants in terms of [...] Read more.

3,3-Bis (azide methyl) oxy-butyl ring (BAMO)-tetrahydrofuran (THF) copolyethers (PBT) are some of the most promising energetic binders. In this paper, the methods of synthesis of PBT binders are reviewed, and the research progress in PBT binders and PBT-based solid propellants in terms of their thermal and combustion behavior, curing and rheology properties, energy and aging properties, and mechanical and safety performances are systematically summarized. The problems and shortcomings of PBT binders in the application of solid propellants and their thriving trends are pointed out, providing support for speeding up the practical application of PBT binders in high-energy solid propellants. Full article

(This article belongs to the Special Issue Eco-Friendly Polymeric Coatings and Adhesive Technology, 2nd Edition)

26 pages, 10757 KiB

Open AccessArticle

Enhancing Wear Resistance and Adhesion of Primer Coatings on Laser-Textured Milled Carbon Fiber-Filled Basalt Composites

by Özer Coşkun, Sinan Fidan, Mehmet İskender Özsoy, Mustafa Özgür Bora, Satılmış Ürgün, Alp Eren Şahin and Taner Yılmaz

Polymers 2025, 17(9), 1150; https://doi.org/10.3390/polym17091150 - 23 Apr 2025

Abstract

The present study explores the effects of pre-coating on the wear performance of milled carbon fiber-filled basalt composites via laser texturing. Laser texturing was used to change surface topography, enhancing adhesion and wear resistance. Incorporated 0 wt.% and 5 wt.% milled carbon fibers [...] Read more.

The present study explores the effects of pre-coating on the wear performance of milled carbon fiber-filled basalt composites via laser texturing. Laser texturing was used to change surface topography, enhancing adhesion and wear resistance. Incorporated 0 wt.% and 5 wt.% milled carbon fibers in an epoxy matrix. A fiber laser system was employed for surface treatment, in which power, scanning speed, and pulse frequency were optimized. For pre-coating, an epoxy-based primer was used, and the adhesion and wear performance of the coating was studied using ball-on-disc wear tests. Experimental results demonstrate that laser texturing significantly increases coating adhesion by enhancing the surface roughness and mechanical interlocking. The laser-induced textures displayed mostly square-shaped dimples, reducing practically by around 22% the deformation of the primer coating when used in combination with 5 wt.% carbon fiber milling. The textured surfaces reduced friction noticeably, leading to a decrease of as much as 23% in the coefficient of friction from untreated surfaces. SEM and 3D profilometry analysis indicate that the lower delamination observed in the laser treatment led to optimal coating retention. The original contribution of this work consists of the unique integration of laser surface engineering with pre-coating treatments toward improved tribological performance. Full article

(This article belongs to the Special Issue Synthesis, Design, Preparation and Processing of Functional Polymer Composites)

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20 pages, 6847 KiB

Open AccessArticle

Thermodynamic and Technological Compatibility of Polyvinyl Chloride, Thermoplastic Polyurethane, and Bio-Plasticizer Blends

by Yitbarek Firew Minale, Ivan Gajdoš, Pavol Štefčák, Ľudmila Dulebová, Tomasz Jachowicz, Tamás Szabó, Andrea Ádámné Major and Kálmán Marossy

Polymers 2025, 17(9), 1149; https://doi.org/10.3390/polym17091149 - 23 Apr 2025

Abstract

Polymer blending enhances material properties by combining different polymers, which requires careful consideration of both thermodynamic and technological compatibility. This study investigates the compatibility of polyvinyl chloride (PVC), thermoplastic polyurethane (TPU), and a bio-plasticizer in blends produced via roll milling at various mixing [...] Read more.

Polymer blending enhances material properties by combining different polymers, which requires careful consideration of both thermodynamic and technological compatibility. This study investigates the compatibility of polyvinyl chloride (PVC), thermoplastic polyurethane (TPU), and a bio-plasticizer in blends produced via roll milling at various mixing ratios. Compatibility and morphology were analyzed using thermally stimulated discharge (TSD), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM), while mechanical and thermal properties were assessed by mechanical testing and thermogravimetric analysis (TGA). The PVC/TPU (100/30) blend exhibited superior phase compatibility over PVC/TPU (100/50), as indicated by a single relaxation peak in TSD and DMA, along with a more homogeneous morphology and enhanced tensile properties. The PVC/TPU/bio-plasticizer (100/20/50) blend showed a well-balanced mechanical performance and improved phase homogeneity. The TSD peak maxima trends for the TPU/bio-plasticizer blend highlighted the bio-plasticizer’s dual role in enhancing flexibility at low concentrations while restricting molecular mobility at higher concentrations. TGA revealed TPU’s positive effect on PVC’s degradation profile, while the bio-plasticizer reduced thermal stability. These findings demonstrate that blending PVC, TPU, and bio-plasticizer creates compatible materials with enhanced and diverse properties, making them suitable for industrial applications. Full article

(This article belongs to the Special Issue Synthesis, Processing, Structure and Properties of Polymer Materials: 3rd Edition)

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17 pages, 7141 KiB

Open AccessArticle

Nano-Hydroxyapatite/Poly(methyl methacrylate) Composite Bone Scaffold: Surfactant Surface Effects

by Muhammed Enes Oruc, Nilüfer Evcimen Duygulu, Betul Onder, Aslihan Yelkenci, Cem Bülent Ustündag and Fatih Ciftci

Polymers 2025, 17(9), 1148; https://doi.org/10.3390/polym17091148 - 23 Apr 2025

Abstract

In this study, poly(methyl methacrylate) (PMMA) nanofiber scaffolds reinforced with synthesized nano-hydroxyapatite (n-HA) were fabricated through electrospinning to enhance their potential for applications in bone tissue engineering. Sodium tripolyphosphate (STTP) was utilized as a surfactant to achieve a uniform distribution of particles and [...] Read more.

In this study, poly(methyl methacrylate) (PMMA) nanofiber scaffolds reinforced with synthesized nano-hydroxyapatite (n-HA) were fabricated through electrospinning to enhance their potential for applications in bone tissue engineering. Sodium tripolyphosphate (STTP) was utilized as a surfactant to achieve a uniform distribution of particles and improve the structural integrity of the scaffolds. PMMA solutions were prepared at concentrations of the addition of STTP effectively stabilized n-HA dispersion, leading to enhanced fiber morphology, as confirmed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). The PMMA_10_HA_S nanofibers demonstrated a homogeneous fiber distribution with an average diameter of 345.40 ± 53.55 nm and a calcium content of 7.1%. Mechanical testing revealed that adding STTP enhanced the mechanical properties, with the n-HA-reinforced 10 wt.% PMMA nanofibers achieving a maximum tensile stress of 4.16 ± 2.13 MPa and an elongation of 7.1 ± 1.95%. Furthermore, cell cytotoxicity assays of different concentrations (25, 50, 75, and 100 mg/mL) using L929 fibroblast cells demonstrated no cytotoxic effect of PMMA_10_HA_S nanofibers. These findings, reinforced by STTP and n-HA, highlight the potential of PMMA_10_HA_S nanofiber scaffolds as promising candidates for bone tissue applications. Full article

(This article belongs to the Special Issue Advancements in the Development of Polymer Composites: Design, Fabrication, Properties and Application)

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17 pages, 5855 KiB

Open AccessArticle

Research on Passivation Simulation of Plasticizer N-Butylnitroxyethylnitramine (BuNENA) in Hydroxy-Terminated Polyether (HTPE) Propellants

by Zhiming Guo, Riccardo Rossi, Rui Deng, Yuheng Wu, Hanwen Liu, Lin Hao and Xiaolong Fu

Polymers 2025, 17(9), 1147; https://doi.org/10.3390/polym17091147 - 23 Apr 2025

Abstract

N-butylnitroxyethylnitramine (BuNENA) is a high-energy plasticizer with high plasticizing ability, low sensitivity, and high energy. It has broad application prospects in HTPE propellants. Nevertheless, as an energetic plasticizer, it requires treatment to reduce its sensitivity. To this end, the passivation process for BuNENA [...] Read more.

N-butylnitroxyethylnitramine (BuNENA) is a high-energy plasticizer with high plasticizing ability, low sensitivity, and high energy. It has broad application prospects in HTPE propellants. Nevertheless, as an energetic plasticizer, it requires treatment to reduce its sensitivity. To this end, the passivation process for BuNENA was simulated using a mixing model analogous to nucleate boiling. This method involves tracking the formation and movement of bubbles using a Lagrange frame, and the bubbles themselves are modeled as rigid spheres subject to buoyancy and viscous forces. A variational multiscale (VMS)-based Euler framework was employed to simulate the fluid surrounding the bubble. The movement process of the bubbles was analyzed, and it was found that the amount of bubbles and the movement speed were higher at high temperatures and in a high vacuum, and the passivation effect on BuNENA was better. At a pressure of 40 mbar and a temperature of 50 °C, BuNENA demonstrated an 89% water removal rate. A comparison of the experimental results with the simulation results revealed slight discrepancies between them. A meticulous analysis of the passivation process for BuNENA is rendered possible by integrating experimental and simulation methodologies, a feat that has immense implications for the realm of composite solid propellant passivation. Full article

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

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20 pages, 14435 KiB

Open AccessArticle

Qualification of the Vitrimeric Matrices in Industrial-Scale Wet Filament Winding Processes for Type-4 Pressure Vessels

by Jonathan Alms, Anna Katharina Sambale, Jannick Fuchs, Niklas Lorenz, Nina von den Berg, Tobias Conen, Hakan Çelik, Rainer Dahlmann, Christian Hopmann and Markus Stommel

Polymers 2025, 17(9), 1146; https://doi.org/10.3390/polym17091146 - 23 Apr 2025

Abstract

The production of fibre-reinforced composites for use in applications such as type-4 pressure vessels for hydrogen storage is achieved through the use of a thermoset matrix. However, the recycling of thermosets presents a significant challenge due to the lack of established recycling methods. [...] Read more.

The production of fibre-reinforced composites for use in applications such as type-4 pressure vessels for hydrogen storage is achieved through the use of a thermoset matrix. However, the recycling of thermosets presents a significant challenge due to the lack of established recycling methods. Epoxy-based vitrimers show thermoset characteristics during the manufacturing and utilisation phases but exhibit thermoplastic behaviour at elevated temperatures of 190 °C. This study investigates the industrial-scale production of carbon fibre reinforced vitrimers via a wet filament winding, as exemplified by a type-4 pressure vessel demonstrator. Processing conditions of industrial processes have yet to be applied to vitrimers; therefore, two vitrimer formulations are compared to a conventional epoxy thermoset. The processability and resulting composite quality of wound composites using these materials as matrices are compared. The mechanical properties of the composites are compared using an interlaminar shear strength test, demonstrating that the vitrimeric matrices exhibit 19.8% (23 °C) and 49.2% (140 °C) improved interlaminar strength. Consequently, the epoxy-based vitrimers investigated in this study can be employed as a direct replacement for the thermoset matrix in industrial-scale applications, with the potential for recycling the composite. To increase composite qualities, the winding process must be adapted for vitrimers, since a pore free composite could not be achieved. Full article

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

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17 pages, 4730 KiB

Open AccessArticle

Enhancement of Partial Nitrification–Anaerobic Ammonia Oxidation in SBR Reactors via Surface-Modified Polyurethane Sponge Biofilm Carrier

by Zexiang Liu, Zhihong Xu, Kelin Li, Li Xie, Biao Han, Qiming Wang, Hainong Song and Jian Zhang

Polymers 2025, 17(9), 1145; https://doi.org/10.3390/polym17091145 - 23 Apr 2025

Abstract

The partial nitrification–anammox process offers a cost-effective, energy-efficient, and environmentally sustainable approach for nitrogen removal in wastewater treatment. However, its application under low ammonia nitrogen conditions faces operational challenges including prolonged start-up periods and excessive nitrite oxidation. This study employed a strategy combining [...] Read more.

The partial nitrification–anammox process offers a cost-effective, energy-efficient, and environmentally sustainable approach for nitrogen removal in wastewater treatment. However, its application under low ammonia nitrogen conditions faces operational challenges including prolonged start-up periods and excessive nitrite oxidation. This study employed a strategy combining polyurethane surface positive charge enhancement and zeolite loading to develop a carrier capable of microbial enrichment and inhibition of nitrate generation, aiming to initiate the partial nitrification-anammox process in a sequencing batch reactor. Operational results demonstrate that the modified carrier enabled the reactor to achieve a total nitrogen removal efficiency of 78%, with the effluent nitrate nitrogen reduced to 6.03 mg-N/L, successfully initiating the partial nitrification-anammox process. The modified carrier also exhibited accelerated biofilm proliferation (both suspended and attached biomass increased). Additionally, 16S rRNA revealed a higher relative abundance of typical anammox bacteria Candidatus Brocadia in the biofilm of the modified carrier compared to the original carrier, alongside a decline in nitrifying genera, such as Nitrolancea. These microbial shifts effectively suppressed excessive nitrite oxidation, limited nitrate accumulation, and sustained efficient nitrogen removal throughout the reactor’s operation. Full article

(This article belongs to the Special Issue Recent Advances in Functional Polymer Materials for Water Treatment)

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13 pages, 3443 KiB

Open AccessArticle

Cinnamon Essential Oil-Loaded Halloysite Nanotubes Applied in Degradable Film: Characterization and Non-Contact Antimicrobial Activity

by Mingyu Zhou, Yuhang Tian, Shuseng Mo, Can Zhang, Ning Zhuang and Huaming Zheng

Polymers 2025, 17(9), 1144; https://doi.org/10.3390/polym17091144 - 23 Apr 2025

Abstract

To extend food shelf life and reduce plastic pollution, halloysite nanotubes (HNTs) were employed as a carrier to load cinnamon essential oils (CEOs), and the nanotubes were blended with polybutylene adipate co-terephthalate (PBAT) resin to fabricate the film with non-contact antimicrobial activity. The [...] Read more.

To extend food shelf life and reduce plastic pollution, halloysite nanotubes (HNTs) were employed as a carrier to load cinnamon essential oils (CEOs), and the nanotubes were blended with polybutylene adipate co-terephthalate (PBAT) resin to fabricate the film with non-contact antimicrobial activity. The results showed that the HNTs had a high loading efficiency (about 11%) for CEOs. The retention rate of CEOs in HNTs was still 33% after twenty days later, which indicated that the CEOs/HNTs nanoparticles had a long-acting controlled-released effect. The composite films represented excellent mechanical properties and antibacterial effects against Staphylococcus aureus and Escherichia coli due to the non-contact antimicrobial activity of CEOs. The strawberries remained fresh after five days when the composite film was applied in the packaging of strawberries, which proves that composite films can extend the shelf life of food. Therefore, it has potential application prospects in the food industry. Full article

(This article belongs to the Special Issue Advances in Biodegradable Polymer Film)

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14 pages, 3604 KiB

Open AccessArticle

Extraction Process Research and Characterization of Microcrystalline Cellulose Derived from Bamboo (Phyllostachys edulis (Carrière) J. Houz.) Fibers

by Zhu Liu, Zhongwei Wang, Shoulu Yang, Ning Ji and Dan Li

Polymers 2025, 17(9), 1143; https://doi.org/10.3390/polym17091143 - 23 Apr 2025

Abstract

Microcrystalline cellulose (MCC) possesses important attributes, including high crystallinity, a large surface area, excellent mechanical strength, chemical stability, and biodegradability. This study aims to research MCC extraction from bamboo (Phyllostachys edulis (Carrière) J. Houz.) fiber by assessing the impact of key processing [...] Read more.

Microcrystalline cellulose (MCC) possesses important attributes, including high crystallinity, a large surface area, excellent mechanical strength, chemical stability, and biodegradability. This study aims to research MCC extraction from bamboo (Phyllostachys edulis (Carrière) J. Houz.) fiber by assessing the impact of key processing variables such as acid concentration, temperature, and hydrolysis duration. Experimental results indicate that hydrolysis time and hydrochloric acid (HCl) concentration significantly influence yield. After evaluating the effects of various hydrolysis conditions, the optimal parameters were determined to be a 2.0 M HCl concentration, 90 °C, and 10 min of reaction time. The MCC produced under optimal conditions displayed improved crystallinity (77.2%) while retaining functional groups similar to those found in raw bamboo. Morphological analysis revealed an irregular rod-like shape with rough surfaces. This optimized hydrolysis process offers a viable approach for MCC production from raw bamboo and holds potential as a precursor for developing environmentally friendly biodegradable fiber materials. Full article

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

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15 pages, 6088 KiB

Open AccessArticle

Study on the Mechanical Properties of Carbon Fabric/Polyetherketoneketone Composites Under Different Environmental Conditions

by Xiangyu Xu, Baoyan Zhang, Fenghui Shi, Kai Liu, Gongqiu Peng and Junpeng Gao

Polymers 2025, 17(9), 1142; https://doi.org/10.3390/polym17091142 - 22 Apr 2025

Abstract

Carbon fabric reinforced polyetherketoneketone (CFF/PEKK) composites have garnered significant attention from researchers due to their superior properties and have been successfully applied in various engineering fields. Environmental conditions are known to directly influence the mechanical properties and service life of composites; however, limited [...] Read more.

Carbon fabric reinforced polyetherketoneketone (CFF/PEKK) composites have garnered significant attention from researchers due to their superior properties and have been successfully applied in various engineering fields. Environmental conditions are known to directly influence the mechanical properties and service life of composites; however, limited literature exists on the mechanical behavior of CFF/PEKK composites under different environmental conditions. This study elucidates the correlation between the bending and shear behaviors of CFF/PEKK composites and environmental factors, thereby offering robust data support for engineering applications. In this work, CFF/PEKK composite laminates with a fiber volume fraction of 55 vol% were fabricated and subjected to saturated moisture absorption treatments at 70 °C. The moisture absorption characteristics of the material were investigated. The bending and shear properties of CFF/PEKK composites were characterized under three environmental conditions: −55 °C dry state (CTD), room temperature dry state (RTD), and 70 °C wet state (ETW). Failure modes and mechanisms of composite specimens were also analyzed. The equilibrium moisture absorption rate of CFF/PEKK composites is approximately 0.27%. Hygrothermal aging resulted in noticeable fiber pull-out in mechanical specimens, indicating damage to the interfacial performance of the composites. Furthermore, no cracks or delamination were observed. Results indicate that in the CTD condition, the bending strength and shear strength of CFF/PEKK composites are higher compared to those in the RTD condition, while the modulus remains relatively unaffected. In the ETW condition, both bending and shear properties exhibit a significant decline, with the most pronounced reduction observed in interlaminar shear strength. No significant differences in failure modes were noted across different environmental conditions. Full article

(This article belongs to the Special Issue Editorial Board Members' Collection Series: Polymer Physics and Theory—2nd Edition)

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21 pages, 4656 KiB

Open AccessArticle

Approach to the Performance of Polymers Designed Based on Poly(methyl methacrylate) (PMMA)/poly(urethane) (PU) with Recycled Cellulose Nanoparticles from Cold Drink Cups

by Erick Habacuc Reyes Piña, Mayra Elizabeth Juárez Méndez, Diana Palma Ramírez, Acela López Benítez, Karen Ailed Neri Espinoza and Nicolás Cayetano Castro

Polymers 2025, 17(9), 1141; https://doi.org/10.3390/polym17091141 - 22 Apr 2025

Abstract

Transparent high-performance polymers are essential to avoid damage in automotive headlights when exposed to environmental conditions. An approach involving the synthesis of reinforced interpenetrating polymer networks (IPNs) based on poly(methyl methacrylate) (PMMA)/poly(urethane) (PU) with crystalline cellulose (C) is here proposed. The valorization of [...] Read more.

Transparent high-performance polymers are essential to avoid damage in automotive headlights when exposed to environmental conditions. An approach involving the synthesis of reinforced interpenetrating polymer networks (IPNs) based on poly(methyl methacrylate) (PMMA)/poly(urethane) (PU) with crystalline cellulose (C) is here proposed. The valorization of single-use cups used for cold beverage applications into reinforcement nanoparticle agents is studied through structural and morphological analysis, revealing intermediate crystallinity (52.51%) with a mixture of Iα (52.9%) and Iβ (46.3%) polymorphs in which the initial fiber had no chemical modification after the involved pretreatments. The effect of dispersing 0.1 wt% of C (d = 29 nm and L= 85–200 nm) into 50/50 and 80/20 PMMA/PU ratios is studied as a reinforcement agent under aging and environmental conditions (ASTM D1435-20) for 672 h. PMMA₈₀/PU₂₀ (σ =4 MPa, ε = 54%, E = 7 MPa) led to lower mechanical properties than PMMA₅₀/PU₅₀ (stress σ =14 MPa, strain ε = 94%, E = 83 MPa). PMMA₅₀/PU₅₀/C is reinforced in σ and ε with C addition (σ = 19 MPa, ε = 41%, E = 585 MPa) while PMMA₈₀/PU₂₀/C reduces both (σ = 3 MPa, ε = 51%, E = 5 MPa). This study indicates that aging increases stress while maintaining strain in the first but decreases in the second. The optical properties indicate no severe damage after aging. Full article

(This article belongs to the Section Polymer Networks and Gels)

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17 pages, 5701 KiB

Open AccessArticle

A Development and Comparison Study of PVDF Membranes Enriched by Metal–Organic Frameworks

by Tatiana Pisarenko, Nikola Papež, Mohammed A. Al-Anber, Rashid Dallaev, Klára Částková and Ştefan Ţălu

Polymers 2025, 17(9), 1140; https://doi.org/10.3390/polym17091140 - 22 Apr 2025

Abstract

This study is concerned with the research and development of nanofibrous hybrid materials functioning as membranes composed of polyvinylidene fluoride (PVDF) polymer and enriched with metal–organic frameworks (MOFs) as dopants for the adsorption and detection of gases, dyes, and heavy metals in wastewater. [...] Read more.

This study is concerned with the research and development of nanofibrous hybrid materials functioning as membranes composed of polyvinylidene fluoride (PVDF) polymer and enriched with metal–organic frameworks (MOFs) as dopants for the adsorption and detection of gases, dyes, and heavy metals in wastewater. Several types of nanofiber composites are fabricated by electrostatic spinning. The prepared samples and their chemical, optical, and material properties are analyzed. Subsequently, the preliminary investigation of dye removal is conducted. Accordingly, the design and investigation of these nanofibrous structures may contribute to addressing critical environmental and technological challenges. Full article

(This article belongs to the Special Issue Preparation and Application of Polymer Membranes)

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22 pages, 9280 KiB

Open AccessArticle

Properties of Emulsion Co-Precipitated Collagen/Bambara Groundnut Protein-Based Film as Influenced by Basil Essential Oil and Soy Lecithin

by Md. Shihabul Awal, Soottawat Benjakul, Thummanoon Prodpran and Krisana Nilsuwan

Polymers 2025, 17(9), 1139; https://doi.org/10.3390/polym17091139 - 22 Apr 2025

Abstract

Protein-based films have gained attention due to their potential as biodegradable packaging. This study investigated the properties and characteristics of film-forming emulsions (FFEs) and their films based on co-precipitated protein (CPP) from Bambara groundnut protein isolate (BGPI) and acid-soluble collagen (ASC) emulsified with [...] Read more.

Protein-based films have gained attention due to their potential as biodegradable packaging. This study investigated the properties and characteristics of film-forming emulsions (FFEs) and their films based on co-precipitated protein (CPP) from Bambara groundnut protein isolate (BGPI) and acid-soluble collagen (ASC) emulsified with different levels of basil essential oil (BE) (50%, 75% and 100%) and soy lecithin (SL) (25% and 50%). The oil droplet size, stability, and distribution of FFEs were characterized. Larger oil droplet sizes, a higher flocculation factor, and a higher coalescence index were observed for FFEs emulsified with higher levels of BE and SL. All FFEs had uniform oil distribution. Films from different FFEs were formed and analyzed. Films containing BE and SL had higher thickness, elongation at break, b*-value, water vapor and UV-light barrier properties, but a lower tensile strength than the control film. Emulsion films exhibited smooth surface and rough cross-section and were heat-sealable. FTIR spectra indicated lower protein interactions in the emulsion film containing higher levels of BE and SL. The film containing 100% BE had the highest antioxidant activities, regardless of the SL level used. The emulsification of BE and SL at various levels thus influenced the properties and characteristics of the FFE and emulsion film. Full article

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

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16 pages, 4271 KiB

Open AccessArticle

The Influence of Spinning Process on the Properties and Structure of PBS Fibers

by Hao Liu, Hui Li and Zexu Hu

Polymers 2025, 17(9), 1138; https://doi.org/10.3390/polym17091138 - 22 Apr 2025

Abstract

As a bio-based polymer, polybutylene succinate (PBS) has extensive applications in plastic products and film manufacturing. However, its low melt strength results in poor spinnability, and during the forming process, it tends to form large-sized spherulites and exhibit filament adhesion phenomena. These limitations [...] Read more.

As a bio-based polymer, polybutylene succinate (PBS) has extensive applications in plastic products and film manufacturing. However, its low melt strength results in poor spinnability, and during the forming process, it tends to form large-sized spherulites and exhibit filament adhesion phenomena. These limitations have hindered its development in the field of fiber spinning. To enhance fiber strength, this work systematically investigated the effects of spinning temperature and spinning speed on the properties and structure of PBS pre-oriented yarns (PBS-POY). The results indicated that appropriately lowering the spinning temperature and increasing the spinning speed could improve the mechanical properties of the fibers. When the spinning temperature was 195 °C and the spinning speed reached 2500 m/min, the tensile strength of pre-oriented yarns achieved 2.09 cN/dtex. Furthermore, the evolution of properties and structures of pre-oriented yarns under maximum drawing conditions across different spinning speed systems was examined. By synchronously analyzing the correlations among mechanical properties, thermal behavior and condensed state structures, the structural performance regulation mechanism under the synergistic effect of spinning–drawing processes was revealed. The results demonstrated that fibers produced at higher spinning speeds contained more numerous and smaller spherulites. After maximum drawing, these smaller spherulites split into lamellae with higher uniformity, resulting in final fibers with smaller crystal sizes, higher crystallinity and improved orientation. As the spinning speed increased, the average crystal size of the final fibers decreased; the long period of the final fibers extended from 8.55 nm to 9.99 nm, and the mechanical strength improved to 2.72 cN/dtex. Full article

(This article belongs to the Section Polymer Fibers)

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23 pages, 6561 KiB

Open AccessArticle

Thin-Film Composite Polyamide Membranes Modified with HKUST-1 for Water Treatment: Characterization and Nanofiltration Performance

by Roman Dubovenko, Mariia Dmitrenko, Anna Mikulan, Margarita Puzikova, Ilnur Dzhakashov, Nadezhda Rakovskaya, Anna Kuzminova, Olga Mikhailovskaya, Rongxin Su and Anastasia Penkova

Polymers 2025, 17(9), 1137; https://doi.org/10.3390/polym17091137 - 22 Apr 2025

Abstract

The development of sustainable nanofiltration membranes requires alternatives to petroleum-derived polymer substrates. This study demonstrates the successful use of an eco-friendly cellulose acetate/cellulose nitrate (CA/CN) blend substrate for fabricating high-performance modified thin-film composite (mTFC) membranes. A dense, non-porous polyamide (PA) selective layer was [...] Read more.

The development of sustainable nanofiltration membranes requires alternatives to petroleum-derived polymer substrates. This study demonstrates the successful use of an eco-friendly cellulose acetate/cellulose nitrate (CA/CN) blend substrate for fabricating high-performance modified thin-film composite (mTFC) membranes. A dense, non-porous polyamide (PA) selective layer was formed via the interfacial polymerization method and modified with 0.05–0.1 wt.% HKUST-1 (Cu₃BTC₂, MOF-199). Characterization by FTIR, XPS, SEM, AFM, and contact angle measurements confirmed the CA/CN substrate’s suitability for TFC membrane fabrication. HKUST-1 incorporation created a distinctive ridge-and-valley morphology while significantly altering PA layer hydrophilicity and roughness. The mTFC membrane performance could be fine-tuned by the controlled incorporation of HKUST-1; incorporation through the aqueous phase slowed down the formation of the PA layer and significantly reduced its thickness, while the addition through the organic phase resulted in the formation of a denser layer due to HKUST-1 agglomeration. Thus, either enhanced permeability (123 LMH bar⁻¹ with 0.05 wt.% aqueous-phase incorporation) or rejection (>89% dye removal with 0.05 wt.% organic-phase incorporation) were achieved. Both mTFC membranes also exhibited improved heavy metal ion rejection (>91.7%), confirming their industrial potential. Higher HKUST-1 loading (0.1 wt.%) caused MOF agglomeration, reducing performance. This approach establishes a sustainable fabrication route for tunable TFC membranes targeting specific separation tasks. Full article

(This article belongs to the Section Polymer Membranes and Films)

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13 pages, 4652 KiB

Open AccessArticle

Effects of the Size and Loading of Chrome-Tanned Leather Shavings on the Properties of Styrene–Butadiene Rubber Compounds

by L. R. Melo de Lima, S. Neves, S. Pinho, C. Coelho, M. F. Almeida, M. A. Lopes and C. Fonseca

Polymers 2025, 17(9), 1136; https://doi.org/10.3390/polym17091136 (registering DOI) - 22 Apr 2025

Abstract

Among the proposed leather recycling options, the incorporation of leather waste in rubber has been the subject of multiple studies, where the effects of leather content on the mechanical and rheological properties of the composites are usually studied. However, the effects of leather [...] Read more.

Among the proposed leather recycling options, the incorporation of leather waste in rubber has been the subject of multiple studies, where the effects of leather content on the mechanical and rheological properties of the composites are usually studied. However, the effects of leather size have never been addressed in a systematic way. The reasons to study this parameter are twofold: it affects the physicochemical properties and processing conditions of the composites, and leather grinding is a costly and time-consuming process. In this work, leather waste (LW) with particle sizes ranging from ≤0.5 mm to ≤3 mm was incorporated in styrene–butadiene rubber (SBR) in contents of up to 50 phr. It was concluded that the composites with finer leather sizes exhibited a more uniform particles dispersion, and tensile strength was not significantly affected by the presence of LW, especially for the finer granulometries. However, there is a remarkable increase in the stiffness with the increase in leather content, particularly with the finer particles. The abrasion increased with the incorporation of leather across all particle sizes, especially for the ≤0.5 mm leather particles. The thermal stability of the composites was not affected by either the particle size or the amount of LW, except for high contents. Full article

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

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17 pages, 5190 KiB

Open AccessArticle

Engineering Photoluminescence of Lanthanide Doped Yttrium-MOF-76 for Volatile Organic Compound Sensing

by Oswaldo Rosas Rivas, Mariana Hamer, Héctor A. Baldoni, Maya Boone, Rik Van Deun and Germán E. Gomez

Polymers 2025, 17(9), 1135; https://doi.org/10.3390/polym17091135 - 22 Apr 2025

Abstract

A set of three-dimensional metal-organic frameworks, named MOF-76, belonging to the tetragonal P4₃22 space group, based on [Y(BTC)(H₂O)](DMF)_1.1 (1,3,5-benzenetricarboxylate) doped with Eu³⁺, Tb³⁺, and Eu³⁺/Tb³⁺ were obtained under solvothermal conditions and [...] Read more.

A set of three-dimensional metal-organic frameworks, named MOF-76, belonging to the tetragonal P4₃22 space group, based on [Y(BTC)(H₂O)](DMF)_1.1 (1,3,5-benzenetricarboxylate) doped with Eu³⁺, Tb³⁺, and Eu³⁺/Tb³⁺ were obtained under solvothermal conditions and fully characterized by powder X-ray diffraction, thermal, and vibrational analyses. In addition, upon UV light excitation (280 nm), all the powdered samples exhibited fine 4f-4f transitions, of which the ⁵D₀ → ⁷F₂ (Eu³⁺) and ⁵D₄ → ⁷F₅ (Tb³⁺) were the most intense ones. All samples were photophysically analyzed by determining the luminescence lifetimes, and their emission colors were quantified by calculating their chromaticities and color purities. Moreover, the intrinsic quantum yield, radiative, and non-radiative constants were calculated and compared to establish a structure–property relationship. Specifically, the Eu/Tb co-doped sample was employed to monitor its hypersensitive emissions in the presence of small volatile organic compounds (VOCs), showing quenching or enhancement of emission in protic and non-protic solvents. Furthermore, DFT calculations were carried out to understand the energy transfer processes between the sensor and the respective analytes. These results are promising for the development of solid-state lighting devices and colorimetric chemical sensors for specific compounds. Full article

(This article belongs to the Special Issue Advances in Polymeric Metal-Organic Frameworks and Composites for Opto-Magnetic Applications)

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Polymers, Volume 17, Issue 9 (May-1 2025) – 36 articles

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