Polymers

17 pages, 4594 KiB

Open AccessArticle

Optimizing Mechanical and Microstructural Properties of Sandy Clayey Silt Stabilized with Lignin Fiber and Cement Synergy

by Shuangfeng Guo, Xiaoyi Jiang, Zhihua Zhang, Qingrui Lu, Zhe Wang and Kai Zhao

Polymers 2025, 17(11), 1584; https://doi.org/10.3390/polym17111584 - 5 Jun 2025

Viewed by 476

Abstract

Soil treatment with natural materials is an effective method to improve the mechanical properties of the original soil for recycling engineering construction. This research aims to evaluate the synergistic effects of lignin fiber and cement on sandy clayey silt stabilization. A factorial experimental [...] Read more.

Soil treatment with natural materials is an effective method to improve the mechanical properties of the original soil for recycling engineering construction. This research aims to evaluate the synergistic effects of lignin fiber and cement on sandy clayey silt stabilization. A factorial experimental design was employed, testing five lignin fiber contents (0%, 2%, 4%, 6%, and 8%) and three cement contents (0%, 2%, and 4%) across four curing periods (1, 7, 14, and 30 days). Unconfined compressive strength (UCS) tests were conducted in triplicate for each combination (total *n* = 180 samples), and failure surfaces were analyzed using Scanning Electron Microscopy with Energy Dispersive X-ray spectroscopy (SEM-EDX). Results indicate a critical lignin fiber threshold of 4%, beyond which UCS decreased by 15–20% due to increased void ratios. Statistical analysis (ANOVA, *p* < 0.05) confirmed significant interactions between lignin fiber, cement content, and curing time. For instance, 4% lignin fiber and 4% cement yielded a 139% UCS increase after 30-day curing compared to untreated soil. SEM-EDX revealed that lignin fiber networks enhance ductility by bridging soil particles, while cement hydration reduced particle detachment. These findings provide a quantitative framework for optimizing lignin fiber-cement stabilization in sustainable geotechnical applications. Full article

(This article belongs to the Special Issue Mechanical Response Characteristics and Performance Evaluation of Polymer Materials)

► Show Figures

Figure 1

29 pages, 3289 KiB

Open AccessArticle

Experimentally and Modeling Assessment of Parameters Affecting Grinding Aid-Containing Cement–PCE Compatibility: CRA, MARS and AOMA-ANN Methods

by Yahya Kaya, Hasan Tahsin Öztürk, Veysel Kobya, Naz Mardani and Ali Mardani

Polymers 2025, 17(11), 1583; https://doi.org/10.3390/polym17111583 - 5 Jun 2025

Viewed by 435

Abstract

In this study, the compatibility of polycarboxylate ether-based water-reducing admixtures (PCE) with cements produced with different types and dosages of grinding aids (GA) was experimentally and statistically investigated. A total of 203 paste mixtures were prepared using seven different types of GA and [...] Read more.

In this study, the compatibility of polycarboxylate ether-based water-reducing admixtures (PCE) with cements produced with different types and dosages of grinding aids (GA) was experimentally and statistically investigated. A total of 203 paste mixtures were prepared using seven different types of GA and one type of PCE at different dosages. The Marsh funnel flow time and mini-slump values of the mixtures were compared. A modeling study was performed using the experimental data. In this direction, Classical Regression Analysis (CRA), Multivariate Adaptive Regression Splines (MARS), and Artificial Neural Networks (AOMA-ANN) were applied. Innovative approaches, AOMA-ANN (AIP) and AOMA-ANN (ONIP), were introduced. The results showed adverse effects on flow performance with increased GA utilization, except for TEA-based GA. TEA-type GA had the lowest flow performance. AOMA-ANN (ONIP) exhibited the best performance in modeling. Marsh funnel flow-time modeling with AOMA-ANN (ONIP) considered parameters such as sieve residue at 60 microns, the number of molecules per fineness, the density of GA, the pH value of GA, and the PCE dosage. Mini-slump modeling with AOMA-ANN (ONIP) considered parameters such as sieve residue at 60 microns, the density of GA, the pH value of GA, and the PCE dosage. Full article

(This article belongs to the Special Issue Preparation, Structure and Characterization of Polymer/Cement Composites—3rd Edition)

► Show Figures

Figure 1

19 pages, 4804 KiB

Open AccessArticle

From Waste to Technological Products: Bioplastics Production from Proteins Extracted from the Black Soldier Fly

by Alessia Di Pasquale, Marina Zoccola, Ashish Mohod, Giulia Dalla Fontana, Anastasia Anceschi and Sara Dalle Vacche

Polymers 2025, 17(11), 1582; https://doi.org/10.3390/polym17111582 - 5 Jun 2025

Viewed by 375

Abstract

The need to find sustainable solutions to conventional plastics has driven research into alternative materials, including bioplastics, which represent a promising option for reducing pollution and enhancing the value of renewable resources. In this study, bioplastics made from polyvinyl alcohol (PVA) and proteins [...] Read more.

The need to find sustainable solutions to conventional plastics has driven research into alternative materials, including bioplastics, which represent a promising option for reducing pollution and enhancing the value of renewable resources. In this study, bioplastics made from polyvinyl alcohol (PVA) and proteins extracted from the larvae of Black Soldier Fly (BSF), an insect capable of converting organic waste into high-value biomass, were produced and characterized. The proteins were obtained by hydrolysis of defatted BSF larvae with superheated water, avoiding harsh chemical reagents. Next, polymer films were fabricated by mixing PVA and hydrolyzed BSF proteins in different proportions and analyzed for morphological, physical-chemical, mechanical and biodegradability characteristics. The results obtained show that as the BSF protein content increases, the films show a reduction in thermal stability and mechanical properties, and also, they exhibit higher biodegradability, correlated with higher wettability, solubility and ability to absorb moisture. This research highlights the value of using organic waste-fed insects as a resource for bioplastic production, offering an alternative to traditional polymers and contributing to the transition to sustainable materials. Full article

(This article belongs to the Special Issue High-Value Polymer Materials from Waste Recovery and Recycling)

► Show Figures

Figure 1

14 pages, 1694 KiB

Open AccessArticle

An Assessment of Anion Exchange Membranes for CO₂ Capture Processes: A Focus on Fumasep^® and Sustainion^®

by Kseniya Papchenko, Sandra Kentish and Maria Grazia De Angelis

Polymers 2025, 17(11), 1581; https://doi.org/10.3390/polym17111581 - 5 Jun 2025

Viewed by 539

Abstract

Anion exchange membranes are utilised in cutting-edge energy technologies including electrolysers and fuel cells. Recently, these membranes have also emerged as a promising tool in CO₂ capture techniques, such as moisture-driven direct air capture and the separation of CO₂ from other [...] Read more.

Anion exchange membranes are utilised in cutting-edge energy technologies including electrolysers and fuel cells. Recently, these membranes have also emerged as a promising tool in CO₂ capture techniques, such as moisture-driven direct air capture and the separation of CO₂ from other gases, leveraging the moisture-induced sorption/desorption and diffusion of CO₂ in its ionic forms. In this study, we examine the absorption and permeation of CO₂ and CH₄ in two commercially available anion exchange membranes, Fumasep^® and Sustainion^®, under dry conditions. With the exception of CO₂ sorption in Fumasep^®, these measurements have not been previously reported. These new data points are crucial for evaluating the fundamental separation capabilities of these materials and for devising innovative CO₂ capture strategies, as well as for the simulation of novel combined processes. In a dry state, both materials demonstrate similar CO₂ absorption levels, with a higher value for Sustainion^®. The CO₂ solubility coefficient decreases with pressure, as is typical for glassy polymers. Fumasep^® exhibits higher CO₂/CH₄ ideal solubility selectivity, equal to ~10 at sub-ambient pressures, and higher diffusivity. The CO₂ diffusion coefficient increases with the CO₂ concentration in both membranes due to swelling of the matrix, varying between 0.7 and 2.2 × 10⁻⁸ cm²/s for Fumasep^® and between 1.6 and 9.0 × 10⁻⁹ cm²/s for Sustainion^®. CO₂ permeability exhibits a minimum at a pressure of approximately 2–3 bar. The CO₂ permeability in the dry state is higher in Fumasep^® than in Sustainion^®: 3.43 and 0.72 Barrer at a 2-bar transmembrane pressure, respectively. The estimated perm-selectivity was found to reach values of up to 40 at sub-ambient pressures. The CO₂ permeability and CO₂/CH₄ estimated perm-selectivity in both polymers are of a similar order of magnitude to those measured in fluorinated ion exchange membranes such as Nafion^®. Full article

(This article belongs to the Special Issue Recent Trends in Polymer Membranes: Fabrication Technique, Characterization, Functionalization, and Applications in Environmental Science, 2nd Edition)

► Show Figures

Figure 1

27 pages, 7515 KiB

Open AccessReview

Molecular Design and Role of the Dynamic Hydrogen Bonds and Hydrophobic Interactions in Temperature-Switchable Polymers: From Understanding to Applications

by Yurij Stetsyshyn, Halyna Ohar, Andrzej Budkowski and Giuseppe Lazzara

Polymers 2025, 17(11), 1580; https://doi.org/10.3390/polym17111580 - 5 Jun 2025

Viewed by 477

Abstract

Temperature-induced transitions in polymer systems, often governed by a phenomenon called critical solution temperatures (CSTs), lie on the basis of various advanced technologies such as tissues detachment, smart windows, enhanced DNA biosensors, etc. Despite this application-oriented progress, the molecular mechanisms of the temperature-induced [...] Read more.

Temperature-induced transitions in polymer systems, often governed by a phenomenon called critical solution temperatures (CSTs), lie on the basis of various advanced technologies such as tissues detachment, smart windows, enhanced DNA biosensors, etc. Despite this application-oriented progress, the molecular mechanisms of the temperature-induced transition based on CSTs remain often underexplored or weakly explained. In this review, we focus on the different molecular mechanisms driving CST-based transitions, systematizing information on homofunctional polymer systems. Understanding these mechanisms is crucial for manipulating temperature-sensitive properties, which offers significant potential for future innovations in smart materials. Full article

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

► Show Figures

Graphical abstract

15 pages, 11557 KiB

Open AccessArticle

Toward Versatile Transient Electronics: Electrospun Biocompatible Silk Fibroin/Carbon Quantum Dot-Based Green-Emission, Water-Soluble Piezoelectric Nanofibers

by Zhipei Xia, Chubao Liu, Juan Li, Biyao Huang, Chu Pan, Yu Lai, Zhu Liu, Dongling Wu, Sen Liang, Xuanlun Wang, Weiqing Yang and Jun Lu

Polymers 2025, 17(11), 1579; https://doi.org/10.3390/polym17111579 - 5 Jun 2025

Viewed by 447

Abstract

The rapid development of wearable electronics requires multifunctional, transient electronic devices to reduce the ecological footprint and ensure data security. Unfortunately, existing transient electronic materials need to be degraded in chemical solvents or body fluids. Here, we report green luminescent, water-soluble, and biocompatible [...] Read more.

The rapid development of wearable electronics requires multifunctional, transient electronic devices to reduce the ecological footprint and ensure data security. Unfortunately, existing transient electronic materials need to be degraded in chemical solvents or body fluids. Here, we report green luminescent, water-soluble, and biocompatible piezoelectric nanofibers developed by electrospinning green carbon quantum dots (G-CQDs), mulberry silk fibroin (SF), and polyvinyl alcohol (PVA). The introduction of G-CQDs significantly enhances the piezoelectric output of silk fibroin-based fiber materials. Meanwhile, the silk fibroin-based hybrid fibers maintain the photoluminescent response of G-CQDs without sacrificing valuable biocompatibility. Notably, the piezoelectric output of a G-CQD/PVA/SF fiber-based nanogenerator is more than three times higher than that of a PVA/SF fiber-based nanogenerator. This is one of the highest levels of state-of-the-art piezoelectric devices based on biological organic materials. As a proof of concept, in the actual scenario of a rope skipping exercise, the G-CQD/PVA/SF fiber-based nanogenerator is further employed as a self-powered wearable sensor for real-time sensing of athletic motions. It demonstrates high portability, good flexibility, and stable piezoresponse for smart sports applications. This class of water-disposable, piezo/photoactive biological materials could be compelling building blocks for applications in a new generation of versatile, transient, wearable/implantable devices. Full article

(This article belongs to the Special Issue Polymer-Based Wearable Electronics)

► Show Figures

Figure 1

30 pages, 3841 KiB

Open AccessArticle

Eco-Friendly Octylsilane-Modified Amino-Functional Silicone Coatings for a Durable Hybrid Organic–Inorganic Water-Repellent Textile Finish

by Mariam Hadhri, Claudio Colleoni, Agnese D’Agostino, Mohamed Erhaim, Raphael Palucci Rosa, Giuseppe Rosace and Valentina Trovato

Polymers 2025, 17(11), 1578; https://doi.org/10.3390/polym17111578 - 5 Jun 2025

Viewed by 727

Abstract

The widespread phase-out of long-chain per- and poly-fluoroalkyl substances (PFASs) has created an urgent need for durable, fluorine-free water-repellent finishes that match the performance of legacy chemistries while minimising environmental impact. Here, the performance of an eco-friendly hybrid organic–inorganic treatment obtained by the [...] Read more.

The widespread phase-out of long-chain per- and poly-fluoroalkyl substances (PFASs) has created an urgent need for durable, fluorine-free water-repellent finishes that match the performance of legacy chemistries while minimising environmental impact. Here, the performance of an eco-friendly hybrid organic–inorganic treatment obtained by the in situ hydrolysis–condensation of triethoxy(octyl)silane (OS) in an amino-terminated polydimethylsiloxane (APT-PDMS) aqueous dispersion was investigated. The sol was applied to plain-weave cotton and polyester by a pad-dry-cure process and benchmarked against a commercial fluorinated finish. Morphology and chemistry were characterised by SEM–EDS, ATR-FTIR, and Raman spectroscopy; wettability was assessed by static contact angle, ISO 4920 spray ratings, and AATCC 193 water/alcohol repellence; and durability, handle, and breathability were evaluated through repeated laundering, bending stiffness, and water-vapour transmission rate measurements. The silica/PDMS coating formed a uniform, strongly adherent nanostructured layer conferring static contact angles of 130° on cotton and 145° on polyester. After five ISO 105-C10 wash cycles, the treated fabrics still displayed a spray rating of 5/5 and AATCC 193 grade 7, outperforming or equalling the fluorinated control, while causing ≤5% loss of water-vapour permeability and only a marginal increase in bending stiffness. These results demonstrate that the proposed one-step, water-borne sol–gel process affords a sustainable, industrially scalable route to high-performance, durable, water-repellent finishes for both natural and synthetic textiles, offering a viable alternative to PFAS-based chemistry for outdoor apparel and technical applications. Full article

(This article belongs to the Special Issue Environmentally Friendly Textiles, Fibers and Their Composites)

► Show Figures

Graphical abstract

13 pages, 3473 KiB

Open AccessArticle

CuO-NiO-Embedded Guar Gum Hydrogel as an Efficient Catalyst for Dyes Removal

by Nujud Maslamani

Polymers 2025, 17(11), 1577; https://doi.org/10.3390/polym17111577 - 5 Jun 2025

Viewed by 333

Abstract

In this work, Guar gum and copper oxide-nickel oxide (GG-CuO-NiO) hydrogel were produced with the help of formaldehyde solution to display an efficient catalytic performance toward the catalytic degradation of selected dyes (Methylene Blue (MB), Methyl Orange (MO), and Eosin Yellow (EY)) in [...] Read more.

In this work, Guar gum and copper oxide-nickel oxide (GG-CuO-NiO) hydrogel were produced with the help of formaldehyde solution to display an efficient catalytic performance toward the catalytic degradation of selected dyes (Methylene Blue (MB), Methyl Orange (MO), and Eosin Yellow (EY)) in the presence of NaBH₄. The morphological and structural properties of the prepared hydrogel were thoroughly analyzed using SEM, EDX, XRD, and FT-IR techniques. According to the results, the GG-CuO-NiO hydrogel was able to reduce MB by 95% in one minute, 90.0% in four minutes, and 80.0% in 10 min for MO and EY, respectively. The catalytic efficiency of the hydrogel for MB was studied by adjusting its concentrations, varying reducing agent concentrations, and altering the amount of gel used. Using the recyclability method, which involved testing the GG-CuO-NiO hydrogel multiple times for the reduction of MB, the stability, reusability, and loss of catalytic activity of the hydrogel were examined. As a result, the designed GG-CuO-NiO hydrogel was stable for up to four times toward the reduction of MB. Lastly, the efficiency of the GG-CuO-NiO hydrogel was evaluated for MB removal in real samples and displayed exceptional reduction capabilities. Full article

(This article belongs to the Special Issue Advances in Natural Fiber-Polymer Composites)

► Show Figures

Figure 1

17 pages, 11231 KiB

Open AccessArticle

Biopolymer/Suture Polymer Interaction: Is It a Key of Bioprosthetic Calcification?

by Irina Yu. Zhuravleva, Anna A. Dokuchaeva, Andrey A. Vaver, Ludmila V. Kreiker, Elena V. Kuznetsova and Rostislav I. Grek

Polymers 2025, 17(11), 1576; https://doi.org/10.3390/polym17111576 - 5 Jun 2025

Viewed by 410

Abstract

The aim of this study was to evaluate the effect of suture material made of polyester (PET), polypropylene (PP), and polytetrafluoroethylene (PTFE) on the calcification of a bovine pericardium (BP) consisting of collagen biopolymer preserved with an epoxy compound. Non-porous film made of [...] Read more.

The aim of this study was to evaluate the effect of suture material made of polyester (PET), polypropylene (PP), and polytetrafluoroethylene (PTFE) on the calcification of a bovine pericardium (BP) consisting of collagen biopolymer preserved with an epoxy compound. Non-porous film made of the synthetic reinforced polymer REPEREN^® was chosen as a control material. Samples of the material (sutured or non-sutured with each of the three types of surgical sutures) were implanted subcutaneously in 45 young rats for 30, 60, and 90 days. The calcium content of the explants was quantified using atomic absorption spectrometry, a histological examination was performed using hematoxylin and eosin and von Kossa staining, and the structure of the calcium phosphate deposits was studied using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) with color field mapping. The results demonstrated the absence of calcification in the non-sutured BP and in all the REPEREN^® groups. In the sutured BP samples, a dynamic increase in the Ca content and the Ca/P ratio to 1.67–1.7 (crystalline hydroxyapatite) was observed by the 90th day. The minimum Ca content among the sutured BP groups was detected in samples where the PET thread was used. The cellular reaction to BP was significantly more pronounced than the reaction to REPEREN^® throughout the entire observation period; collagen homogenization was noted near the sutures. It can be concluded that all the studied suture materials provoke BP calcification. PET has the minimal negative effect. Full article

(This article belongs to the Special Issue Polymer-Based Materials for Drug Delivery and Biomedical Applications)

► Show Figures

Figure 1

19 pages, 12347 KiB

Open AccessArticle

Long-Term Physical and Chemical Stability and Energy Recovery Potential Assessment of a New Chelating Resin Used in Brine Treatment for Chlor-Alkali Plants

by Liliana Lazar, Loredana-Vasilica Postolache, Valeria Danilova, Dumitru Coman, Adrian Bele, Daniela Rusu, Mirela-Fernanda Zaltariov and Gabriela Lisa

Polymers 2025, 17(11), 1575; https://doi.org/10.3390/polym17111575 - 5 Jun 2025

Viewed by 378

Abstract

Brine purification is an important process unit in chlor-alkali industrial plants for the production of sodium hydroxide, chlorine, and hydrogen. The membrane cell process requires ultrapure brine, which is obtained through mechanical filtration, chemical precipitation and fine polishing, and ion exchange using polymer [...] Read more.

Brine purification is an important process unit in chlor-alkali industrial plants for the production of sodium hydroxide, chlorine, and hydrogen. The membrane cell process requires ultrapure brine, which is obtained through mechanical filtration, chemical precipitation and fine polishing, and ion exchange using polymer resins. Temperature variations can lead to the degradation of the exchange properties of these resins, primarily causing a decrease in their exchange capacity, which negatively impacts the efficiency of the brine purification. After multiple ion exchange regeneration cycles, significant quantities of spent resins may be generated. These must be managed in accordance with resource efficiency and hazardous waste management to ensure the sustainability of the industrial process. In this paper, a comparative study is conducted to characterize the long-term stability of a new commercial chelating resin used in the industrial electrolysis process. The spectroscopic methods of physicochemical characterization included: scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR). The thermal behavior of the polymer resins was evaluated using the following thermogravimetric methods: thermogravimetry (TG), derivative thermogravimetry (DTG), and differential thermal analysis (DTA), while the moisture behavior was studied using dynamic vapor sorption (DVS) analysis. To assess the energy potential, the polymer resins were analyzed to determine their calorific value and overall energy content. Full article

(This article belongs to the Special Issue Current and Future Trends in Thermosetting Resins)

► Show Figures

Figure 1

17 pages, 3550 KiB

Open AccessArticle

Substrate-Dependent Performance of ZnTTBPc–PMMA Composite Films on Rigid, Flexible, and Sustainable Materials for Wearable Devices

by María Elena Sánchez Vergara, Ismael Cosme and José Ramón Álvarez Bada

Polymers 2025, 17(11), 1574; https://doi.org/10.3390/polym17111574 - 5 Jun 2025

Viewed by 384

Abstract

The purpose of this work is to evaluate the potential use of zinc 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (ZnTTBPc) embedded in polymethyl methacrylate (PMMA) and deposited on different substrates in active films for wearable device (WD) applications. The inclusion of PMMA as a matrix facilitates the incorporation [...] Read more.

The purpose of this work is to evaluate the potential use of zinc 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (ZnTTBPc) embedded in polymethyl methacrylate (PMMA) and deposited on different substrates in active films for wearable device (WD) applications. The inclusion of PMMA as a matrix facilitates the incorporation of ZnTTBPc. The composite films were deposited by drop casting on PET, glass, and n-type silicon, as well as on innovative substrates, such as palm leaves and polyester. Regarding the composite films, surface analysis using SEM and AFM revealed substrate-dependent differences in film roughness, grain distribution, and crack formation, highlighting the influence of substrate morphology and drying dynamics on the structural integrity of the composite films. With respect to fluorescent and optical behavior, the highest fluorescence intensity (2573) and reflectance (75%) were obtained for the film deposited on palm, while the lowest optical band gap (1.52 eV) was found in the film on polyester fabric. Substrate–film interactions and deposition dynamics play a critical role in determining the structural integrity and topography of composite films, which, in turn, influence optical properties, fluorescence, and band gap. The multifaceted properties of all tested systems with the film structure, substrate/ZnTTBPc–PMMA suggest new possibilities for wearable electronics applications. Full article

(This article belongs to the Special Issue Polymer Thin Films and Their Applications)

► Show Figures

Figure 1

17 pages, 5039 KiB

Open AccessArticle

Comparative Study on Pervaporation Performance of Polyphosphazene Membranes with Different Fluorine Side Groups for Thiophene/n-Heptane Separation

by Bingcong Xu, Xingmei Zhang, Wenwen He and Xiaolong Han

Polymers 2025, 17(11), 1573; https://doi.org/10.3390/polym17111573 - 5 Jun 2025

Viewed by 352

Abstract

In recent years, polyphosphazene (POP) membranes have been gaining more and more attention owing to their excellent pervaporation desulfurization performance. To develop new POP membranes, three kinds of POPs with different side groups, Poly[bis(trifluoroethoxy)phosphazene] (PTFEP), Poly[bis(trifluorobutoxy)phosphazene] (PTFBP), and Poly[bis(octafluoropentyloxy)phosphazene] (POFPP), were synthesized. The [...] Read more.

In recent years, polyphosphazene (POP) membranes have been gaining more and more attention owing to their excellent pervaporation desulfurization performance. To develop new POP membranes, three kinds of POPs with different side groups, Poly[bis(trifluoroethoxy)phosphazene] (PTFEP), Poly[bis(trifluorobutoxy)phosphazene] (PTFBP), and Poly[bis(octafluoropentyloxy)phosphazene] (POFPP), were synthesized. The NMR spectroscopy demonstrated that POPs with a designed structure were successfully prepared. Subsequently, the composite membranes based on these POPs were fabricated by solution casting. The influence of side groups on the desulfurization performance of membranes was systematically evaluated via a pervaporation test. Among these membranes, the PTFBP membrane exhibited the highest separation efficiency, significantly outperforming other membrane types with a permeation flux of 0.284 kg·m⁻²·h⁻¹ at 200 ppm and 85 °C, along with a sulfur enrichment factor of 26.48. In addition, the effects of temperature and feed concentration on separation performance were investigated in detail. Full article

(This article belongs to the Special Issue Polymer Membranes for Gas and Liquid Filtration Techniques)

► Show Figures

Figure 1

16 pages, 4371 KiB

Open AccessArticle

Graphitization Optimization of Cobalt-Doped Porous Carbon Derived from Seaweed Sludge for Enhanced Microwave Absorption

by Kai Liu, Yusen Ai, Mei Cui, Renliang Huang and Rongxin Su

Polymers 2025, 17(11), 1572; https://doi.org/10.3390/polym17111572 - 5 Jun 2025

Viewed by 320

Abstract

Utilizing biomass resources to develop carbon-based microwave-absorbing materials adheres to the principles of sustainable development. Nevertheless, the single loss mechanism of pure carbon materials is limited. Additionally, the carbonization of artificially synthesized polymers has poor environmental performance and involves complex processes. These issues [...] Read more.

Utilizing biomass resources to develop carbon-based microwave-absorbing materials adheres to the principles of sustainable development. Nevertheless, the single loss mechanism of pure carbon materials is limited. Additionally, the carbonization of artificially synthesized polymers has poor environmental performance and involves complex processes. These issues restrict their performance and broader applicability. In this study, cobalt-doped seaweed sludge porous carbon (Co/SSPC) with different cobalt contents was synthesized via a simple grinding–carbonization treatment. The addition of cobalt can regulate the graphitization degree of porous carbon, achieving a suitable amorphous-to-crystalline carbon ratio of 2.05. This not only enhances magnetic loss but also modifies dielectric loss and optimizes impedance matching. The construction of synergistic magnetic and dielectric loss mechanisms enables Co/SSPC to exhibit excellent microwave absorption performance. Specifically, Co/SSPC achieved a minimum reflection loss (RL_min) of −66.91 dB at a thickness of 4.79 mm and an effective absorption bandwidth (EAB) of 5.09 GHz at a thickness of 1.6 mm. This study provides a practical approach for the functional application of natural polymer waste algal sludge and highlights its potential in the low-cost production of microwave absorbing materials. Full article

(This article belongs to the Section Polymer Applications)

► Show Figures

Figure 1

25 pages, 6135 KiB

Open AccessArticle

Enhancement of Polyvinyl Alcohol-Based Films by Chemically Modified Lignocellulosic Nanofibers Derived from Bamboo Shoot Shells

by Jingjing Du, Jianlong Guo, Qian Zhu, Jiagang Guo, Jiayu Gu, Yuhan Wu, Ling Ren, Song Yang and Jian Jiang

Polymers 2025, 17(11), 1571; https://doi.org/10.3390/polym17111571 - 5 Jun 2025

Viewed by 445

Abstract

In this study, polyvinyl alcohol (PVA) films were reinforced with lignocellulosic nanofibers (LCNFs) extracted from bamboo shoot shells using a choline chloride-based deep eutectic solvent (DES). A filler loading of 10 wt% was identified as the optimal condition for enhancing film performance. To [...] Read more.

In this study, polyvinyl alcohol (PVA) films were reinforced with lignocellulosic nanofibers (LCNFs) extracted from bamboo shoot shells using a choline chloride-based deep eutectic solvent (DES). A filler loading of 10 wt% was identified as the optimal condition for enhancing film performance. To improve interfacial compatibility between the PVA matrix and LCNFs, three surface modification treatments were applied to the nanofibers: hydrochloric acid (HCl) hydrolysis, citric acid (CA) crosslinking, and a dual modification combining both methods (HCl&CA). Among all formulations, films incorporating dual-modified LCNF at 10 wt% loading exhibited the most significant improvements. Compared to neat PVA, these composites showed a 79.2% increase in tensile strength, a 15.1% increase in elongation at break, and a 33.1% enhancement in Young’s modulus. Additionally, thermal stability and barrier properties were improved, while water swelling and solubility were reduced. Specifically, the modified films achieved a thermal residue of 9.21% and the lowest degradation rate of 10.81%/min. Water vapor transmission rate and oxygen permeability decreased by 18.8% and 18.6%, respectively, and swelling and solubility dropped to 14.26% and 3.21%. These results highlight the synergistic effect of HCl hydrolysis and CA crosslinking in promoting uniform filler dispersion and strong interfacial adhesion, offering an effective approach to valorizing bamboo shoot shell waste into high-performance, eco-friendly packaging materials. Full article

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

► Show Figures

Graphical abstract

23 pages, 348 KiB

Open AccessArticle

Bouncy Idea or Solid Practice? Exploring Industry Barriers in the Incorporation of Devulcanized Rubber into Compounds for Rubber Products

by Eric Roetman, Jelle Joustra, Geert Heideman and Ruud Balkenende

Polymers 2025, 17(11), 1570; https://doi.org/10.3390/polym17111570 - 5 Jun 2025

Viewed by 516

Abstract

Devulcanization has the potential to help meet circular economy goals by recovering end-of-life rubber. However, the adoption of devulcanized rubber by manufacturers remains low at the industry level. Devulcanization value chains are complex and involve multiple stakeholders, including waste collectors, sorters, recyclers, compounders, [...] Read more.

Devulcanization has the potential to help meet circular economy goals by recovering end-of-life rubber. However, the adoption of devulcanized rubber by manufacturers remains low at the industry level. Devulcanization value chains are complex and involve multiple stakeholders, including waste collectors, sorters, recyclers, compounders, manufacturers and regulatory bodies. This study investigated the barriers compounders and manufacturers face when incorporating devulcanized rubber into new compounds and identified primary underlying causes. The research was conducted through in-depth interviews with compounders and manufacturers of tires and general rubber goods, focusing on the technical, market, institutional, and cultural factors related to incorporating recycled materials, specifically devulcanized rubber. From the results, we identified a number of barriers faced by the industry. A key barrier was the heterogeneity of devulcanized rubber, which made it more difficult to add to new rubber compounds with consistent quality. Other barriers included a lack of standardization and coordination, along with misaligned regulations that hamper the market adoption of devulcanized rubber. This implies that increasing the uptake of devulcanized rubber at the industry level will not be achieved through technological advancements alone or isolated market interventions; instead, it requires comprehensive, systemic solutions. Full article

(This article belongs to the Special Issue Exploration and Innovation in Sustainable Rubber Performance)

17 pages, 3986 KiB

Open AccessArticle

Dual-Surface-Modified Triboelectric Nanogenerator with Polymer Microcone Array and Its Application to Impact Visual and Voice Warning

by Dong-Yi Lin and Chen-Kuei Chung

Polymers 2025, 17(11), 1569; https://doi.org/10.3390/polym17111569 - 5 Jun 2025

Viewed by 481

Abstract

Poly(dimethylsiloxane) (PDMS) is a predominantly utilized negative triboelectric material in triboelectric nanogenerators (TENGs). Its surface topography and synergistic interaction with positive triboelectric materials significantly impact the performance of TENGs. Here, we propose a simple and cost-effective approach to promote the performance of a [...] Read more.

Poly(dimethylsiloxane) (PDMS) is a predominantly utilized negative triboelectric material in triboelectric nanogenerators (TENGs). Its surface topography and synergistic interaction with positive triboelectric materials significantly impact the performance of TENGs. Here, we propose a simple and cost-effective approach to promote the performance of a dual-surface-modified TENG using microwave-structured aluminum (MW-Al) together with microcone-structured polydimethylsiloxane (MC-PDMS). Laser-engraved molds were employed to cold-imprint the MC-Al and pattern the MC-PDMS. Subsequently, the impact of the heights of microcones generated under varying laser powers on the performance of TENGs was explored. The output performance of the MW-MC-TENG significantly increased with microcone heights from 0 to 228 μm. The MW-MC228-TENG, with the highest cone heights, can produce the best open-circuit voltage of 157 V and a short-circuit current of 78.5 µA, resulting in a more than 37% improvement compared to the TENG using flat polymer. Furthermore, the MW-MC228-TENG showed a power density of 16.4 W/m², sufficient to power 198 LEDs. Finally, the proposed TENG was integrated as a sensor into an impact warning system. We triggered a voice–visual warning when the TENG impacted, proving its potential for intelligent home safety monitoring. Full article

(This article belongs to the Section Polymer Applications)

► Show Figures

Figure 1

21 pages, 2001 KiB

Open AccessArticle

Effect of Continuous Mixer Design and Parameters on the Degradation of Polylactic Acid

by Mansour Alotaibi, Jainam Shah, Aniket Sadani and Carol Forance Barry

Polymers 2025, 17(11), 1568; https://doi.org/10.3390/polym17111568 - 4 Jun 2025

Viewed by 398

Abstract

Polylactic acid (PLA) has gained attention as a sustainable, compostable polyester, but process-induced degradation in single- and twin-screw extruders reduces PLA’s molecular weight and affects its properties. In addition, PLA is often blended with other materials to improve its properties. A continuous mixer, [...] Read more.

Polylactic acid (PLA) has gained attention as a sustainable, compostable polyester, but process-induced degradation in single- and twin-screw extruders reduces PLA’s molecular weight and affects its properties. In addition, PLA is often blended with other materials to improve its properties. A continuous mixer, which provides tighter control of shear levels and lower processing temperatures, produces less degradation of heat-sensitive polymers like polyvinyl chloride, but there is limited information about the effects of machine design and processing parameters. Therefore, this work investigated three parameters in the mixer section (rotor design, rotor speed, and orifice position) and screw speeds in the extruder section when processing PLA using a continuous mixer. The resultant PLA samples were characterized for their rheological, thermal, and chemical structure properties. It was found that higher rotor speeds and smaller orifice openings resulted in lower molecular weights, whereas varying the screw speed in the extruder did not significantly affect the molecular weight. Rotor design substantially impacted degradation, with rotors that provided lower shear stress and residence time producing very low reductions in molecular weight. Overall, this work provided insight on how to select rotors and processing parameters to reduce degradation of PLA for continuous mixer Full article

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

► Show Figures

Figure 1

18 pages, 3417 KiB

Open AccessArticle

Design and Preparation of Inherently Photostable Poly(Butylene Adipate-Co-Terephthalate) by Chemically Bonding UV-Stabilizing Moieties in Molecular Chains

by Xinpeng Zhang, Yan Ye, Yaqiao Wang, Hongli Bian, Jing Yuan, Jianping Ding, Wanli Li, Jun Xu and Baohua Guo

Polymers 2025, 17(11), 1567; https://doi.org/10.3390/polym17111567 - 4 Jun 2025

Viewed by 427

Abstract

Poly(butylene adipate-co-terephthalate) (PBAT) is a promising biodegradable polymer with balanced mechanical properties and excellent degradability, making it an ideal material to reduce plastic pollution. However, its susceptibility to ultraviolet (UV) degradation, due to photosensitive aromatic rings and carbonyl groups in its structure, limits [...] Read more.

Poly(butylene adipate-co-terephthalate) (PBAT) is a promising biodegradable polymer with balanced mechanical properties and excellent degradability, making it an ideal material to reduce plastic pollution. However, its susceptibility to ultraviolet (UV) degradation, due to photosensitive aromatic rings and carbonyl groups in its structure, limits its use in outdoor settings like mulch films. Conventional methods of incorporating small-molecule UV stabilizers face challenges such as poor compatibility, uneven dispersion, and migration under environmental conditions, reducing their effectiveness over time. This study developed a novel strategy to enhance PBAT’s UV resistance by chemically bonding UV-stabilizing moieties directly into its molecular chains to address these limitations. A novel UV absorber containing a polymerizable group was synthesized and copolymerized with PBAT’s main chain, creating an intrinsically UV-stable PBAT. The UV-stable PBAT was evaluated for UV resistance, mechanical performance, and durability through accelerated aging and solvent extraction tests. The results demonstrated that UV-stable PBAT exhibited exceptional light stabilization effects, with no detectable UV absorber leaching in ethanol even after 114 h, whereas PBAT blends lost nearly 90% of UV-0 within 24 h. Furthermore, UV-stable PBAT maintained 67.1% tensile strength and 48.8% elongation at break after aging, which exhibited the best mechanical retention performance. Even when subjected to solvent extraction, the 42.6% tensile strength retention outperformed the PBAT blends. This innovative chemical modification overcomes the limitations of additive-based stabilization, offering improved durability, compatibility, and performance in outdoor applications. Our research provides key insights into the fundamental properties of PBAT films for UV resistance, demonstrating their potential for use in demanding fields such as agricultural films. Full article

(This article belongs to the Section Polymer Applications)

► Show Figures

Figure 1

34 pages, 2275 KiB

Open AccessReview

A State-of-the-Art Review on Recent Biomedical Application of Polysaccharide-Based Niosomes as Drug Delivery Systems

by Andreea-Teodora Iacob, Andra Ababei-Bobu, Oana-Maria Chirliu, Florentina Geanina Lupascu, Ioana-Mirela Vasincu, Maria Apotrosoaei, Bianca-Stefania Profire, Georgiana-Roxana Tauser, Dan Lupascu and Lenuta Profire

Polymers 2025, 17(11), 1566; https://doi.org/10.3390/polym17111566 - 4 Jun 2025

Viewed by 559

Abstract

The development of nanocarriers for drug delivery has drawn a lot of attention due to the possibility for tailored delivery to the ill region while preserving the neighboring healthy tissue. In medicine, delivering drugs safely and effectively has never been easy; therefore, the [...] Read more.

The development of nanocarriers for drug delivery has drawn a lot of attention due to the possibility for tailored delivery to the ill region while preserving the neighboring healthy tissue. In medicine, delivering drugs safely and effectively has never been easy; therefore, the creation of surfactant-based vesicles (niosomes) to enhance medication delivery has gained attention in the past years. Niosomes (NIOs) are versatile drug delivery systems that facilitate applications varying from transdermal transport to targeted brain delivery. These self-assembling vesicular nano-carriers are formed by hydrating cholesterol, non-ionic surfactants, and other amphiphilic substances. The focus of the review is to report on the latest NIO-type formulations which also include biopolymers from the polysaccharide class, highlighting their role in the development of these drug delivery systems (DDSs). The NIO and polysaccharide types, together with the recent pharmaceutical applications such as ocular, oral, nose-to brain, pulmonary, cardiac, and transdermal drug delivery, are all thoroughly summarized in this review, which offers a comprehensive compendium of polysaccharide-based niosomal research to date. Lastly, this delivery system’s limits and prospects are also examined. Full article

(This article belongs to the Special Issue Biomedical Applications of Polymeric Materials, 3rd Edition)

► Show Figures

Graphical abstract

36 pages, 13208 KiB

Open AccessReview

Additive Manufacturing of Metal-Infilled Polylactic Acid-Based Sustainable Biocomposites—A Review of Methods, Properties and Applications Abetted with Patent Landscape Analysis

by Sengottaiyan Sivalingam, Venkateswaran Bhuvaneswari, Lakshminarasimhan Rajeshkumar and Devarajan Balaji

Polymers 2025, 17(11), 1565; https://doi.org/10.3390/polym17111565 - 4 Jun 2025

Viewed by 679

Abstract

Innovations in additive manufacturing (AM) methods represent a significant advancement in manufacturing technology, opening new avenues for creating objects in various shapes and sizes. Fused deposition modeling (FDM) is a specialized AM technique in which computers build layers upon each other to form [...] Read more.

Innovations in additive manufacturing (AM) methods represent a significant advancement in manufacturing technology, opening new avenues for creating objects in various shapes and sizes. Fused deposition modeling (FDM) is a specialized AM technique in which computers build layers upon each other to form a complete 3D object. The feasibility of producing metal parts using these methods has been thoroughly analyzed, but the design process has yet to catch up with manufacturing capabilities. Biodegradable aliphatic polyester PLA is derived from lactic acid. To enhance its strength, PLA is combined with metal particles, resulting in versatile property improvements and applications. While the aesthetic and functional qualities of PLA–metal composite filaments are intriguing, they also present difficulties related to extrusion, equipment wear, and maintaining consistent print quality. These challenges could be mitigated, to some extent, with careful tuning and specialized hardware. However, the inferior mechanical properties of bioresorbable PLA filaments highlight the need for the development of infilled PLA filaments to improve strength and other characteristics. This review discusses the 3D printing of PLA infilled with metal particles, various materials used, and their properties as a matter of interest in AM technology. Additionally, the applications of PLA–metal composites, along with their implications, limitations, and prospects, are comprehensively examined in this article. This sets the stage for the development of high-strength, sustainable materials for use in a range of engineering and technology fields. Full article

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

► Show Figures

Figure 1

18 pages, 2724 KiB

Open AccessArticle

Projection-Based Simulation Method for Robotic 3D Printing of Large-Scale Polymer Composite Structures

by Yuen Xia, Kil-Sung Lee and Sung Kyu Ha

Polymers 2025, 17(11), 1564; https://doi.org/10.3390/polym17111564 - 4 Jun 2025

Viewed by 399

Abstract

As large-scale additive manufacturing advances, the reliable prediction of the structural behavior of FDM-printed composites is becoming increasingly important. However, existing finite element methods often oversimplify the material anisotropy introduced by the printing path. This study proposes a projection-based method that maps toolpath-defined [...] Read more.

As large-scale additive manufacturing advances, the reliable prediction of the structural behavior of FDM-printed composites is becoming increasingly important. However, existing finite element methods often oversimplify the material anisotropy introduced by the printing path. This study proposes a projection-based method that maps toolpath-defined fiber orientations directly into a finite element model to represent anisotropic mechanical behavior. The mechanical properties of printed carbon fiber-reinforced ABS were experimentally characterized in three directions (UDL, UDT, and UD10). The results confirmed strong anisotropy, with elastic moduli ranging from 3.2 to 9.8 GPa and tensile strengths from 20 to 81 MPa. The shear modulus and strength obtained from the 10° off-axis tensile tests were 1.17 GPa and 10.9 MPa, respectively. This directional data enabled the implementation of the FE model of a 20 m-long printed ship structure. The predicted mid-span deflection (2.19 mm) differed by only 5% from the experimental measurement (2.08 mm). While effective, this method may face challenges with highly irregular geometries. Nevertheless, it offers a scalable approach for the accurate simulation of FDM-printed composites. Full article

(This article belongs to the Special Issue Sustainable Cost-Effective Lightweight Polymer Composites)

► Show Figures

Figure 1

19 pages, 5240 KiB

Open AccessArticle

Development of Lightweight Thermoplastic Acrylic PMMA Composites and Characterization of Their Mechanical Properties

by Jiming Sun, Hyeonseok Han, Sooyeon Ahn, Seongsu Jung and Sung Kyu Ha

Polymers 2025, 17(11), 1563; https://doi.org/10.3390/polym17111563 - 4 Jun 2025

Viewed by 406

Abstract

The effects of benzoyl peroxide (BPO) and dimethylaniline (DMA) composition on the induction time and the tensile strength of thermoplastic acrylic (PMMA) resins have been investigated in this study. Eighteen resin formulations were prepared with different BPO/DMA ratios (2.0–9.5) and DMA contents (0.28–0.65 [...] Read more.

The effects of benzoyl peroxide (BPO) and dimethylaniline (DMA) composition on the induction time and the tensile strength of thermoplastic acrylic (PMMA) resins have been investigated in this study. Eighteen resin formulations were prepared with different BPO/DMA ratios (2.0–9.5) and DMA contents (0.28–0.65 mol%), and it was observed that tensile strengths reached up to 66 MPa, and induction times (ITs) ranged from 100 to 207 min. Higher BPO/DMA ratios improved tensile strength but shortened IT, while greater DMA content accelerated curing. Polynomial regression models were successfully established, i.e., a third-order equation for the strength and a second-order equation for the IT, based on the BPO/DMA ratio and DMA content to identify the optimal formulation to balance the strength and the IT time. Two selected formulations, P-4-0.5 and P-3-0.3, were applied in vacuum-assisted resin infusion of glass fiber composites. The best-performing unidirectional (UD) laminate achieved a tensile strength of 1244 MPa. As regards ±45° biaxial (BX45) laminates, they exhibited a tensile strength of 124 MPa and a failure strain of 9.02%, which, while lower than that of epoxy, indicates competitive performance. These results demonstrate that the resin was well infused, resulting in 64% higher fiber volume fraction than typical infused glass/epoxy composites, and compositionally optimized PMMA resins can deliver epoxy-comparable strength and enhance damage tolerance in structural composite applications. Full article

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

► Show Figures

Figure 1

19 pages, 4886 KiB

Open AccessArticle

Feasibility of 3D-Printed PLA Meshes in Gypsum Composites: Preliminary Experiments and Insights

by Ahmet Hayrullah Sevinç and Muhammed Yasin Durgun

Polymers 2025, 17(11), 1562; https://doi.org/10.3390/polym17111562 - 4 Jun 2025

Viewed by 387

Abstract

The mechanical limitations of gypsum-based composites necessitate reinforcement strategies to enhance their structural performance. This study investigates the feasibility of integrating 3D-printed polylactic acid (PLA) meshes into gypsum composites through a series of preliminary experiments. Various mesh configurations were tested, including different fiber [...] Read more.

The mechanical limitations of gypsum-based composites necessitate reinforcement strategies to enhance their structural performance. This study investigates the feasibility of integrating 3D-printed polylactic acid (PLA) meshes into gypsum composites through a series of preliminary experiments. Various mesh configurations were tested, including different fiber thicknesses, mesh grid sizes, and single- and double-layer applications. The impact of mesh incorporation on bulk density, ultrasonic pulse velocity (UPV), bending strength, and compressive strength was assessed. The results indicate that the inclusion of PLA meshes had a limited effect on bulk density and led to a slight decrease in UPV values, suggesting increased porosity. Although improvements in mechanical properties were anticipated, most specimens exhibited lower bending and compressive strengths compared to the reference specimen. Among the tested configurations, 2 mm thick meshes demonstrated relatively higher performance, particularly in bending strength, with narrow-mesh aperture yielding better results. However, double-layer mesh applications consistently resulted in lower strength values. These findings highlight the challenges associated with integrating 3D-printed PLA meshes into gypsum composites. While the study provides valuable insights into mesh-based reinforcement, further investigations are required to optimize fiber–matrix interactions and enhance mechanical performance. Future research should explore alternative printing parameters, improved adhesion techniques, and hybrid reinforcement approaches to fully exploit the potential of additive manufacturing in gypsum-based composites. Full article

(This article belongs to the Special Issue Recent Advances in 3D Printing of Polymer Composites)

► Show Figures

Figure 1

17 pages, 2567 KiB

Open AccessArticle

Enhancing Technical Performance of PVC Production: A WEP-Based Energy and Water Assessment

by Rolando Manuel Guardo-Ruiz, Linda Mychell Puello-Castellón, Rodrigo Ortega-Toro, Eduardo Andrés Aguilar-Vásquez and Ángel Darío González-Delgado

Polymers 2025, 17(11), 1561; https://doi.org/10.3390/polym17111561 - 4 Jun 2025

Viewed by 390

Abstract

Polyvinyl chloride (PVC) is one of the most widely used polymers due to its physical properties and versatility. Water consumption of the suspension method is a critical issue that hinders competitiveness. In that case, this study implements water integration through direct recycling, with [...] Read more.

Polyvinyl chloride (PVC) is one of the most widely used polymers due to its physical properties and versatility. Water consumption of the suspension method is a critical issue that hinders competitiveness. In that case, this study implements water integration through direct recycling, with the aim of minimizing both freshwater consumption and wastewater generation. The source–sink diagram was used to generate the recycled water network, and the integrated process was simulated using software. From simulation data, the water–energy–product (WEP) analysis method was used to assess the process performance, and sustainability indicators for water, energy, and product were evaluated. Fractional water consumption and wastewater production ratio indicators increased to 51.1% and 55.0%, compared to 41% and 54% in the non-integrated process, showing improved water efficiency and cost reduction. The unreacted material reuse index reached 100%, while the production yield was 99.8%, due to effective recycling of unreacted VCM. The use of natural gas and energy integration led to optimal performance in TCE, NGCI, and EECI indicators. However, the ESI indicator was high (3.59 MJ/t) due to energy demands from thermal control equipment for water recirculation. Full article

(This article belongs to the Special Issue Biodegradable and Functional Polymers for Food Packaging)

► Show Figures

Figure 1

13 pages, 2036 KiB

Open AccessArticle

Oxidative Decomposition of Poly(phenylene sulfide) Composites Under Fast Elevation of Temperature

by Aurélie Bourdet, Yann Carpier, Eric Dargent, Benoit Vieille and Nicolas Delpouve

Polymers 2025, 17(11), 1560; https://doi.org/10.3390/polym17111560 - 3 Jun 2025

Viewed by 530

Abstract

The thermal resistance of carbon fiber–reinforced poly(phenylene sulfide) to harsh oxidative conditions is investigated through thermogravimetric experiments performed in an oxygen atmosphere. While these materials usually show great resistance against thermal decomposition in a nitrogen atmosphere, the experiments in oxygen reveal the total [...] Read more.

The thermal resistance of carbon fiber–reinforced poly(phenylene sulfide) to harsh oxidative conditions is investigated through thermogravimetric experiments performed in an oxygen atmosphere. While these materials usually show great resistance against thermal decomposition in a nitrogen atmosphere, the experiments in oxygen reveal the total decomposition of both the matrix and the carbon fibers. The Gram–Schmidt signal, obtained by coupling thermogravimetric analysis in standard conditions with Fourier-transform infrared spectroscopy, exhibits multiple events, evidencing that the decomposition proceeds through distinct stages. The first step characterizes the char formation, while the second relates to its oxidative decomposition. A third step, only observed for composites, is interpreted as the signature of the oxidative decomposition of carbon fibers. To mimic the sudden elevation of temperature encountered during a fire, the analyses are performed at rates of up to 500 K min⁻¹. These specific experimental conditions reveal a complex dependence of the thermogravimetric signature on the heating rate. Independent of the atmosphere, nitrogen or oxygen, the characteristic temperature of decomposition follows a bell-shape trend, resulting from the combination of lag effects and thermal-conductivity limitations. Additionally, the increase of the heating rate causes the Gram–Schmidt signal to evolve toward a broad peak with indistinct events. To investigate whether these changes affect the decomposition products, the infrared spectra, continuously recorded to probe the whole decomposition, are compared with those from the database. The char formation is characterized by the production of sulfur dioxide, while carbon dioxide is the main product emitted during both char and fiber oxidative decomposition. Owing to the merging of the decomposition stages, sulfur-dioxide detection is partly supplanted by that of carbon dioxide under fast elevations of temperature. Full article

(This article belongs to the Special Issue Advances in the Thermal Characterization of Polymers and Plastic Waste)

► Show Figures

Figure 1

27 pages, 6117 KiB

Open AccessArticle

Biocomposites Based on Biopolyamide with Reduced Water Absorption and Increased Fatigue Strength

by Patrycja Bazan, Elisabeth Egholm Jacobsen, Anna Olsen and Kristofer Gunnar Paso

Polymers 2025, 17(11), 1559; https://doi.org/10.3390/polym17111559 - 3 Jun 2025

Viewed by 431

Abstract

In this study, composites were developed using a biopolyamide matrix modified with microsilica at varying concentrations (0.5–2% by weight). These composites underwent water absorption analysis, and diffusion velocity was assessed. Based on the findings, hybrid composites incorporating aramid, basalt, and carbon fibers, further [...] Read more.

In this study, composites were developed using a biopolyamide matrix modified with microsilica at varying concentrations (0.5–2% by weight). These composites underwent water absorption analysis, and diffusion velocity was assessed. Based on the findings, hybrid composites incorporating aramid, basalt, and carbon fibers, further modified with 2% microsilica by weight, were fabricated. Investigations into fundamental mechanical properties, microstructure analysis, and accelerated fatigue tests were conducted. The results demonstrate that microsilica positively influences the enhancement of fatigue strength and mechanical properties of the composites. Specifically, microsilica is found to increase the approximate fatigue strength by 15% for the base material modified with 2 wt.% microsilica, by approximately 5% for composites with aramid fiber, and by between 10 and 15% for composites with basalt and carbon fiber. Furthermore, the incorporation of microsilica reduces water absorption in polymer composites, potentially enhancing their durability in humid environments and increasing resistance to degradation. Full article

(This article belongs to the Special Issue Polymer Nanocomposites and Nanoparticles: Preparation and Applications)

► Show Figures

Graphical abstract

26 pages, 11179 KiB

Open AccessArticle

Surface Morphology and Degradation of Poly[(R)-3-Hydroxybutyrate]-block-Poly(ε-Caprolactone) and Poly[(R)-3-Hydroxybutyrate]-block-Poly(l-Lactide) Biodegradable Diblock Copolymers

by Ayan Bartels-Ellis, Senri Hayashi, Tomohiro Hiraishi, Takeharu Tsuge and Hideki Abe

Polymers 2025, 17(11), 1558; https://doi.org/10.3390/polym17111558 - 3 Jun 2025

Viewed by 430

Abstract

Bacterially produced poly[(R)-3-hydroxybutyrate] (P3HB) was subjected to an alcoholysis reaction to produce low-molecular-weight (M_n ≈ 10,000 g mol⁻¹) hydroxy-terminated P3HB (LMPHB). Using diethyl zinc as a catalyst, LMPHB was reacted with the cyclic monomers ε-caprolactone and l [...] Read more.

Bacterially produced poly[(R)-3-hydroxybutyrate] (P3HB) was subjected to an alcoholysis reaction to produce low-molecular-weight (M_n ≈ 10,000 g mol⁻¹) hydroxy-terminated P3HB (LMPHB). Using diethyl zinc as a catalyst, LMPHB was reacted with the cyclic monomers ε-caprolactone and l-lactide in separate ring-opening polymerization (ROP) reactions to produce PHB-b-PCL (PHBCL) and PHB-b-PLA (PHBLA) AB-type crystalline–crystalline diblock copolymers with varying PCL and PLA block lengths. ¹H NMR and GPC were used to confirm the structure of the polymers. DSC was used to measure the thermal properties as well as assessing crystallization. A single-shifting T_g for PHBLA showed the two blocks to be miscible in the melt. The TGA results indicate enhanced thermal stability over the homopolymer P3HB. A study of the crystallization was undertaken by combining WAXD, a second DSC heating regime, and POM. POM showed that the crystallization in PHBCL to be dependent on the crystallization temperature more so than PHBLA, whose composition appeared to be the more definitive factor determining the spherulitic morphology. The results informed the crystallization temperatures used in the production of the melt-crystallized thin films that were imaged using AFM. AFM images showed unique surface morphologies dependent on the diblock copolymer composition, block length, and crystallization temperature. Finally, the enzymatic degradation studies showed these unique surface morphologies to influence how these block copolymers were degraded by enzymes. Full article

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

► Show Figures

Graphical abstract

19 pages, 6726 KiB

Open AccessArticle

Simulation of Aging and Bonding Properties of the Matrix/Filler Interface in Particle-Reinforced Composites

by Zebin Chen, Xueren Wang, Zijie Zou, Hongfu Qiang and Xiao Fu

Polymers 2025, 17(11), 1557; https://doi.org/10.3390/polym17111557 - 3 Jun 2025

Viewed by 473

Abstract

To investigate the microscopic mechanism of aging-induced “dewetting” at the matrix/filler interface in Nitrate Ester Plasticized Polyether (NEPE) propellant, this study decoupled the aging process into two factors: crosslinking density evolution and nitrate ester decomposition. Molecular dynamics (MD) simulations were employed to construct [...] Read more.

To investigate the microscopic mechanism of aging-induced “dewetting” at the matrix/filler interface in Nitrate Ester Plasticized Polyether (NEPE) propellant, this study decoupled the aging process into two factors: crosslinking density evolution and nitrate ester decomposition. Molecular dynamics (MD) simulations were employed to construct all-component matrix models and matrix/filler interface models with varying aging extents. Key parameters including crosslinking density, mechanical properties, free volume fraction, diffusion coefficients of the matrix, as well as interfacial binding energy and radial distribution function (RDF) were calculated to analyze the effects of both aging factors on “debonding”. The results indicate the following: 1. Increased crosslinking density enhances matrix rigidity, suppresses molecular mobility, and causes interfacial binding energy to initially rise then decline, peaking at 40% crosslinking degree. 2. Progressive nitrate ester decomposition expands free volume within the matrix, improves binder system mobility, and weakens nitrate ester-induced interfacial damage, thereby strengthening hydrogen bonding and van der Waals interactions at the interface. 3. The addition of a small amount of bonding agent improved the interfacial bonding energy but did not change the trend of the bonding energy with aging. Full article

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

► Show Figures

Figure 1

16 pages, 1795 KiB

Open AccessFeature PaperArticle

Sustainable Polypropylene Blends: Balancing Recycled Content with Processability and Performance

by Tatiana Zhiltsova and Mónica S. A. Oliveira

Polymers 2025, 17(11), 1556; https://doi.org/10.3390/polym17111556 - 3 Jun 2025

Viewed by 582

Abstract

The increasing demand for sustainable materials has renewed interest in recycling polyolefins, particularly polypropylene (PP), due to its widespread use and environmental persistence. Post-consumer recycled polypropylene (PP_r), however, often exhibits compromised properties from prior exposure to thermal, oxidative, and mechanical degradation. [...] Read more.

The increasing demand for sustainable materials has renewed interest in recycling polyolefins, particularly polypropylene (PP), due to its widespread use and environmental persistence. Post-consumer recycled polypropylene (PP_r), however, often exhibits compromised properties from prior exposure to thermal, oxidative, and mechanical degradation. This study investigates the potential of using post-consumer PP_r in melt-blended extrusion formulations with virgin PP (PP_v), focusing on how different PP_r contents affect processability, thermal stability, oxidative resistance, and mechanical performance. Blends containing 25%, 50%, and 75% PP_r, as well as 100% PP_r and virgin PP, were evaluated using melt flow index (MFI), differential scanning calorimetry (DSC), oxidation induction time (OIT), thermogravimetric analysis (TGA), and tensile testing. Results show that increasing PP_r content improves polymer fluidity and thermal stability under inert conditions but significantly reduces oxidation resistance and ductility. However, the 25% PP_r blend demonstrated a favourable balance between performance and recyclability, presenting 96% of the elastic modulus and 101% of the yield strength of PP_v. Homogenization by extrusion improved the oxidative stability of recycled PP by 22% compared to its non-extruded form. These findings support the use of low-to-moderate levels of PP_r in virgin PP for applications requiring predictable and tunable performance. contributing to circular economy goals. Full article

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

► Show Figures

Figure 1

22 pages, 8987 KiB

Open AccessArticle

Inclusion of Magnesium- and Strontium-Enriched Bioactive Glass into Electrospun PCL Scaffolds for Tissue Regeneration

by Francesco Gerardo Mecca, Nathália Oderich Muniz, Devis Bellucci, Cécile Legallais, Timothée Baudequin and Valeria Cannillo

Polymers 2025, 17(11), 1555; https://doi.org/10.3390/polym17111555 - 3 Jun 2025

Viewed by 577

Abstract

Bioactive glass (BG) is a promising material known for its osteogenic, osteoinductive, antimicrobial, and angiogenic properties. For this reason, melt-quench-derived BG powders embedded into composite electrospun poly(ε-caprolactone) (PCL) mats represent an interesting option for the fabrication of bioactive scaffolds. However, incorporating BG into [...] Read more.

Bioactive glass (BG) is a promising material known for its osteogenic, osteoinductive, antimicrobial, and angiogenic properties. For this reason, melt-quench-derived BG powders embedded into composite electrospun poly(ε-caprolactone) (PCL) mats represent an interesting option for the fabrication of bioactive scaffolds. However, incorporating BG into nano-/micro-fibers remains challenging. Our research focused on integrating two BG compositions into the mat structure: 45S5 and 45S5_MS (the former being a well-known, commercially available BG composition, and the latter a magnesium- and strontium-enriched composition based on 45S5). Both BG types were added at concentrations of 10 wt.% and 20 wt.%. A careful grinding process enabled effective dispersion of BG into a PCL solution, resulting in fibers ranging from 500 nm to 2 µm in diameter. The mats’ mechanical properties were not hindered by the inclusion of BG powder within the fibrous structure. Furthermore, our results indicate that BG powders were successfully incorporated into the scaffolds, not only preserving their properties but potentially enhancing their biological performance compared to unloaded PCL electrospun scaffolds. Our findings indicate proper cell differentiation and proliferation, supporting the potential of these devices for tissue regeneration applications. Full article

(This article belongs to the Special Issue Biomedical Applications of Polymeric Materials, 3rd Edition)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Polymers, Volume 17, Issue 11 (June-1 2025) – 160 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI