Polymers

13 pages, 693 KiB

Open AccessArticle

Effect of Recycling on the Thermal and Rheological Properties of PP/MWCNT Composites Used as Liner Materials

by Attila Bata, Ferenc Ronkay, Caizhi Zhang and Péter Gerse

Polymers 2025, 17(16), 2178; https://doi.org/10.3390/polym17162178 (registering DOI) - 8 Aug 2025

In this study, we developed polypropylene-based nanocomposites using different (0.3, 0.5, and 1 wt%) fillers of multi-walled carbon nanotubes (MWCNTs), with a particular focus on their applicability as lining materials for Type IV hydrogen storage tanks. The aim of this research was to [...] Read more.

In this study, we developed polypropylene-based nanocomposites using different (0.3, 0.5, and 1 wt%) fillers of multi-walled carbon nanotubes (MWCNTs), with a particular focus on their applicability as lining materials for Type IV hydrogen storage tanks. The aim of this research was to improve the thermal stability and rheological behavior of PP, while also evaluating the recyclability of the resulting composites in order to support sustainability goals. A realistic recycling approach was simulated by producing original and regranulated (REG) samples using a twin-screw extruder. Thermal analysis showed that the incorporation of MWCNTs promoted crystallization, increasing both the degree of crystallinity and lamellar thickness, which are beneficial factors in terms of reducing gas permeability. Rheological tests showed increased storage and loss moduli in both nanocomposites and their recycled counterparts, especially at low frequencies. It is noteworthy that in REG samples with 0.3 and 1 wt% content, the zero-shear viscosity increased by approximately 50% and 90%, respectively, compared to pure PP. In our research, we produced nanocomposites that could offer significant advances in the field of hydrogen storage and liner materials, while the results of the regranulated composites could further enhance the sustainability of our materials. Full article

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

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24 pages, 2980 KiB

Open AccessArticle

Study on a Rheological Constitutive Model with Yield and Aging Effects for Polyethylene Gas Pipes

by Rui-Hua Yin, Si-Xi Zha, Jun-Qiang Wang and Hui-Qing Lan

Polymers 2025, 17(16), 2177; https://doi.org/10.3390/polym17162177 (registering DOI) - 8 Aug 2025

Abstract

Constitutive models and deformation behaviors for polymer materials have long been complex and are always a hot research focus. As a typical semi-crystalline polymer, polyethylene (PE) gas pipes exhibit pronounced nonlinearity, strain dependence, and time dependence during long-term service. Simple material models fail [...] Read more.

Constitutive models and deformation behaviors for polymer materials have long been complex and are always a hot research focus. As a typical semi-crystalline polymer, polyethylene (PE) gas pipes exhibit pronounced nonlinearity, strain dependence, and time dependence during long-term service. Simple material models fail to capture the scale-dependent characteristics of the PE pipes, resulting in difficulties in accurately describing and simulating their deformation and damage behavior. Currently, some PE gas pipes have entered the mid-to-late stages of service life, so it is necessary to propose a constitutive model representing their complex mechanical behavior for simulation and performance evaluation purposes. Based on results from aging tests, tensile tests, differential scanning calorimetry, and Fourier-transform infrared spectroscopy, this study proposes a method to select a rheological framework and a constitutive model that couples thermo-oxidative aging effects in PE gas pipes. The model is developed within the widely recognized rheological framework and is grounded in continuum mechanics, continuum damage mechanics, and the aging behavior of polymer materials. This method and model are suitable for characterizing the mechanical dependency of PE pipes and demonstrate strong fitting performance. According to the calculation results, the goodness of fit of this constitutive model for the uniaxial tensile test results at the different aging times ranges from 0.982 to 0.999. The findings provide theoretical support for the simulation and service life prediction for PE pipelines. Full article

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

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22 pages, 3060 KiB

Open AccessArticle

Predictive Analysis of the Mechanical Properties of Biopolymer–Fiber-Reinforced Composite-Stabilized Soil Based on Genetic Algorithm-Optimized Back Propagation Neural Networks

by Guotao Wei, Zhaoping Wang, Xuanhao Cao and Jiuran Wen

Polymers 2025, 17(16), 2176; https://doi.org/10.3390/polym17162176 (registering DOI) - 8 Aug 2025

Abstract

The limitations imposed by the inherent complexity of multi-component composition ratios in biological polymer-stabilized soils have hindered rapid and accurate performance prediction. To enhance the predictive accuracy for biopolymer–fiber-stabilized soils, an optimized GA-driven backpropagation (BP) neural network was developed. Three key factors influencing [...] Read more.

The limitations imposed by the inherent complexity of multi-component composition ratios in biological polymer-stabilized soils have hindered rapid and accurate performance prediction. To enhance the predictive accuracy for biopolymer–fiber-stabilized soils, an optimized GA-driven backpropagation (BP) neural network was developed. Three key factors influencing mechanical strength (guar gum (GG), xanthan gum (XG), and polybutylene succinate (PBS)) were identified. The global optimization capability of GA was utilized to construct an integrated GA-BP model, with these factors serving as inputs and 7d compressive strength as the output. Support vector machine (SVM) was also incorporated to provide a benchmark comparison of predictive performance. Validation was performed using 80% of the dataset, with the remaining 20% used for testing. The optimal biopolymer dosage was found to be within the range of 0.5% to 1.0%, and the maximum 7d compressive strength achieved was 466.67 kPa at the 0.5% XG–0.5% GG combination, representing a 273% increase over untreated soil. The GA-BP model demonstrated superior performance in terms of prediction accuracy and stability, as indicated by an R² of 0.887—significantly higher than those of the BP (0.714) and SVM (0.554) models. The mean squared error was substantially reduced to 1413, compared to 2130 and 3113 for BP and SVM, respectively. Although MAPE approached those of the GA-BP, the overall predictive efficacy of SVM was found to be inferior. A reliable and robust methodology for forecasting the mechanical behavior of stabilized soils has thus been provided by this model, supporting advanced applications within geotechnical engineering. Full article

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

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27 pages, 3616 KiB

Open AccessArticle

Structural and Material Optimization of a Sensor-Integrated Autonomous Aerial Vehicle Using KMU-3 CFRP

by Yerkebulan Nurgizat, Arman Uzbekbayev, Igor Fedorov, Andrey Bebenin and Andrey Karypov

Polymers 2025, 17(16), 2175; https://doi.org/10.3390/polym17162175 (registering DOI) - 8 Aug 2025

Abstract

This study addresses the selection and application of composite materials for aerospace systems operating in extreme environmental conditions, with a particular focus on high-altitude pseudo-satellites (HAPS). This research is centered on the development of a 400 kg autonomous aerial vehicle (AAV) capable of [...] Read more.

This study addresses the selection and application of composite materials for aerospace systems operating in extreme environmental conditions, with a particular focus on high-altitude pseudo-satellites (HAPS). This research is centered on the development of a 400 kg autonomous aerial vehicle (AAV) capable of sustained operations at altitudes of up to 30 km. KMU-3’s microstructure, comprising high-modulus carbon fibers (5–7 µm diameter) in a 5-211B epoxy matrix, provides a high specific strength (1000–2500 MPa), low density (1.6–1.8 g/cm³), and thermal stability (−60 °C to +600 °C), ensuring structural integrity in stratospheric conditions. The mechanical, thermal, and aerodynamic properties of KMU-3-based truss structures were evaluated using finite element method (FEM) simulations, computational fluid dynamics (CFD) analysis, and experimental prototyping. The results indicate that ultra-thin KMU-3 with a wall thickness of 0.1 mm maintains structural integrity under dynamic loads while minimizing overall mass. A novel thermal bonding technique employing 5-211B epoxy resin was developed, resulting in joints with a shear strength of 40 MPa and fatigue life exceeding 10⁶ cycles at 50% load. The material properties remained stable across the operational temperature range of −60 °C to +80 °C. An optimized fiber orientation (0°/90° for longerons and ±45° for diagonals) enhanced the resistance to axial, shear, and torsional stresses, while the epoxy matrix ensures radiation resistance. Finite element method (FEM) and computational fluid dynamics (CFD) analyses, validated by prototyping, confirm the performance of ultra-thin (0.1 mm) truss structures, achieving a lightweight (45 kg) design. These findings provide a validated, lightweight framework for next-generation HAPS, supporting extended mission durations under harsh stratospheric conditions. Full article

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

14 pages, 3600 KiB

Open AccessArticle

Edible Films Based on Fish Gelatin and Soluble Soybean Polysaccharide Enriched with Tea Polyphenol for Active Food Packaging

by Jie Liu, Zhongfeng Song, Yiwei Wang, Ying Pei and Keyong Tang

Polymers 2025, 17(16), 2174; https://doi.org/10.3390/polym17162174 - 8 Aug 2025

Abstract

The increasing demand for environmentally friendly alternatives to conventional plastic packaging has driven interest in the development of biodegradable edible films with functional properties. In this work, edible blend films were developed based on fish gelatin (FG), soluble soybean polysaccharide (SSPS), and tea [...] Read more.

The increasing demand for environmentally friendly alternatives to conventional plastic packaging has driven interest in the development of biodegradable edible films with functional properties. In this work, edible blend films were developed based on fish gelatin (FG), soluble soybean polysaccharide (SSPS), and tea polyphenol (TP) for active food packaging applications. The FG/SSPS/TP films were prepared by solvent casting and characterized in terms of their structural, mechanical, optical, thermal, and barrier properties. FTIR, SEM, and XRD analyses revealed TP-induced morphological and structure changes in the biopolymer matrix. The incorporation of TP significantly enhanced the antioxidant activity and UV-shielding properties of the films, while also modifying their flexibility and surface hydrophilicity. The packaging performance of FG/SSPS/TP films was evaluated using beef tallow as a model food product. Compared to neat FG/SSPS and polyethylene films, the FG/SSPS/TP films effectively suppressed lipid oxidation of the samples during storage. The results demonstrated that the prepared FG/SSPS/TP films possess strong potential for use as edible and active packaging materials for food products. Full article

(This article belongs to the Special Issue Smart and Active Food Packaging Systems Based on Natural Polymers)

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19 pages, 6153 KiB

Open AccessArticle

Copper–PLLA-Based Biopolymer Wrinkle Structures for Enhanced Antibacterial Activity

by Petr Slepička, Iva Labíková, Bára Frýdlová, Aneta Pagáčová, Nikola Slepičková Kasálková, Petr Sajdl and Václav Švorčík

Polymers 2025, 17(16), 2173; https://doi.org/10.3390/polym17162173 - 8 Aug 2025

Abstract

The increasing prevalence of antibiotic-resistant bacteria has intensified the need for innovative antibacterial surfaces, particularly in biomedical applications. Traditional approaches often rely on chemical agents alone, which may lead to diminishing efficacy over time. To address this, we investigated the development of a [...] Read more.

The increasing prevalence of antibiotic-resistant bacteria has intensified the need for innovative antibacterial surfaces, particularly in biomedical applications. Traditional approaches often rely on chemical agents alone, which may lead to diminishing efficacy over time. To address this, we investigated the development of a novel antibacterial surface by combining the inherent antimicrobial properties of copper with an engineered surface topography on a biopolymer matrix. A copper–poly-L-lactic acid (Cu-PLLA) composite system was fabricated using sputtering deposition followed by controlled thermal treatment to induce wrinkle-like micro- and nanostructures on the surface. The surface morphology was characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM), confirming the formation of hierarchical wrinkle patterns. The chemical composition and distribution of copper were analyzed via energy-dispersive X-ray spectroscopy (EDS). Antibacterial performance was assessed against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus using standard colony count reduction assays. The Cu-PLLA wrinkled surfaces demonstrated significantly enhanced bactericidal activity compared with flat PLLA and copper-free controls, a finding attributed to a synergistic effect of mechanical membrane disruption and copper-mediated chemical toxicity. These findings suggest that biopolymer–metal hybrid surfaces with engineered topography offer a promising strategy for developing next-generation antibacterial materials suitable for biomedical and clinical use. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Science and Technology)

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33 pages, 13337 KiB

Open AccessArticle

Machinability of Basalt and Glass Fiber Hybrid Composites in Dry Drilling Using TiN/TiAlN-Coated Drill Bits

by Mehmet İskender Özsoy, Satılmış Ürgün, Sinan Fidan, Eser Yarar, Erman Güleç and Mustafa Özgür Bora

Polymers 2025, 17(16), 2172; https://doi.org/10.3390/polym17162172 - 8 Aug 2025

Abstract

Drilling-induced damage in fiber-reinforced polymer composite materials was measured excavating four laminates, basalt (B₁₄), glass (G₁₄) and their two sandwich type hybrids (B₄G₆B₄, G₄B₆G₄), with 6 mm [...] Read more.

Drilling-induced damage in fiber-reinforced polymer composite materials was measured excavating four laminates, basalt (B₁₄), glass (G₁₄) and their two sandwich type hybrids (B₄G₆B₄, G₄B₆G₄), with 6 mm twist drills at 1520 revolutions per minute and 0.10 mm rev⁻¹ under dry running with an uncoated high-speed steel (HSS-R), grind-coated high-speed steel (HSS-G) or physical vapor deposition-coated (high-speed steel coated with Titanium Nitride (TiN) and Titanium Aluminum Nitride (TiAlN)) drill bits. The hybrid sheets were deliberately incorporated to clarify how alternating basalt–glass architectures redistribute interlaminar stresses during drilling, while the hard, low-friction TiN and TiAlN ceramic coatings enhance cutting performance by forming a heat-resistant tribological barrier that lowers tool–workpiece adhesion, reduces interface temperature, and thereby suppresses thrust-induced delamination. Replacement of an uncoated, grind-coated, high-speed-steel drill (HSS-G) with the latter coats lowered the mechanical and thermal loads substantially: mean thrust fell from 79–94 N to 24–30 N, and peak workpiece temperatures from 112 °C to 74 °C. Accordingly, entry/exit oversize fell from 2.5–4.7% to under 0.6% and, from the surface, the SEM image displayed clean fiber severance rather than pull-out and matrix smear. By analysis of variance (ANOVA), 92.7% of the variance of thrust and 86.6% of that of temperature could be accounted for by the drill-bit factor, thus confirming that the coatings overwhelm the laminate structure and hybrid stacking simply redistribute, but cannot overcome, the former influence. Regression models and an artificial neural network optimized via meta-heuristic optimization foretold thrust, temperature and delamination with an R² value of 0.94 or higher, providing an instant-screening device with which to explore industrial application. The work reveals TiAlN- and TiN-coated drills as financially competitive alternatives with which to achieve ±1% dimensional accuracy and minimum subsurface damage during multi-material composite machining. Full article

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

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28 pages, 3518 KiB

Open AccessArticle

Synthesis and Properties of Degradable Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] Derived from Waste Fish Oil

by Tatiana G. Volova, Evgeniy G. Kiselev, Alexey G. Sukovatyi, Natalia O. Zhila, Kristina Yu. Sapozhnikova, Natalia D. Ipatova and Peter O. Shishatskii

Polymers 2025, 17(16), 2171; https://doi.org/10.3390/polym17162171 - 8 Aug 2025

Abstract

The article presents the results of the first successful synthesis of degradable microbial copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate [P(3HB-co-3HV)] by the wild-type strain C. necator B-10646 using waste fish oil (WFO) obtained from the heads of Sprattus sprattus balticus. Samples [...] Read more.

The article presents the results of the first successful synthesis of degradable microbial copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate [P(3HB-co-3HV)] by the wild-type strain C. necator B-10646 using waste fish oil (WFO) obtained from the heads of Sprattus sprattus balticus. Samples of copolymers with 3HV monomer contents from 11.9 to 59.7 mol.% were synthesized with fractional and controlled feeding of potassium valerate, a precursor of 3HV monomers, into the bacterial culture. Samples synthesized on WFO with different contents of 3HV monomers had a reduced degree of crystallinity (36.5% and below), and close average molecular weight (390–573 kDa), with polydispersity of 2.6–3.0, and retained thermal stability, with a gap between the melting point and the thermal degradation temperature of over 100 °C. The thermal behavior of the samples, including the kinetics of exothermic crystallization and spherulite formation, was studied. Demonstrating the possibility of using WFO for the effective synthesis of P(3HB-co-3HV) with macroinclusions of 3HV monomers without deterioration of their properties is important for expanding the raw material base, reducing costs and increasing the availability of these promising bioplastics. Full article

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

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2 pages, 345 KiB

Open AccessCorrection

Correction: Sarwar et al. Evaluating Antibacterial Efficacy and Biocompatibility of PAN Nanofibers Loaded with Diclofenac Sodium Salt. Polymers 2021, 13, 510

by Muhammad Nauman Sarwar, Azeem Ullah, Md. Kaiser Haider, Nadir Hussain, Sana Ullah, Motahira Hashmi, Muhammad Qamar Khan and Ick Soo Kim

Polymers 2025, 17(16), 2170; https://doi.org/10.3390/polym17162170 - 8 Aug 2025

Abstract

In the originally published manuscript [...] Full article

(This article belongs to the Special Issue Polymeric Materials for Biomedical Applications)

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21 pages, 1757 KiB

Open AccessArticle

Description of Gas Transport in Polymers: Integrated Thermodynamic and Transport Modeling of Refrigerant Gases in Polymeric Membranes

by Matteo Minelli, Marco Giacinti Baschetti and Virginia Signorini

Polymers 2025, 17(16), 2169; https://doi.org/10.3390/polym17162169 - 8 Aug 2025

Abstract

Hydrofluorocarbons (HFC) are today widely used as refrigerants, solvents, or aerosols for fire protection. Due to their non-negligible environmental impact, there exists an increasing interest towards their effective separation and recovery, which still remains a major challenge. This work presents a comprehensive thermodynamic [...] Read more.

Hydrofluorocarbons (HFC) are today widely used as refrigerants, solvents, or aerosols for fire protection. Due to their non-negligible environmental impact, there exists an increasing interest towards their effective separation and recovery, which still remains a major challenge. This work presents a comprehensive thermodynamic and transport modeling approach able to describe HFC sorption and transport in different amorphous polymers, including glassy, rubbery, and copolymers, as well as in supported Ionic Liquid membranes (SILMs). In particular, the literature solubility data for refrigerants such as R-32, R-125, R-134a, and R-152a is analyzed by means of the Sanchez–Lacombe Equation of State (SL-EoS), and its non-equilibrium extension (NELF), to predict gas uptake in complex polymeric materials. The Standard Transport Model (STM) is then employed to describe permeability behaviors, incorporating concentration-dependent diffusion using a mobility coefficient and thermodynamic factor. Results demonstrate that fluorinated gases exhibit strong affinity to fluorinated and high free-volume polymers, and that solubility is primarily governed by gas condensability, molecular size, and polymer structure. The combined EoS–STM approach accurately predicts both solubility and permeability across different pressures in all polymers, including SILM. The thorough study of HFC transport in polymer membranes provided both systematic insights and predictive capabilities to guide the design of next-generation materials for refrigerant recovery and low-GWP separation processes. Full article

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

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12 pages, 1175 KiB

Open AccessArticle

Physical Assessment of CAD/CAM and 3D-Printed Resin-Based Ceramics Integrating Additive and Subtractive Methods

by Khalid K. Alanazi and Ali A. Elkaffas

Polymers 2025, 17(16), 2168; https://doi.org/10.3390/polym17162168 - 8 Aug 2025

Abstract

Additive manufacturing (3D printing) using Computer-Aided Design (CAD) has emerged as a cost-effective alternative to subtractive milling in restorative dentistry, offering reduced material waste and lower production costs. This study aimed to compare the physical properties, specifically water sorption, water solubility, and surface [...] Read more.

Additive manufacturing (3D printing) using Computer-Aided Design (CAD) has emerged as a cost-effective alternative to subtractive milling in restorative dentistry, offering reduced material waste and lower production costs. This study aimed to compare the physical properties, specifically water sorption, water solubility, and surface roughness, of milled and 3D-printed hybrid resin composite materials. Standardized disk-shaped samples were fabricated using a digital workflow. The additive group included 15 samples printed with a DLP printer using CROWNTEC resin at three different orientations (0°, 45°, and 90°), with five samples prepared at each printing orientation. The subtractive group consisted of specimens milled from the SHOFU DISK hybrid resin composite. Surface roughness samples were also prepared for both methods. Statistical analysis using one-way ANOVA, post hoc tests, and paired t-tests revealed significant differences among groups in all tested properties (p < 0.001). Subtractive manufacturing consistently outperformed additive techniques. Among the printed groups, orientation at 0° showed the most favorable outcomes. Moreover, polishing significantly improved surface roughness in both manufacturing methods (p < 0.001). These findings emphasize the influence of the fabrication method and printing orientation on the clinical performance of hybrid resin composites, highlighting the importance of polishing in optimizing the surface quality for 3D-printed restorations. Full article

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

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30 pages, 13403 KiB

Open AccessArticle

Baicalein-Loaded Chitosan Films for Local Treatment of Oral Infections

by Magdalena Paczkowska-Walendowska, Anna Rył, Jakub Kwiatek, Natalia Rosiak, Kamil Szarzyński, Weronika Wawrzyniak, Julia Ziółkowska, Weronika Kuderska, Kaja Kręcka, Anna Marciniak, Tomasz M. Karpiński, Tomasz Plech, Andrzej Miklaszewski, Piotr Owczarz and Judyta Cielecka-Piontek

Polymers 2025, 17(16), 2167; https://doi.org/10.3390/polym17162167 - 8 Aug 2025

Abstract

Oral infections and tissue defects remain significant clinical challenges, often requiring localized, sustained, and multifunctional therapeutic solutions. In this study, baicalein-loaded chitosan films were developed and comprehensively characterized as novel biomaterials for oral and maxillofacial applications. Using a 3² factorial design, nine [...] Read more.

Oral infections and tissue defects remain significant clinical challenges, often requiring localized, sustained, and multifunctional therapeutic solutions. In this study, baicalein-loaded chitosan films were developed and comprehensively characterized as novel biomaterials for oral and maxillofacial applications. Using a 3² factorial design, nine film formulations were prepared via solvent casting, varying chitosan molecular weight and composition. Physicochemical and structural analyses (microscopy, SEM, FTIR, and XRPD) confirmed uniform drug distribution and matrix compatibility. Mechanical testing and dissolution studies demonstrated zero-order baicalein release kinetics, with controlled, sustained delivery influenced by chitosan content and molecular weight. The optimal formulation (F5: CS MMW 2%, Gel 2%) combined favorable mechanical integrity, drug release, and potent antioxidant and anti-inflammatory activities. Further evaluation on 3D anatomical models simulating bone and soft tissue defects highlighted excellent membrane adaptability, stability, and ease of handling under conditions mimicking clinical surgery. The films acted as effective barriers in guided tissue regeneration and donor site protection, with improved surgical visibility due to their baicalein-induced coloration. Biocompatibility assays confirmed the safety of the materials, while antibacterial testing demonstrated activity against Streptococcus mutans. These results support the potential of baicalein-loaded chitosan films as multifunctional membranes for regenerative dentistry, periodontal therapy, and peri-implant care. The modular formulation design provides a platform for future integration of additional bioactive agents, paving the way for personalized, advanced wound healing solutions. Full article

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

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11 pages, 861 KiB

Open AccessArticle

Synergistic Optimization of Polymer–Surfactant Binary Flooding for EOR: Core-Scale Experimental Analysis of Formulation, Slug Design, and Salinity Effect

by Wenjie Tang, Patiguli Maimaiti, Hongzhi Shao, Tingli Que, Jiahui Liu and Shixun Bai

Polymers 2025, 17(16), 2166; https://doi.org/10.3390/polym17162166 - 8 Aug 2025

Abstract

As conventional waterflooding enters mid-to-late stages, chemical enhanced oil recovery (EOR) technologies such as polymer–surfactant binary flooding have emerged to address declining recovery rates. This study systematically investigates the synergistic effects of polymer–surfactant binary formulations through core-flooding experiments under varying concentrations, injection volumes, [...] Read more.

As conventional waterflooding enters mid-to-late stages, chemical enhanced oil recovery (EOR) technologies such as polymer–surfactant binary flooding have emerged to address declining recovery rates. This study systematically investigates the synergistic effects of polymer–surfactant binary formulations through core-flooding experiments under varying concentrations, injection volumes, and salinity conditions. The optimal formulation, identified as 0.5% surfactant and 0.15% polymer, achieves a maximum incremental oil recovery of 42.19% with an interfacial tension (IFT) reduction to 0.007 mN/m. A 0.5 pore volume (PV) injection volume balances sweep efficiency and economic viability, while sequential slug design with surfactant concentration gradients demonstrates superior displacement efficacy compared with fixed-concentration injection. Salinity sensitivity analysis reveals that high total dissolved solids (TDS) significantly degrade viscosity, whereas low TDS leads to higher viscosity but only marginally enhances the recovery. These findings provide experimental evidence for optimizing polymer–surfactant flooding strategies in field applications, offering insights into balancing viscosity control, interfacial tension reduction, and operational feasibility. Full article

(This article belongs to the Special Issue Advanced Polymer-Surfactant Systems for Petroleum Applications)

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21 pages, 333 KiB

Open AccessArticle

Toward National Guidelines for Biodegradable and Compostable Bioplastics: A Case Study in the Federal Territory of Kuala Lumpur, Malaysia

by Zurina Mahadi, Emirul Adzhar Yahya, Mashitoh Yaacob, Wardah Mustafa Din, Ahmad Firdhaus Arham and Nur Asmadayana Hasim

Polymers 2025, 17(16), 2165; https://doi.org/10.3390/polym17162165 - 8 Aug 2025

Abstract

Malaysia has committed to phasing out single-use plastics as part of its national sustainability agenda; however, the specific regulatory guidelines for implementing biodegradable and compostable bioplastics remain underdeveloped. This study aims to formulate practical and scalable guidelines for biodegradable and compostable bioplastic products, [...] Read more.

Malaysia has committed to phasing out single-use plastics as part of its national sustainability agenda; however, the specific regulatory guidelines for implementing biodegradable and compostable bioplastics remain underdeveloped. This study aims to formulate practical and scalable guidelines for biodegradable and compostable bioplastic products, with a focus on the Federal Territory of Kuala Lumpur as a pilot case. Using a stakeholder-driven approach, a series of focus group discussions (FGDs) was conducted with key representatives from government bodies and the bioplastics industry. The guideline development process encompassed the identification and standardisation of terminology, definition of scope, certification frameworks, regulatory alignment, implementation strategies, and compliance mechanisms. The findings reveal a consensus among stakeholders on the need for clear and harmonised definitions to prevent ambiguity, as well as for certification protocols and enforcement mechanisms to align with existing legal frameworks. Revisions were proposed to terms, scope, and timelines to ensure legal compatibility and practical enforceability. The proposed guideline framework offers substantial potential for national adoption, contingent on inclusive stakeholder engagement across all Malaysian states to ensure uniformity and contextual relevance in its implementation. This study advances Malaysia’s SDG commitments by promoting sustainable bioplastics guidelines, encouraging national adoption through stakeholder engagement, and emphasising future integration of the life cycle assessment (LCA) to enhance the policy’s impact. Full article

(This article belongs to the Special Issue Challenge and Prospect of Plastics and Bioplastics for Sustainable Circular Economy)

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15 pages, 1615 KiB

Open AccessArticle

Additive-Free Multiple Processing of PLA Pre-Consumer Waste: Influence on Mechanical and Thermal Properties

by Aleksandra Nešić, Rebeka Lorber, Silvester Bolka, Blaž Nardin and Branka Pilić

Polymers 2025, 17(16), 2164; https://doi.org/10.3390/polym17162164 - 8 Aug 2025

Abstract

Poly(lactide) (PLA) is the most versatile biopolymer with few possible end-of-life scenarios, like recycling, biodegradation/composting, and incineration. Biodegradation occurs under strictly defined conditions, and ultimately, PLA is landfilled, where it behaves like conventional plastics. To completely utilize the potential of PLA, it is [...] Read more.

Poly(lactide) (PLA) is the most versatile biopolymer with few possible end-of-life scenarios, like recycling, biodegradation/composting, and incineration. Biodegradation occurs under strictly defined conditions, and ultimately, PLA is landfilled, where it behaves like conventional plastics. To completely utilize the potential of PLA, it is necessary to increase the recycling and upcycling rates. In this work, the influence of 10 cycles of reprocessing PLA pre-consumer industrial waste on the material’s properties was examined. The mechanical milling of the material was followed by injection molding, and after each cycle, mechanical, thermal, chemical, and optical properties were studied. Between the cycles, no virgin PLA or any additives were added to enhance the properties. Results showed a slight decrease in molecular weight, while the thermal properties remained unchanged compared to the starting material. Full article

(This article belongs to the Special Issue Biobased and Biodegradable Polymer-Based Packaging—Sustainable by Design)

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Polymers, Volume 17, Issue 16 (August-2 2025) – 15 articles

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