Polymers

35 pages, 11787 KB

Open AccessArticle

A Data-Driven Framework for Predicting PHBV Biodegradation-Induced Weight Loss Based on Laboratory and Real-Environment Condition Tests

by Marianna I. Kotzabasaki, Leonidas Mindrinos, Nikolaos P. Sotiropoulos, Konstantina V. Filippou and Chrysanthos Maraveas

Polymers 2026, 18(7), 897; https://doi.org/10.3390/polym18070897 - 7 Apr 2026

Cited by 2 | Viewed by 831

Abstract

Polyhydroxyalkanoates (PHAs) emerge as promising biodegradable polymers for sustainable applications, yet predicting their biodegradation behavior under different environmental conditions remains challenging. In this study, we propose a novel data-driven computational framework for predicting biodegradation-induced weight/mass loss in PHA-based materials. A comprehensive database of [...] Read more.

Polyhydroxyalkanoates (PHAs) emerge as promising biodegradable polymers for sustainable applications, yet predicting their biodegradation behavior under different environmental conditions remains challenging. In this study, we propose a novel data-driven computational framework for predicting biodegradation-induced weight/mass loss in PHA-based materials. A comprehensive database of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)-based formulations was manually curated by systematically collecting and harmonizing material descriptors, environmental parameters, and experimental biodegradation outcomes from laboratory- and large-scale studies conducted in soil, marine, freshwater, and compost environments. Multiple regression-based quantitative structure–activity relationship (QSAR) models were developed and rigorously validated, demonstrating high predictive performance and strong correlations between polymer structure, environmental conditions and degradation behavior. “Exposure time”, “degradation environment” and “hydroxybutyrate (HB) ratio” were identified as the most important features for weight loss. Finally, the predictive model was integrated into the Jaqpot computational platform, enabling open access and facilitating data-driven assessment and design of biodegradable polymer systems. Full article

(This article belongs to the Special Issue Advances in Modeling and Simulations of Polymers)

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23 pages, 6903 KB

Open AccessArticle

Production and Characterization of Poly(lactic acid) and Poly(ε-caprolactone) Films Enriched with Pomegranate Peel Extract: Toward Biodegradable and Sustainable Food Packaging

by Ömer Faruk Uslu, Nebahat Aral, Sinem Argün and Özge Taştan Ülkü

Polymers 2026, 18(7), 896; https://doi.org/10.3390/polym18070896 - 7 Apr 2026

Cited by 1 | Viewed by 1035

Abstract

Recently, more sustainable and biodegradable packaging materials have begun to attract attention in food packaging due to major, rising concerns related to plastic usage. This study aims to develop and characterize biodegradable food packaging materials, namely poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) enriched [...] Read more.

Recently, more sustainable and biodegradable packaging materials have begun to attract attention in food packaging due to major, rising concerns related to plastic usage. This study aims to develop and characterize biodegradable food packaging materials, namely poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) enriched with pomegranate peel extract (PoPE). Firstly, the optimal extract selected was a 24 h maceration of PoPE with 60% ethanol, after production with different solvents and methods. PLA- and PCL-based films were produced via melt compounding with the addition of PoPE at different concentrations (1, 3, 5 and 10%, w/w). FTIR confirmed that the PoPE did not modify the chemical backbones of PLA or PCL, with only a more pronounced O–H band in PCL, suggesting mainly non-covalent/physical interactions. UV–Vis spectroscopy showed tunable warm coloration and strong UV shielding with reduced transparency; for PLA ~3–5 wt.%, PoPE enabled near-complete UV blocking, while PCL achieved very high UV protection even at low loadings. PoPE improved toughness in PLA (3–5 wt.%) and maintained ductility in PCL (1–10 wt.%). PoPE-added PLA and PCL films maintained thermal stability up to 10 wt.% according to TGA results. DSC/XRD indicated a matrix-dependent crystallization response. PLA remained largely amorphous, whereas PoPE promoted PCL crystallinity without changing polymer crystal polymorphs. SEM images revealed homogenous dispersion of PoPE in the films. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Environmental Assessment of Novel Polymeric Materials for Sustainable Applications)

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7 pages, 170 KB

Open AccessEditorial

Recent Trends in Polymer Membranes: Fabrication Technique, Characterization, Functionalization, and Applications in Environmental Science (Part II)

by Gang Wei and Yan Wang

Polymers 2026, 18(7), 895; https://doi.org/10.3390/polym18070895 - 7 Apr 2026

Viewed by 650

Abstract

Polymeric membranes have been widely applied in various fields such as adsorption, separation, energy conversion, chemical production, antibacterial, antifouling, and biomedicine due to their excellent porous and channel structure, as well as tailored separation performance, ease of operation, and low energy consumption [...] [...] Read more.

Polymeric membranes have been widely applied in various fields such as adsorption, separation, energy conversion, chemical production, antibacterial, antifouling, and biomedicine due to their excellent porous and channel structure, as well as tailored separation performance, ease of operation, and low energy consumption [...] 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)

27 pages, 4347 KB

Open AccessReview

Collagen Scaffolds in Regenerative Endodontic Procedures: Current Evidence, Limitations, and Future Perspectives

by Qiong-Ling Shi, Xiao Zhu, Chen Chen, Jing-Yi Chen, Dan-Yang Lu, Ying Shi, Yan-Qi Chen and Zhi-Fang Wu

Polymers 2026, 18(7), 894; https://doi.org/10.3390/polym18070894 - 7 Apr 2026

Viewed by 1247

Abstract

Predictable pulp-dentin regeneration continues to represent a major challenge in regenerative endodontic procedures (REPs). Although collagen-based scaffolds are widely investigated for their excellent biocompatibility, their ability to deliver consistent clinical and histological outcomes requires critical evaluation. This review summarizes recent advances in the [...] Read more.

Predictable pulp-dentin regeneration continues to represent a major challenge in regenerative endodontic procedures (REPs). Although collagen-based scaffolds are widely investigated for their excellent biocompatibility, their ability to deliver consistent clinical and histological outcomes requires critical evaluation. This review summarizes recent advances in the application of collagen scaffolds for REPs. Clinical studies demonstrate that these scaffolds support high tooth survival rates and promote vitality recovery, root wall thickening, and apical closure. However, consistent root lengthening remains elusive. Histologically, the newly formed mineralized tissue from collagen scaffolds within REPs tends to be cementum-like or bone-like rather than reparative dentin, a pattern closely associated with the physicochemical properties of collagen, including pore size, porosity, concentration, stiffness, viscosity, and viscoelasticity. We conclude that while collagen scaffolds represent a “promising platform” for REPs due to their biocompatibility and clinical performance, current evidence indicates that they do not consistently achieve true pulp-dentin regeneration. We therefore propose targeted modification and advanced tissue engineering strategies to direct genuine regeneration. This review offers a framework for the rational design of next-generation collagen constructs toward more predictable regenerative outcomes. Full article

(This article belongs to the Section Polymer Applications)

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21 pages, 5133 KB

Open AccessArticle

Mechanical, Thermal and X-Ray Shielding Properties of Lead-Free Composites of HDPE Filled with Metal-Based Powders

by Sitah Alanazi, Shahad Alshadokhi, Eid Alosime, Mansour Almurayshid, Mohammed Alsuhybani and Mohammad Marashdeh

Polymers 2026, 18(7), 893; https://doi.org/10.3390/polym18070893 - 6 Apr 2026

Cited by 2 | Viewed by 949

Abstract

The increasing utilization of radiation in medicine, industry, and water purification highlights the need for efficient radiation-protection materials. This study investigates lead-free polymer composites based on high-density polyethylene (HDPE) filled with four metallic fillers: tungsten carbide (WC), molybdenum carbide (MoC), tungsten (W), and [...] Read more.

The increasing utilization of radiation in medicine, industry, and water purification highlights the need for efficient radiation-protection materials. This study investigates lead-free polymer composites based on high-density polyethylene (HDPE) filled with four metallic fillers: tungsten carbide (WC), molybdenum carbide (MoC), tungsten (W), and molybdenum (Mo) at 15 wt%. The objective is to evaluate their potential as alternatives to lead for shielding ionizing radiation. Mechanical performance was examined through tensile testing, while thermal stability was assessed based on the residual mass. Radiation-attenuation behavior was analyzed through linear and mass attenuation coefficients (µ and µₘ), radiation protection efficiency (RPE), half-value layer (HVL), mean free path (MFP), buildup factors (B), and effective atomic number (Z_eff) within the 47.9–248 keV energy range. The HDPE/W composite exhibited the greatest enhancement, with a mass attenuation coefficient (µₘ) 82.5% higher than that of pure HDPE, along with the highest linear attenuation coefficient (µ). Furthermore, tungsten-loaded samples achieved an RPE of 98.05% at 47.9 keV. The increased density, low B, and high Z_eff values collectively contribute to superior shielding performance. These findings indicate that HDPE filled with WC, MoC, W, and Mo are promising lead-free candidates for low-energy X-ray shielding applications. Full article

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

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24 pages, 26931 KB

Open AccessArticle

Mechanical Properties and Feasibility of GFRP from Decommissioned Large-Scale Wind Turbine Blades for Wave Energy Converter: A Case Study

by Yan-Wen Li, Jin-Sheng Lai, Bin-Zhen Zhou and Li Cheng

Polymers 2026, 18(7), 892; https://doi.org/10.3390/polym18070892 - 6 Apr 2026

Viewed by 1122

Abstract

Repurposing decommissioned wind turbine blades provides a vital pathway to mitigate carbon emissions, yet the escalating volume of large-scale waste poses a severe environmental challenge. Recognizing the limitation that existing research focuses predominantly on small-scale legacy blades, this study addresses this gap by [...] Read more.

Repurposing decommissioned wind turbine blades provides a vital pathway to mitigate carbon emissions, yet the escalating volume of large-scale waste poses a severe environmental challenge. Recognizing the limitation that existing research focuses predominantly on small-scale legacy blades, this study addresses this gap by assessing the mechanical properties and microstructure of a 54-m (2.0 MW) blade decommissioned due to repowering after 10 years of service. GFRP samples extracted from the root, mid-span, and tip were investigated using X-ray computed tomography and a comprehensive suite of mechanical tests. The investigation confirmed a low internal porosity (~1.2%) without service-induced macroscopic interfacial cracking, alongside superior residual performance, exemplified by a tensile strength of 849.5 MPa at the root. Statistical analysis employing ANOVA revealed significant spatial variations, supporting a graded reuse strategy: roots with superior tensile strengths for critical members, mid-spans for axial compression, and tips as a reliable property baseline for general reuse, while Weibull analysis verified the statistical reliability required for structural design. Based on these superior residual properties, a raft-type wave energy converter utilizing repurposed blade segments was proposed. A comparative carbon footprint assessment revealed that this blade-repurposed WEC achieved a 71.5% reduction in carbon emissions and a 37.4% reduction in structural mass compared to conventional steel counterparts. These findings substantiate the viability of large-scale DWTBs as high-value resources for decarbonizing marine infrastructure within a circular economy. Full article

(This article belongs to the Special Issue Recent Advances in Sustainable Polymer Composites and Advanced End-of-Life/Recycling Strategies)

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19 pages, 4343 KB

Open AccessArticle

Tribomechanical Behaviour and Elasto-Plastic Contact Response of 3D-Printed Versus Conventional Polymer Inserts in Robotic Gripping Interfaces

by Georgiana Ionela Păduraru, Andrei Călin, Marilena Stoica, Delia Alexandra Prisecaru and Petre Lucian Seiciu

Polymers 2026, 18(7), 891; https://doi.org/10.3390/polym18070891 - 6 Apr 2026

Viewed by 630

Abstract

Three-dimensional printed polymers produced using Fused Deposition Modelling (FDM) exhibit directional microstructures resulting from filament paths, layer interfaces, and cellular infill, leading to mechanical and tribological responses distinct from those of homogeneous bulk materials. This study presents a comparative tribomechanical evaluation of polypropylene [...] Read more.

Three-dimensional printed polymers produced using Fused Deposition Modelling (FDM) exhibit directional microstructures resulting from filament paths, layer interfaces, and cellular infill, leading to mechanical and tribological responses distinct from those of homogeneous bulk materials. This study presents a comparative tribomechanical evaluation of polypropylene (PP) bulk inserts and 3D-printed polyethylene terephthalate glycol (PETG) inserts with a 30% hexagonal infill, relevant for robotic gripping applications. Progressive scratch tests were performed under loads from 5 to 100 N (150 N for PP), and profilometry was applied to quantify groove morphology, ridge formation, and displaced-volume ratios. An elasto-plastic conical indentation model was used to derive indentation pressures and elastic–plastic transition radii from groove geometry. The PETG inserts exhibited heterogeneous groove depth, intermittent ridge tearing, and friction fluctuations associated with the internal infill structure, consistent with previous findings on anisotropy and architecture-dependent behaviour in additively manufactured polymers. In contrast, bulk PP demonstrated smoother friction profiles and more stable plastic flow under increasing loads. Two functional indices—specific frictional work and ridge-to-trace volumetric ratio—are introduced to support material selection for robotic gripping systems. The results show that local contact mechanics in 3D-printed inserts are governed by print-induced structural features and can be effectively evaluated through a scratch-based elasto-plastic analysis. The methods and results presented in this work support the rational selection and design of polymer inserts for robotic gripper fingertips. The proposed scratch-based elasto-plastic evaluation framework enables manufacturers and automation engineers to compare 3D-printed and conventional materials based on friction stability, wear response, and deformation resistance. This approach can be directly applied to optimise gripping performance in industrial handling, packaging, and collaborative robotics. Full article

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

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25 pages, 10246 KB

Open AccessArticle

Development and Characterization of Active Pectin–Curdlan Biopolymer Films with Cannabigerol (CBG) Oil as Innovative Materials with Plant Metabolism–Stimulating Properties and Potential to Extend the Postharvest Shelf Life of Blackberries (Black Satin) Fruits

by Renata Dobrucka, Maja Paterska and Marcin Szymański

Polymers 2026, 18(7), 890; https://doi.org/10.3390/polym18070890 - 6 Apr 2026

Cited by 1 | Viewed by 664

Abstract

In the present study, the physicochemical, mechanical, and functional properties of biodegradable pectin/cudlan gum polysaccharide films with CBG oil were evaluated. In these studies, the TS values for the films ranged from 8.50 MPa to 14.80 MPa. The EB values ranged from 33.06% [...] Read more.

In the present study, the physicochemical, mechanical, and functional properties of biodegradable pectin/cudlan gum polysaccharide films with CBG oil were evaluated. In these studies, the TS values for the films ranged from 8.50 MPa to 14.80 MPa. The EB values ranged from 33.06% to 39.07%. The WVTR ranged from 13.7 to 9.51 g/m² d. In all the films tested, the change in the L* parameter did not change significantly statistically (p ≥ 0.05). In films with low CBG content (0.125F, 0.25F, 0.35F), L* remained stable, which indicated their resistance to darkening. However, film 0.5F was an exception, as it showed a decrease in L*, suggesting darkening or photodegradation processes. CBG films reduced mold growth, water loss, color degradation, and anthocyanin content in stored fruit, especially films with a content of 0.125F–0.35F, while higher concentrations (0.5F–0.75F) could cause pro-oxidative effects. Soil application of the film showed that moderate CBG concentrations (0.25F–0.35F) increased the content of chlorophyll, carotenoids, and phenols, indicating biostimulating potential, while the highest concentrations could cause oxidative stress. At the highest CBG concentration (0.75F), the carotenoid content decreased to 0.054–0.113 mg·g⁻¹ FW. At higher concentrations of active substances in the film (0.5F and 0.75F), stabilization or a decrease in O₂•⁻ levels was observed, which may indicate the effective activation of protective mechanisms leading to the neutralization of excess free radicals. Full article

(This article belongs to the Special Issue Functional Polymer Composites: Synthesis and Application)

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13 pages, 3831 KB

Open AccessArticle

Rosin-Modified Microcrystalline Cellulose for Enhancing Polylactic Acid-Based Composites with Good Interfacial Compatibility and Mechanical Performance

by Fuquan Zhao, Xiaoyu Xie, Yu Meng, Lijia Wang, Zilin Zhu, Lingqing Chen, Lijie Jiang, Xiaofan Zhou and Ming Yan

Polymers 2026, 18(7), 889; https://doi.org/10.3390/polym18070889 - 6 Apr 2026

Viewed by 919

Abstract

The interfacial incompatibility and insufficient mechanical performance of polylactic acid (PLA)/cellulose composites have severely restricted their practical applications. To address the critical issue of interfacial incompatibility in PLA/cellulose composites, this work developed a novel strategy employing rosin emulsion for blending modification of microcrystalline [...] Read more.

The interfacial incompatibility and insufficient mechanical performance of polylactic acid (PLA)/cellulose composites have severely restricted their practical applications. To address the critical issue of interfacial incompatibility in PLA/cellulose composites, this work developed a novel strategy employing rosin emulsion for blending modification of microcrystalline cellulose (MCC), followed by a one-step extrusion process to fabricate PLA composites. The corresponding analyses confirmed that the rosin has been successfully added to MCC surfaces, forming the hydrophobic interface while maintaining the cellulose I crystalline structure. Subsequently, rosin emulsion-modified MCC (MCC-R) reinforced PLA (PLA/MCC-R) composites were fabricated via twin-screw extrusion at varying MCC-R contents. The testing results illustrated that the introduction of 8 wt% MCC-R can enhance the mechanical properties of PLA/MCC-R composites with the flexural strength (125.5 MPa), tensile strength (30.8 MPa), Young’s modulus (1.19 GPa), and elongation at break (3.07%), which was attributed to enhanced filler dispersion and interfacial stress transfer. Overall, this work established a facile and sustainable strategy for developing multifunctional PLA composites with engineered interfaces and mechanical robustness, which is vital for practical application. The as-prepared PLA composites show promising application prospects in environmentally friendly packaging, biodegradable disposable products, and lightweight structural components. Full article

(This article belongs to the Special Issue Application and Characterization of Cellulose-Based Polymers)

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14 pages, 1908 KB

Open AccessArticle

Strength and Degradation Characteristics of Zein Biopolymer-Treated Sands Under Wetting–Drying Cycles

by Quadri Olakunle Babatunde, Woonjae Yeo and Yong-Hoon Byun

Polymers 2026, 18(7), 888; https://doi.org/10.3390/polym18070888 - 5 Apr 2026

Cited by 2 | Viewed by 734

Abstract

Repeated wetting–drying cycles accelerate scouring and deteriorate soil structure by increasing pore-water pressure. This study examines the durability of sand treated with zein biopolymers subjected to wetting–drying cycles and compares its uncycled condition with that of xanthan gum (XG). The treated specimens are [...] Read more.

Repeated wetting–drying cycles accelerate scouring and deteriorate soil structure by increasing pore-water pressure. This study examines the durability of sand treated with zein biopolymers subjected to wetting–drying cycles and compares its uncycled condition with that of xanthan gum (XG). The treated specimens are prepared with biopolymer contents of 1% and 3% by mass of sand. The specimens are cured for an initial period of 7 days under atmospheric conditions, whereafter they are subjected to a series of wetting–drying cycles. Subsequently, the dimensions and mass of the specimens are measured to evaluate bulk density-related changes during the cycles. The strength and degradation characteristics of the specimens are evaluated through unconfined compression tests after being subjected to different numbers of cycles. The bulk unit weight after the drying phase remains nearly constant, whereas that after the wetting phase increases with both the number of cycles and biopolymer content. Overall, specimens with higher biopolymer content exhibit lower bulk unit weights. The XG-treated specimens show earlier strength improvement than the zein-treated specimens due to the faster curing-related strength development associated with water-based gelation. Moreover, the XG-treated sand rapidly fails after the first wetting phase, while the compressive strength of the cycled zein-treated specimens is lower than that of the uncycled specimens. Zein-treated sand with 3% biopolymer content shows a higher durability index after 10 cycles than sand treated with 1% biopolymer content. Therefore, a higher zein content can be used to enhance the durability of sand subject to frequent wetting and drying cycles. Full article

(This article belongs to the Special Issue Derived Polymers from Biomass and Wastes)

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16 pages, 3588 KB

Open AccessArticle

Effect of Fiber Surface Characteristics on the Interfacial Properties of T1100-Grade Carbon Fiber Bismaleimide Composites

by Tianshu Li, Fenghui Shi, Weihan Wang, Hongchen Yan, Xiangyu Xu and Baoyan Zhang

Polymers 2026, 18(7), 887; https://doi.org/10.3390/polym18070887 - 5 Apr 2026

Viewed by 832

Abstract

To clarify the effect of surface characteristics on the interfacial properties of T1100-grade carbon fiber (CF)/bismaleimide (BMI) composites, three CFs (F1, F2, and F3) with different surface treatments and sizing agents were studied. Surface physicochemical properties and sizing–resin reaction behavior were characterized; nano-infrared [...] Read more.

To clarify the effect of surface characteristics on the interfacial properties of T1100-grade carbon fiber (CF)/bismaleimide (BMI) composites, three CFs (F1, F2, and F3) with different surface treatments and sizing agents were studied. Surface physicochemical properties and sizing–resin reaction behavior were characterized; nano-infrared spectroscopy was innovatively used to quantify interfacial structure. The correlation among surface features, interfacial structure, and mechanical properties was established. All dry-jet wet-spun T1100 CFs show smooth surfaces with similar roughness, and mechanical interlocking contributes little to interfacial adhesion. F3 possesses the highest active carbon, oxygen content, and epoxy value. Its sizing agent exhibits strong reactivity with BMI, forming a ~200 nm thick interface and the highest interfacial shear strength (IFSS) of 95.9 MPa. Constructing a “thick and strong” interface promotes shear failure from brittle to tough, significantly enhancing 90° tensile and interlaminar shear strength (ILSS). This work provides guidance for interface design and engineering applications of T1100/BMI composites in aerospace primary load-bearing structures. Full article

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

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31 pages, 5755 KB

Open AccessArticle

Machine Learning-Driven Prediction of Manufacturing Parameters and Analysis of Mechanical Properties of PC-ABS Specimens Produced by the Fused Deposition Modeling Additive Manufacturing Method

by Arda Pazarcıkcı, Koray Özsoy and Bekir Aksoy

Polymers 2026, 18(7), 886; https://doi.org/10.3390/polym18070886 - 4 Apr 2026

Cited by 2 | Viewed by 1192

Abstract

This study aims to investigate the effect of manufacturing parameters on the mechanical properties of PC-ABS samples produced by the Fused Deposition Modeling (FDM) additive manufacturing method and to model these relationships using machine learning methods. In the study, the parameters of printing [...] Read more.

This study aims to investigate the effect of manufacturing parameters on the mechanical properties of PC-ABS samples produced by the Fused Deposition Modeling (FDM) additive manufacturing method and to model these relationships using machine learning methods. In the study, the parameters of printing speed, infill density, and raster angle were determined according to the Taguchi L16 experimental design, and tensile, bending, and impact tests were performed on the produced samples. Experimental results showed that the infill density parameter resulted in an increase in tensile strength of approximately 62% (from 25.10 MPa to 40.71 MPa) and an increase in flexural strength of approximately 46% (from 45.13 MPa to 66.13 MPa). Furthermore, an improvement in impact energy of approximately 45% (from 1.698 J to 2.467 J) was achieved under optimum printing speed conditions. Mechanistic properties were predicted using Decision Tree, Random Forest, K-Nearest Neighbors, and Multilayer Perceptron models with a dataset generated from experimental data. Comparing the model performances, the Random Forest algorithm was found to provide the highest prediction performance with accuracy in the R² range of 0.94–0.99 and RMSE values below 0.5, demonstrating strong generalization capabilities. The results showed that infill density is the most decisive parameter on both tensile and flexural strength, and that printing speed has a significant effect, especially on impact energy. ANOVA analyses revealed that all main parameters have statistically significant effects on mechanical properties. In the performance comparison of the machine learning models, the Random Forest algorithm provided the highest prediction accuracy, demonstrating that mechanical properties can be reliably predicted. In conclusion, it has been shown that the mechanical performance of PC-ABS parts produced by the FDM method can be optimized by using the correct selection of production parameters and machine learning-based modeling approaches. Full article

(This article belongs to the Special Issue Polymer Composites: Mechanical Characterization)

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12 pages, 1120 KB

Open AccessArticle

Types of Resin Composite and Filling Techniques: How They Affect Internal Void Volume and Compressive Strength

by Pirat Karntiang, Chitpol Chaimanakarn, Daranee Chaimanakarn, Thanyaporn Niyomdee and Hiroshi Ikeda

Polymers 2026, 18(7), 885; https://doi.org/10.3390/polym18070885 - 4 Apr 2026

Cited by 2 | Viewed by 1090

Abstract

Background: This study evaluated the void volume percentage and compressive strength of restorations prepared with different resin composite materials and techniques. Methods: There were five experimental groups: (1) ZS (Filtek™ Z350XT, single layer); (2) ZH (Filtek™ Z350XT, horizontal increment); (3) ZO (Filtek™ Z350XT, [...] Read more.

Background: This study evaluated the void volume percentage and compressive strength of restorations prepared with different resin composite materials and techniques. Methods: There were five experimental groups: (1) ZS (Filtek™ Z350XT, single layer); (2) ZH (Filtek™ Z350XT, horizontal increment); (3) ZO (Filtek™ Z350XT, oblique increment); (4) BS (Filtek™ One Bulk Fill, single layer); (5) BF (Filtek™ One Bulk Fill and Filtek™ Z350XT Flowable Composite). Specimen dimensions were 4 mm high and 5 mm in diameter. Internal void evaluation was done by micro-CT, followed by a compressive strength test. Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey’s post hoc test (p = 0.05) and Pearson’s correlation analysis. Results: Group BF had the largest void volume percentage (0.5501 ± 0.2031%), and groups ZS and BS had the smallest (0.0366 ± 0.0279% and 0.1991 ± 0.1463%, respectively). Groups ZH and ZS showed significantly higher compressive strength values (200.18 ± 16.32 MPa, 192.18 ± 17.23 MPa, respectively) than groups BS and BF. Pearson’s correlation analysis revealed no statistically significant correlation. Conclusions: The multilayer filling technique created significantly more voids than the single-layer technique. Some materials also contain inherent voids. However, these voids may not directly affect the strength of the restoration. Full article

(This article belongs to the Special Issue Polymeric Biomaterials for Dental Regeneration and Antimicrobial Applications)

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13 pages, 2315 KB

Open AccessArticle

Use of Waste Red Seaweed Furcellaran for Development of Green Thermoplastically Processable Bioplastics

by Remo Merijs-Meri, Jānis Zicāns, Tatjana Ivanova, Juris Bitenieks, Pēteris Patriks Jefimovs, Ivans Bočkovs, Žanis Edvards Rībens, Rita Bērziņa, Aina Bernava, Reina Rozentāle, Karina Bāliņa and Uldis Žaimis

Polymers 2026, 18(7), 884; https://doi.org/10.3390/polym18070884 - 4 Apr 2026

Viewed by 701

Abstract

Bioplastics are in focus for the development of sustainable materials due to the depletion of fossil resources, generation of solid waste and global climate change. Considering this, the current research is devoted to the valorization of beachcast red seaweed F. lumbricalis for the [...] Read more.

Bioplastics are in focus for the development of sustainable materials due to the depletion of fossil resources, generation of solid waste and global climate change. Considering this, the current research is devoted to the valorization of beachcast red seaweed F. lumbricalis for the development of thermoplastically processable bioplastics. The composites have been developed from beachcast red seaweed-derived furcellaran (FUR) and potato-derived thermoplastic starch (TPS) by using an ultrasound-assisted technique. Three different FUR concentrations (10, 30 and 50 wt.%) in relation to potato starch were examined for their thermoplastic processability. Fourier infrared spectroscopy (FTIR) was used to reveal the structural changes in the developed TPS/FUR composites depending on FUR content as well as thermal pre-treatment. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and tensile mechanical tests were performed to assess the performance of the developed TPS/FUR composites. It was demonstrated that the ultrasound-assisted manufacturing route allowed TPS/FUR composites with an improved spectrum of properties to be obtained. The highest mechanical stress at break (almost three times higher than for neat TPS) was observed for the TPS + 50 wt.% FUR composite, which also possessed decreased deformability (only ca 10%), reduced thermal resistance at processing temperatures (150 °C) and high shear sensitivity. Thus, the TPS + 30 wt.% FUR and especially the TPS + 10 wt.% FUR composites were recognized as more suitable for thermoplastic processing and the development of TPS-based composites with improved exploitation properties. Full article

(This article belongs to the Special Issue Application and Characterization of Multifunctional and Sustainable Polymers and Composites)

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19 pages, 6291 KB

Open AccessArticle

Nanoengineered Chitosan–Genipin Coating of Yeast-Derived Biopolymer Microcapsules for Theranostic Applications

by Beata Miksa, Katarzyna Trzeciak, Slawomir Kaźmierski, Patrycja Przygodzka, Magdalena Ziąbka, Aneta Węgierek-Ciuk, Paulina Blazinska and Damian Mickiewicz

Polymers 2026, 18(7), 883; https://doi.org/10.3390/polym18070883 - 3 Apr 2026

Viewed by 662

Abstract

The development of effective and trackable drug delivery systems remains a major challenge in anticancer therapy. In this study, we designed novel polysaccharide-based theranostic carriers using a yeast-shell (YC) framework, providing a biocompatible platform for intracellular drug delivery. For the first time, a [...] Read more.

The development of effective and trackable drug delivery systems remains a major challenge in anticancer therapy. In this study, we designed novel polysaccharide-based theranostic carriers using a yeast-shell (YC) framework, providing a biocompatible platform for intracellular drug delivery. For the first time, a chitosan–genipin bioconjugate was synthesized via a solvent-free, green mechanochemical method and applied as an outer coating to microcarriers encapsulating the anticancer drug 5-fluorouracil (5-FU) and the fluorescent dye phenosafranin. The resulting system enabled simultaneous fluorescence tracking and the controlled release of the chemotherapeutic agent. In vitro evaluation using the MDA-MB-231 triple-negative breast cancer cell line demonstrated that 5-FU retained its antiproliferative activity, while the carriers facilitate sustained intracellular delivery. These findings highlight the potential of YC-based polysaccharide carriers, surface- modified with chitosan–genipin to enhance hydrophilicity, as a versatile platform for anticancer therapy, combining biocompatibility, traceability, and controlled drug release. Full article

(This article belongs to the Special Issue Biobased Nanoparticles Derived from Natural Polymers and Their Use in Polymer Nanocomposites)

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21 pages, 6168 KB

Open AccessArticle

3D-Bioprinted Gelatin Hydrogels with Human Umbilical Cord Mesenchymal Stem Cell-Derived Small Extracellular Vesicles Promote Cutaneous Wound Healing In Vivo

by Manal Hussein Taghdi, Ibrahim N. Amirrah, Nurul Izzati Uda Zahli, Kavita Chirara, Mh Busra Fauzi, Jia Xian Law and Yogeswaran Lokanathan

Polymers 2026, 18(7), 882; https://doi.org/10.3390/polym18070882 - 3 Apr 2026

Cited by 1 | Viewed by 1002

Abstract

Small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) are emerging as potent acellular therapeutics; however, their rapid clearance hinders their clinical translation. To address this issue, 3D-bioprinted genipin-crosslinked gelatin (GECL) was engineered for human health. GECL hydrogels were functionalised with human [...] Read more.

Small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) are emerging as potent acellular therapeutics; however, their rapid clearance hinders their clinical translation. To address this issue, 3D-bioprinted genipin-crosslinked gelatin (GECL) was engineered for human health. GECL hydrogels were functionalised with human umbilical cord MSC-derived sEVs (hUCMSC-sEVs) to create a bioactive wound-healing platform. These hydrogels demonstrated favourable physicochemical, mechanical, and biodegradable properties while providing an extracellular matrix (ECM)-mimetic environment conducive to tissue regeneration. MSCs were isolated from the umbilical cords, and their small extracellular vesicles (sEVs) were extracted and incorporated into gelatin-based hydrogels via 3D bioprinting. These sEV-loaded scaffolds were embedded in full-thickness wounds in mice, and healing was evaluated through macroscopic observation, histological analysis, collagen deposition, and angiogenesis assessment. Compared with the untreated controls, both the hydrogel-only (B) and sEV-loaded hydrogel (BE) groups significantly accelerated in vivo wound healing. Notably, the BE group achieved complete wound closure within 14 days, restoring the skin architecture, which closely resembled the native tissue with well-organised epidermal and dermal layers, optimal thickness, and skin appendages. Histological and ultrastructural assessments revealed an increased collagen type I deposition, a reduced α-smooth muscle actin (α-SMA) expression, and a robust neovascularisation. The TEM revealed tight junctions and active cellular infiltration, indicating scaffold integration and functional remodelling. Immunohistochemistry further revealed an upregulated CD31 expression with a balanced α-smooth muscle actin (α-SMA) expression, reflecting coordinated angiogenesis and myofibroblast regulation. These results highlight sEV-functionalised GECL hydrogels as robust and clinically translatable acellular therapeutic green products for accelerated wound closure and functional skin regeneration, advancing the fields of regenerative medicine and life expectancy. Full article

(This article belongs to the Special Issue Polymeric Materials for Wound Dressing)

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15 pages, 3396 KB

Open AccessArticle

Waterproof and Breathable Polyurethane Membranes with Self-Healing and Self-Cleaning Properties: Synergistic Enhancement by Polydimethylsiloxane and Phenolic Carbamate Network and Photocatalytic Effect

by Yuqing He, Xiaohan Yang, Fufen Li, Xiudan Tao, Chenhui Liu and Zhengjun Li

Polymers 2026, 18(7), 881; https://doi.org/10.3390/polym18070881 - 3 Apr 2026

Viewed by 881

Abstract

Developing environmentally friendly, multifunctional waterproof and breathable membranes (WBMs) has attracted extensive attention and is of great significance but remains challenging. Herein, an environmentally friendly and multifunctional waterborne polyurethane WBM with self-healing and self-cleaning properties is developed in two steps. Firstly, by using [...] Read more.

Developing environmentally friendly, multifunctional waterproof and breathable membranes (WBMs) has attracted extensive attention and is of great significance but remains challenging. Herein, an environmentally friendly and multifunctional waterborne polyurethane WBM with self-healing and self-cleaning properties is developed in two steps. Firstly, by using polydimethylsiloxane (PDMS) as a hydrophobicity giver and tannic acid (TA) as a crosslinker, a dual-modified waterborne polyurethane (PTWPU) is prepared, which has high surface hydrophobicity due to the surface enrichment of siloxane segments and self-healing performance from the formation of a dynamic phenolic carbamate network. Secondly, by incorporating titanium dioxide (TiO₂) photocatalyst nanoparticles to increase internal porosity and establish hydrophilic pathways, a multifunctional waterborne polyurethane WBM (TPTWPU) is developed. This membrane features further enhanced surface hydrophobicity from generated micro-roughness and effective self-cleaning performance, because TA acts as an electron trap to promote the photocatalytic activity of TiO₂. The TPTWPU membrane shows good hydrophobicity (water contact angle of 115.3°) and satisfactory moisture permeability of 135.0 g/(m²·24 h), which is 61.2% higher than unmodified membranes. Furthermore, it exhibits efficient self-healing, with a recovery rate exceeding 80% within 2 h. This feasible strategy will provide guidance for materials design in multifunctional coatings for textiles and leather. Full article

(This article belongs to the Special Issue Fabrication of Colouristic and Functional Polymers with Special Focus on the Sustainability and Efficiency)

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20 pages, 2211 KB

Open AccessArticle

Liquefaction of Ruscus aculeatus Branches into Bio-Polyols: Process Optimization and Polyol Characterization

by Yuliya Dulyanska, Luísa Cruz-Lopes, Fábio Bernardo, Dmitry V. Evtuguin, Raquel P. F. Guiné, Fernando J. Gonçalves, Luís A. E. Batista de Carvalho, Maria João Barroca and Bruno Esteves

Polymers 2026, 18(7), 880; https://doi.org/10.3390/polym18070880 - 3 Apr 2026

Viewed by 977

Abstract

The conversion of lignocellulosic biomass into bio-polyols through liquefaction has attracted increasing interest as a sustainable route for polymer feedstock production. The liquefaction of Ruscus aculeatus L. branches was investigated to identify optimal processing conditions and to evaluate the properties of the resulting [...] Read more.

The conversion of lignocellulosic biomass into bio-polyols through liquefaction has attracted increasing interest as a sustainable route for polymer feedstock production. The liquefaction of Ruscus aculeatus L. branches was investigated to identify optimal processing conditions and to evaluate the properties of the resulting bio-polyols. The effects of temperature, reaction time, particle size, and material-to-solvent ratio on liquefaction yield were systematically studied. Liquefaction yield increased markedly with temperature, reaching up to 92% at 180 °C after 60 min of reaction, while reaction time showed only a marginal effect beyond 15 min. Smaller particle sizes and higher solvent ratios improved liquefaction efficiency, with optimal conditions identified between 1:7 and 1:10 material-to-solvent ratios. The hydroxyl number decreases with increasing liquefaction temperature due to dehydration and condensation reactions. Thermal and rheological analyses indicated improved thermal stability and increased viscosity at higher liquefaction temperatures. These results highlight the potential of Ruscus aculeatus branches as a promising renewable feedstock for bio-polyol production and polyurethane applications. Full article

(This article belongs to the Special Issue Advances in Cellular Polymeric Materials)

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12 pages, 1754 KB

Open AccessArticle

Fine-Tuning Directional Message Passing Neural Networks: Predicting Properties of Conjugated Organic Polymers with High Accuracy

by Igor P. Koskin, Lev S. Petrosyan and Maxim S. Kazantsev

Polymers 2026, 18(7), 879; https://doi.org/10.3390/polym18070879 - 2 Apr 2026

Viewed by 2610

Abstract

Conjugated organic polymers are the cornerstone of modern organic electronics, yet accurate prediction of their properties remains a challenging task due to their synthetic complexity and high computational cost of quantum-chemical methods. Here, we develop a graph neural network based on the DimeNet++ [...] Read more.

Conjugated organic polymers are the cornerstone of modern organic electronics, yet accurate prediction of their properties remains a challenging task due to their synthetic complexity and high computational cost of quantum-chemical methods. Here, we develop a graph neural network based on the DimeNet++ direct message passing architecture to predict HOMO, LUMO and energy gaps of conjugated polymers directly from their 3D monomer structure. The model was pre-trained on TD-DFT-extrapolated data and trained on a limited dataset of experimentally measured properties. As a result, pre-training had significantly improved model’s accuracy compared to direct training (MAEs ~0.3 eV vs. 0.074 eV, 0.141 and 0.172 for HOMO/LUMO and energy gap, respectively). Pre-training on monomer DFT data did not provide comparable gains. The results demonstrate that polymer-relevant pre-training is critical for capturing structure–property relationships and enables accurate predictions without delta-learning or prior quantum-chemical calculations, facilitating efficient screening and rational design of conjugated polymers for organic optoelectronics. Full article

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

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18 pages, 2344 KB

Open AccessArticle

Amino–MIL-101(Fe)/Chitosan–Graphene Oxide Cross-Linked Nanocomposite for High-Performance Adsorptive Remediation of Wastewater Microplastics from Environmental Samples

by Amr A. Yakout, Ahmed S. Badr El-din, Amani Al Solami and Abeer H. Aljadaani

Polymers 2026, 18(7), 878; https://doi.org/10.3390/polym18070878 - 2 Apr 2026

Cited by 3 | Viewed by 1037

Abstract

One of the main sources of microplastic pollution in aquatic ecosystems is municipal wastewater, and preserving the ecological security of water depends on its effective removal. In this study, a potential multi-functionalized nanocomposite (NH₂-MIL-101(Fe)/CS/GO), which consists of an iron-based metal–organic framework [...] Read more.

One of the main sources of microplastic pollution in aquatic ecosystems is municipal wastewater, and preserving the ecological security of water depends on its effective removal. In this study, a potential multi-functionalized nanocomposite (NH₂-MIL-101(Fe)/CS/GO), which consists of an iron-based metal–organic framework (NH₂-MIL-101(Fe)) integrated with chitosan (CS) as a biopolymer matrix and graphene oxide (GO) as a conductive support, was exploited to enhance microplastic removal via different adsorptive hydrophilic/hydrophobic interactions. According to adsorption tests, the removal efficiencies of NH₂-MIL-101(Fe)/CS/GO for polyethylene terephthalate (PET) and polystyrene (PS) microplastics (25–30 μm) were 93.8% and 89.7%, respectively, at pH 6.2 and for 40 min of contact time. Adsorption isotherms were well fitted to both the Langmuir and the Freundlich models, and the maximum adsorption capacities of PET and PS were 321.4 and 255.1 mg·g⁻¹, respectively. The removal efficiency reached 92.5% after six cycles. The proposed MOF-based CS/GO nanocomposite provides an efficient and durable method of controlling microplastic contamination in urban wastewater. The developed multi-functionalized nanocomposite offers excellent electrostatic and hydrophobic synergy through a large surface area and π–π interactions for GO, positively charged CS, and a very high surface area with tunable porosity for the amino–MIL-101 (Fe) moiety. The proposed MOF-based nanocomposite provides an effective and persistent method of reducing microplastic contamination in constructed wetlands and water/wastewater treatment plants. Full article

(This article belongs to the Special Issue Polymer Materials for Ecological and Environmental Applications)

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11 pages, 669 KB

Open AccessArticle

Decoding Polyether–Cation Interactions: Computational Strategies for Agricultural Applications

by João Vitor de Jesus Damante, Enzo Ernani da Silva, Felipe Breda Alves, Bruno Andrade Fico, Renato Luis Tame Parreira, Eduardo Ferreira Molina and Renato Pereira Orenha

Polymers 2026, 18(7), 877; https://doi.org/10.3390/polym18070877 - 2 Apr 2026

Viewed by 607

Abstract

Zinc and iron are essential micronutrients in crop nutrition, and polymer-based nanogels have emerged as promising carriers to modulate their availability in sustainable agricultural systems. Here, a polymeric model receptor was designed to investigate how the nature and position of electron-donating (–NH₂ [...] Read more.

Zinc and iron are essential micronutrients in crop nutrition, and polymer-based nanogels have emerged as promising carriers to modulate their availability in sustainable agricultural systems. Here, a polymeric model receptor was designed to investigate how the nature and position of electron-donating (–NH₂) and electron-withdrawing (–NO₂) substituents control the recognition of Zn²⁺ and Fe²⁺ cations. Using a combination of density functional theory calculations, energy decomposition analysis with natural orbitals for chemical valence (EDA–NOCV), electrostatic potential (ESP) mapping, and quantum theory of atoms in molecules (QTAIM) method, the receptor–cation interactions are dissected into electrostatic, Pauli repulsion, orbital, and dispersion contributions. The results show that complex stability is governed mainly by orbital and electrostatic terms, with Fe²⁺ forming the most stable complex (−393.57 kcal mol⁻¹) with regard to a Zn²⁺ similar complex (−288.80 kcal mol⁻¹). Zn²⁺ complexes exhibit a broad tunability with substituent pattern. Electron-donating groups systematically strengthen both electrostatic and orbital components, whereas nitro substituents display a pronounced positional effect, ranging from strong destabilization to significant stabilization of Zn²⁺ binding. These findings establish molecular-level guidelines for engineering polymeric nanogels with tunable affinity and selectivity toward micronutrient cations in agricultural applications. Full article

(This article belongs to the Special Issue Modeling of Polymer Composites and Nanocomposites (2nd Edition))

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19 pages, 2951 KB

Open AccessReview

Next-Generation PVA–Dye Complex Film with Advanced Properties for Optical Applications

by Rong Ma and Yuncheng Yu

Polymers 2026, 18(7), 876; https://doi.org/10.3390/polym18070876 - 2 Apr 2026

Viewed by 1214

Abstract

With the development of the information society, display technologies are evolving toward greater flexibility and advanced performance. Dye-based polyvinyl alcohol (PVA) complex films have gained widespread attention for their excellent resistance to high temperature and humidity. This review systematically summarizes the research progress [...] Read more.

With the development of the information society, display technologies are evolving toward greater flexibility and advanced performance. Dye-based polyvinyl alcohol (PVA) complex films have gained widespread attention for their excellent resistance to high temperature and humidity. This review systematically summarizes the research progress of dye-based polarizers using PVA as the substrate, focusing on their preparation principles, film properties, and impacts on optical performance. Strategies to enhance optical properties and durability are discussed, including dye molecular optimization, formulation design, control of the dyeing process, and PVA substrate film modification. Notably, improving interfacial interactions between dyes and PVA enhances molecular orientation and stability, while PVA modification improves mechanical properties, water resistance, thermal stability, and flame retardancy. By demonstrating these enhanced comprehensive properties, this review highlights the potential of PVA–based films to serve as high-performance platforms for the development of next-generation multifunctional optical and display materials. Finally, the challenges and development directions of dye-based PVA complex films for optical applications in harsh environments are prospected. This review provides a theoretical basis and technical pathway for the design and development of next-generation high-performance composite polarizers. Full article

(This article belongs to the Special Issue Next-Generation Flame-Retardant Polymer Materials for Advanced Applications)

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19 pages, 7327 KB

Open AccessArticle

Homogeneously Blending PBAT with Silanized Cellulose for Composite Film: Characterization and Physicochemical Property

by Ce Zhao, Xinxin Yan, Zhou Zhou, Lukuan Guo, Shilong Yang, Zhen Chen, Fengwei Jia, Junlong Song and Jiaqi Guo

Polymers 2026, 18(7), 875; https://doi.org/10.3390/polym18070875 - 2 Apr 2026

Cited by 1 | Viewed by 892

Abstract

Improving the interfacial compatibility between cellulose and poly(butylene adipate-co-terephthalate) (PBAT) is critical for enhancing the performance of PBAT-based composites. Here, microcrystalline cellulose (MCC) was homogeneously silanized at the molecular chain level using t-hexyldimethylchlorosilane (TDMS-Cl) as the modifier, yielding t-hexyldimethylsilylated cellulose (TDMS-Cell). [...] Read more.

Improving the interfacial compatibility between cellulose and poly(butylene adipate-co-terephthalate) (PBAT) is critical for enhancing the performance of PBAT-based composites. Here, microcrystalline cellulose (MCC) was homogeneously silanized at the molecular chain level using t-hexyldimethylchlorosilane (TDMS-Cl) as the modifier, yielding t-hexyldimethylsilylated cellulose (TDMS-Cell). TDMS-Cell/PBAT composite films were then prepared by solution blending and casting in tetrahydrofuran (THF). Structural characterizations confirmed the successful grafting of TDMS-Cl onto cellulose chains, resulting in TDMS-Cell with a degree of substitution of approximately 2. Microstructural observations combined with thermal analysis revealed that TDMS-Cell exerted a dual effect on the crystallization behavior of PBAT: it acted as a heterogeneous nucleating agent that increased the crystallization temperature, while the pronounced steric hindrance simultaneously suppressed crystal growth. Mechanical testing showed that simultaneous strengthening and toughening were achieved at an optimal TDMS-Cell loading of 3–5 wt%. Specifically, the tensile strength increased from ~16 MPa for neat PBAT to 21 MPa (31.25% improvement), and the elongation at break increased from ~700% to 964% (37.7% improvement). In addition, the incorporation of an appropriate amount of TDMS-Cell effectively enhanced the surface hydrophobicity of the composite films. At higher filler loading, however, solvent evaporation-induced phase separation led to self-aggregation of TDMS-Cell, which in turn deteriorated both the mechanical properties and surface hydrophobicity of the composites. Overall, this work systematically elucidates the structure–property relationships of silanized cellulose/PBAT composites in a homogeneous solution system, providing a rational basis for interfacial design and property optimization of PBAT/biomass-based composite materials. The prepared TDMS-Cell/PBAT composite films with balanced mechanical strength, tunable crystallization behavior, and improved surface hydrophobicity exhibit great potential for practical applications in high-performance flexible packaging materials, functional film substrates, lightweight composite structural components, and tunable hydrophobicity coating substrates. Full article

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

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12 pages, 3127 KB

Open AccessArticle

Stabilizing the Sealing Performance of EPDM by the Incorporation of a ZIF-8 Network

by Jiahui Chen, Qian Peng, Huadong Liu, Xingtao Xiao, Xiaotao Fu, Hanlin Wen, Zhicheng Huang, Fangqiang Wang and Xiaoliang Zeng

Polymers 2026, 18(7), 874; https://doi.org/10.3390/polym18070874 - 2 Apr 2026

Viewed by 827

Abstract

Ethylene–propylene–diene monomer rubber (EPDM) is commonly used as a gas-tight sealing material in electrical equipment. Factors such as media exposure, thermal oxidative stress, and abrasion frequently cause deterioration of EPDM’s mechanical properties, significantly compromising the reliability of electrical equipment. Traditional activator ZnO provides [...] Read more.

Ethylene–propylene–diene monomer rubber (EPDM) is commonly used as a gas-tight sealing material in electrical equipment. Factors such as media exposure, thermal oxidative stress, and abrasion frequently cause deterioration of EPDM’s mechanical properties, significantly compromising the reliability of electrical equipment. Traditional activator ZnO provides limited enhancement to the properties of EPDM. The reaction between Zn²⁺ on the surface of zinc oxide interacts with the accelerator during curing of rubber, forming zinc chelates, which interact with sulfur to form zinc polysulfide complexes. But the release of zinc complexes has adverse effects on humans and ecosystems. To reduce ZnO usage and further improve the performance of EPDM in terms of mechanical properties and aging resistance, zeolitic imidazolate framework-8 (ZIF-8) is developed as a multifunctional additive in this work. Mechanical testing demonstrates that the incorporation of ZIF-8 enhances the mechanical performance and resistance to thermal oxidative aging of EPDM. Crosslink density testing, FTIR, and XPS show that ZIF-8 promotes the crosslinking reaction during rubber curing, resulting in improved mechanical performance for EPDM. Analysis of crosslinking density testing and SEM images shows that EPDM-ZIF-8 composite exhibits a slower increase in crosslinking density during thermal oxidative aging. TGA results indicate that ZIF-8 enhances the thermal stability of EPDM, which leads to improved aging resistance properties. This study provides new insights for the design and development of rubber composite materials, offering a reliable solution to the challenge of seal failure in electrical equipment. Full article

(This article belongs to the Special Issue Additive Manufactuging of Polymer-Based Nanocomposites and Composites: Progress and Prospects)

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17 pages, 3726 KB

Open AccessArticle

Influence of Steel and Polypropylene Fibers on Flexural Strength and Fracture Properties of Ambient-Cured Geopolymer Concrete

by Mustafa Oguz, Süleyman Özen, Şemsi Yazıcı and Ali Mardani

Polymers 2026, 18(7), 873; https://doi.org/10.3390/polym18070873 - 2 Apr 2026

Cited by 2 | Viewed by 944

Abstract

The environmental urgency of reducing Portland cement consumption has driven research into geopolymer concrete (GPC) as a sustainable alternative. However, its inherent brittleness limits structural applications. This study addresses this critical challenge by investigating the efficacy of steel fibers (SF) and polypropylene fibers [...] Read more.

The environmental urgency of reducing Portland cement consumption has driven research into geopolymer concrete (GPC) as a sustainable alternative. However, its inherent brittleness limits structural applications. This study addresses this critical challenge by investigating the efficacy of steel fibers (SF) and polypropylene fibers (PP) in enhancing the mechanical properties of slag-based GPC. Thirteen mixtures, including a control, were designed with varying fiber types, lengths (35/60 mm for SF, 40/60 mm for PP) and dosages (25–75 kg/m³ for SF, 3–9 kg/m³ for PP). Comprehensive tests evaluated workability, flexural/compressive strength, and toughness. Results demonstrated that while both fibers reduced workability (PP > SF), they significantly improved ductility, with SFs increasing toughness by 6–15 times. A key finding was the time-dependent performance: SF enhanced early-age flexural strength by up to 38%, though this benefit declined at 28 days for most mixes under ambient curing. PP fibers reduced flexural strength by 25–40% at 28 days. Compressively, SF increased strength by up to 60%, while PP led to reductions up to 27%. The study conclusively establishes SF’s superiority due to its superior bonding and crack-bridging capabilities, providing essential insights for designing durable fiber-reinforced GPC. This research directly contributes to advancing sustainable construction materials by overcoming a fundamental limitation of geopolymers. Full article

(This article belongs to the Special Issue Fiber-Reinforced Polymer Composites for Civil Engineering Applications)

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11 pages, 3286 KB

Open AccessArticle

Enhanced Electromechanical Performance of Dielectric Elastomer by Co-Crosslinking of Silane-Functionalized TiO₂ with Polyacrylate

by Lingxiao Peng, Wenjie Si, Yuhui He, Nanying Ning and Jianfeng Wang

Polymers 2026, 18(7), 872; https://doi.org/10.3390/polym18070872 - 1 Apr 2026

Cited by 1 | Viewed by 845

Abstract

Dielectric elastomer actuators (DEAs) are attracting much attention as candidates for next-generation flexible actuation. Among various DE matrices, polyacrylate rubber (AR) is especially promising owing to their intrinsically high dielectric constant (ε_r) and good mechanical performance. In particular, its mechanical [...] Read more.

Dielectric elastomer actuators (DEAs) are attracting much attention as candidates for next-generation flexible actuation. Among various DE matrices, polyacrylate rubber (AR) is especially promising owing to their intrinsically high dielectric constant (ε_r) and good mechanical performance. In particular, its mechanical behavior is close to that of porcine bladder tissue, making it a potentially good material for soft biomedical actuators for artificial bladder constructs. To achieve high actuated strain, which requires high ε_r, high breakdown strength, and low elastic modulus, an AR DE composite filled with silane-functionalized TiO₂ was fabricated, exhibiting good electromechanical performance enabled by strengthened interfacial polarization. To improve compatibility between TiO₂ and AR matrix, TiO₂ was preferentially modified with a silane coupling agent (CA) that features a double bond as its functional group, which can be introduced on TiO₂ surface and participate in vulcanization with AR, thereby forming co-crosslinking bridges that strengthen interfacial bonding, improve filler dispersion, and increase interfacial polarizability within the matrix. As a result, at relatively low filler loadings, the composite exhibits a significantly increased ε_r, while maintaining low modulus, low dielectric loss and high elasticity. The 10 CA@TiO₂/AR composite exhibits a maximal actuated strain of 7.9% at 31.9 kV/mm without pre-stretch, which is 1.48 times that of pure AR and 1.32 times that of the 10 TiO₂/AR composite. Full article

(This article belongs to the Collection Polymers and Polymer Composites: Structure-Property Relationship)

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16 pages, 2839 KB

Open AccessArticle

Impact of Processing and Char Feedstock on the Thermal, Mechanical, and Electrical Behavior of PLLA Composites

by Donatella Duraccio, Boutheina Rzig, Mattia Di Maro, Giulio Malucelli, Finizia Auriemma, Federica Pignatelli, Giuliana Magnacca, Pier Paolo Capra, Mattia Bartoli and Maria Giulia Faga

Polymers 2026, 18(7), 871; https://doi.org/10.3390/polym18070871 - 1 Apr 2026

Viewed by 711

Abstract

This work explores the influence of two preparation methods, solvent casting and melt mixing, on the structure–property relationships of poly-L-lactic acid (PLLA) composites reinforced with char derived from different waste feedstocks. Three types of char were produced by slow pyrolysis at 550 °C: [...] Read more.

This work explores the influence of two preparation methods, solvent casting and melt mixing, on the structure–property relationships of poly-L-lactic acid (PLLA) composites reinforced with char derived from different waste feedstocks. Three types of char were produced by slow pyrolysis at 550 °C: olive pruning waste biochar (OC), tyre-derived char (TC), and a 1:1 hybrid co-pyrolyzed char (OTC). Each filler was incorporated into PLLA at 1 and 2 wt.% loadings, and the resulting composites were characterized through physicochemical, thermal, mechanical, and electrical analyses. Raman, FTIR, and SEM analyses revealed distinct structural characteristics for each char, with the hybrid OTC exhibiting the highest structural order due to synergistic interactions during co-pyrolysis. The preparation method affected filler dispersion. Solvent-cast films displayed micrometric agglomerates and interfacial voids, whereas melt mixing ensured a more homogeneous distribution. Thermal characterization showed that char addition did not significantly alter the crystallization or melting behavior of PLLA, although melt-mixed samples exhibited restricted chain mobility. Mechanical tests revealed opposing effects of filler loading depending on processing: in solvent-cast materials, stiffness increased while strength remained nearly unaffected, whereas melt-mixed composites exhibited reduced modulus and strength, attributed to the disruption of the denser amorphous structure generated during melt processing. Electrical resistivity depended on the preparation method. Solvent-cast composites remained insulating, while melt mixing, with OTC at 2 wt.%, led to a resistivity drop (down to 0.02 × 10¹⁵ Ω·cm from 20 × 10¹⁵ Ω·cm for unfilled PLLA), although all materials remained within the insulating regime. Overall, this work provides insight into the role of sustainable char fillers in improving the performance of PLLA composites and highlights the interplay between processing method and material properties. The developed PLLA/char composites are promising candidates for applications in flexible electronics, sensors, and antistatic components, as well as in lightweight structural materials and energy devices. Full article

(This article belongs to the Special Issue Advanced Poly(lactic Acid) Materials and PLA-Based Composites: From Fundamentals to Applications)

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26 pages, 1394 KB

Open AccessReview

Lipid-Enriched Biopolymer Films for Active Packaging: A Review of Structure, Properties, and Preservation Performance

by Bruna Moura Bastos, Janaína Oliveira Gonçalves, Mariano Michelon and Luiz Antonio de Almeida Pinto

Polymers 2026, 18(7), 870; https://doi.org/10.3390/polym18070870 - 1 Apr 2026

Viewed by 1222

Abstract

Amid growing environmental concerns regarding the use of non-biodegradable plastic packaging and its potential emerging contaminants, such as microplastics, currently among the most pressing global challenges, researchers in the food sector are increasingly pursuing sustainable alternatives. In this context, various organic sources have [...] Read more.

Amid growing environmental concerns regarding the use of non-biodegradable plastic packaging and its potential emerging contaminants, such as microplastics, currently among the most pressing global challenges, researchers in the food sector are increasingly pursuing sustainable alternatives. In this context, various organic sources have been explored for the development of innovative biocompatible films. These films exhibit properties such as low water vapor permeability, transparency, and biodegradability, and have recently gained active functionalities. These enable the extension of the shelf life of packaged foods by controlling microbial activity and oxidative degradation. Lipid-based compounds derived from animal and plant sources—including phospholipids, essential oils, free fatty acids, and saturated and polyunsaturated fatty acids—have proven highly effective when incorporated into films, leading to significant physicochemical, mechanical, and microbiological improvements in both the films and the packaged products. Owing to their high hydrophobic capacity, these lipids markedly reduce water vapor permeability, which is crucial for extending the shelf life of high-moisture foods. Studies have shown that the incorporation of lipid compounds can increase film tensile strength by up to 37% and enhance antioxidant activity by over 75%. Moreover, many of these compounds exhibit antibacterial and antimicrobial activities, becoming active on the surface of food in contact. However, many bioactive compounds have poor dispersion in aqueous solutions, limiting their effectiveness in the final product. When encapsulated with the aid of a lipid fraction, the bioavailability of these compounds is improved, and their release can be effectively controlled. This review aims to consolidate recent research on the production of biopolymer films incorporating various types of lipid compounds, highlighting their enhancements and potential applications in active food packaging systems. Full article

(This article belongs to the Special Issue Biodegradable Polymers: Innovations in Processing, Diverse Applications, and Sustainable Solutions)

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14 pages, 3785 KB

Open AccessArticle

Topology-Induced Reduction in the Order–Disorder Transition in AB Block Copolymer: A Unit-Matched Comparison of Diblock, Multiblock, Comb, and Star Architectures

by June Huh

Polymers 2026, 18(7), 869; https://doi.org/10.3390/polym18070869 - 1 Apr 2026

Viewed by 688

Abstract

Chain topology offers a chemistry-preserving route to tune block copolymer (BCP) self-assembly by modifying intrachain correlations and relaxation pathways without changing monomer interactions. Here, we perform a unit-matched comparison of four lamella-forming AB architectures reconstructed from an identical constitutive diblock unit ( [...] Read more.

Chain topology offers a chemistry-preserving route to tune block copolymer (BCP) self-assembly by modifying intrachain correlations and relaxation pathways without changing monomer interactions. Here, we perform a unit-matched comparison of four lamella-forming AB architectures reconstructed from an identical constitutive diblock unit (

N_{0}

): a linear diblock (DB), a linear multiblock (MB), a comb-like architecture (CB), and a star-like architecture (SB). Using dynamical density functional theory (DDFT), we quantify topology-dependent bulk ordering thresholds and show that architectural reconfiguration systematically stabilizes the ordered phase, reducing the order–disorder transition relative to DB (MB/CB/SB

\approx 0.793 / 0.762 / 0.752

of the diblock value), in semi-quantitative agreement with random phase approximation (RPA) spinodal trends. We also compare topology-dependent directed self-assembly in a common trench geometry under matched reduced quench depth

Δ (χ N_{0}) = χ N_{0} - {(χ N_{0})}_{ODT}

, thereby isolating kinetic differences at comparable thermodynamic distance from bulk ordering. A Fourier-based alignment order parameter

α (t)

reveals sigmoidal alignment kinetics over decades in time and is well captured by a logistic form in

ln t

, enabling compact descriptors (

t_{50}

,

t_{90}

, and a steepness parameter k) that separate alignment onset from late-stage defect annihilation, while selective sidewalls robustly template sidewall-parallel lamellae across all topologies, the late-stage kinetics remain strongly connectivity dependent and can exhibit long-tailed completion associated with slow late-stage defect annihilation. These results demonstrate a dual role of topology in DSA: lowering the segregation strength required for bulk ordering while reshaping defect-mediated alignment pathways under confinement. Full article

(This article belongs to the Special Issue Material-Process-Structure Integrated Design for Advanced Polymeric Composites, 2nd Edition)

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27 pages, 2109 KB

Open AccessSystematic Review

Are Polymeric Membranes Truly Sustainable? Life Cycle Assessment Studies of Polymeric Membranes in Post-Combustion CO₂ Capture: A Systematic Review

by Talha Kemal Koçak, Aytac Perihan Akan and Eric Favre

Polymers 2026, 18(7), 868; https://doi.org/10.3390/polym18070868 - 1 Apr 2026

Cited by 1 | Viewed by 1138

Abstract

Polymeric membranes are promising materials for post-combustion CO₂ capture (PCC), yet their life cycle environmental performance remains uncertain. This review synthesizes 21 life cycle assessment (LCA) studies of polymeric membrane-based PCC systems to examine methodological choices, quantify environmental trade-offs, and identify research [...] Read more.

Polymeric membranes are promising materials for post-combustion CO₂ capture (PCC), yet their life cycle environmental performance remains uncertain. This review synthesizes 21 life cycle assessment (LCA) studies of polymeric membrane-based PCC systems to examine methodological choices, quantify environmental trade-offs, and identify research gaps. Google Scholar, Web of Science, ScienceDirect, and MDPI were searched up to January 2026. Methodological quality and risk of bias were assessed against a 10-criteria framework derived from ISO 14044. Results indicate widely varying system boundaries and functional units, with only four studies performing formal uncertainty analysis. Within individual study contexts, polymeric membrane gas separation systems can reduce global warming potential (GWP) by up to 89% compared to no-capture plants, though other impacts, like ozone depletion potential, increase by up to 780%. Compared to amine-based absorption, membranes showed superior performance, with reductions up to 26% in GWP and 98% in other categories. In some cases, large relative reductions are driven by scenario-specific baselines and should be interpreted with caution. Outcomes were most sensitive to background energy mixes and raw material demand. The absence of commercial-scale data highlights the need for harmonized frameworks and standardized functional units. Future research should prioritize membrane material selection, renewable energy integration, and coordinated policy–industry collaboration. Full article

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

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Polymers, Volume 18, Issue 7 (April-1 2026) – 118 articles

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