Polymers

25 pages, 4366 KB

Open AccessArticle

Flexible Polypyrrole-Based Composite Films with Tailored Electrical and Mechanical Properties for Electrocardiographic Sensing

by Alin-Alexandru Andrei, Izabell Craciunescu, Lucian Barbu Tudoran, Rodica Paula Turcu, George Marian Ispas, Gavril-Ionel Giurgi, Alexandru Oprea, Mioara Zagrai and Cristian Sevcencu

Polymers 2026, 18(6), 779; https://doi.org/10.3390/polym18060779 - 23 Mar 2026

Cited by 1 | Viewed by 770

Abstract

Flexible electrode materials with tailored electrical and mechanical properties are essential for reliable electrocardiographic (ECG) sensing. In this work, p-toluenesulfonic-acid-doped polypyrrole (PPy–TSA) films were modified using polymeric and inorganic fillers, as well as their combinations (polyethylene glycol, graphene, carbon nanotubes, and zeolite), to [...] Read more.

Flexible electrode materials with tailored electrical and mechanical properties are essential for reliable electrocardiographic (ECG) sensing. In this work, p-toluenesulfonic-acid-doped polypyrrole (PPy–TSA) films were modified using polymeric and inorganic fillers, as well as their combinations (polyethylene glycol, graphene, carbon nanotubes, and zeolite), to tune their functional performance. The reference PPy–TSA film exhibits typical morphological and chemical characteristics of doped polypyrrole and serves as a reliable baseline for comparison. All composite films retain electrical conductivity within the range required for ECG applications while showing improved mechanical compliance (i.e., enhanced ability to conform to the skin and sustain deformation). Based on the optimized balance between electrical and mechanical properties, flexible ECG electrodes were fabricated using the TSA-doped PPy-based composite film. ECG recordings obtained with the several proposed electrodes show good agreement with those acquired using a commercial ECG electrode, demonstrating the potential of PPy-based composite films for flexible bioelectronic sensing applications. Full article

(This article belongs to the Special Issue Advances in Polymer-Based Nanomaterials for Electrochemical Applications)

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20 pages, 2974 KB

Open AccessArticle

Dynamics of Drone Blades Based on Polymer Nanocomposites Incorporating Graphene, Carbon Nanotube, and Fullerene

by Workineh G. Gomera, Tomasz Tański and Jung Yong Kim

Polymers 2026, 18(6), 778; https://doi.org/10.3390/polym18060778 - 23 Mar 2026

Viewed by 1063

Abstract

Polymer nanocomposites offer significant potential for improving the strength-to-weight ratio and dynamic behavior of drone blades. This study examines the vibration characteristics of tapered aramid (Kevlar)/epoxy composite blades reinforced with nanocarbon fillers—graphene (2D), multi-walled carbon nanotubes (MWCNTs, 1D), and fullerene (0D)—to determine the [...] Read more.

Polymer nanocomposites offer significant potential for improving the strength-to-weight ratio and dynamic behavior of drone blades. This study examines the vibration characteristics of tapered aramid (Kevlar)/epoxy composite blades reinforced with nanocarbon fillers—graphene (2D), multi-walled carbon nanotubes (MWCNTs, 1D), and fullerene (0D)—to determine the most effective filler for enhancing stiffness and operational stability. The laminated blades (300 mm length, 200 mm width, root thickness 13 mm, tip thickness 8 mm) incorporate ply drop-offs and a central honeycomb core. Modeling was performed using classical laminate plate theory integrated with the finite element method (FEM) in MATLAB (R2016a). Under clamped–free–free–free boundary conditions, the study considered rotational speeds of 750–2250 rpm, setting angles of 30–60°, various fiber orientations, and nanofiller contents of 0–10 wt.%. The results indicate that while the setting angle minimally affects natural frequency, it significantly influences damping in modes (1,2) and (2,1). Increasing nanofiller content improves stiffness, with optimal performance observed near 5 wt.%. At 1500 rpm in mode (1,1), MWCNTs provided the greatest enhancement. Overall, MWCNTs exhibited superior stiffness improvement and rotational stability compared to other fillers. Full article

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

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15 pages, 5166 KB

Open AccessArticle

Improving and Optimizing Mechanical Properties of Glass Fiber-Reinforced Composites via Geometric Optimization of Nanofillers Using Co-Curing Processes

by Eonsu Yun, Hyunjong Choi, Joon Seok Lee, Byoung-Sun Lee and Hyunchul Ahn

Polymers 2026, 18(6), 777; https://doi.org/10.3390/polym18060777 - 23 Mar 2026

Viewed by 626

Abstract

This study investigates the effects of the co-curing process and nanoparticle reinforcement on the mechanical performance of plain-woven glass fiber-reinforced plastic (GFRP) adhesive joints, aiming to address the limitations of traditional fastening methods and the inherent brittleness of epoxy adhesives. Specifically, spherical silica [...] Read more.

This study investigates the effects of the co-curing process and nanoparticle reinforcement on the mechanical performance of plain-woven glass fiber-reinforced plastic (GFRP) adhesive joints, aiming to address the limitations of traditional fastening methods and the inherent brittleness of epoxy adhesives. Specifically, spherical silica (SiO₂) and plate-like graphene nanoplatelets (GNPs) were incorporated into the epoxy matrix at varying concentrations (0.25 to 1.0 wt.%) to evaluate the influence of particle geometry on joint integrity. Experimental results demonstrated that the co-curing technique yields superior mechanical properties compared to secondary bonding, exhibiting improvements of 35% in shear strength (from 10.97 MPa to 14.83 MPa) and 12% in flexural strength (from 72.57 MPa to 81.28 MPa) due to enhanced chemical interlocking. Furthermore, the addition of nanoparticles significantly improved joint performance, with the optimal content identified at 0.75 wt.% for both particle types. Notably, GNPs outperformed SiO₂, enhancing shear and flexural strengths compared to the neat co-cured baseline. Ultimately, the 0.75 wt.% GNP-reinforced material exhibited a shear strength of 21.22 MPa and a flexural strength of 104.09 MPa. Morphological analysis revealed that while SiO₂ contributes to reinforcement primarily via crack deflection, the high-aspect-ratio GNPs provide superior energy dissipation through crack bridging and pull-out mechanisms. Consequently, this study suggests that the co-curing process combined with an optimal concentration of GNPs presents a highly effective strategy for maximizing the reliability and structural efficiency of composite joints in weight-critical applications. Full article

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

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21 pages, 15375 KB

Open AccessArticle

Experimental Study on the Influence of Ultraviolet Aging on the Shear Characteristics of HDPE Geomembrane/Sand Interface

by Hai Lin, Ruimin Chen, Haonan Li, Qiang Zhou, Guanghui Di and Xiaohaobo Wang

Polymers 2026, 18(6), 776; https://doi.org/10.3390/polym18060776 - 23 Mar 2026

Viewed by 676

Abstract

High-density polyethylene (HDPE) geomembranes (GMs) in landfill liners experience UV exposure during installation. While tensile strength deterioration after UV aging is known, changes in interfacial shear properties are rarely reported. This study investigates the evolution of interfacial shear behavior at the GM/sand interface [...] Read more.

High-density polyethylene (HDPE) geomembranes (GMs) in landfill liners experience UV exposure during installation. While tensile strength deterioration after UV aging is known, changes in interfacial shear properties are rarely reported. This study investigates the evolution of interfacial shear behavior at the GM/sand interface by subjecting GM specimens to varying durations of indoor UV aging followed by direct shear tests. Underlying mechanisms were explored through tensile strength, melt flow index, crystallinity, and oxidation induction time (OIT) measurements. Results show that displacement required to reach peak shear strength for smooth geomembrane (GMS)/sand interface decreased with aging time (49.0–70.1% reduction), while no clear trend emerged for textured geomembrane (GMX)/sand interface. Following 80 days of UV exposure, the GMS/sand interfacial shear strength declined, with the peak friction angle dropping 20.6% from 26.2° to 20.8°. For the GMX/sand interface, the peak friction angle dropped to its lowest value of 31.2° after 40 days of exposure (from 34.3°), and then exhibited an increase with further UV aging. The large displacement shear strength followed a trend similar to that of the peak strength. Among the other tested indicators, the variation pattern of OIT with UV exposure exhibited the best correlation with the GMS/sand interface shear strength. Full article

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

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19 pages, 5708 KB

Open AccessArticle

Tracking Solar Optimization in Renewable Energy Systems by Using Multiplexed Holograms in Bayfol^® Photopolymers

by Pedro Mas-Abellán, Pablo Beléndez, Jesús Gea-Caselles, José Carlos García-Vázquez, Belén Nieto-Rodríguez, Tomás Lloret and Inmaculada Pascual

Polymers 2026, 18(6), 775; https://doi.org/10.3390/polym18060775 - 23 Mar 2026

Viewed by 693

Abstract

Multidisciplinary technologies are truly driving major transformations in industries, innovating to become more efficient. The need for more efficient renewable energy systems, such as solar energy, has recently been addressed with the innovation of using holographic photonic devices to avoid solar tracking devices [...] Read more.

Multidisciplinary technologies are truly driving major transformations in industries, innovating to become more efficient. The need for more efficient renewable energy systems, such as solar energy, has recently been addressed with the innovation of using holographic photonic devices to avoid solar tracking devices as much as possible. In this work, a multiplexed holographic device is created and characterized for use in front of a photocell, thereby eliminating the need for tracking systems due to its wide acceptance angle and high diffraction efficiency. Commercial Bayfol^® HX121 photopolymer was used as the holographic recording material to manufacture holograms, achieving high performance and facilitating the industrial scaling of this technique. Results obtained using the multiplexing technique enable low-frequency holograms (478 lines/mm) with a 43° acceptance angle. Using three of these devices, a 129° angular sweep is possible without the need for tracking. Full article

(This article belongs to the Section Polymer Applications)

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15 pages, 5247 KB

Open AccessArticle

Differentiated Stem Cell-Seeded Gelatin/PLA/P(3HB-co-4HB) Meniscal Scaffold with Biocompatibility and Mechanical Strength

by Peng Li, Xiaoxin Cheng, Wuwei Li, Haiqing Yang and Yubi Jiang

Polymers 2026, 18(6), 774; https://doi.org/10.3390/polym18060774 - 23 Mar 2026

Viewed by 680

Abstract

Laceration is one of the most common meniscus injuries, which can cause knee joint dysfunction. The treatment of meniscus injuries remains one of the greatest challenges in orthopedics. In this study, a three-dimensional sponge-like Poly(lactic acid)/Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (PLA/P(3HB-co-4HB)) scaffold with oriented microtubules was fabricated [...] Read more.

Laceration is one of the most common meniscus injuries, which can cause knee joint dysfunction. The treatment of meniscus injuries remains one of the greatest challenges in orthopedics. In this study, a three-dimensional sponge-like Poly(lactic acid)/Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (PLA/P(3HB-co-4HB)) scaffold with oriented microtubules was fabricated using an improved gradient thermal phase separation technique. The scaffold surface was modified by adsorbing gelatin. The surface-modified scaffolds and the unmodified scaffolds were divided into two groups. All preparation parameters were adjusted to meet tissue engineering requirements. The prepared scaffolds were tested for porosity, compression modulus, hydrophilicity, and degradability. Following scaffold preparation, induced differentiated rabbit bone marrow mesenchymal stem cells (BMSCs) were seeded to evaluate scaffold cytocompatibility. Cell proliferation was observed in the two scaffold groups, and cell viability was analyzed using CCK-8 assay, scanning electron microscopy (SEM), and confocal microscopy. Histological staining was performed to comparatively study cell synthetic function. Subsequently, tissue reconstruction and regeneration were evaluated following subcutaneous implantation of gelatin/PLA/P(3HB-co-4HB) scaffolds loaded with induced differentiated BMSCs in the dorsal regions of athymic nude mice. Results demonstrated that the gelatin/PLA/P(3HB-co-4HB) scaffold exhibited good cell compatibility, providing a suitable microenvironment for cell proliferation and differentiation. Furthermore, the scaffold supported the growth of seeded induced differentiated rabbit MSCs in vivo, maintaining meniscus cell phenotyping and function. The cell-laden scaffold has the potential to generate meniscus fibrocartilage. Full article

(This article belongs to the Special Issue Smart and Bio-Medical Polymers: 3rd Edition)

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16 pages, 5729 KB

Open AccessArticle

A Hybrid Oleic-Acid-Derived Polymer Electrolyte Integrating Single- and Dual-Ion Conducting Systems for Lithium-Ion Batteries

by Wansu Bae, Sutradhar Sabuj Chandra, Doyul Lee, Donghoon Kang, Hyewon Na, Jiye Lee and Hohyoun Jang

Polymers 2026, 18(6), 773; https://doi.org/10.3390/polym18060773 - 23 Mar 2026

Viewed by 773

Abstract

In this work, a hybrid polymer electrolyte integrating single- and dual-ion conducting systems was developed for lithium-ion batteries using bio-based materials, namely oleic-acid derivatives and epoxidized soybean oil, through an in situ polymerization process. The fixed FSI anions in LiEFSOA enhance the selectivity [...] Read more.

In this work, a hybrid polymer electrolyte integrating single- and dual-ion conducting systems was developed for lithium-ion batteries using bio-based materials, namely oleic-acid derivatives and epoxidized soybean oil, through an in situ polymerization process. The fixed FSI anions in LiEFSOA enhance the selectivity of Li⁺ transport, while the cross-linked network formed by ESO provides mechanical stability, and the LiFSI incorporated into the polymer matrix helps maintain sufficient overall ionic conductivity. In addition, the long C18 oleic chains increase the internal free volume of the matrix, thereby improving segmental mobility within the amorphous phase. The in situ polymerization inside the cell causes intimate interfacial contact between the electrode and electrolyte, achieving an ionic conductivity of 1.05 × 10⁻⁴ S cm⁻¹ at 30 °C. Electrochemical evaluation using LiFePO₄/FSOA-2/Li cells shows an initial discharge capacity of 149.09 mAh g⁻¹ and a capacity retention of 81.09% after 100 cycles, and the average coulombic efficiency was 99.62%, demonstrating that the designed FSOA electrolyte exhibits stable cycling performance and competitive capacity. Overall, the combination of eco-friendly materials and a hybrid ion transport strategy provides a promising platform for developing sustainable and high-performance polymer electrolytes for lithium-ion batteries. Full article

(This article belongs to the Special Issue Advanced Polymer Electrolytes for Fuel Cell and Lithium-Ion Battery Applications)

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28 pages, 5620 KB

Open AccessArticle

In Situ Growth of MIL-100(Fe) on Coconut Shell Activated Carbon for High-Efficiently Removal of Microplastics from Water

by Qianyi Wang, Guohan Wang, Sasa Ma, Zichen Wang, Lijie Luo and Yongjun Chen

Polymers 2026, 18(6), 772; https://doi.org/10.3390/polym18060772 - 23 Mar 2026

Cited by 1 | Viewed by 829

Abstract

The widespread use of plastics has inevitably led to the accumulation of persistent plastic debris in aquatic systems, where gradual fragmentation generates microplastics (MPs) that threaten ecological and biological health. Their small size, chemical stability, and resistance to degradation make effective removal particularly [...] Read more.

The widespread use of plastics has inevitably led to the accumulation of persistent plastic debris in aquatic systems, where gradual fragmentation generates microplastics (MPs) that threaten ecological and biological health. Their small size, chemical stability, and resistance to degradation make effective removal particularly challenging. In this work, a composite adsorbent was fabricated through the in situ solvothermal growth of Materials of Institute Lavoisier 100 (Iron) (MIL-100(Fe)) onto coconut shell-derived activated carbon (CSAC), yielding a monolithic material denoted as CSAC@MIL-100(Fe). The integration of porous C with a metal–organic framework created a hierarchically structured adsorbent rich in accessible binding sites. The composite achieved a maximum polystyrene (PS) removal efficiency of 97.4% and maintained 91.44% efficiency after seven regeneration cycles. Stable adsorption performance was observed across a broad pH range. Structural and chemical analyses (scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS)) combined with adsorption modeling revealed heterogeneous multilayer adsorption behavior consistent with the Freundlich isotherm and pseudo-second-order kinetics. π–π interactions, electrostatic attraction, and coordination effects jointly governed PS capture. The Langmuir maximum adsorption capacity reached 746.27 mg/g. These findings demonstrate a practical and recyclable strategy for efficient MP remediation in aquatic environments. Full article

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

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25 pages, 13415 KB

Open AccessArticle

Microstructure and Mechanical Performance of 3D-Printed Carbon Fibre—PLA-PHA Composites

by David Bassir and Sofiane Guessasma

Polymers 2026, 18(6), 771; https://doi.org/10.3390/polym18060771 - 23 Mar 2026

Cited by 2 | Viewed by 783

Abstract

This research delves into the impact of varying printing angles in the range (0°, 15°, 30°, 45°) on the thermal and mechanical characteristics of carbon fibre–PLA/PHA composites fabricated via fused filament fabrication (FFF). The microstructural arrangement within the 3D-printed PLA/PHA is unveiled through [...] Read more.

This research delves into the impact of varying printing angles in the range (0°, 15°, 30°, 45°) on the thermal and mechanical characteristics of carbon fibre–PLA/PHA composites fabricated via fused filament fabrication (FFF). The microstructural arrangement within the 3D-printed PLA/PHA is unveiled through the application of SEM, X-ray microtomography and optical imaging. Tensile loading conditions are employed to extract meaningful mechanical parameters such as Young’s modulus, tensile strength, elongation at break, and mechanical energy, all of which are associated with the printing angle settings. The results indicate that the filaments exhibit a porosity of approximately 3%, while the porosity of the printed structure ranges from 27% to 38%, depending on the printing angle. Tensile modulus in the range 840 to 890 MPa is found not to be highly sensitive to the printing angle. However, tensile strength reaches 37 MPa for a printing angle of 30°. The variations across conditions are limited to approximately 6% in tensile stiffness and 16% in tensile strength. Finite element simulations based on 3D imaging indicate that an effective modulus of the solid phase between 1.6 and 1.8 GPa provides the closest agreement between experimental measurements and numerical predictions. This study presents novel findings concerning the deformation mechanisms associated with different length scales, from filament composite to filament arrangement, in the carbon fibre–PLA/PHA composite. This study highlights that while printing angle has a moderate influence on mechanical response, the overall structural integrity and interlayer cohesion of carbon fibre–PLA/PHA composites remain robust across a wide range of processing parameters, demonstrating their potential for reliable structural applications in additive manufacturing. Full article

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

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17 pages, 3368 KB

Open AccessArticle

C. albicans Detection with Electrochemical Sensors by Using Molecular Imprinted Polymer Technique

by Naphatsawan Vongmanee, Jindapa Nampeng, Chuchart Pintavirooj and Sarinporn Visitsattapongse

Polymers 2026, 18(6), 770; https://doi.org/10.3390/polym18060770 - 22 Mar 2026

Viewed by 635

Abstract

Candida albicans (C. albicans) is an opportunistic fungal pathogen and a major cause of nosocomial infections, especially in immunocompromised patients. Conventional diagnostic approaches such as blood culture and biochemical assays are accurate but require multi-step sample processing and prolonged turnaround times, [...] Read more.

Candida albicans (C. albicans) is an opportunistic fungal pathogen and a major cause of nosocomial infections, especially in immunocompromised patients. Conventional diagnostic approaches such as blood culture and biochemical assays are accurate but require multi-step sample processing and prolonged turnaround times, limiting their applicability for rapid clinical screening. In the present study, we developed an electrochemical biosensor based on molecularly imprinted polymer (MIP) technology for the rapid and selective detection of intact C. albicans cells. The MIP layer was electropolymerized onto a screen-printed carbon electrode (SPCE), forming selective recognition cavities complementary to the fungal morphology. Electrochemical characterization and detection were performed using cyclic voltammetry in phosphate-buffered saline (PBS). The system demonstrated a wide linear detection range, enabling reliable quantification of C. albicans across concentrations spanning from 1 to 10⁴ CFU/mL and achieved an ultralow limit of detection (LOD) of 1.30 CFU/mL, demonstrating high sensitivity. High selectivity was confirmed against E. coli, S. aureus, and P. aeruginosa, demonstrating that the imprinted cavities effectively distinguish fungal cells from bacterial contaminants. These findings highlight the promise of MIP-based electrochemical biosensors as a simple, low-cost, and portable alternative for early fungal diagnostics. Full article

(This article belongs to the Special Issue Polymeric Composite for Biosensor Applications)

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22 pages, 3812 KB

Open AccessArticle

Upcycling 3D Printing PLA Waste into Functional Electrospun Membranes: Effect of Polymer Concentration on Morphology, Surface Properties and Particle Filtration Efficiency

by Manuel J. Torres-Calla, Geraldine Denise Bazan-Panana, Fatimah N. Jacinto, Diego E. Velásquez, J. I. Gonzáles-Coronel, Manuel Chávez-Ruiz, María Verónica Carranza-Oropeza, J. Quispe-Marcatoma and C. V. Landauro

Polymers 2026, 18(6), 769; https://doi.org/10.3390/polym18060769 - 22 Mar 2026

Cited by 1 | Viewed by 789

Abstract

This study investigates the reutilization of polylactic acid (PLA) waste generated by 3D printing through its transformation into electrospun membranes with tunable morphological, surface, thermal, and filtration properties. Polymer solutions containing 5–10 wt % recycled PLA were prepared in a dichloromethane/dimethylformamide system and [...] Read more.

This study investigates the reutilization of polylactic acid (PLA) waste generated by 3D printing through its transformation into electrospun membranes with tunable morphological, surface, thermal, and filtration properties. Polymer solutions containing 5–10 wt % recycled PLA were prepared in a dichloromethane/dimethylformamide system and characterized in terms of viscosity and electrical conductivity. Increasing PLA concentration raised solution viscosity (41.87–339.83 mPa·s) and reduced conductivity (7.63–1.63 µS·cm⁻¹), promoting the formation of bead-free fibers with larger diameters (0.221–1.213 µm) and enhanced hydrophobicity (contact angles 112.34–124.38°). FTIR confirmed preservation of the polymer chemical structure after recycling and electrospinning, while DSC revealed reduced crystallinity in the fibrous membranes. Exploratory correlation analysis indicated consistent associations between solution properties, fiber morphology, and wettability. Increasing the number of electrospun layers (1–3) generated denser networks with reduced pore size and improved particle retention. Filtration tests conducted under controlled airflow conditions (85 L min⁻¹, 1 cm s⁻¹ frontal velocity, 50 cm² effective area) showed removal efficiencies above 90% for PM2.5 and PM5, while PM1 capture improved with increasing membrane thickness. Quality factor analysis highlighted the trade-off between filtration efficiency and pressure drop, identifying intermediate multilayer configurations as providing a favorable balance. These findings demonstrate that electrospinning offers an effective strategy for converting recycled PLA into structurally tunable membranes with adjustable filtration performance, supporting sustainable valorization of additive manufacturing waste. Full article

(This article belongs to the Special Issue Sustainable Polymers for a Circular Economy)

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35 pages, 20337 KB

Open AccessArticle

The Use of Recycled Poly(Ethylene Terephthalate)/Amorphous Polyester Blends/Composites in Materials Extrusion (MEX) Additive Manufacturing Techniques: The Influence of Talc and Carbon Fiber on the Mechanical Performance and Hear Resistance

by Jacek Andrzejewski, Natan Zelewski, Wiktoria Gosławska, Adam Piasecki, Patryk Mietliński, Frederik Desplentere and Aleksander Hejna

Polymers 2026, 18(6), 768; https://doi.org/10.3390/polym18060768 - 22 Mar 2026

Cited by 2 | Viewed by 880

Abstract

The conducted study was focused on the development of a new type of polymer blends intended for additive manufacturing applications, in particular, the material extrusion method (MEX). The developed materials were prepared from recycled poly(ethylene terephthalate) and amorphous copolymers poly(ethylene terephthalate-glycol) (PETG), and [...] Read more.

The conducted study was focused on the development of a new type of polymer blends intended for additive manufacturing applications, in particular, the material extrusion method (MEX). The developed materials were prepared from recycled poly(ethylene terephthalate) and amorphous copolymers poly(ethylene terephthalate-glycol) (PETG), and poly(cyclohexylenedimethyl terephthalate-glycol) (PCTG). The basic blend systems were additionally modified with POE-g-GMA impact modifier (IM) during the reactive extrusion process. The main aim of the work was to assess the effectiveness of using composite additives and their influence on the mechanical and thermomechanical parameters of the tested systems. To prepare the composites, selected polymer blends were modified with 10% of talc (T) and carbon fibers (CF). The properties evaluation includes the mechanical/thermomechanical testing, thermal analysis and structural observations. The accuracy of printing was measured using optical scanning methods. The test results indicate that even the relatively small amount of the CF filler could lead to a significant increase in tensile modulus from reference 1.6 GPa to 2.9 GPa; the same improvement applies to strength values, where the CF-modified materials reached 45 MPa, compared to the reference 31 MPa. The heat deflection tests (0.455 MPa) after annealing revealed the maximum HDT of around 170 °C for both types of CF-modified materials. The Vicat test results were also favorable for annealed materials. Considering that the Vicat/HDT results after the 3D-printing process usually reach around 70 °C, the performed heat treatment strongly enhanced the heat resistance for most of the prepared blends. The performed studies revealed that for most of the prepared materials, the brittleness was a common drawback for both MEX-printed and injection-molded materials. Full article

(This article belongs to the Special Issue Processing of Polymer Composites—Preparation, Structure, Properties and Applications)

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16 pages, 2452 KB

Open AccessArticle

Investigations on the Performances of Corn Starch/PBAT Blends

by Wenzhuo Zhao, Rui Qiu, Miaoyi Fang, Wen Lei and Yong Chen

Polymers 2026, 18(6), 767; https://doi.org/10.3390/polym18060767 - 21 Mar 2026

Viewed by 757

Abstract

Corn starch (CS)/poly (butylene adipate-co-terephthalate) (PBAT) blends were prepared by extrusion and injection molding processes. The CS content in the blends changed between 0 and 50 wt.% in 10 wt.% steps. Melt flow rates, mechanical properties, thermal stability, melting and crystallization behavior, as [...] Read more.

Corn starch (CS)/poly (butylene adipate-co-terephthalate) (PBAT) blends were prepared by extrusion and injection molding processes. The CS content in the blends changed between 0 and 50 wt.% in 10 wt.% steps. Melt flow rates, mechanical properties, thermal stability, melting and crystallization behavior, as well as hydrophilicity of the blends were investigated. Based on these, the degradation properties of PBAT and the blend containing 50 wt.% CS (50%CS/PBAT) in water and open-air storage were comparatively studied via visual appearance observation, Shore hardness testing, and water absorption measurement. The results showed that the melt flow rates and the mechanical properties of the blends, including the tensile strength, tensile modulus, impact strength, and elongation at break, initially increased before decreasing as CS content in the blends increased, while the flexural strength and flexural modulus of the samples increased monotonously. The sample would become more thermal unstable when more CS was used. Besides these, the crystallinity and water contact angle became smaller. Immersion in water would blacken the visual appearances of PBAT and 50%CS/PBAT samples, but cracks could be found much more obviously in the blend than in neat PBAT; both the hardness and the mass of PBAT rose slightly while those of 50%CS/PBAT dropped significantly. An open-air storage would also blacken the visual appearances of PBAT and 50%CS/PBAT, and the hardness of the two samples would be decreased to almost the same extent. The results showed that the incorporation of CS in PBAT had much greater effects on the flow ability, mechanical properties, thermal stability, melt and crystallization behavior, as well as hydrophilicity of the blends. Immersion in water or being placed in air could accelerate the degradation of 50%CS/PBAT much more seriously than PBAT. Compared with PBAT, 50%CS/PBAT was of much lower cost and easier to be degraded, especially in water; it should be an ideal degradable blend for applications in packaging, agricultural mulch, and some other areas. Full article

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

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27 pages, 6691 KB

Open AccessArticle

Polymer-Embedded Deep Eutectic Solvents: Mechanistic Insights into Storage and Supersaturation Stabilization

by Afroditi Kapourani, Theodora Karyofylli-Tamisoglou, Ioannis Pantazos, Maria-Emmanouela Anagnostaki, Ioannis Gkougkourelas and Panagiotis Barmpalexis

Polymers 2026, 18(6), 766; https://doi.org/10.3390/polym18060766 - 21 Mar 2026

Viewed by 791

Abstract

Poor aqueous solubility remains a major limitation for the oral delivery of many active pharmaceutical ingredients (APIs). Deep eutectic solvents (DESs) exhibit remarkable drug-solubilization capacity, yet rapid precipitation upon aqueous dilution can compromise their ability to sustain supersaturation. This study investigates polymer-embedded DES [...] Read more.

Poor aqueous solubility remains a major limitation for the oral delivery of many active pharmaceutical ingredients (APIs). Deep eutectic solvents (DESs) exhibit remarkable drug-solubilization capacity, yet rapid precipitation upon aqueous dilution can compromise their ability to sustain supersaturation. This study investigates polymer-embedded DES (PEDES) systems as liquid supersaturating drug delivery platforms in which hydration and polymer chemistry jointly govern thermodynamic solubilization and kinetic stabilization. A choline chloride/DL-malic acid DES was prepared with 5% or 15% (w/w) water and combined with polyvinylpyrrolidone (PVP) or polyacrylic acid (PAA). Griseofulvin (GRF) was used as a precipitation-prone model drug. Structural characterization (ATR-FTIR, ¹H-NMR), equilibrium solubility measurements, storage stability studies, and non-sink dissolution testing were conducted to elucidate formulation behavior. The DES systems enhanced GRF solubility by up to ~59-fold relative to phosphate buffer (PBS, pH 6.8). Polymer incorporation produced hydration- and concentration-dependent effects. These results suggest the presence of competitive or cooperative interaction regimes. At 5% water, PEDES formulations failed to prevent recrystallization and showed limited supersaturation maintenance. In contrast, PEDES systems containing 15% water exhibited improved stability, with the formulation containing 4% PAA sustaining elevated drug concentrations for 120 min under non-sink conditions. Low-frequency solution-state ¹H-NMR confirmed stronger GRF–PAA interactions relative to PVP, supporting the role of polymer–drug association in supersaturation stabilization. These findings demonstrate that PEDES performance emerges from a hydration-dependent balance between solvent structuring and drug–polymer interactions, highlighting hydration and polymer functionality as key parameters for the rational design of liquid supersaturating systems. Full article

(This article belongs to the Special Issue Polymers and Their Role in Drug Delivery, 3rd Edition)

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20 pages, 5013 KB

Open AccessArticle

Deinking of Post-Consumer Waste Flakes—Objective Assessment of Ink Removal on Inhomogeneous Film Fractions

by Steven Zimmer, Lukas Seifert and Rainer Dahlmann

Polymers 2026, 18(6), 765; https://doi.org/10.3390/polym18060765 - 21 Mar 2026

Viewed by 688

Abstract

The deinking of plastic packaging waste offers the potential of decreasing contamination and thus increasing the overall quality of recycled plastics, enabling their use in more demanding applications. However, for flexible polyethylene packaging waste, deinking is not yet implemented on an industrial scale [...] Read more.

The deinking of plastic packaging waste offers the potential of decreasing contamination and thus increasing the overall quality of recycled plastics, enabling their use in more demanding applications. However, for flexible polyethylene packaging waste, deinking is not yet implemented on an industrial scale and there is currently no objective methodology to evaluate the deinking effect on those inhomogeneous flakes. In this study, a novel approach for the objective assessment of ink removal on flexible post-consumer waste (PCW) is proposed. Via an image-based analysis, the transparency of the flakes is transformed into the 8-bit grey scale, and the deinking efficiency of several experiments is compared via the skewness and median of grey value distributions. The method is compared to the International Commission on Illumination (CIE) Lab-method and its robustness against wrinkles and overlaps is critically discussed. Using this analysis method enables the investigation of the general behaviour of contaminated PCW materials in deinking and identifies the most effective parameters for ink removal on inhomogeneous flakes. Full article

(This article belongs to the Special Issue Recycling and Management of Polymer Waste)

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20 pages, 1860 KB

Open AccessArticle

Kombucha SCOBY as a Fermentation-Derived Biofilm Matrix: Species-Resolved Microbial Communities and Multidimensional In Vitro Bioactivities

by Anita Hartono, Kyra Singgih Palupi, Riza-Arief Putranto, Antonello Santini and Fahrul Nurkolis

Polymers 2026, 18(6), 764; https://doi.org/10.3390/polym18060764 - 20 Mar 2026

Viewed by 1437

Abstract

Kombucha fermentation is driven by a Symbiotic Culture of Bacteria and Yeast (SCOBY), a cellulose-rich biofilm that hosts a complex microbial consortium. While most kombucha studies focus on the liquid beverage, the SCOBY pellicle itself remains underexplored, particularly with respect to species-level microbial [...] Read more.

Kombucha fermentation is driven by a Symbiotic Culture of Bacteria and Yeast (SCOBY), a cellulose-rich biofilm that hosts a complex microbial consortium. While most kombucha studies focus on the liquid beverage, the SCOBY pellicle itself remains underexplored, particularly with respect to species-level microbial resolution and its intrinsic biological activities. In this study, a commercial kombucha SCOBY was characterized using full-length 16S rRNA gene and ITS amplicon sequencing based on Oxford Nanopore Technology, enabling species-level taxonomic resolution. In parallel, hydroalcoholic and aqueous extracts of dried SCOBY biomass were evaluated for in vitro antioxidant activity (DPPH and ABTS assays), antidiabetic-related enzyme inhibition (α-glucosidase and dipeptidyl peptidase-4, DPP4), and anti-aging-related enzyme inhibition (tyrosinase and elastase). The SCOBY bacterial community was strongly dominated by acetic acid bacteria, with Komagataeibacter saccharivorans and Acetobacter tropicalis accounting for more than 60% of total reads, reflecting a biofilm structure optimized for cellulose production and oxidative metabolism. The yeast community showed marked unevenness, with Brettanomyces bruxellensis representing over 80% of reads, consistent with its known role in ethanol production and stress tolerance within kombucha systems. In vitro assays revealed that hydroalcoholic SCOBY extracts consistently exhibited higher biological activity than aqueous extracts across all tested assays. However, both extracts showed substantially lower potency than purified reference compounds, indicating moderate but measurable bioactivity typical of complex fermented matrices. These findings support the potential valorization of SCOBY as a fermentation-derived biomaterial and functional ingredient while underscoring the need for further chemical characterization, mechanistic studies, and biological validation beyond enzyme-based assays. Full article

(This article belongs to the Special Issue Natural and Biodegradable Polymers in Healthcare and Biomedical Innovation)

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20 pages, 4125 KB

Open AccessArticle

Characterization of PC-ABS and PETG Multi-Material Laminates Fabricated by MEX Method

by Mahalingam Nainaragaram Ramasamy, Ales Sliva, Akash Nag, Quoc-Phu Ma, Ondrej Hilser, Marie Heliova, Grazyna Simha Martynkova, Silvie Brozova and Jan Dizo

Polymers 2026, 18(6), 763; https://doi.org/10.3390/polym18060763 - 20 Mar 2026

Viewed by 899

Abstract

Material-extrusion (MEX) printing with automated filament switching enables single-build multi-material laminates, but interfaces between dissimilar polymers may govern failure. Here, monolithic PETG, monolithic PC–ABS, and an alternating PETG/PC–ABS laminate (COMP) with 0.2 mm laminae (4 mm total) were fabricated and benchmarked. Tensile behavior [...] Read more.

Material-extrusion (MEX) printing with automated filament switching enables single-build multi-material laminates, but interfaces between dissimilar polymers may govern failure. Here, monolithic PETG, monolithic PC–ABS, and an alternating PETG/PC–ABS laminate (COMP) with 0.2 mm laminae (4 mm total) were fabricated and benchmarked. Tensile behavior was measured using ISO 527-2 Type 1B specimens at 5 and 50 mm/min, complemented by three-point bending in horizontal/vertical orientations, unnotched Charpy impact (ISO 179), Shore D hardness (ISO 868), and SEM fractography. COMP delivered the highest horizontal flexural strength (159.82 ± 25.42 MPa), exceeding both single-material baselines, indicating improved bending load capacity in the preferred orientation. In Charpy impact, COMP absorbed more energy than PETG in the horizontal condition (0.86 ± 0.14 J vs. 0.57 ± 0.06 J) but remained below PC–ABS. In tension, COMP strength decreased by ~21–23% relative to PETG and by ~5–6% relative to PC–ABS at both speeds, consistent with interface-controlled damage. SEM revealed void-assisted crack initiation and interfacial debonding aligned with raster paths, highlighting interfacial strengthening and porosity reduction as key routes to improve tensile performance while retaining favorable flexural and impact response. Full article

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

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18 pages, 3625 KB

Open AccessArticle

About the Relevance of Triboelectric Effects and Conductive Particles in Nanogenerators Based on Cellulose Materials and Their Composites

by Ivan Muñoz, Franck Quero, Francisco Fernández-Gil, Jorge Maureira, Nicolás Rosales-Cuello and Humberto Palza

Polymers 2026, 18(6), 762; https://doi.org/10.3390/polym18060762 - 20 Mar 2026

Viewed by 788

Abstract

Cellulose is a well-known biopolymer with excellent properties for a broad range of applications, including piezoelectricity for the development of nanogenerators. However, similar to other piezoelectric materials, the voltage outputs currently reported from cellulose-based piezoelectric nanogenerators (PENGs) could be overestimated due to the [...] Read more.

Cellulose is a well-known biopolymer with excellent properties for a broad range of applications, including piezoelectricity for the development of nanogenerators. However, similar to other piezoelectric materials, the voltage outputs currently reported from cellulose-based piezoelectric nanogenerators (PENGs) could be overestimated due to the appearance of triboelectric processes. To understand the appearance of both phenomena, cellulose films and aerogels that had undergone several modifications to improve their piezoelectric behavior (i.e., thermal treatment and presence of piezoelectric/conductive particles) were developed and characterized. Our results show that these modifications significantly changed the dielectric properties (ε) and the piezoelectric coefficients (d₃₃), with increments as high as a factor of 4, although without a clear tendency regarding the sample characteristics. Under finger-tapping mechanical stimulation, nanogenerators (NGs) using pure cellulose films generated 6 V, whereas the modified cellulose films and aerogels either increased or decreased this value, with outputs between 2 and 10 V. Notably, ternary composites, having both conductive and piezoelectric ZnO particles, increased the generation up to 24 V. There was no correlation between the voltage generated and d₃₃ or d₃₃/ε values, although some relationship with ε was observed, meaning that a pure piezoelectric phenomenon was not observed. This lack of correlation and the drastic decrease in the voltage generated (around 0.2 V) after changing the NG configuration show that a triboelectric phenomenon from the multilayered structure significantly contributes to the voltage generation from cellulose samples. Full article

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

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16 pages, 3777 KB

Open AccessArticle

From Film Processing to Microphase Orientation: Structure–Property Relationships in Commercial PBSA/PLA Blend Films

by Guru Geertz, Stefan Böhler, Bastian Barton, Frank Malz, Andreas Bohn, Olaf Kahle, Robert Brüll and Jens Balko

Polymers 2026, 18(6), 761; https://doi.org/10.3390/polym18060761 - 20 Mar 2026

Viewed by 650

Abstract

The commercialization of poly(butylene succinate-co-adipate) (PBSA), a biodegradable and potentially fully biobased random copolyester, is still ongoing. Due to its high relevance as mono material or as blend component in flexible film applications, a sound understanding of compounding, further processing and film properties [...] Read more.

The commercialization of poly(butylene succinate-co-adipate) (PBSA), a biodegradable and potentially fully biobased random copolyester, is still ongoing. Due to its high relevance as mono material or as blend component in flexible film applications, a sound understanding of compounding, further processing and film properties is necessary. In this work, PBSA, poly (lactic acid) (PLA) and blends at three different compositions thereof were processed into flat films and blown films, respectively. Investigating the films with X-ray diffraction (XRD), multivariate confocal Raman microscopy (CRM) and scanning electron microscopy (SEM) revealed the semicrystalline order as well as the blend morphology. While PBSA is semicrystalline, PLA remains amorphous after the processing step. As imaged by CRM, flat films exhibit lamellar-like domains formed during uniaxial stretching and rapid cooling, whereas blown films show no pronounced preferential orientation. Tensile tests in both the machine and transverse directions demonstrate the versatility of PBSA and its blends in spanning a wide range of mechanical strength and flexibility, covering and partly exceeding the stiffness and strength ranges typically reported for commodity polyolefins while exhibiting reduced ductility. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) provide further insights into the thermal properties of the pure and blend materials. Full article

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

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19 pages, 3610 KB

Open AccessArticle

Effects of Thermal Aging on Optical, Surface, Mechanical, and Biological Properties of CAD/CAM Polymer-Based Dental Materials

by Gül Ateş and Mustafa Gungormus

Polymers 2026, 18(6), 760; https://doi.org/10.3390/polym18060760 - 20 Mar 2026

Viewed by 891

Abstract

CAD/CAM polymer-based dental materials are increasingly used as metal-free alternatives for fixed and implant-supported restorations. High-performance polymers such as polyetheretherketone (PEEK), fiber-reinforced composites, and graphene-reinforced polymers have been introduced to improve material stability; however, evidence regarding the effects of thermal aging on their [...] Read more.

CAD/CAM polymer-based dental materials are increasingly used as metal-free alternatives for fixed and implant-supported restorations. High-performance polymers such as polyetheretherketone (PEEK), fiber-reinforced composites, and graphene-reinforced polymers have been introduced to improve material stability; however, evidence regarding the effects of thermal aging on their physicochemical and biological properties remains limited. In this study, PEEK, a fiber-reinforced composite (FRC), and a graphene-reinforced PMMA-based polymer (G-CAM) were evaluated. Twenty-seven disc-shaped specimens (10 × 2 mm; n = 9 per material) were fabricated and subjected to 10,000 thermal cycles between 5 and 55 °C. Color change (ΔE₀₀), surface roughness (Ra), and Vickers microhardness (VHN) were measured before and after aging. Chemical stability was assessed using FTIR and Raman spectroscopy, surface morphology by SEM analysis, and biological safety by cytotoxicity testing. Material-dependent differences were observed in color stability, surface roughness, and microhardness after thermal aging (p < 0.05). Microhardness decreased in the fiber-reinforced and graphene-reinforced materials, whereas PEEK showed no significant change. Spectroscopic analyses indicated preserved chemical structure, and all materials demonstrated acceptable cytocompatibility. Thermal aging influenced material behavior while chemical stability and biological safety were maintained, highlighting the importance of considering aging behavior during material selection for prosthetic restorations. Full article

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

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44 pages, 6890 KB

Open AccessArticle

Evaluation of Aging Effects on Asphalt Binders and Pavements: Rheological Responses to Rejuvenators and Numerical Analysis of Polymer Modification

by Ahmet Sertac Karakas

Polymers 2026, 18(6), 759; https://doi.org/10.3390/polym18060759 - 20 Mar 2026

Cited by 1 | Viewed by 880

Abstract

The restricted availability of raw materials underscores the significance of recycling asphalt materials that have reached the end of their service life, facilitating their reuse with additives for economic and sustainability benefits. The study includes both empirical investigations and numerical analyses. Empirical studies [...] Read more.

The restricted availability of raw materials underscores the significance of recycling asphalt materials that have reached the end of their service life, facilitating their reuse with additives for economic and sustainability benefits. The study includes both empirical investigations and numerical analyses. Empirical studies were conducted in four stages to evaluate the binder and mixture. First, the rheological properties of binders obtained from various sources were assessed in both unmodified and modified states. Second, the binders were subjected to different levels of aging. Third, the presence of additives in the binders was investigated. In the final stage, the analysis of asphalt pavement layers was conducted using the finite element method (FEM) for both modified and unmodified binders. Performance tests were carried out to evaluate the binder’s properties, and physical examinations were conducted to compare these properties. The binders were tested under both unaged and aged conditions using linear amplitude sweep (LAS), frequency sweep (FS), multiple stress creep recovery (MSCR), and bending beam rheometer (BBR) tests. The results indicated that aging increased the stiffness of the binders, regardless of their source. Additionally, the introduction of a rejuvenator reduced the binder’s stiffness, particularly at low temperatures. Findings showed that the growth rate (GR) and rutting parameters increased with binder aging, while the frequency decreased. The R² value of 0.92 demonstrates a strong correlation between the parameters. Polymer-modified binders demonstrated superior deformation resistance and higher stiffness stability. Overall, aging reduced asphalt flexibility, whereas modified binders improved long-term pavement deformation performance. Full article

(This article belongs to the Section Polymer Applications)

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19 pages, 3460 KB

Open AccessReview

Protective and Modification Strategies for Instrument Wood: A Critical Review

by Qingdong Liang and Junfei Ou

Polymers 2026, 18(6), 758; https://doi.org/10.3390/polym18060758 - 20 Mar 2026

Viewed by 670

Abstract

Wood is the quintessential material for musical instruments due to its superior acoustic properties. However, its inherent susceptibility to environmental degradation—including moisture-induced dimensional changes, photodegradation, and biological attack—presents a fundamental challenge that treatment strategies must address. This critical review systematically examines recent advances [...] Read more.

Wood is the quintessential material for musical instruments due to its superior acoustic properties. However, its inherent susceptibility to environmental degradation—including moisture-induced dimensional changes, photodegradation, and biological attack—presents a fundamental challenge that treatment strategies must address. This critical review systematically examines recent advances in wood modification and surface protection technologies for musical instruments, encompassing chemical and thermal modification, protective coatings, physical densification, and biological treatments. Drawing on studies published over the past two decades, this review synthesizes current knowledge on how these interventions affect wood’s acoustic performance, dimensional stability, mechanical integrity, and long-term durability. A central finding is that treatment outcomes are highly species-specific and involve complex performance trade-offs: acoustic optimization often comes at the expense of mechanical strength or dimensional stability, and the optimal solution varies depending on the functional requirements of specific instrument components (e.g., soundboards versus fingerboards). Emerging bio-based and nanocomposite coatings show promise for enhancing environmental resistance, but their acoustic implications remain largely unexplored. Furthermore, most research remains at the laboratory scale, with limited validation on full instruments and a notable absence of long-term performance data under natural aging conditions. To advance the field from empirical trial-and-error toward predictive, knowledge-based design, this review identifies three priority areas for future research: (1) establishing cross-scale “treatment-structure-performance” correlation models that bridge molecular-level modifications to instrument-level acoustic outcomes; (2) developing intelligently engineered surface systems capable of multi-objective synergistic optimization; and (3) creating comprehensive assessment standards that encompass acoustics, durability, and sustainability. By systematically synthesizing current knowledge and identifying critical gaps, this review provides a foundation for more targeted, interdisciplinary research in instrument wood protection. Full article

(This article belongs to the Special Issue Cellulose and Wood-Based Materials in Polymer Systems and Materials Engineering)

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19 pages, 3866 KB

Open AccessArticle

A Sustainable Path for Automotive Composite Tooling: Novel Materials, Design, and Technologies Through FEM and LCA

by Gloria Anna Carallo, Laura Magnasco, Stefano Chiocca, Andrea Lessio, Michela Mattia, Michele Morbarigazzi and Alessio Verdulli

Polymers 2026, 18(6), 757; https://doi.org/10.3390/polym18060757 - 20 Mar 2026

Viewed by 695

Abstract

In the automotive industry, the push for lightweighting, sustainability, and performance underpins the need for continuous improvement of materials and processes; thus, this research explores the introduction of different approaches for processing optimization. The Finite Element Method (FEM) excels at enhancing structural efficiency [...] Read more.

In the automotive industry, the push for lightweighting, sustainability, and performance underpins the need for continuous improvement of materials and processes; thus, this research explores the introduction of different approaches for processing optimization. The Finite Element Method (FEM) excels at enhancing structural efficiency and reducing material use in composite tooling like stamping dies, while Life Cycle Assessment (LCA) quantifies environmental impacts over the product life cycle. Coupling these approaches is promising but challenging due to difficult integration into well-established industrial practices. In this framework, the study presents the combination of FEM-LCA analyses on a tool for a composite car bonnet, considering an industrial case. The reduction in weight (−85%) obtained through FEM topology optimization, along with novel materials (thermoplastic polymers) and processes (3D printing, internal recycling), results in an environmental impact reduction over the tooling process (−43% in climate change). The two analyses enable a holistic tool design that balances mechanical performance with reduced carbon footprint, aligning with the European regulatory framework and emission targets. The results demonstrate the feasibility of a coupled FEM-LCA approach to optimize composite tooling in the automotive context, with a positive prospect of full-scale integration into the industrial value chain. Full article

(This article belongs to the Special Issue Polymer Science and Technology: When Progress Meets Sustainability and Reliability)

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16 pages, 1761 KB

Open AccessArticle

Effects of Gastric Acid and Antiacid Medications on Surface Roughness, Morphology, and Optical Properties of Resin-Based Materials

by Ezgi Tüter Bayraktar, Ayşe Aslı Şenol, Elif Alkan, Bengü Doğu Kaya and Dilek Tağtekin

Polymers 2026, 18(6), 756; https://doi.org/10.3390/polym18060756 - 20 Mar 2026

Viewed by 725

Abstract

Effects of gastric acid and antiacid medications on the surface and optical properties of resin-based restorative materials were evaluated. A hybrid-CAD/CAM block, a 3D-printed resin, a paste-type composite, and a flowable composite were investigated (n = 9). Samples were prepared (1 mm thickness) [...] Read more.

Effects of gastric acid and antiacid medications on the surface and optical properties of resin-based restorative materials were evaluated. A hybrid-CAD/CAM block, a 3D-printed resin, a paste-type composite, and a flowable composite were investigated (n = 9). Samples were prepared (1 mm thickness) and polished. All samples were exposed to gastric acid for 6 days, followed by a second exposure to distilled water, antiacid medication, or gastric acid for 56 min. Surface roughness, translucency, and fluorescence were assessed at baseline (T₀), after gastric acid exposure (T₁), and after the second exposure (T₂). Surface morphology was examined by scanning electron microscopy. Data were analyzed with a significance level of p < 0.05. Gastric acid exposure caused a significant increase in surface roughness and a significant reduction in translucency in all materials (p < 0.05). CAD/CAM and paste-type composites exhibited significantly higher roughness values than the 3D-printed and flowable composites (p < 0.001). Fluorescence changes were observed in all groups, but the highest ΔE₀₀ values were observed in the 3D-printed and flowable composites (p < 0.001). Gastric acid adversely affected the surface and optical properties of resin-based restorative materials, while antiacid medication showed limited, material-dependent protective effects. Full article

(This article belongs to the Special Issue Advanced Polymers for Dental Applications)

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18 pages, 2851 KB

Open AccessArticle

Investigating the Triaxial Mechanical Behaviour of Silicone Rubber Material

by Jie Yang, Nan Chen, Jun Gao, Yang Wang, Shuchang Long, Xiaohu Yao, Zhibin Wu and Junfeng Zhao

Polymers 2026, 18(6), 755; https://doi.org/10.3390/polym18060755 - 20 Mar 2026

Viewed by 512

Abstract

Silicone rubber is extensively used in engineering applications due to its toughness and impact resistance; however, traditional characterisation methods fail to capture its nonlinear deformation characterisation and triaxial mechanical behaviour. To address this, we derived a constitutive model within the framework of continuum [...] Read more.

Silicone rubber is extensively used in engineering applications due to its toughness and impact resistance; however, traditional characterisation methods fail to capture its nonlinear deformation characterisation and triaxial mechanical behaviour. To address this, we derived a constitutive model within the framework of continuum mechanics that assumes a condition of near incompressibility and conducted uniaxial, planar, and equibiaxial tension tests to fit the model parameters. Through systematic analysis of triaxial mechanical responses under these three loading modes, we determined the material’s nonlinear large-deformation behaviour and sensitivity to the biaxiality ratio. Comparative analyses with classical hyperelastic models show that the proposed model achieves a good balance between the number of parameters and fitting accuracy. After the parameter-fitting process, we performed finite element simulations of the three loading modes. The simulation results show good agreement with experimental data in terms of deformation patterns and stress–strain curves. This study provides a novel theoretical tool for evaluating the mechanical properties and structural designs of soft materials. Full article

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

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34 pages, 6168 KB

Open AccessArticle

Hybrid Nanocomposites Based on Poly(2,5-dichloro-3,6-bis(phenylamino)-p-benzoquinone) and MWCNTs: Synthesis, Structure, and the Role of ZnO

by Svetlana G. Kiseleva, Galina N. Bondarenko, Dmitriy G. Muratov, Vladimir V. Kozlov, Andrey A. Vasilev and Galina P. Karpacheva

Polymers 2026, 18(6), 754; https://doi.org/10.3390/polym18060754 - 19 Mar 2026

Viewed by 654

Abstract

For the first time, hybrid nanocomposites based on poly(2,5-dichloro-3,6-bis(phenylamino)-p-benzoquinone) (PCPAB) and multi-walled carbon nanotubes (MWCNTs) were obtained and the influence of the preparation method on their structure and functional properties was demonstrated. The nanocomposites were obtained both by ultrasonic mixing of PCPAB and [...] Read more.

For the first time, hybrid nanocomposites based on poly(2,5-dichloro-3,6-bis(phenylamino)-p-benzoquinone) (PCPAB) and multi-walled carbon nanotubes (MWCNTs) were obtained and the influence of the preparation method on their structure and functional properties was demonstrated. The nanocomposites were obtained both by ultrasonic mixing of PCPAB and MWCNTs, and via in situ oxidative polymerization of CPAB in the presence of MWCNTs or MWCNTs with the addition of ZnO. The formation of hybrid nanocomposites occurs due to non-covalent interaction (π-stacking) between the graphene structures of the MWCNT surface and the phenyl rings of PCPAB. It was found that during the in situ oxidative polymerization of CPAB in the presence of MWCNTs, the growth of polymer chains occurred in close proximity to the filler surface, which led to the formation of a polymer coating. ZnO particles, localized on MWCNTs, on the one hand, prevent their aggregation, and on the other hand, create additional polymerization reaction centers due to the coordination of the Zn-O bond at the H and O atoms of the monomer. An increase in the concentration of reaction centers as a result led to a 2–2.5-fold reduction in the induction polymerization period. According to SEM data, in this case, a more ordered and denser polymer layer is formed due to intermolecular complexation between the main and side chains of the growing polymer with the participation of Zn²⁺ ions formed as a result of the transformation of ZnO to ZnCl₂ in the acidic reaction medium of polymerization. The results of the study of the frequency dependences of conductivity indicate a hopping mechanism of conductivity of nanocomposites. The electrical conductivity of nanocomposites depends on their production method and the MWCNT content and varies between 0.5 and 1.1 S∙cm⁻¹, which is 6–12 times higher than the conductivity of the original polymer. Thermogravimetric analysis revealed that the nanocomposites exhibit enhanced thermal stability compared to PCPAB. The best results were shown by nanocomposites with a higher content of MWCNTs, for which the residual mass at 450 °C was 51–53%. Full article

(This article belongs to the Special Issue Novel Carbon-Based Polymer Composites: Preparation, Properties and Applications)

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36 pages, 4295 KB

Open AccessReview

Polyester Resin–Quartz Composites in the Age of Artificial Intelligence and Digital Twins: Current Advances, Future Perspectives and an Application Example

by Marco Suess and Peter Kurzweil

Polymers 2026, 18(6), 753; https://doi.org/10.3390/polym18060753 - 19 Mar 2026

Cited by 1 | Viewed by 931

Abstract

Unsaturated polyester resin (UPR)–quartz composites have become increasingly important in structural, sanitary, and architectural applications. However, their manufacturing processes still rely heavily on empirical knowledge. This review compiles recent developments in materials science, curing kinetics, and digital manufacturing, outlining a pathway toward data-driven, [...] Read more.

Unsaturated polyester resin (UPR)–quartz composites have become increasingly important in structural, sanitary, and architectural applications. However, their manufacturing processes still rely heavily on empirical knowledge. This review compiles recent developments in materials science, curing kinetics, and digital manufacturing, outlining a pathway toward data-driven, adaptive production of quartz-filled thermosets. The chemical and physical fundamentals of UPR polymerization are summarized, including the influence of initiator systems, filler characteristics, and thermal management on network formation. Challenges associated with highly filled formulations—such as viscosity control, dispersion, shrinkage, and exothermic peak prediction—are discussed in detail. Recent advances in digital twins (DTs) and artificial intelligence (AI) are reviewed, demonstrating how physics-based simulations, machine learning models, and hybrid mechanistic–data-driven approaches improve the prediction of rheology, curing behavior, and quality outcomes in thermoset polymer processes. A practical application example demonstrates the prediction of peak time in quartz–UPR composites using Random Forest and Gradient Boosting ensemble models. Two prediction scenarios are evaluated: Scenario A with gel time by Leave-One-Out cross-validation, and Scenario B without gel time, representing post-mixing and pre-process prediction contexts, respectively. Stratified bootstrap augmentation improves Gradient Boosting in both scenarios. Principal component analysis confirms that the curing process is governed by three independent physical dimensions: curing reactivity, thermal environment and resin thermal state. Full article

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

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22 pages, 5749 KB

Open AccessArticle

Multi-Scale Tribo–Thermo–Viscoelastic Engineering of Sustainable Bio-Based Epoxy Through Hybrid Carbon Nano Architectures and Energy Partition Modeling

by Kiran Keshyagol, Pavan Hiremath, Rakesh Sharma, Muralishwara K, Santhosh K, Suhas Kowshik and Nithesh Naik

Polymers 2026, 18(6), 752; https://doi.org/10.3390/polym18060752 - 19 Mar 2026

Cited by 1 | Viewed by 562

Abstract

This study investigates the multi-scale tribo–thermo–viscoelastic performance of a sustainable bio-based FormuLITE epoxy reinforced with single and hybrid carbon nanofillers (0.1 wt.% total loading) under dry sliding up to 50 N. Pin-on-disk tests at 10, 30, and 50 N showed a consistent reduction [...] Read more.

This study investigates the multi-scale tribo–thermo–viscoelastic performance of a sustainable bio-based FormuLITE epoxy reinforced with single and hybrid carbon nanofillers (0.1 wt.% total loading) under dry sliding up to 50 N. Pin-on-disk tests at 10, 30, and 50 N showed a consistent reduction in contact pressure and wear volume in the order: neat epoxy > 0.1 CNT > 0.1 GNP > 0.1 ND > 0.1 CNT/GNP > 0.1 CNT/ND > 0.1 GNP/ND. At 50 N and 1500 m sliding distance, neat epoxy exhibited a wear volume of 13.43 mm³ and contact pressure of 13.4 N/cm², while the GNP/ND hybrid reduced wear to 4.86 mm³ and contact pressure to 6.2 N/cm², corresponding to reductions of 64% and 54%, respectively. The accelerating wear coefficient decreased from 2.9 × 10⁻⁶ to 8.5 × 10⁻⁷, confirming slower damage accumulation in hybrid systems. Time-dependent contact pressure analysis revealed reduced asymptotic intensity and suppressed mid-cycle pressure spikes, indicating enhanced tribolayer stability. Effective surface hardness increased from 0.18 GPa (neat epoxy) to 0.30 GPa (GNP/ND), while normalized wear decreased from 1.00 to 0.36. Enhanced damping behavior and improved thermal conductivity in hybrid systems promoted stress redistribution and minimized flash-temperature localization. An interfacial energy-partition framework calibrated to experimental wear data quantitatively linked effective driving pressure, tribofilm stabilization, and surface hardness to material removal. The results demonstrate that wear mitigation in sustainable bio-epoxy systems is governed by coupled mechanical, viscoelastic, and thermal energy redistribution, with GNP/ND hybrids providing the most stable tribological interface under severe sliding. The findings contribute to the development of durable and sustainable bio-epoxy composite systems for engineering applications, supporting broader goals of responsible material utilization and sustainable industrial innovation aligned with the United Nations Sustainable Development Goals (SDG 9 and SDG 12). Full article

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

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22 pages, 3582 KB

Open AccessArticle

Atomic Layer Deposition of ZnO and ZnO/Cu Coatings for Fresh Food Packaging Application

by Adriana Lordi, Regina Del Sole, Fabio Palumbo, Alberto Perrotta, Francesco Fracassi, Marianna Roggio, Antonella Milella, Amalia Conte and Matteo Alessandro Del Nobile

Polymers 2026, 18(6), 751; https://doi.org/10.3390/polym18060751 - 19 Mar 2026

Viewed by 769

Abstract

Active antimicrobial films based on polyethylene terephthalate (PET) were developed through atomic layer deposition (ALD) and plasma sputtering to obtain ZnO (≈15 nm) and ZnO/Cu (≈18 nm) coatings. Surface characterization by X-ray photoelectron spectroscopy confirmed zinc in ZnO form and copper as Cu [...] Read more.

Active antimicrobial films based on polyethylene terephthalate (PET) were developed through atomic layer deposition (ALD) and plasma sputtering to obtain ZnO (≈15 nm) and ZnO/Cu (≈18 nm) coatings. Surface characterization by X-ray photoelectron spectroscopy confirmed zinc in ZnO form and copper as Cu₂O/CuO, while mass spectrometry quantified approximately 10 µg/cm² of Zn in both samples and about 130 ng/cm² of Cu in the ZnO/Cu films. The antimicrobial performance of the coatings was evaluated on burrata cheese and turkey fillets stored under refrigeration, assessing microbial growth and sensory quality over time. The films exhibited different effects depending on food type and the initial contamination levels. On burrata cheese, PET-ZnO moderately extended the shelf life by inhibiting Pseudomonas spp., while PET-ZnO/Cu further enhanced preservation. Cheese packaged with PET-ZnO/Cu remained acceptable for over 21 days compared to 19–20 days for the controls. More pronounced effects were observed in turkey fillets, characterized by a higher initial contamination. In control samples, Staphylococcus spp. rapidly proliferated, leading to spoilage within one day. Both active films significantly delayed microbial growth and sensory decay, with PET-ZnO/Cu providing the best performance, extending acceptability beyond two days compared to less than one day for the controls. Full article

(This article belongs to the Special Issue Smart and Functional Biopolymers)

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21 pages, 3775 KB

Open AccessArticle

Optimization of Bleaching Process and Evaluation of Pulp Performance for Super-Arundo Donax Kraft Pulp

by Zhangming Cai, Xingxiang Ji, Jie Liang, Zhongjian Tian and Jingpeng Zhou

Polymers 2026, 18(6), 750; https://doi.org/10.3390/polym18060750 - 19 Mar 2026

Viewed by 811

Abstract

With the increasing emphasis and protection on forest resources worldwide, the development of non-wood plant fiber raw materials has become a key path to promote the green and sustainable development of China’s pulp and paper industry. In this study, Super-Arundo donax, a new [...] Read more.

With the increasing emphasis and protection on forest resources worldwide, the development of non-wood plant fiber raw materials has become a key path to promote the green and sustainable development of China’s pulp and paper industry. In this study, Super-Arundo donax, a new non-wood fiber raw material, was systematically investigated for its applicability in the bleaching process. Firstly, by adjusting key bleaching technical variables such as alkali dosage, time, oxygen pressure and temperature, the oxygen delignification process of the Super-Arundo donax kraft pulp was optimized. The data revealed that under the experimental conditions of 3.0% alkali dosage, 60 min bleaching time, 100 °C bleaching temperature, 0.6 MPa oxygen pressure and 0.6% MgSO₄ dosage, the bleached pulp yield reached 91.58%, the brightness was 42.04% ISO, and its tensile index was 60.92 N·m/g, bursting index was 4.16 kPa·m²/g, and tear index was 5.45 mN·m²/g, respectively. To further enhance the bleaching effect, the study introduced the H₂O₂ enhanced oxygen delignification process. The alkali dosage, bleaching temperature and H₂O₂ dosage were selected as the process parameters, with the pulp yield and brightness as the response indicators. A central composite design was adopted to construct a response surface model, and the interaction effects among various factors were analyzed. The optimized optimal process conditions are as follows: pulp concentration 10%, alkali dosage 2.84%, bleaching temperature 105 °C, H₂O₂ dosage 4.85%, bleaching time 60 min, MgSO₄ dosage 0.6%. Under these conditions, the pulp yield was 89.76% and the brightness reached 53.85% ISO. Therefore, Super-Arundo donax possesses excellent pulp-making and papermaking properties, and is expected to serve as a high-quality non-wood fiber raw material to alleviate the pressure on traditional papermaking raw materials and contribute to the green, sustainable and low-carbon transformation of the pulp and paper industry. Full article

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

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Polymers, Volume 18, Issue 6 (March-2 2026) – 113 articles

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