Journal Description
Polymers
Polymers
is an international, peer-reviewed, open access journal of polymer science published semimonthly online by MDPI. Belgian Polymer Group (BPG), European Colloid & Interface Society (ECIS), National Interuniversity Consortium of Materials Science and Technology (INSTM) and North American Thermal Analysis Society (NATAS) are affiliated with Polymers and their members receive a discount on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Ei Compendex, PubMed, PMC, FSTA, CAPlus / SciFinder, Inspec, and other databases.
- Journal Rank: JCR - Q1 (Polymer Science) / CiteScore - Q1 (Polymers and Plastics)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 13.7 days after submission; acceptance to publication is undertaken in 2.9 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in MDPI journals, in appreciation of the work.
- Testimonials: See what our authors and editors say about Polymers.
Impact Factor:
5.0 (2022);
5-Year Impact Factor:
5.0 (2022)
Latest Articles
UV-Cured Highly Crosslinked Polyurethane Acrylate to Serve as a Barrier against Chemical Warfare Agent Simulants
Polymers 2024, 16(11), 1578; https://doi.org/10.3390/polym16111578 (registering DOI) - 2 Jun 2024
Abstract
Ultraviolet (UV) curing is an efficient and environmentally friendly curing method. In this paper, UV-cured polyurethane acrylates (PUAs) were investigated as potential military coatings to serve as barriers against chemical warfare agents (CWAs). Seven UV-cured PUA coatings were formulated utilizing hydroxyethyl methacrylate-capped hexamethylene
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Ultraviolet (UV) curing is an efficient and environmentally friendly curing method. In this paper, UV-cured polyurethane acrylates (PUAs) were investigated as potential military coatings to serve as barriers against chemical warfare agents (CWAs). Seven UV-cured PUA coatings were formulated utilizing hydroxyethyl methacrylate-capped hexamethylene diisocyanate trimer (HEMA-Htri) and trimethylolpropane triacrylate-capped polycarbonate prepolymer (PETA-PCDL) as the PUA monomers. Isobornyl acrylate (IBOA) and triethyleneglycol divinyl ether (DVE-3) were employed as reactive diluents. Gas chromatography was utilized to investigate the constitutive relationships between the structures of the PUA coatings and their protective properties against simulant agents for CWAs, including dimethyl methylphosphonate (DMMP), a nerve agent simulant, and 2-chloroethyl ethyl sulfide (CEES), a mustard simulant. The glass transition temperature (Tg) and crosslinking density (υe) of PUAs were found to be crucial factors affecting their ability to serve as barriers against CWAs. The incorporation of IBOA units led to enhanced Tg and barrier performance of the PUAs, resulting in a DMMP retention of less than 0.5% and nearly 0 retention of CEES. However, an excessive introduction of polycarbonate chains decreased the υe and barrier performance of the PUAs. These findings may offer valuable insights for enhancing the protection of UV-cured PU coatings against CWAs.
Full article
(This article belongs to the Special Issue Application of Novel Polymer Coatings)
Open AccessArticle
Comparison of Polylactide-Based Active Films Containing Berberine and Quercetin as Systems for Maintaining the Quality and Safety of Blueberries
by
Ewa Olewnik-Kruszkowska, Martina Ferri, Mariana C. Cardeira, Magdalena Gierszewska and Anna Rudawska
Polymers 2024, 16(11), 1577; https://doi.org/10.3390/polym16111577 (registering DOI) - 2 Jun 2024
Abstract
Polymeric thin films based on polylactide with an addition of poly(ethylene glycol) as a plasticizer and flavonoids in the form of quercetin and berberine were subjected to tests that were particularly relevant from the point of view of contact with food. A comparative
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Polymeric thin films based on polylactide with an addition of poly(ethylene glycol) as a plasticizer and flavonoids in the form of quercetin and berberine were subjected to tests that were particularly relevant from the point of view of contact with food. A comparative analysis of the effect of individual flavonoids on the antioxidative properties of tested films and blueberry storage was carried out. The influence of active compounds on the water vapor permeability, as well as UV protection, of the obtained materials was investigated. Also, the specific migration of individual flavonoids from obtained materials to food simulants in the form of acetic acid and ethyl alcohol was determined. The crucial point of this study is the storage of blueberries. The obtained results indicate that the selection of packaging, containing individual active compounds, depends on the purpose and requirements that the packaging must meet for particular types of food.
Full article
(This article belongs to the Special Issue Polymer Thin Films and Their Applications)
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Open AccessArticle
Mechanical Properties of Raw Filaments and Printed Specimens: Effects of Fiber Reinforcements and Process Parameters
by
Daniel Vieweger, Sergej Diel, Hans-Georg Schweiger and Ulrich Tetzlaff
Polymers 2024, 16(11), 1576; https://doi.org/10.3390/polym16111576 (registering DOI) - 2 Jun 2024
Abstract
Fused Deposition Modeling (FDM) is a well-established manufacturing method for producing both prototype and functional components. This study investigates the mechanical properties of FDM components by material and process-related influencing variables. Tensile tests were conducted on seven different materials in their raw filament
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Fused Deposition Modeling (FDM) is a well-established manufacturing method for producing both prototype and functional components. This study investigates the mechanical properties of FDM components by material and process-related influencing variables. Tensile tests were conducted on seven different materials in their raw filament form, two of which were fiber-reinforced, to analyze their material-related influence. To cover a wide range from standard to advanced materials relevant for load-carrying components as well as their respective variations, polylactic acid (PLA), 30% wood-fiber-reinforced PLA, acrylonitrile butadiene styrene (ABS), polycarbonate (PC), a blend of ABS and PC, Nylon, and 30% glass-fiber-reinforced Nylon were selected. The process-related influencing variables were studied using the following process parameters: layer thickness, nozzle diameter, build orientation, nozzle temperature, infill density and pattern, and raster angle. The first test series revealed that the addition of wood fibers significantly worsened the mechanical behavior of PLA due to the lack of fiber bonding to the matrix and significant pore formation. The polymer blend of ABS and PC only showed improvements in stiffness. Significant strength and stiffness improvements were found by embedding glass fibers in Nylon, despite partially poor fiber–matrix bonding. The materials with the best properties were selected for the process parameter analysis. When examining the impact of layer thickness on part strength, a clear correlation was evident. Smaller layer thicknesses resulted in higher strength, while stiffness did not appear to be affected. Conversely, larger nozzle diameters and lower nozzle temperatures only positively impacted stiffness, with little effect on strength. The part orientation did alter the fracture behavior of the test specimens. Although an on-edge orientation resulted in higher stiffness, it failed at lower stresses. Higher infill densities and infill patterns aligned with the load direction led to the best mechanical results. The raster angle had a significant impact on the behavior of the printed bodies. An alternating raster angle resulted in lower strengths and stiffness compared to a unidirectional raster angle. However, it also caused significant stretching due to the rotation of the beads.
Full article
(This article belongs to the Section Polymer Processing and Engineering)
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Open AccessArticle
Study of the Thermal Phase Transition of Poly(N,N-diethylacrylamide-co-N-ethylacrylamide) Random Copolymers in Aqueous Solution
by
José Javier Coca-Hidalgo, Maricarmen Recillas-Mota, Daniel Fernández-Quiroz, Jaime Lizardi-Mendoza, Carlos Peniche-Covas, Francisco M. Goycoolea and Waldo M. Argüelles-Monal
Polymers 2024, 16(11), 1575; https://doi.org/10.3390/polym16111575 (registering DOI) - 2 Jun 2024
Abstract
N-alkyl-substituted polyacrylamides exhibit a thermal coil-to-globule transition in aqueous solution driven by an increase in hydrophobic interactions with rising temperature. With the aim of understanding the role of N-alkyl substituents in the thermal transition, this study focuses on the molecular interactions
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N-alkyl-substituted polyacrylamides exhibit a thermal coil-to-globule transition in aqueous solution driven by an increase in hydrophobic interactions with rising temperature. With the aim of understanding the role of N-alkyl substituents in the thermal transition, this study focuses on the molecular interactions underlying the phase transition of poly(N,N-diethylacrylamide-co-N-ethylacrylamide) random copolymers. Poly(N,N-diethylacrylamide) (PDEAm), poly(N-ethylacrylamide) (PNEAm), and their random copolymers were synthesized by free radical polymerization and their chemical structure characterized spectroscopically. It was found that the values of the cloud-point temperature increased with PNEAm content, and particle aggregation processes took place, increasing the negative charge density on their surface. The cloud-point temperature of each copolymer decreased with respect to the theoretical values calculated assuming an absence of interactions. It is attributed to the formation of intra- and interchain hydrogen bonding in aqueous solutions. These interactions favor the formation of more hydrophobic macromolecular segments, thereby promoting the cooperative nature of the transition. These results definitively reveal the dominant mechanism occurring during the phase transition in the aqueous solutions of these copolymers.
Full article
(This article belongs to the Special Issue Polymer Theory and Simulation)
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Open AccessArticle
Active Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) Films Containing Phenolic Compounds with Different Molecular Structures
by
Carla Ivonne La Fuente Arias, Chelo González-Martínez and Amparo Chiralt
Polymers 2024, 16(11), 1574; https://doi.org/10.3390/polym16111574 (registering DOI) - 2 Jun 2024
Abstract
To obtain more sustainable and active food packaging materials, PHBV films containing 5% wt. of phenolic compounds with different molecular structures (ferulic acid, vanillin, and catechin) and proved antioxidant and antimicrobial properties were obtained by melt blending and compression molding. These were characterized
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To obtain more sustainable and active food packaging materials, PHBV films containing 5% wt. of phenolic compounds with different molecular structures (ferulic acid, vanillin, and catechin) and proved antioxidant and antimicrobial properties were obtained by melt blending and compression molding. These were characterized by their structural, mechanical, barrier, and optical properties, as well as the polymer crystallization, thermal stability, and component migration in different food simulants. Phenolic compounds were homogenously integrated within the polymer matrix, affecting the film properties differently. Ferulic acid, and mainly catechin, had an anti-plasticizing effect (increasing the polymer glass transition temperature), decreasing the film extensibility and the resistance to breaking, with slight changes in the elastic modulus. In contrast, vanillin provoked a plasticizing effect, decreasing the elastic modulus without notable changes in the film extensibility while increasing the water vapor permeability. All phenolic compounds, mainly catechin, improved the oxygen barrier capacity of PHBV films and interfered with the polymer crystallization, reducing the melting point and crystallinity degree. The thermal stability of the material was little affected by the incorporation of phenols. The migration of passive components of the different PHBV films was lower than the overall migration limit in every simulant. Phenolic compounds were released to a different extent depending on their thermo-sensitivity, which affected their final content in the film, their bonding forces in the polymer matrix, and the simulant polarity. Their effective release in real foods will determine their active action for food preservation. Catechin was the best preserved, while ferulic acid was the most released.
Full article
(This article belongs to the Special Issue Functional Polymers: Interaction, Surface, Processing and Applications II)
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Open AccessArticle
Preparation and Characterization of Novel Multifunctional Wound Dressing by Near-Field Direct-Writing Electrospinning and Its Application
by
Dingfan Li, Dongsong Lin, Yun Li, Sikun Xu, Qingyun Cao and Wuyi Zhou
Polymers 2024, 16(11), 1573; https://doi.org/10.3390/polym16111573 (registering DOI) - 1 Jun 2024
Abstract
Near-field direct-writing electrospinning technology can be used to produce ordered micro/nanofiber membrane dressings. The application of this technology can simply realize the control of dressing porosity, compound different functional substances, and adjust their distribution, thus improving the defects of common dressings such as
[...] Read more.
Near-field direct-writing electrospinning technology can be used to produce ordered micro/nanofiber membrane dressings. The application of this technology can simply realize the control of dressing porosity, compound different functional substances, and adjust their distribution, thus improving the defects of common dressings such as insufficient breathability, poor moisture retention performance, and single function. Herein, a novel multifunctional wound dressing was prepared to utilize near-field direct-writing electrospinning technology, in which calf skin collagen type I (CSC-I) and polycaprolactone (PCL) were used as the composite matrix, Hexafluoroisopropanol (HFIP) as the solvent, and erythromycin (ERY) as an anti-infective drug component. The results show that the micro/nanofiber membranes prepared by near-field direct-writing electrospinning technology can all present a complete mesh structure, excellent thermal stability, and good moisturizing properties. Moreover, the composite fiber membrane loaded with ERY not only had obvious antibacterial properties against E. coli and S. thermophilus but also a better slow-release function of drugs (it is rare to have both in traditional wound dressings). Therefore, this experimental design can provide relevant theories and an experimental foundation for preparing a new type of medical dressing with drug loading and has good guiding significance for the application and promotion of near-field direct-writing electrospinning in medical dressings.
Full article
(This article belongs to the Section Smart and Functional Polymers)
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Open AccessArticle
Screening of MMP-13 Inhibitors Using a GelMA-Alginate Interpenetrating Network Hydrogel-Based Model Mimicking Cytokine-Induced Key Features of Osteoarthritis In Vitro
by
Qichan Hu, Steven L. Williams, Alessandra Palladino and Melanie Ecker
Polymers 2024, 16(11), 1572; https://doi.org/10.3390/polym16111572 (registering DOI) - 1 Jun 2024
Abstract
Osteoarthritis (OA) is a chronic joint disease characterized by irreversible cartilage degradation. Current clinical treatment options lack effective pharmaceutical interventions targeting the disease's root causes. MMP (matrix metalloproteinase) inhibitors represent a new approach to slowing OA progression by addressing cartilage degradation mechanisms. However,
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Osteoarthritis (OA) is a chronic joint disease characterized by irreversible cartilage degradation. Current clinical treatment options lack effective pharmaceutical interventions targeting the disease's root causes. MMP (matrix metalloproteinase) inhibitors represent a new approach to slowing OA progression by addressing cartilage degradation mechanisms. However, very few drugs within this class are in preclinical or clinical trial phases. Hydrogel-based 3D in vitro models have shown promise as preclinical testing platforms due to their resemblance to native extracellular matrix (ECM), abundant availability, and ease of use. Metalloproteinase-13 (MMP-13) is thought to be a major contributor to the degradation of articular cartilage in OA by aggressively breaking down type II collagen. This study focused on testing MMP-13 inhibitors using a GelMA-alginate hydrogel-based OA model induced by cytokines interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α). The results demonstrate a significant inhibition of type II collagen breakdown by measuring C2C concentration using ELISA after treatment with MMP-13 inhibitors. However, inconsistencies in human cartilage explant samples led to inconclusive results. Nonetheless, the study highlights the GelMA-alginate hydrogel-based OA model as an alternative to human-sourced cartilage explants for in vitro drug screening.
Full article
(This article belongs to the Special Issue Polymer-Based Biomaterials for Tissue Engineering Applications)
Open AccessArticle
Modification of Epoxy Coatings with Fluorocontaining Organosilicon Copolymers
by
Dmitriy V. Krutskikh, Aleksey V. Shapagin, Irina O. Plyusnina, Nikita Yu. Budylin, Anna A. Shcherbina and Mikhail A. Soldatov
Polymers 2024, 16(11), 1571; https://doi.org/10.3390/polym16111571 (registering DOI) - 1 Jun 2024
Abstract
Preparation of hydrophobic coatings is still a challenge for researchers in various fields of science. One of the easiest ways consists of the use of special modifiers. However, usually such modifiers are poorly compatible with organic polymeric matrixes, which leads to segregation of
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Preparation of hydrophobic coatings is still a challenge for researchers in various fields of science. One of the easiest ways consists of the use of special modifiers. However, usually such modifiers are poorly compatible with organic polymeric matrixes, which leads to segregation of modifiers and deterioration of coating properties. In this work, we have synthesized a number of organosilicon copolymers and studied their compatibility with epoxy matrix and hydrophobic efficiency. It was shown that the increase of phenyl-containing units leads to increase of compatibility but decreases hydrophobic efficiency. Addition of small amounts of such modifiers into commercial epoxy paint material can lead to an increase of contact angle of the final coating from 63 to 87° without deterioration of other physico-mechanical properties. These results open new perspectives in preparation of organosilicon hydrophobic modifiers with directed properties for fields of application such as paints and coating materials.
Full article
(This article belongs to the Section Polymer Membranes and Films)
Open AccessArticle
Surface Reconstruction of Silicone-Based Amphiphilic Polymers for Mitigating Marine Biofouling
by
Chuanying Wei, Yan Zhang, Zhen Tang, Changan Zhang, Jianhua Wu and Bo Wu
Polymers 2024, 16(11), 1570; https://doi.org/10.3390/polym16111570 (registering DOI) - 1 Jun 2024
Abstract
Poly(dimethylsiloxane) (PDMS) coatings are considered to be environmentally friendly antifouling coatings. However, the presence of hydrophobic surfaces can enhance the adhesion rate of proteins, bacteria and microalgae, posing a challenge for biofouling removal. In this study, hydrophilic polymer chains were synthesised from methyl
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Poly(dimethylsiloxane) (PDMS) coatings are considered to be environmentally friendly antifouling coatings. However, the presence of hydrophobic surfaces can enhance the adhesion rate of proteins, bacteria and microalgae, posing a challenge for biofouling removal. In this study, hydrophilic polymer chains were synthesised from methyl methacrylate (MMA), Poly(ethylene glycol) methyl ether methacrylate (PEG-MA) and 3-(trimethoxysilyl) propyl methacrylate (TPMA). The crosslinking reaction between TPMA and PDMS results in the formation of a silicone-based amphiphilic co-network with surface reconstruction properties. The hydrophilic and hydrophobic domains are covalently bonded by condensation reactions, while the hydrophilic polymers migrate under water to induce surface reconstruction and form hydrogen bonds with water molecules to form a dense hydrated layer. This design effectively mitigates the adhesion of proteins, bacteria, algae and other marine organisms to the coating. The antifouling performance of the coatings was evaluated by assessing their adhesion rates to proteins (BSA-FITC), bacteria (B. subtilis and P. ruthenica) and algae (P. tricornutum). The results show that the amphiphilic co-network coating (e.g., P-AM-15) exhibits excellent antifouling properties against protein, bacterial and microalgal fouling. Furthermore, an overall assessment of its antifouling performance and stability was conducted in the East China Sea from 16 May to 12 September 2023, which showed that this silicon-based amphiphilic co-network coating remained intact with almost no marine organisms adhering to it. This study provides a novel approach for the development of high-performance silicone-based antifouling coatings.
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(This article belongs to the Section Polymer Applications)
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Green Foaming of Biologically Extracted Chitin Hydrogels Using Supercritical Carbon Dioxide for Scaffolding of Human Osteoblasts
by
Mariana Quintana-Quirino, Adriana Hernández-Rangel, Phaedra Silva-Bermudez, Julieta García-López, Víctor Manuel Domínguez-Hernández, Victor Manuel Araujo Monsalvo, Miquel Gimeno and Keiko Shirai
Polymers 2024, 16(11), 1569; https://doi.org/10.3390/polym16111569 (registering DOI) - 1 Jun 2024
Abstract
Chitin is a structural polysaccharide abundant in the biosphere. Chitin possesses a highly ordered crystalline structure that makes its processing a challenge. In this study, chitin hydrogels and methanogels, prepared by dissolution in calcium chloride/methanol, were subjected to supercritical carbon dioxide (scCO2
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Chitin is a structural polysaccharide abundant in the biosphere. Chitin possesses a highly ordered crystalline structure that makes its processing a challenge. In this study, chitin hydrogels and methanogels, prepared by dissolution in calcium chloride/methanol, were subjected to supercritical carbon dioxide (scCO2) to produce porous materials for use as scaffolds for osteoblasts. The control of the morphology, porosity, and physicochemical properties of the produced materials was performed according to the operational conditions, as well as the co-solvent addition. The dissolution of CO2 in methanol co-solvent improved the sorption of the compressed fluid into the hydrogel, rendering highly porous chitin scaffolds. The chitin crystallinity index significantly decreased after processing the hydrogel in supercritical conditions, with a significant effect on its swelling capacity. The use of scCO2 with methanol co-solvent resulted in chitin scaffolds with characteristics adequate to the adhesion and proliferation of osteoblasts.
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(This article belongs to the Special Issue Synthesis, Characterization and Applications of Natural Polymers)
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In Situ Synthesis of CsPbX3/Polyacrylonitrile Nanofibers with Water-Stability and Color-Tunability for Anti-Counterfeiting and LEDs
by
Yinbiao Shi, Xiaojia Su, Xiaoyan Wang and Mingye Ding
Polymers 2024, 16(11), 1568; https://doi.org/10.3390/polym16111568 (registering DOI) - 1 Jun 2024
Abstract
Inorganic CsPbX3 (X = Cl, Br, I) perovskite quantum dots (PQDs) have attracted widespread attention due to their excellent optical properties and extensive application prospects. However, their inherent structural instability significantly hinders their practical application despite their outstanding optical performance. To enhance
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Inorganic CsPbX3 (X = Cl, Br, I) perovskite quantum dots (PQDs) have attracted widespread attention due to their excellent optical properties and extensive application prospects. However, their inherent structural instability significantly hinders their practical application despite their outstanding optical performance. To enhance stability, an in situ electrospinning strategy was used to synthesize CsPbX3/polyacrylonitrile composite nanofibers. By optimizing process parameters (e.g., halide ratio, electrospinning voltage, and heat treatment temperature), all-inorganic CsPbX3 PQDs have been successfully grown in a polyacrylonitrile (PAN) matrix. During the electrospinning process, the rapid solidification of electrospun fibers not only effectively constrained the formation of large-sized PQDs but also provided effective physical protection for PQDs, resulting in the improvement in the water stability of PQDs by minimizing external environmental interference. Even after storage in water for over 100 days, the PQDs maintained approximately 93.5% of their photoluminescence intensity. Through the adjustment of halogen elements, the as-obtained composite nanofibers exhibited color-tunable luminescence in the visible light region, and based on this, a series of multicolor anti-counterfeiting patterns were fabricated. Additionally, benefiting from the excellent water stability and optical performance, the CsPbBr3/PAN composite film was combined with red-emitting K2SiF6:Mn4+ (KSF) on a blue LED (460 nm), producing a stable and efficient WLED device with a color temperature of around 6000 K and CIE coordinates of (0.318, 0.322). These results provide a general approach to synthesizing PQDs/polymer nanocomposites with excellent water stability and multicolor emission, thereby promoting their practical applications in multifunctional optoelectronic devices and advanced anti-counterfeiting.
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(This article belongs to the Special Issue New Advances in Polymer Electrospun Fibers)
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Supercritical Impregnation of PETG with Olea europaea Leaf Extract: Influence of Operational Parameters on Expansion Degree, Antioxidant and Mechanical Properties
by
Noelia D. Machado, José E. Mosquera, Cristina Cejudo-Bastante, María L. Goñi, Raquel E. Martini, Nicolás A. Gañán, Casimiro Mantell-Serrano and Lourdes Casas-Cardoso
Polymers 2024, 16(11), 1567; https://doi.org/10.3390/polym16111567 (registering DOI) - 1 Jun 2024
Abstract
PETG (poly(ethylene glycol-co-cyclohexane-1,4-dimethanol terephthalate)) is an amorphous copolymer, biocompatible, recyclable, and versatile. Nowadays, it is being actively researched for biomedical applications. However, proposals of PETG as a platform for the loading of bioactive compounds from natural extract are scarce, as well as the
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PETG (poly(ethylene glycol-co-cyclohexane-1,4-dimethanol terephthalate)) is an amorphous copolymer, biocompatible, recyclable, and versatile. Nowadays, it is being actively researched for biomedical applications. However, proposals of PETG as a platform for the loading of bioactive compounds from natural extract are scarce, as well as the effect of the supercritical impregnation on this polymer. In this work, the supercritical impregnation of PETG filaments with Olea europaea leaf extract was investigated, evaluating the effect of pressure (100–400 bar), temperature (35–55 °C), and depressurization rate (5–50 bar min−1) on the expansion degree, antioxidant activity, and mechanical properties of the resulting filaments. PETG expansion degree ranged from ~3 to 120%, with antioxidant loading ranging from 2.28 to 17.96 g per 100 g of polymer, corresponding to oxidation inhibition values of 7.65 and 66.55%, respectively. The temperature and the binary interaction between pressure and depressurization rate most affected these properties. The mechanical properties of PETG filaments depended greatly on process variables. Tensile strength values were similar or lower than the untreated filaments. Young’s modulus and elongation at break values decreased below ~1000 MPa and ~10%, respectively, after the scCO2 treatment and impregnation. The extent of this decrease depended on the supercritical operational parameters. Therefore, filaments with higher antioxidant activity and different expansion degrees and mechanical properties were obtained by adjusting the supercritical processing conditions.
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(This article belongs to the Special Issue Additive Manufacturing of (Bio) Polymeric Materials)
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Preparation of Polydopamine Functionalized HNIW Crystals and Application in Solid Propellants
by
Fengdan Zhu, Chang Liu, Desheng Yang and Guoping Li
Polymers 2024, 16(11), 1566; https://doi.org/10.3390/polym16111566 (registering DOI) - 1 Jun 2024
Abstract
The application of hexanitrohexaazaisowurtzitane (HNIW) as an oxidizer in solid propellants aligns with the pursuit of high-energy materials. However, the phase transformation behavior and high impact sensitivity of HNIW are its limitations. Due to the strong adhesion and mild synthesis conditions, polydopamine (PDA)
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The application of hexanitrohexaazaisowurtzitane (HNIW) as an oxidizer in solid propellants aligns with the pursuit of high-energy materials. However, the phase transformation behavior and high impact sensitivity of HNIW are its limitations. Due to the strong adhesion and mild synthesis conditions, polydopamine (PDA) has been employed to modify HNIW. However, the method suffers from a slow coating process and a non-ideal coating effect under short reaction time. Herein, oxygen-accelerated dopamine in situ polymerization coating method was developed. It was found that oxygen not only reduced the coating time but also contributed to forming a dense and uniform PDA layer. HNIW@PDA coated in oxygen for 6 h exhibited the most favorable performance, with a delay of 20.8 °C in the phase transition temperature and a reduction of 145.45% in the impact sensitivity. The -OH groups on the surface of PDA enhanced the interaction between HNIW and polymer binders, resulting in a 20.36% reduction in the dewetting percentage. The lower content of PDA in HNIW@PDA (1.17%) resulted in minimal variation in the heat of explosion for HNIW@PDA-based HTPB propellant (6287 kJ/kg) in comparison to HNIW-based HTPB propellant (6297 kJ/kg). Hence, HNIW@PDA-based propellants are expected to offer an alternative with promising safety and mechanical performance compared to existing HNIW-based propellants, thus facilitating the application of HNIW in high-energy propellants. This work presents a low-cost method for efficiently inhibiting the phase transformation of polycrystalline explosives and reducing the impact sensitivity. It also offers a potential approach to enhance the interfacial interaction between nitro-containing explosives and polymer binders.
Full article
(This article belongs to the Special Issue Polymeric Composites: Manufacturing, Processing and Applications)
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Open AccessArticle
Electromagnetic Interference Shielding Properties of Highly Flexible Poly(styrene-co-butyl acrylate)/PEDOT:PSS Films Fabricated by Latex Technology
by
Seung Chang Lee, Yong Bin Bang, Hyun Ho Park, Hyo Yeol Na and Seong Jae Lee
Polymers 2024, 16(11), 1565; https://doi.org/10.3390/polym16111565 - 31 May 2024
Abstract
As the use of stretchable electronic devices increases, the importance of flexible electromagnetic interference (EMI) shielding films is emerging. In this study, a highly flexible shielding film was fabricated using poly(styrene-co-butyl acrylate) (p(St-co-BA)) latex as a matrix and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as a conductive
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As the use of stretchable electronic devices increases, the importance of flexible electromagnetic interference (EMI) shielding films is emerging. In this study, a highly flexible shielding film was fabricated using poly(styrene-co-butyl acrylate) (p(St-co-BA)) latex as a matrix and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as a conductive filler, and then the mechanical properties and EMI shielding performance of the film were examined. Styrene and butyl acrylate were copolymerized to lower the high glass transition temperature and increase the ductility of brittle polystyrene. The latex blending technique was used to produce a shielding film in which the aqueous filler dispersion was uniformly dispersed in the emulsion polymerized resin. To determine the phase change in the copolymer matrix with temperature, the storage modulus was measured, and a time–temperature superposition master curve was constructed. The drying temperature of water-based copolymer resin suitable for film fabrication was set based on this curve. The glass transition temperature and flexibility of the blends were determined by evaluating the thermomechanical analysis and tensile tests. The EMI shielding effectiveness (SE) of the films was analyzed at frequencies from 50 MHz to 1.5 GHz, covering the VHF and UHF ranges. As the filler content increased, the SE of the blend film increased, but the elongation increased until a certain content and then decreased. The optimal content of PEDOT:PSS that satisfied both the ductility and shielding performance of the film was found to be 10 wt%. In this case, the elongation at break reached 300%, and the SE of a 1.6 mm thick film was about 35 dB. The film developed in this study can be used as an EMI shielding material that requires high flexibility.
Full article
(This article belongs to the Section Polymer Membranes and Films)
Open AccessArticle
Efficient Alcoholysis of Poly(ethylene terephthalate) by Using Supercritical Carbon Dioxide as a Green Solvent
by
Yiwei Xu, Ran Cui, Yuqing Han, Jie Jiang, Dongdong Hu, Ling Zhao and Zhenhao Xi
Polymers 2024, 16(11), 1564; https://doi.org/10.3390/polym16111564 - 31 May 2024
Abstract
In order to reduce the environmental impact of poly(ethylene terephthalate) (PET) plastic waste, supercritical fluids were used to facilitate effective recovery via improved solvent effects. This work focuses on the mechanisms of supercritical CO2 (ScCO2) during the alcoholysis processing of
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In order to reduce the environmental impact of poly(ethylene terephthalate) (PET) plastic waste, supercritical fluids were used to facilitate effective recovery via improved solvent effects. This work focuses on the mechanisms of supercritical CO2 (ScCO2) during the alcoholysis processing of PET using systematic experiments and molecular dynamics (MD) simulations. The results of the alcoholysis experiment indicated that PET chips can be completely depolymerized within only an hour at 473 K assisted with ScCO2 at an optimal molar ratio of CO2/ethanol of 0.2. Random scission of PET dominates the early stage of the depolymerization reaction process, while specific scission dominates the following stage. Correspondingly, molecular dynamics (MD) simulations revealed that the solubilization and self-diffusion properties of ScCO2 facilitate the transportation of alcohol molecules into the bulk phase of PET, which leads to an accelerated diffusion of both oligomers and small molecules in the system. However, the presence of excessive CO2 has a negative impact on depolymerization by weakening the hydrogen bonding between polyester chain segments and ethanol, as well as decreasing the swelling degree of PET. These data provide a deep understanding of PET degradation by alcohols and the enhancement of ScCO2. It should be expected to achieve an efficient and high-yield depolymerization process of wasted polyesters assisted with ScCO2 at a relatively low temperature.
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(This article belongs to the Special Issue Degradation and Stabilization of Polymer Materials 2nd Edition)
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Gelatin and Collagen from Sheepskin
by
Andrea Marie E. Matinong, Kim L. Pickering, Mark R. Waterland, Yusuf Chisti and Richard G. Haverkamp
Polymers 2024, 16(11), 1563; https://doi.org/10.3390/polym16111563 - 31 May 2024
Abstract
Abattoirs dispose of sheepskins as solid waste due to low price and poor demand for sheepskin leather. In principle, as an alternative to being disposed of in landfill, sheepskins can serve as a source of the protein collagen or the hydrolysis product, gelatin.
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Abattoirs dispose of sheepskins as solid waste due to low price and poor demand for sheepskin leather. In principle, as an alternative to being disposed of in landfill, sheepskins can serve as a source of the protein collagen or the hydrolysis product, gelatin. In this research, sheepskins collected from abattoirs were used as a source of collagen. Three extraction methods were compared: acid extraction, acid with enzymes, and alkali extraction. The extracted material was characterized using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), small angle X-ray scattering (SAXS), and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The collagen and gelatin extraction yield ranged from 3.1% to 4.8% with the product purity determined by hydroxyproline, ranging from 7.8% for the alkali process to 59% and 68% for the acid and acid-enzyme processes. SDS PAGE showed that the acid process produced fragments with molecular weights in the range 100 to >250 kDa, while acid–enzyme resulted in smaller fragments, below 30 kDa. The FTIR region of the amide I band at 1800–1550 cm−1, which was used as an indicator of the collagen and gelatin content, showed that the gelatin dominated in the acid extracts, and the alkaline extract contained a large portion of keratin. SAXS was found to be a sensitive method for showing the presence of intact collagen fibrils in materials from all of the extraction methods, albeit at low concentrations. Herein, sheepskin is shown to be a useful source for collagen–gelatin material of varying molecular weights.
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(This article belongs to the Section Biomacromolecules, Biobased and Biodegradable Polymers)
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Experimental Study of the Tensile Behavior of Structures Obtained by FDM 3D Printing Process
by
Salem Ben hadj Hassine, Sami Chatti, Borhen Louhichi and Abdennour Seibi
Polymers 2024, 16(11), 1562; https://doi.org/10.3390/polym16111562 - 31 May 2024
Abstract
Fused Deposition Modelling (FDM) is one of the layer-based technologies that fall under the umbrella term “Additive Manufacturing”, where the desired part is created through the successive layer-by-layer addition process with high accuracy using computer-aided design data. Additive manufacturing technology, or as it
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Fused Deposition Modelling (FDM) is one of the layer-based technologies that fall under the umbrella term “Additive Manufacturing”, where the desired part is created through the successive layer-by-layer addition process with high accuracy using computer-aided design data. Additive manufacturing technology, or as it is commonly known, 3D (three-dimensional) printing, is a rapidly growing sector of manufacturing that is incorporated in automotive, aerospace, biomedical, and many other fields. This work explores the impact of the Additive Manufacturing process on the mechanical proprieties of the fabricated part. To conduct this study, the 3D printed tensile specimens are designed according to the ASTM D638 standards and printed from a digital template file using the FDM 3D printer Raise3D N2. The material chosen for this 3D printing parameter optimization is Polylactic acid (PLA). The FDM process parameters that were studied in this work are the infill pattern, the infill density, and the infill cell orientation. These factors’ effects on the tensile behavior of printed parts were analyzed by the design of experiments method, using the statistical software MINITAB2020.
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(This article belongs to the Section Polymer Processing and Engineering)
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Stable 3D Deep Convolutional Autoencoder Method for Ultrasonic Testing of Defects in Polymer Composites
by
Yi Liu, Qing Yu, Kaixin Liu, Ningtao Zhu and Yuan Yao
Polymers 2024, 16(11), 1561; https://doi.org/10.3390/polym16111561 - 31 May 2024
Abstract
Ultrasonic testing is widely used for defect detection in polymer composites owing to advantages such as fast processing speed, simple operation, high reliability, and real-time monitoring. However, defect information in ultrasound images is not easily detectable because of the influence of ultrasound echoes
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Ultrasonic testing is widely used for defect detection in polymer composites owing to advantages such as fast processing speed, simple operation, high reliability, and real-time monitoring. However, defect information in ultrasound images is not easily detectable because of the influence of ultrasound echoes and noise. In this study, a stable three-dimensional deep convolutional autoencoder (3D-DCA) was developed to identify defects in polymer composites. Through 3D convolutional operations, it can synchronously learn the spatiotemporal properties of the data volume. Subsequently, the depth receptive field (RF) of the hidden layer in the autoencoder maps the defect information to the original depth location, thereby mitigating the effects of the defect surface and bottom echoes. In addition, a dual-layer encoder was designed to improve the hidden layer visualization results. Consequently, the size, shape, and depth of the defects can be accurately determined. The feasibility of the method was demonstrated through its application to defect detection in carbon-fiber-reinforced polymers.
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(This article belongs to the Special Issue Scientific Machine Learning for Polymeric Materials)
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Structural Health Monitoring of Fiber Reinforced Composites Using Integrated a Linear Capacitance Based Sensor
by
Khalid S. Alblalaihid, Saad A. Aldoihi and Abdulaziz A. Alharbi
Polymers 2024, 16(11), 1560; https://doi.org/10.3390/polym16111560 - 31 May 2024
Abstract
The demand for fiber-reinforced polymers (FRPs) has significantly increased in various industries due to their attributes, including low weight, high strength, corrosion resistance, and cost-efficiency. Nevertheless, FRPs, such as glass and Kevlar fiber composites, exhibit anisotropic properties and relatively low interlaminar strength, rendering
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The demand for fiber-reinforced polymers (FRPs) has significantly increased in various industries due to their attributes, including low weight, high strength, corrosion resistance, and cost-efficiency. Nevertheless, FRPs, such as glass and Kevlar fiber composites, exhibit anisotropic properties and relatively low interlaminar strength, rendering them susceptible to undetected damage. The integration of real-time damage detection processes can effectively mitigate this issue. This paper introduces a novel method for fabricating embedded capacitive sensors within FRPs using a coating technique. The study encompasses two types of fibers, namely glass and Kevlar fiber/epoxy composites. The physical vapor deposition (PVD) technique is employed to coat bundle fibers with conductive material, thus creating embedded electrodes. The results demonstrate the uniform distribution of nanoparticles of gold (Au) along the fibers using PVD, resulting in a favorable resistance of approximately ≈100 Ω. Two sensor configurations are explored: axial and lateral embedding of the coated yarn (electrodes) to investigate the influence of load direction on the coating yarn. Axial-sensor configuration specimens undergo tensile testing, showcasing a linear response to axial loads with average sensitivities of 1 for glass and 1.5 for Kevlar fiber/epoxy composites. Additionally, onset damage is detected in both types of fiber composites, occurring before final fracture, with average stress at the turning point measuring 208 MPa for glass and 144 MPa for Kevlar. The lateral-sensor configuration for glass fiber-reinforced polymer (GFRP) exhibits good linearity towards strain until failure, with average gauge factors of 0.25 and −2.44 in the x and y axes, respectively.
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(This article belongs to the Special Issue Conductive Polymers for Smart Textile Applications)
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Stability and Biaxial Behavior of Fresh Cheese Coated with Nanoliposomes Encapsulating Grape Seed Tannins and Polysaccharides Using Immersion and Spray Methods
by
Angela Monasterio, Emerson Núñez, Valeria Verdugo and Fernando A. Osorio
Polymers 2024, 16(11), 1559; https://doi.org/10.3390/polym16111559 - 31 May 2024
Abstract
In the food industry context, where fresh cheese stands out as a highly perishable product with a short shelf life, this study aimed to extend its preservation through multi-layer edible coatings. The overall objective was to analyze the biaxial behavior and texture of
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In the food industry context, where fresh cheese stands out as a highly perishable product with a short shelf life, this study aimed to extend its preservation through multi-layer edible coatings. The overall objective was to analyze the biaxial behavior and texture of fresh cheese coated with nanoliposomes encapsulating grape seed tannins (NTs) and polysaccharides (hydroxypropyl methylcellulose; HPMC and kappa carrageenan; KC) using immersion and spray methods, establishing comparisons with uncoated cheeses and commercial samples, including an accelerated shelf-life study. NT, HPMC, and KC were employed as primary components in the multi-layer edible coatings, which were applied through immersion and spray. The results revealed significant improvements, such as a 20% reduction in weight loss and increased stability against oxidation, evidenced by a 30% lower peroxide index than the uncoated samples. These findings underscore the effectiveness of edible coatings in enhancing the quality and extending the shelf life of fresh cheese, highlighting the innovative application of nanoliposomes and polysaccharide blends and the relevance of applying this strategy in the food industry. In conclusion, this study provides a promising perspective for developing dairy products with improved properties, opening opportunities to meet market demands and enhance consumer acceptance.
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(This article belongs to the Special Issue Application of Polymers in Food Sciences)
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