Polymers

8 pages, 1709 KiB

Open AccessCommunication

Unveiling the Mechanics Behind Polyimide’s Friction-Greening Phenomenon

by Zhipeng Li, Dawei Ma, Haowen Li, Baojie Zhao, Yinglong Huang and Yanbo Li

Polymers 2024, 16(23), 3253; https://doi.org/10.3390/polym16233253 - 22 Nov 2024

Polyimide (PI) has been widely used as a flexible substrate in the OLED display industry to achieve folding and other functions. However, it has unintended side effects, such as friction-greening, a green screen phenomenon caused by friction after prolonged usage. This is related [...] Read more.

Polyimide (PI) has been widely used as a flexible substrate in the OLED display industry to achieve folding and other functions. However, it has unintended side effects, such as friction-greening, a green screen phenomenon caused by friction after prolonged usage. This is related to drifting TFT characteristics caused by charge accumulating in the PI in combination with the high efficiency of green pixels. In this study, the mechanism of the influence of PI structure on friction-greening was investigated. Increasing the process temperature from 350 °C to 470 °C, the chain segment structure within the PI became more regularized. Thus, the material had higher conductivity and shallower trap energy levels, which was confirmed by X-ray small angle scattering, dielectric, photoluminescence, and other methods. Under prolonged discharge conditions, less charge accumulated within PI, thus effectively mitigating the threshold voltage drift of the thin-film transistor (TFT). These results will contribute to the further optimization of the process and the development of PI materials. Full article

(This article belongs to the Section Polymer Applications)

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17 pages, 5645 KiB

Open AccessArticle

Kinematic Analysis of Plasticization and Transportation System of Tri-Screw Dynamic Extruder

by Bin Xue, Jun Li, Qu Yang, Guiting Wu, Danxiang Wei, Yijie Ding, Zhenbin Du and Mingshi Huang

Polymers 2024, 16(23), 3252; https://doi.org/10.3390/polym16233252 - 22 Nov 2024

Abstract

With the growing demand for high-performance polymer composites, conventional single- and twin-screw extruders often fall short of meeting industrial requirements for effective mixing and compounding. This research investigates the kinematic behavior of the plasticization and transport mechanisms in tri-screw extruders when subjected to [...] Read more.

With the growing demand for high-performance polymer composites, conventional single- and twin-screw extruders often fall short of meeting industrial requirements for effective mixing and compounding. This research investigates the kinematic behavior of the plasticization and transport mechanisms in tri-screw extruders when subjected to a vibrational force field. The study specifically examines how applying vibrational force technology can improve the efficiency of polymer mixing. Vibration force field means that in a three-screw mechanism, an axial vibration is applied to the middle screw to produce a vibration force field. Through the development of mathematical and physical models, this study analyzed the motion dynamics of the screw and the influence of a vibrational force field on polymer transport and mixing efficiency. The findings indicate that, in comparison to traditional twin-screw extruders, tri-screw systems can achieve higher shear and elongational rates, leading to enhanced polymer mixing uniformity. Furthermore, applying an axial vibrational force field significantly influenced the shear and elongational strain rates of the material, thereby optimizing its rheological behavior and processing quality. This research not only establishes a theoretical foundation for the design and optimization of tri-screw extruders but also opens new pathways for the efficient processing of high-viscosity composite materials. Full article

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

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10 pages, 3038 KiB

Open AccessArticle

Theoretical Study on the High Polymer Molecular Weight of Heteroatom-Substituted Constrained Geometry Catalyst

by Xinyue Du, Congjing Ren, Xiaodong Hong, Jingdai Wang, Yongrong Yang and Zuwei Liao

Polymers 2024, 16(23), 3251; https://doi.org/10.3390/polym16233251 - 22 Nov 2024

Abstract

This theoretical study investigates the high molecular weight (Mw) production in copolymerization of ethylene and 1-octene using heteroatom-substituted constrained geometry catalysts (CGCs). The research explores the correlation between chain termination reactions and polymer molecular weight, revealing that the Gibbs free energy barrier of [...] Read more.

This theoretical study investigates the high molecular weight (Mw) production in copolymerization of ethylene and 1-octene using heteroatom-substituted constrained geometry catalysts (CGCs). The research explores the correlation between chain termination reactions and polymer molecular weight, revealing that the Gibbs free energy barrier of the chain termination reactions is positively linked to the molecular weight. Quantitative structure–property relationship models were constructed, indicating that molecular descriptors such as atom charge, orbital energy, and buried volume significantly influence the polymer molecular weight. Full article

(This article belongs to the Section Polymer Chemistry)

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14 pages, 5160 KiB

Open AccessArticle

Exploring Crystal Structure Features in Proton Exchange Membranes and Their Correlation with Proton and Heat Transport

by Cong Feng, Cong Luo, Pingwen Ming and Cunman Zhang

Polymers 2024, 16(23), 3250; https://doi.org/10.3390/polym16233250 - 22 Nov 2024

Abstract

Proton exchange membranes (PEMs) are dominated by semicrystalline structures because highly pure crystals are still challenging to produce and control. Currently, the development and application of PEMs have been hindered by a lack of understanding regarding the effects of microstructure on proton and [...] Read more.

Proton exchange membranes (PEMs) are dominated by semicrystalline structures because highly pure crystals are still challenging to produce and control. Currently, the development and application of PEMs have been hindered by a lack of understanding regarding the effects of microstructure on proton and heat transport properties. Based on an experimentally characterized perfluoro sulfonic acid membrane, the corresponding semicrystalline model and the crystal model contained therein were constructed. The water distribution, proton, and heat transport in the crystal, amorphous, and semicrystalline regions were examined using molecular dynamics simulations and energy-conserving dissipative particle dynamics simulations. The crystal structure had pronounced water connection pathways, a proton transport efficiency 5–10 times higher than that of the amorphous structure, and an in-plane covalent bonding that boosted the thermal diffusion coefficient and thermal conductivity by more than 1–3 times. The results for the semicrystalline structure were validated by the corresponding experiments. In addition, a proportionality coefficient that depended on both temperature and water content was proposed to explain how vehicle transport contributed to the proton conductivities, facilitating our understanding of the proton transport mechanism. Our findings enhance our theoretical understanding of PEMs in proton and heat transport, considering both the semicrystalline and crystalline regions. Additionally, the research methods employed can be applied to the study of other semicrystalline polymers. Full article

(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage, 2nd Edition)

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19 pages, 1604 KiB

Open AccessArticle

Investigation of the Weldability of 3D-Printed Multi-Material Materials (PLA and PLA Wood) Using Friction Stir Welding

by Gökhan Şahin, Nergizhan Anaç and Oğuz Koçar

Polymers 2024, 16(23), 3249; https://doi.org/10.3390/polym16233249 - 22 Nov 2024

Abstract

In the industry sector, it is very common to have different types of dissimilar materials on the same construction rather than products made from a single type of material. Traditional methods (welding, mechanical fastening, and adhesive bonding) and hybrid techniques (friction stir welding, [...] Read more.

In the industry sector, it is very common to have different types of dissimilar materials on the same construction rather than products made from a single type of material. Traditional methods (welding, mechanical fastening, and adhesive bonding) and hybrid techniques (friction stir welding, weld bonding, and laser welding) are used in the assembly or joining of these materials. However, while joining similar types of materials is relatively easy, the process becomes more challenging when joining dissimilar materials due to the structure and properties of the materials involved. In recent years, additive manufacturing and 3D printing have revolutionized the manufacturing landscape and have provided great opportunities for the production of polymer-based multi-materials. However, developments in the joining of multi-material parts are limited, and their limits are not yet clear. This study focuses on the joining of 3D-printed products made from PLA-based multiple materials (PLA and PLA Wood) using friction stir welding. Single-material and multi-material parts (with 100% infill ratio and three different combinations of 50% PLA/50% PLA Wood) were welded at a feed rate of 20 mm/min and three different tool rotational speeds (1750, 2000, and 2250 rpm). Tensile and bending tests were conducted on the welded samples, and temperature measurements were taken. The fractured surfaces of the samples were examined to perform a damage analysis. It is determined that the weld strength of multi-materials changes depending on the combination of the material (material design). For multi-materials, a welding efficiency of 74.3% was achieved for tensile strength and 142.68% for bending load. Full article

(This article belongs to the Special Issue Advanced Joining Technologies for Polymers and Polymer Composites)

16 pages, 2430 KiB

Open AccessArticle

Novel Simple Approach for Production of Elastic Poly(propylene carbonate)

by Elena S. Trofimchuk, Igor V. Chernov, Roman V. Toms, Sergey A. Rzhevskiy, Andrey F. Asachenko, Anna V. Plutalova, George A. Shandryuk, Elena V. Chernikova and Irina P. Beletskaya

Polymers 2024, 16(23), 3248; https://doi.org/10.3390/polym16233248 - 22 Nov 2024

Abstract

The simple approach of increasing the elastic properties of atactic poly(propylene carbonate) (PPC) with Mn = 71.4 kDa, ĐM = M_w/M_n = 1.86, and predominantly carbonate units (>99%) is suggested by selecting the appropriate hot pressing temperature for PPC between [...] Read more.

The simple approach of increasing the elastic properties of atactic poly(propylene carbonate) (PPC) with Mn = 71.4 kDa, ĐM = M_w/M_n = 1.86, and predominantly carbonate units (>99%) is suggested by selecting the appropriate hot pressing temperature for PPC between 110 and 140 °C. Atactic PPC is synthesized through ring-opening copolymerization of (rac)-propylene oxide and CO2 mediated by racemic salen complex of Co(III). Hot pressing PPC results in the release of a small amount of propylene carbonate (PC), sufficient to lower the glass transition temperature from 39.4 to 26.1 °C. Consequently, increasing the pressing temperature from 110 to 140 °C generates materials with a reduced modulus of elasticity (from 1.94 to 0.09 GPa), yield strength (from 38 to 2 MPa) and increased tensile elongation (from 140 to 940%). Thermomechanical analysis has shown a significant expansion in sample volume by hundreds of percent within the 80–130 °C range. PPC also displays large, reversible deformations, which can be utilized by creating shape memory materials. Full article

(This article belongs to the Section Polymer Applications)

19 pages, 928 KiB

Open AccessReview

Combating Bacterial Resistance by Polymers and Antibiotic Composites

by Iulia Olaru, Alina Stefanache, Cristian Gutu, Ionut Iulian Lungu, Cozmin Mihai, Carmen Grierosu, Gabriela Calin, Constantin Marcu and Tudor Ciuhodaru

Polymers 2024, 16(23), 3247; https://doi.org/10.3390/polym16233247 - 22 Nov 2024

Abstract

(1) Background: Since the discovery of antibiotics in the first half of the 20th century, humans have abused this privilege, giving rise to antibiotic-resistant pathogens. Recent research has brought to light the use of antimicrobial peptides in polymers, hydrogels, and nanoparticles (NPs) as [...] Read more.

(1) Background: Since the discovery of antibiotics in the first half of the 20th century, humans have abused this privilege, giving rise to antibiotic-resistant pathogens. Recent research has brought to light the use of antimicrobial peptides in polymers, hydrogels, and nanoparticles (NPs) as a newer and safer alternative to traditional antibiotics. (2) Methods: This review article is a synthesis of the scientific works published in the last 15 years, focusing on the synthesis of polymers with proven antimicrobial properties. (3) Results: After a critical review of the literature was made, information and data about the synthesis and antimicrobial activity of antibacterial polymers and NPs functionalized with antibiotics were extracted. Fluorinated surfactants such as the Quaterfluo^® series presented significant antimicrobial effects and could be modulated to contain thioesters to boost this characteristic. Biopolymers like chitosan and starch were also doped with iodine and used as iodophors to deliver iodine atoms directly to pathogens, as well as being antimicrobial on their own. Quaternary phosphonium salts are known for their increased antimicrobial activity compared to ammonium-containing polymers and are more thermally stable. (4) Conclusions: In summary, polymers and polymeric NPs seem like future alternatives to traditional antibiotics. Future research is needed to determine functional doses for clinical use and their toxicity. Full article

(This article belongs to the Section Polymer Applications)

33 pages, 10134 KiB

Open AccessArticle

Study on the Microscopic Distribution Pattern of Residual Oil and Exploitation Methods Based on a Digital Pore Network Model

by Xianda Sun, Xudong Qin, Chengwu Xu, Ling Zhao and Huili Zhang

Polymers 2024, 16(23), 3246; https://doi.org/10.3390/polym16233246 - 22 Nov 2024

Abstract

With the persistent rise in global energy demand, the efficient extraction of petroleum resources has become an urgent and critical issue. Polymer flooding technology, widely employed for enhancing crude oil recovery, still lacks an in-depth understanding of the distribution of residual oil within [...] Read more.

With the persistent rise in global energy demand, the efficient extraction of petroleum resources has become an urgent and critical issue. Polymer flooding technology, widely employed for enhancing crude oil recovery, still lacks an in-depth understanding of the distribution of residual oil within the microscopic pore structure and the associated displacement mechanisms. To address this, a digital pore network model was established based on mercury intrusion experimental data, and pore structure visualization was achieved through 3Dmax software, simulating the oil displacement process under various polymer concentrations, molecular weights, and interfacial tension conditions. The findings reveal that moderately increasing the polymer concentration (from 1000 [mg/L] to 2000 [mg/L]) improves the recovery factor during polymer flooding by approximately 1.45%, effectively emulsifying larger masses of residual oil and reducing the proportion of throats with high oil saturation. However, when the concentration exceeds 2500 [mg/L], the dispersion of residual oil is hindered, and the enhancement in displacement efficiency becomes marginal. Increasing the molecular weight from 12 million to 16 million and subsequently to 24 million elevates the recovery factor by approximately 1.07% and 1.37%, respectively, reducing clustered residual oil while increasing columnar residual oil; high molecular weight polymers exhibit a more significant effect on channels with high oil saturation. Lowering the interfacial tension (from 30 [mN/m] to 0.005 [mN/m]) markedly enhances the binary flooding recovery factor, with the overall recovery reaching 71.72%, effectively reducing the residual oil within pores of high oil saturation. The study concludes that adjusting polymer concentration, molecular weight, and interfacial tension can optimize the microscopic distribution of residual oil, thereby enhancing oil displacement efficiency and providing a scientific foundation for further improving oilfield recovery and achieving efficient reservoir development. Full article

(This article belongs to the Special Issue Stimuli-Responsive Polymers: Advances and Prospects)

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22 pages, 8243 KiB

Open AccessArticle

Novel Mixed-Matrix Pervaporation Membrane Based on Polyether Block Amide Modified with Ho-Based Metal–Organic Framework

by Anna Kuzminova, Mariia Dmitrenko, Anastasia Stepanova, Anna Karyakina, Artem Selyutin, Rongxin Su and Anastasia Penkova

Polymers 2024, 16(23), 3245; https://doi.org/10.3390/polym16233245 - 22 Nov 2024

Abstract

Segmented polymers, such as polyether block amide (PEBA), exhibit unique properties due to the combination of different segments. PEBA consists of soft polyester and rigid polyamide blocks, enabling its use in various industrial applications, including membrane technologies. In this study, PEBA membranes modified [...] Read more.

Segmented polymers, such as polyether block amide (PEBA), exhibit unique properties due to the combination of different segments. PEBA consists of soft polyester and rigid polyamide blocks, enabling its use in various industrial applications, including membrane technologies. In this study, PEBA membranes modified with a holmium-based metal–organic framework (Ho-1,3,5-H₃btc) were developed for enhanced pervaporation separation of water/isopropanol and water/phenol mixtures. The effect of 1–7 wt.% Ho-1,3,5-H₃btc content variation and the selection of a porous substrate (commercial from fluoroplast F42L (MFFC) and developed membranes from polyvinylidene fluoride without (PVDF) and with a non-woven polyester support (PVDF-s)) on dense and/or supported membrane properties, respectively, was investigated. The dense and supported PEBA/Ho-1,3,5-H₃btc membranes were studied by use of Fourier transform infrared spectroscopy, scanning electron and atomic force microscopies, swelling measurements, and pervaporation experiments. The supported membrane from PEBA with 5 wt.% Ho-1,3,5-H₃btc applied onto the PVDF-s substrate exhibited optimal pervaporation performance: a 1040 g/(m²h) permeation flux and a 5.2 separation factor in water/phenol (1 wt.%) mixture separation at 50 °C due to optimal values of roughness, swelling degree, and selective layer thickness. This finding highlights the potential of incorporating Ho-1,3,5-H₃btc into PEBA for developing high-performance pervaporation membranes. Full article

(This article belongs to the Section Polymer Applications)

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14 pages, 4458 KiB

Open AccessArticle

Development of Conductive Antibacterial Coatings on Cotton Fabrics via Polyphenol-Mediated Silver Mirror Reaction

by Yixiao Wu, Chenlin Fu, Jiaxin Xin, Lin Yang, Chong Zhao and Kun Yan

Polymers 2024, 16(23), 3244; https://doi.org/10.3390/polym16233244 - 22 Nov 2024

Abstract

Herein, this study reports the development of a multifunctional conductive antibacterial cotton fabric through the utilization of the natural polyphenol-mediated silver mirror reaction. The experimental results demonstrate that polyphenols can effectively facilitate the deposition of silver nanoparticles (AgNPs), resulting in a uniform and [...] Read more.

Herein, this study reports the development of a multifunctional conductive antibacterial cotton fabric through the utilization of the natural polyphenol-mediated silver mirror reaction. The experimental results demonstrate that polyphenols can effectively facilitate the deposition of silver nanoparticles (AgNPs), resulting in a uniform and durable hybrid nanocoating on the cotton fabric. The effects of polyphenol’s molecular weights on the coating structures and stabilities have been revealed via two distinct approaches: washing resistance and electrochemical testing systems. It has been concluded that lower-molecular-weight phenols induce a compact and dense coating structure, whereas polyphenols such as tannic acid exhibit relatively high stability, achieving an excellent conductivity of 0.2 S/cm and a good washing resistance of 67% over five cycles. The underlying mechanism has been further confirmed by the cyclic voltammetry measurements, suggesting that polyphenols play a significant role in stabilizing AgNPs and preventing their dissolution. Furthermore, the Ag-doped polyphenol-coated fabrics exhibit notable antibacterial properties. By coupling natural polyphenols with typical silver mirror reactions, this study not only offers a sustainable alternative to synthetic chemicals but also presents a promising method to endow cotton textiles with the dual properties of conductivity and antibacterial activity. Full article

(This article belongs to the Special Issue Biomaterials Modification, Characterization and Applications)

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12 pages, 3663 KiB

Open AccessArticle

Mechanical Performance of Structural Polymethyl Methacrylate Joints at Different Temperatures

by Chenxing Kang, Lei Peng, Yantao Li and Jinhui Zong

Polymers 2024, 16(23), 3243; https://doi.org/10.3390/polym16233243 - 22 Nov 2024

Abstract

This paper introduces a novel technique for enhancing the joint strength in structural acrylic glass (polymethyl methacrylate, PMMA) under thermal cycling conditions. By employing bulk polymerization, the strength of PMMA joints was significantly reinforced. Tensile assessments from 20 °C to 140 °C were [...] Read more.

This paper introduces a novel technique for enhancing the joint strength in structural acrylic glass (polymethyl methacrylate, PMMA) under thermal cycling conditions. By employing bulk polymerization, the strength of PMMA joints was significantly reinforced. Tensile assessments from 20 °C to 140 °C were conducted to evaluate the mechanical properties of acrylic joints under varying temperature conditions. A constitutive model was established to correlate the strength of both the base material and the joints with temperature variations. The tensile test outcomes demonstrated that the innovative bulk polymerization method under thermal cycling conditions effectively increased the joint material strength to reach up to 90% of the base material’s strength, and the post-thermal cycling tests demonstrate that post-thermal cycling has essentially no impact on the strength and modulus. This advancement in joint strength enhancement not only expands the potential applications of acrylic glass in architectural structures but also lays a substantial theoretical foundation for construction practices. Full article

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

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16 pages, 3967 KiB

Open AccessArticle

Sustainable Transformation of Cellulose-Containing Textile Waste into Multifunctional Panels with Tailored FR-Lignocellulosic Fibres

by Hamid Lamoudan, Lahbib Abenghal, Dan Belosinschi, François Brouillette, Patricia Dolez, Raymond Panneton and Cécile Fonrouge

Polymers 2024, 16(23), 3242; https://doi.org/10.3390/polym16233242 - 22 Nov 2024

Abstract

The fashion industry significantly impacts the environment, mainly through the substantial generation of waste textiles fostered by fast fashion business models. This study introduces an innovative approach to textile waste management by recycling waste textiles without the use of chemical or mechanical treatments. [...] Read more.

The fashion industry significantly impacts the environment, mainly through the substantial generation of waste textiles fostered by fast fashion business models. This study introduces an innovative approach to textile waste management by recycling waste textiles without the use of chemical or mechanical treatments. Herein, we developed a method adhering to the principles of circular economy to transform these textile wastes into high-quality construction panels using a papermaking process. This method not only provides a sustainable solution to reduce landfill dependency but also enhances resource efficiency in the construction industry. The fabricated panels, composed of a blend of 45% textile waste microfibres and 55% fire-retardant fibres, exhibit several advantageous properties. They feature a low apparent density ranging between 170–180 kg/m³ and a low thermal conductivity coefficient of 0.047 W/m∗K at 50 kPa. It revealed that phosphorylated fibres not only provide flame-retardant properties, but they also significantly improve the mechanical properties of the panels. For example, load at break increases from 12.4 to 81.1 N, stress at break from 0.44 to 3.59 MPa, and E-modulus from 29.2 to 198.8 MPa after the addition of these 55% fibres. Moreover, these panels successfully met the criteria set by international standards for construction products satisfying the fire test, EN ISO 11925-2. These characteristics make the panels superior options for sustainable construction materials, offering enhanced fire resistance and insulation properties, which are critical to meet modern building standards. They mark a pivotal step towards sustainable construction and waste reduction in the fashion industry. Full article

(This article belongs to the Special Issue Polysaccharide-Based Materials: Developments and Properties)

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24 pages, 5116 KiB

Open AccessArticle

Optimization of Metal Injection Molding Processing Conditions for Reducing Black Lines and Meld Lines in Bone Plates

by Chao-Ming Lin, Po-Yu Yen and Chung-Ming Tan

Polymers 2024, 16(23), 3241; https://doi.org/10.3390/polym16233241 - 22 Nov 2024

Abstract

The bone plates used in surgery to assist in fracture healing are often manufactured by metal injection molding (MIM) using a feedstock material consisting of metal powder and polymer binder. However, if the local powder concentration is too low or uneven, black lines [...] Read more.

The bone plates used in surgery to assist in fracture healing are often manufactured by metal injection molding (MIM) using a feedstock material consisting of metal powder and polymer binder. However, if the local powder concentration is too low or uneven, black lines may be formed, which impair the product appearance. Furthermore, if the melding temperature is too low, it can lead to meld lines and reduced mechanical properties. Accordingly, this study combines mold flow analysis simulations with the single-objective Taguchi robust design method to determine the MIM processing conditions that optimize the powder concentration and melding temperature. Grey relational analysis (GRA) is then used to establish the processing conditions that simultaneously optimize both MIM objectives. It is found that the processing conditions determined through GRA provide a significant improvement over the original design; however, the experimental outcomes are poorer than those achieved through the single-objective Taguchi experiments since the melt temperature effect suppresses that of all the other processing conditions. Consequently, a robust multi-criteria optimization (RMCO) technique is employed to improve the optimization outcome by identifying the dominant factors in the MIM process and fixing them at optimal levels to redesign the Taguchi experiments to optimize the non-primary factors. It is shown that the RMCO method eliminates interference between the multiple factors and hence provides an improved multi-objective optimization outcome. Overall, the integrated framework proposed in this study advances the optimization of the MIM process for bone plates and leads to improved product quality and performance. Full article

(This article belongs to the Special Issue Molding Process of Polymers and Composites)

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36 pages, 11045 KiB

Open AccessReview

Polymeric Membranes for Liquid Separation: Innovations in Materials, Fabrication, and Industrial Applications

by Lalit Ranjan Sahu, Diksha Yadav, Debasish Borah, Anuranjit Gogoi, Subrata Goswami, Gauri Hazarika, Sachin Karki, Moucham Borpatra Gohain, Saurabh V. Sawake, Sumit V. Jadhav, Soumya Chatterjee and Pravin G. Ingole

Polymers 2024, 16(23), 3240; https://doi.org/10.3390/polym16233240 - 22 Nov 2024

Abstract

Polymeric membranes have emerged as a versatile and efficient liquid separation technology, addressing the growing demand for sustainable, high-performance separation processes in various industrial sectors. This review offers an in-depth analysis of recent developments in polymeric membrane technology, focusing on materials’ advancements, innovative [...] Read more.

Polymeric membranes have emerged as a versatile and efficient liquid separation technology, addressing the growing demand for sustainable, high-performance separation processes in various industrial sectors. This review offers an in-depth analysis of recent developments in polymeric membrane technology, focusing on materials’ advancements, innovative fabrication methods, and strategies for improving performance. We discuss the underlying principles of membrane separation, selecting suitable polymers, and integrating novel materials, such as mixed-matrix and composite membranes, to enhance selectivity, permeability, and antifouling properties. The article also highlights the challenges and limitations associated with polymeric membranes, including stability, fouling, and scalability, and explores potential solutions to overcome these obstacles. This review aims to guide the development of next-generation polymeric membranes for efficient and sustainable liquid separation by offering a detailed analysis of current research and future directions. Full article

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

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21 pages, 7540 KiB

Open AccessArticle

Green Chemically Synthesized Iron Oxide Nanoparticles–Chitosan Coatings for Enhancing Strawberry Shelf-Life

by Ayesha Sani, Dilawar Hassan, Ghulam Qadir Chanihoon, Dulce Viridiana Melo Máximo and Elvia Patricia Sánchez-Rodríguez

Polymers 2024, 16(23), 3239; https://doi.org/10.3390/polym16233239 - 22 Nov 2024

Abstract

To enhance the preservation of strawberries, a novel coating formulation was developed using chitosan (CH) and iron oxide (IO) nanoparticles (NPs) supplemented with ginger and garlic extracts and combined with varying concentrations of 1%, 2%, and 3% Fe₃O₄ NPs. The [...] Read more.

To enhance the preservation of strawberries, a novel coating formulation was developed using chitosan (CH) and iron oxide (IO) nanoparticles (NPs) supplemented with ginger and garlic extracts and combined with varying concentrations of 1%, 2%, and 3% Fe₃O₄ NPs. The results of XRD revealed an average crystalline size of 48.1 nm for Fe₃O₄ NPs. SEM images identified Fe₃O₄ NPs as bright spots on the surface of the fruit, while FTIR confirmed their presence by detecting specific functional groups. Additional SEM analysis revealed clear visibility of CH coatings on the strawberries. Both uncoated and coated strawberry samples were stored at room temperature (27 °C), and quality parameters were systematically assessed, including weight loss, firmness, pH, titratable acidity (TA), total soluble solids (TSSs), ascorbic acid content, antioxidant activity, total reducing sugars (TRSs), total phenolic compounds (TPCs), and infection rates. The obtained weight loss was 21.6% and 6% for 1.5% CH and 3% IO with 1.5% CH, whereas the obtained infection percentage was 19.65% and 13.68% for 1.5% CH and 3% IO with 1.5% CH. As strawberries are citric fruit, 3% IO with 1.5% CH contains 55.81 mg/100 g ascorbic acid. The antioxidant activity for 1.5% CH coated was around 73.89%, whereas 3% IO with 1.5% CH showed 82.89%. The studies revealed that coated samples showed better results, whereas CH that incorporates Fe₃O₄ NP coatings appears very promising for extending the shelf life of strawberries, preserving their quality and nutritional value during storage and transportation. Full article

(This article belongs to the Special Issue Green Polymers from Renewable Resources)

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19 pages, 58206 KiB

Open AccessArticle

Aging and Modified Washing Process for Polyester Fabrics—Environmental Impact

by Ana Šaravanja, Tanja Pušić, Julija Volmajer Valh and Tihana Dekanić

Polymers 2024, 16(23), 3238; https://doi.org/10.3390/polym16233238 - 22 Nov 2024

Abstract

Aging and washing factors have a direct influence on changing the properties of textile products, e.g., causing a release of textile fragments in the washing process. In this study, polyester fabrics were exposed to artificial aging under controlled conditions. Using a modified washing [...] Read more.

Aging and washing factors have a direct influence on changing the properties of textile products, e.g., causing a release of textile fragments in the washing process. In this study, polyester fabrics were exposed to artificial aging under controlled conditions. Using a modified washing process, polyester fabrics were subjected to 10 washing cycles before and after the aging process. To monitor the influence of aging and the modified washing process on the polyester fabrics, the physical, structural and morphological properties of the fabrics and the composition of the collected wastewater were analyzed. The results indicate a slight degradation and increased defragmentation of the polyester fabric due to the processes used. Aging caused the phenomenon of “annealing”, photo-oxidative degradation, and the local thickening of the individual fibers. Aging and washing processes influence the change in tensile strength properties. An analysis of zeta potential and BET results confirmed that the aging process results in surface modifications that depend on the time of exposure. The physico-chemical characterization and microscopic analysis of the wastewater revealed various fragments and short, detached fibrils. The results confirmed that both aging and washing significantly affect the properties of polyester fabrics and the composition of the wastewater resulting from the washing process. The relevance of this research to environmental matters is emphasized through the parameters chosen, which reveal the influence of aging on polyester fabric characteristics and the contamination detected in wash wastewater. In conclusion, several avenues for future research have been identified, including lowering washing temperatures, choosing more appropriate detergents, and adjusting standard washing protocols. Full article

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

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17 pages, 10028 KiB

Open AccessArticle

Biodegradable TPS/PBAT Blown Films with Ascorbyl Palmitate and Sodium Ascorbyl Phosphate as Antioxidant Packaging

by Rosi Andini Arumsari, Phanwipa Wongphan and Nathdanai Harnkarnsujarit

Polymers 2024, 16(23), 3237; https://doi.org/10.3390/polym16233237 - 22 Nov 2024

Abstract

The development of biodegradable active packaging is a relevant topic demanding the development of film properties, biodegradability, and the potential to preserve food quality. This study aimed to develop thermoplastic starch (TPS) blended with polybutylene adipate-co-terephthalate (PBAT) films via blown-film extrusion containing ascorbyl [...] Read more.

The development of biodegradable active packaging is a relevant topic demanding the development of film properties, biodegradability, and the potential to preserve food quality. This study aimed to develop thermoplastic starch (TPS) blended with polybutylene adipate-co-terephthalate (PBAT) films via blown-film extrusion containing ascorbyl palmitate (AP) and sodium ascorbyl phosphate (SAP) as antioxidants. The morphology, mechanism, and barrier and antioxidant properties of the films were analyzed to determine the presence of AP, SAP, and their interaction effect on the film properties. SEM showed that increasing AP and SAP content increased fibrous-like morphology, improving the TPS dispersion. AP slightly decreased mechanical properties, while SAP increased the tensile properties and seal strength of the films. All of the YM values were increased by adding AP and SAP content. The addition of AP and SAP content enhanced the interaction with TPS/PBAT networks due to increasing C-O stretching of ester bonds, compatibility, and hydrophobicity of the polymer. Both water vapor and the oxygen barrier were insignificantly affected by AP and SAP up to 1%, while the permeabilities greatly increased at higher AP and SAP contents due to non-homogeneous and void spaces between the film matrix. TPS/PBAT containing AP and SAP (≥0.5%) effectively enhanced antioxidant capacity in 95% ethanol as a food simulant and reduced the UV light transmission of the films. Finding, the interaction between AP, SAP, and TPS/PBAT matrices effectively changed the microstructures and properties as functionalized antioxidant biodegradable packaging. Full article

(This article belongs to the Special Issue Natural Polymers: Design, Characterization and Applications)

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22 pages, 19199 KiB

Open AccessArticle

Impact of Hexyl Branch Content on the Mechanical Properties and Deformation Mechanisms of Amorphous Ethylene/1-Octene Copolymers: A Molecular Dynamics Study

by Ruijun Zhang, Qiqi He, Hongbo Yu, Junhua Li, Yuexin Hu and Jianhua Qian

Polymers 2024, 16(23), 3236; https://doi.org/10.3390/polym16233236 - 21 Nov 2024

Abstract

Ethylene/1-octene copolymers exhibit enhanced flexibility and impact resistance compared to polyethylene, which makes them well suited for applications in advanced plastics and elastomers. United-atom molecular dynamics (MD) simulations were conducted to explore the mechanical behavior and deformation mechanisms of ethylene/1-octene copolymers under uniaxial [...] Read more.

Ethylene/1-octene copolymers exhibit enhanced flexibility and impact resistance compared to polyethylene, which makes them well suited for applications in advanced plastics and elastomers. United-atom molecular dynamics (MD) simulations were conducted to explore the mechanical behavior and deformation mechanisms of ethylene/1-octene copolymers under uniaxial tensile loading. This study systematically examined the influence of temperature, polymer chain length, chain quantity, and strain rate, with a specific focus on how hexyl branch content impacts the mechanical properties of amorphous ethylene/1-octene copolymers. The simulation results indicate that as the branch content increases, the yield strength and elastic modulus decrease, suggesting a trade-off between flexibility and mechanical strength. Energy decomposition analysis reveals that copolymers with more branched chains undergo greater changes in van der Waals energy. Additionally, as the branch content increases, the reduction in dihedral angle energy in the strain hardening region becomes more gradual, and the rate and the extent of the transition of dihedral angles from gauche to trans conformation decrease under deformation. Ethylene/1-octene copolymers exhibit higher chain entanglement parameters compared to linear polyethylene, with these parameters increasing as the branch content rises. Moreover, increasing the branch content results in a less pronounced increase in chain orientation along the loading direction. Full article

(This article belongs to the Special Issue Advanced Polymer Materials: Synthesis, Structure, and Properties)

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18 pages, 9524 KiB

Open AccessArticle

Synthesis, Characterization, and Application Prospects of Novel Soluble Polysilsesquioxane Bearing Glutarimide Side-Chain Groups

by Yuliya I. Bolgova, Artem I. Emel’yanov, Olga M. Trofimova, Anastasiya A. Ivanova, Alexander I. Albanov, Nadezhda P. Kuznetsova, Tatyana A. Semenova and Alexander S. Pozdnyakov

Polymers 2024, 16(23), 3235; https://doi.org/10.3390/polym16233235 - 21 Nov 2024

Abstract

The requirement for the development of advanced technologies is the need to create new functional thermostable soluble polysilsesquioxanes. Combining the potential of organosilicon chemistry and the chemistry of heterocyclic compounds is a promising direction for the formation of novel organosilicon polymer systems with [...] Read more.

The requirement for the development of advanced technologies is the need to create new functional thermostable soluble polysilsesquioxanes. Combining the potential of organosilicon chemistry and the chemistry of heterocyclic compounds is a promising direction for the formation of novel organosilicon polymer systems with new properties and new possibilities for their practical application. Using the classical method of hydrolysis and polycondensation of previously unknown trifunctional (trimethoxysilylpropyl)glutarimide in the presence or absence of an acid or base catalyst, a universal approach to the formation of new thermostable soluble polysilsesquioxanes with glutarimide side-chain groups is proposed, which forms the basis for the synthesis of polysilsesquioxane polymers with different functionality. The weight average molecular weight of silsesquioxanes, determined by gel permeation chromatography, is practically independent of the reaction conditions and is 10–12 kDa; at the same time, the molecular weight distribution remains low and amounts to 1.38–1.47. According to thermogravimetric analysis, the resulting polysiloxanes have high thermal stability up to 335 °C. By the dynamic light scattering method, it was established that in an aqueous solution, silsesquioxane macromolecules are in an associated state, forming supramolecular structures due to the intermolecular interaction of individual macromolecules. The average hydrodynamic diameter of the particles was 46 nm. X-ray diffraction analysis showed the amorphous nature of the polymer. Polymer film coatings based on synthesized silsesquioxanes are characterized by 98% transmission in the visible spectrum and resistance to ultraviolet radiation, which is promising for the creation of functional transparent film coatings. Full article

(This article belongs to the Special Issue Silicon-Based Polymers: From Synthesis to Applications)

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