Polymers

16 pages, 4403 KiB

Open AccessArticle

The Influence of Conditions of Polycondensation in Acid Medium on the Structure of Oligosilsesquioxanes with a Novel Eugenol-Containing Substituent

by Alexander D. Ageenkov, Nikolay S. Bredov, Anna A. Shcherbina, Ramil R. Khasbiullin, Anton S. Tupikov and Mikhail A. Soldatov

Polymers 2024, 16(20), 2951; https://doi.org/10.3390/polym16202951 - 21 Oct 2024

Viewed by 1127

Abstract

Eugenol-containing oligoorganosilsesquioxanes were synthesized by the method of hydrolytic polycondensation in an active medium under various reaction conditions. The obtained products were characterized by ²⁹Si NMR spectroscopy and MALDI-TOF spectrometry. It was shown that factors such as the reaction temperature, polycondensation duration, [...] Read more.

Eugenol-containing oligoorganosilsesquioxanes were synthesized by the method of hydrolytic polycondensation in an active medium under various reaction conditions. The obtained products were characterized by ²⁹Si NMR spectroscopy and MALDI-TOF spectrometry. It was shown that factors such as the reaction temperature, polycondensation duration, and molar ratio between the initial alkoxysilane monomer and acetic acid may affect the molecular weight characteristics and molecular structure of the formed oligomer, like the content of stressed cyclic units (T₃, DTT, TDT) and unstressed silsesquioxane units T_nD_m. In particular, an increase in the ratio of the initial reagents led to an increase in the content of silsesquioxane T_n fragments from 28.2%_mol to 41.7%_mol, while the number of strained cyclic structures decreased by more than two times. An increase in the synthesis time is of no particular practical value since it was found that the composition of the oligomers synthesized for 6 h and 12 h was practically identical, as was that of the oligomers synthesized for 24 h and 48 h. A noticeable transition in the oligomer composition was observed only when the synthesis time was changed from 12 h to 24 h. Finally, it was shown that the choice of synthesis temperature had the strongest effect on the oligomer composition. The oligomer synthesized at 95 °C contained the highest amount of silsesquioxane T_n fragments, >77%_mol, while a T_n fragment content of ~42%_mol was observed during the synthesis at 117 °C. It was shown that silsesquioxanes are devitrified at room temperature (T_g from −6.4 to −10.6 °C), and their thermal stability in an inert atmosphere is 300 °C. The synthesized oligomers, due to the presence of hydroxyl-containing eugenol units, may be promising binders and additives for functional epoxy–silicone paints and coating materials. Full article

(This article belongs to the Section Polymer Chemistry)

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22 pages, 4087 KiB

Open AccessArticle

Polymer-Modified Fertilizers for Mitigating Strawberry Root Burn

by Ibragim Bamatov, Kirill Perevertin and Nadezda Vasilyeva

Polymers 2024, 16(20), 2950; https://doi.org/10.3390/polym16202950 - 21 Oct 2024

Viewed by 874

Abstract

Polymer-modified fertilizers (PMFs) with prolonged nutrient release present a promising solution to address the challenges associated with conventional fertilization practices, particularly for sensitive crops such as strawberries. This study investigates the effectiveness of biodegradable PMFs in maintaining nutrient availability at optimal levels while [...] Read more.

Polymer-modified fertilizers (PMFs) with prolonged nutrient release present a promising solution to address the challenges associated with conventional fertilization practices, particularly for sensitive crops such as strawberries. This study investigates the effectiveness of biodegradable PMFs in maintaining nutrient availability at optimal levels while minimizing root burn and nutrient losses. In a factorial field experiment, we obtaineda total of 3780 sets of parallel measured time series for soil EC, moisture, and temperature as well as two sets of harvest data to evaluate the impact of varying concentrations of polyvinyl alcohol (PVA) on the nutrient release rates from complex NPK fertilizer and monoammonium phosphate. Results indicate that polymer modifications significantly slow down nutrient release, leading to optimal salt levels and maximizing yield while remaining low enough to prevent the risk of root burn (EC of soil solution below 1 mS/cm). Consequently, the application of PMFs enhances strawberry yield surplus (on average 2.8 times in the second harvest) by ensuring a steady supply of nutrients throughout the growing season without inducing stress, which reduces the yield by nearly half. This research provides valuable insights into the development of more effective fertilization strategies for strawberry cultivation and other sensitive crops using PMFs. Full article

(This article belongs to the Section Polymer Applications)

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16 pages, 13082 KiB

Open AccessArticle

Chemical and Resistive Switching Properties of Elaeodendron buchananii Extract–Carboxymethyl Cellulose Composite: A Potential Active Layer for Biodegradable Memory Devices

by Zolile Wiseman Dlamini, Sreedevi Vallabhapurapu, Jennifer Nambooze, Anke Wilhelm, Elizabeth Erasmus, Refilwe Mogale, Marthinus Rudi Swart, Vijaya Srinivasu Vallabhapurapu, Bheki Mamba, Wendy Setlalentoa, Tebogo Sfiso Mahule, Vanessa de Oliveira Arnoldi Pellegrini, Shaun Cronje and Igor Polikarpov

Polymers 2024, 16(20), 2949; https://doi.org/10.3390/polym16202949 - 21 Oct 2024

Viewed by 846

Abstract

Biodegradable electronic devices play a crucial role in addressing the escalating issue of electronic waste accumulation, which poses significant environmental threats. In this study, we explore the utilization of a methanol-based extract of the Elaeodendron buchananii plant blended with a carboxymethyl cellulose biopolymer [...] Read more.

Biodegradable electronic devices play a crucial role in addressing the escalating issue of electronic waste accumulation, which poses significant environmental threats. In this study, we explore the utilization of a methanol-based extract of the Elaeodendron buchananii plant blended with a carboxymethyl cellulose biopolymer to produce a biodegradable and environmentally friendly functional material for a resistive switching memory system using silver and tungsten electrodes. Our analyses revealed that these two materials chemically interact to generate a perfect composite with near semiconducting optical bandgap (4.01 eV). The resultant device exhibits O-type memory behavior, with a low ON/OFF ratio, strong endurance (≥

10^{3}

write/erase cycles), and satisfactory (≥

10^{3}

) data retention. Furthermore, through a comprehensive transport mechanism analysis, we observed the formation of traps in the composite that significantly improved conduction in the device. In addition, we established that altering the voltage amplitude modifies the concentration of traps, leading to voltage amplitude-driven multiple resistance states. Overall, our findings underscore the potential of functionalizing polymers that can be functionalized by incorporating plant extracts, resulting in biodegradable and nonvolatile memory devices with promising performance metrics. Full article

(This article belongs to the Special Issue Natural-Based Biodegradable Polymeric Materials II)

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10 pages, 868 KiB

Open AccessArticle

Effect of Multivitamins on the Color Stability of Dental Materials Used in Pediatric Dentistry: An In Vitro Study

by María Arregui, Josefina del Pilar Contreras Arellano, Ana Veloso Durán and Francisco Guinot Jimeno

Polymers 2024, 16(20), 2948; https://doi.org/10.3390/polym16202948 - 21 Oct 2024

Viewed by 674

Abstract

The longevity and acceptance of aesthetic dental materials are directly proportional to color stability. The aim of this study was to analyze the relationship between the use of multivitamins and the color stability of dental restorative materials. A total of 45 discs of [...] Read more.

The longevity and acceptance of aesthetic dental materials are directly proportional to color stability. The aim of this study was to analyze the relationship between the use of multivitamins and the color stability of dental restorative materials. A total of 45 discs of nanohybrid composite, 45 of Reinforced Glass Ionomer (RGI), and 45 of Giomer were prepared. Subsequently, the samples were randomly divided into three solution groups (n = 15): Group 1—Sambucol Pediatric Syrup, Group 2—Hidropolivital Baby Drops, and Group 3—artificial saliva, which is preparation for patients with xerostomia. For 28 days, the specimens were immersed in 10 mL of each multivitamin for two minutes every 24 h. Color measurements were repeated on days 7, 14, 21, and 28. Statistical analysis was performed using the Jamovi software version 2.2.5, employing the Shapiro–Wilk test for normality and the Kruskal–Wallis test for non-parametric data. When comparing materials, statistically significant differences (p < 0.001) were observed between RGI and Giomer, and RGI and composite, but not between Giomer and composite (p = 0.716). The highest change was observed in RGI–Hidropolivital ΔE₀₀ = 3.27 (2.38–4.59) and the least in composite–Sambucol ΔE₀₀ = 0.72 (0.30–1.18). In conclusion, the exposure time and the multivitamin influence the color change of restorative materials. Full article

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

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27 pages, 9475 KiB

Open AccessReview

Phenylethynyl-Terminated Imide Oligomer-Based Thermoset Resins

by Minju Kim, Kiyeong Kim, Joon Hyuk Lee, Eunkyung Jeon, Jungkun Song, Jaeho Choi, Hyeonuk Yeo and Ki-Ho Nam

Polymers 2024, 16(20), 2947; https://doi.org/10.3390/polym16202947 - 21 Oct 2024

Viewed by 833

Abstract

Phenylethynyl-terminated imide (PETI) oligomers are highly valued for their diverse applications in films, moldings, adhesives, and composite material matrices. PETIs can be synthesized at varying molecular weights, enabling the fine-tuning of their properties to meet specific application requirements. Upon thermal curing, these oligomers [...] Read more.

Phenylethynyl-terminated imide (PETI) oligomers are highly valued for their diverse applications in films, moldings, adhesives, and composite material matrices. PETIs can be synthesized at varying molecular weights, enabling the fine-tuning of their properties to meet specific application requirements. Upon thermal curing, these oligomers form super-rigid network structures that enhance solvent resistance, increase glass-transition temperatures, and improve elastic moduli. Their low molecular weights and melt viscosities further facilitate processing, making them particularly suitable for composites and adhesive bonding. This review examines recent advancements in developing ultra-high-temperature PETIs, focusing on their structure–processing–properties relationships. It begins with an overview of the historical background and key physicochemical characteristics of PETIs, followed by a detailed discussion of PETIs synthesized from monomers featuring noncoplanar configurations (including kink and cardo structures), fluorinated groups, flexible linkages, and liquid crystalline mesogenic structures. The review concludes by addressing current challenges in this research field and exploring potential future directions. Full article

(This article belongs to the Special Issue Advanced Polymer Structures: Chemistry for Engineering Applications)

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14 pages, 5112 KiB

Open AccessArticle

Preparation of Montmorillonite–Melamine Cyanurate and Inhibition of the Emission of Phosphine from PA6/Aluminum Hypophosphate

by Lin Wang, Yuyang Li, Chenyang Yan, Xiangmei Li, Jiyu He and Rongjie Yang

Polymers 2024, 16(20), 2946; https://doi.org/10.3390/polym16202946 - 21 Oct 2024

Viewed by 669

Abstract

In order to mitigate the release of toxic phosphine from aluminum hypophosphite in twin-screw processing, montmorillonite–melamine cyanurate was prepared by three methods: (1) mechanical intercalation, (2) water intercalation and (3) in situ intercalation. The sheet spacing of montmorillonite was increased from 1.140 nm [...] Read more.

In order to mitigate the release of toxic phosphine from aluminum hypophosphite in twin-screw processing, montmorillonite–melamine cyanurate was prepared by three methods: (1) mechanical intercalation, (2) water intercalation and (3) in situ intercalation. The sheet spacing of montmorillonite was increased from 1.140 nm to 1.141 nm, 1.208 nm and 1.217 nm for these three methods, respectively, and scanning electron microscope (SEM) and transmission electron microscopy (TEM) proved that melamine cyanurate was successfully inserted into the montmorillonite sheets. The montmorillonite–melamine cyanurate from in situ intercalation can best inhibit the release of PH₃ from aluminum hypophosphite, and the peaks of phosphine, mean values of phosphine and integral of phosphine were reduced by 81.9%, 72.1% and 72.2%, respectively. The mode of action of montmorillonite–melamine cyanuric inhibition of the emission of phosphine from aluminum hypophosphite can be attributed to the physical absorption of montmorillonite and the chemical bonding of melamine cyanurate. In addition, in situ intercalation can slightly improve flame retardancy, attributed to incomplete exfoliation of montmorillonite sheets. Full article

(This article belongs to the Special Issue Flame Retardant Polymers: 2024 National Flame Retardant Academic Annual Conference)

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19 pages, 20663 KiB

Open AccessArticle

Corrosion Properties of the Composite Coatings Formed on PEO Pretreated AlMg3 Aluminum Alloy by Dip-Coating in Polyvinylidene Fluoride-Polytetrafluoroethylene Suspension

by Vladimir S. Egorkin, Igor E. Vyaliy, Andrey S. Gnedenkov, Ulyana V. Kharchenko, Sergey L. Sinebryukhov and Sergey V. Gnedenkov

Polymers 2024, 16(20), 2945; https://doi.org/10.3390/polym16202945 - 21 Oct 2024

Viewed by 738

Abstract

This paper presents the results of an evaluation of corrosion properties of PEO pretreated AlMg3 aluminum alloy samples with polymer coatings obtained by dip-coating in a suspension of superdispersed polytetrafluoroethylene (SPTFE) in a solution of polyvinylidene fluoride (PVDF) in N-methyl-2-pyrrolidone at different PVDF:SPTFE [...] Read more.

This paper presents the results of an evaluation of corrosion properties of PEO pretreated AlMg3 aluminum alloy samples with polymer coatings obtained by dip-coating in a suspension of superdispersed polytetrafluoroethylene (SPTFE) in a solution of polyvinylidene fluoride (PVDF) in N-methyl-2-pyrrolidone at different PVDF:SPTFE ratios (1:1, 1:3, 1:5, and 1:10). The electrochemical tests showed that samples with a coating formed at a ratio of PVDF to SPTFE of 1:5 possessed the best corrosion properties. The corrosion current density of these samples was more than five orders of magnitude lower than this parameter for bare aluminum alloy. During the 40-day salt spray test (SST) for samples prepared in a suspension at a PVDF:SPTFE ratio of 1:1–1:5, the formation of any pittings or defects was not detected. The PVDF:SPTFE 1:5 sample demonstrated, as a result of the 40-day SST, an increase in corrosion current density of less than an order of magnitude. The evolution of the protective properties of the studied samples was assessed by a two-year field atmospheric corrosion test on the coast of the Sea of Japan. It was revealed that the samples with the PVDF:SPTFE 1:5 coating had electrochemical parameters that remained consistently high throughout the one year of exposure. After this period, the polymer layer was destroyed, which led to a deterioration in the protective characteristics of the coatings. Full article

(This article belongs to the Special Issue Polymers and Their Composites Applied in Extreme Environments)

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21 pages, 3836 KiB

Open AccessArticle

Physical, Mechanical, and Flammability Properties of Wood–Plastic Composites (WPC) Containing Beech-Wood Flour and Flame-Retardant Additives

by Yalçın Boztoprak

Polymers 2024, 16(20), 2944; https://doi.org/10.3390/polym16202944 - 21 Oct 2024

Viewed by 924

Abstract

This study aims to develop a recyclable, economical, and flame-retardant composite material using polypropylene, beech flour, tetrabromobisphenol A bis (TBBPA), and antimony trioxide (ATO). Flame-retardant additives (TBBPA and ATO) were initially added into polypropylene at different rates, and masterbatch (MB) samples were produced [...] Read more.

This study aims to develop a recyclable, economical, and flame-retardant composite material using polypropylene, beech flour, tetrabromobisphenol A bis (TBBPA), and antimony trioxide (ATO). Flame-retardant additives (TBBPA and ATO) were initially added into polypropylene at different rates, and masterbatch (MB) samples were produced by the extrusion method. Subsequently, different percentages of wood flour (10%, 15%, 20%, 25%, and 30%) along with 60% MB were added to the polypropylene to create wood–polymer composites (WPC) using the injection method. The TBBPA, ATO, and wood flour were introduced through side-feeding hoppers during injection to ensure a homogeneous distribution within the WPC. Physical, thermal, and mechanical tests were conducted on the WPC samples. Additionally, TGA, FTIR, and SEM analyses were performed. The results indicated that the optimal ratios for TBBPA and ATO additives were 20% and 10%, respectively. It was observed that increasing the wood flour content in the WPC samples led to enhanced density, water absorption, hardness, impact, and abrasion resistance. Conversely, MFI, bending strength, and tensile strength decreased with higher wood flour content. It was observed that WPC samples exhibited flame resistance up to 725 °C. The produced WPC materials can be used in flooring applications, interior furniture, decorative wall panels, and aesthetic structural elements due to their fire behavior, good mechanical properties, low water-absorption rates, and aesthetic appearance. Full article

(This article belongs to the Special Issue Thermal Behavior of Polymer Materials II)

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25 pages, 2910 KiB

Open AccessReview

Role of Sterilization on In Situ Gel-Forming Polymer Stability

by Elena O. Bakhrushina, Alina M. Afonina, Iosif B. Mikhel, Natalia B. Demina, Olga N. Plakhotnaya, Anastasiya V. Belyatskaya, Ivan I. Krasnyuk, Jr. and Ivan I. Krasnyuk

Polymers 2024, 16(20), 2943; https://doi.org/10.3390/polym16202943 - 21 Oct 2024

Viewed by 1359

Abstract

In recent years, stimulus-sensitive drug delivery systems have been developed for parenteral administration as a depot system. In situ systems incorporate smart polymers that undergo a phase transition at the site of administration. All parenteral and ocular dosage forms must meet sterility requirements. [...] Read more.

In recent years, stimulus-sensitive drug delivery systems have been developed for parenteral administration as a depot system. In situ systems incorporate smart polymers that undergo a phase transition at the site of administration. All parenteral and ocular dosage forms must meet sterility requirements. Careful selection of the sterilization method is required for any type of stimuli-sensitive system. Current sterilization methods are capable of altering the conformation of polymers or APIs to a certain extent, ultimately causing the loss of pharmacological and technological properties of the drug. Unfortunately, the issues of risk assessment and resolution regarding the sterilization of stimuli-sensitive systems, along with ways to stabilize such compositions, are insufficiently described in the scientific literature to date. This review provides recommendations and approaches, formulated on the basis of published experimental data, that allow the effective management of risks arising during the development of in situ systems requiring sterility. Full article

(This article belongs to the Special Issue Polymer Hydrogels: Synthesis, Characterization and Applications)

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15 pages, 5900 KiB

Open AccessArticle

Preparation and Performance of PBAT/PLA/CaCO₃ Composites via Solid-State Shear Milling Technology

by Xuehua Jia, Qilin Wen, Yanjun Sun, Yinghong Chen, Dali Gao, Yue Ru and Ning Chen

Polymers 2024, 16(20), 2942; https://doi.org/10.3390/polym16202942 - 20 Oct 2024

Viewed by 1145

Abstract

Replacing traditional disposable, non-biodegradable plastic packaging with biodegradable plastic packaging is one of the key approaches to address the issue of “white pollution”. PBAT/PLA/inorganic filler composites are widely utilized as a biodegradable material, commonly employed in the field of packaging films. However, the [...] Read more.

Replacing traditional disposable, non-biodegradable plastic packaging with biodegradable plastic packaging is one of the key approaches to address the issue of “white pollution”. PBAT/PLA/inorganic filler composites are widely utilized as a biodegradable material, commonly employed in the field of packaging films. However, the poor dispersion of inorganic fillers in the polymer matrix and the limited compatibility between PBAT and PLA have led to inferior mechanical properties and elevated costs. In this work, we propose a simple and effective strategy to improve the dispersion of nano-CaCO₃ in a PBAT/PLA matrix through solid-state shear- milling (S³M) technology, combined with mechanochemical modification and in situ compatibilization to enhance the compatibility between PBAT and PLA. The impact of varying milling conditions on the structure and performance of the PBAT/PLA/CaCO₃ composites was investigated. During the milling process, PBAT and PLA undergo partial molecular chain fragmentation, generating more active functional groups. In the presence of the chain extender ADR during melt blending, more branched PBAT-g-PLA is formed, thereby enhancing matrix compatibility. The results indicate that the choice of milling materials significantly affects the structure and properties of the composite. The film obtained by milling only PBAT and CaCO₃ exhibited the best performance, with its longitudinal tensile strength and fracture elongation reaching 22 MPa and 437%, respectively. This film holds great potential for application in the field of green packaging. Full article

(This article belongs to the Special Issue Biodegradable Polymer Composites: Fabrication and Applications II)

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13 pages, 3055 KiB

Open AccessArticle

Enhanced Photovoltaic Performance of Poly(3,4-Ethylenedioxythiophene)Poly(N-Alkylcarbazole) Copolymer-Based Counter Electrode in Dye-Sensitized Solar Cells

by Sherif Dei Bukari, Aliya Yelshibay, Bakhytzhan Baptayev and Mannix P. Balanay

Polymers 2024, 16(20), 2941; https://doi.org/10.3390/polym16202941 - 20 Oct 2024

Viewed by 704

Abstract

Conducting polymers are emerging as promising alternatives to rare and expensive platinum for counter electrodes in dye-sensitized solar cells; due to their ease of synthesis, they can be chemically tuned and are suitable for roll-to-roll production. Among these, poly (3,4-ethylenedioxythiophene) (PEDOT)-based counter electrodes [...] Read more.

Conducting polymers are emerging as promising alternatives to rare and expensive platinum for counter electrodes in dye-sensitized solar cells; due to their ease of synthesis, they can be chemically tuned and are suitable for roll-to-roll production. Among these, poly (3,4-ethylenedioxythiophene) (PEDOT)-based counter electrodes have shown leading photovoltaic performance. However, certain conductivity issues remain that affect the effectiveness of these counter electrodes. In this study, we present an electropolymerized PEDOT and poly(N-alkylated-carbazole) copolymer as an efficient electrocatalyst for the reduction in

I_{3}^{-}

in dye-sensitized solar cells. Copolymerization with N-alkylated carbazoles significantly increases the conductivity of the polymer film and facilitates rapid charge transport at the interface between the polymer electrode and the electrolyte. The length of the alkyl substituents also plays a crucial role in this improvement. Electrochemical analysis showed a reduction in charge transport resistance from 3.31 Ω·cm² for PEDOT to 2.26 Ω·cm² for the PEDOT:poly(N-octylcarbazole) copolymer, which is almost half the resistance of a platinum-based counter electrode (4.12 Ω·cm²). Photovoltaic measurements showed that the solar cell with the PEDOT:poly(N-octylcarbazole) counter electrode achieved an efficiency of 8.88%, outperforming both PEDOT (7.90%) and platinum-based devices (7.57%). Full article

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

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14 pages, 2973 KiB

Open AccessArticle

Biodegradation Study of Food Packaging Materials: Assessment of the Impact of the Use of Different Biopolymers and Soil Characteristics

by Amanda Martinello Neres de Souza, Luisa Bataglin Avila, Camila Ramão Contessa, Alaor Valério Filho, Gabriela Silveira de Rosa and Caroline Costa Moraes

Polymers 2024, 16(20), 2940; https://doi.org/10.3390/polym16202940 - 20 Oct 2024

Viewed by 1012

Abstract

In this article, the relationship between the properties of different membranes (agar, chitosan, and agar + chitosan) and biodegradability in natural and sterilized soil was investigated. The membranes under investigation exhibited variations in the biodegradation process, a phenomenon closely linked to both the [...] Read more.

In this article, the relationship between the properties of different membranes (agar, chitosan, and agar + chitosan) and biodegradability in natural and sterilized soil was investigated. The membranes under investigation exhibited variations in the biodegradation process, a phenomenon closely linked to both the soil microbiota composition and their water affinity. Higher solubility in water and greater swelling tendencies correlated with shorter initiation times for the biodegradation process in soil. Overall, all tested membranes began biodegradation within 14 days, as assessed through thickness and morphological analysis parameters, demonstrating a superior degradation rate compared to low-density polyethylene films. Full article

(This article belongs to the Special Issue Degradation and Stabilization of Polymer Materials 2nd Edition)

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13 pages, 3877 KiB

Open AccessArticle

Covalent Pectin/Arabinoxylan Hydrogels: Rheological and Microstructural Characterization

by Claudia Lara-Espinoza, Agustín Rascón-Chu, Valérie Micard, Carole Antoine-Assor, Elizabeth Carvajal-Millan, Rosalba Troncoso-Rojas, Federico Ohlmaier-Delgadillo and Francisco Brown-Bojorquez

Polymers 2024, 16(20), 2939; https://doi.org/10.3390/polym16202939 - 20 Oct 2024

Viewed by 866

Abstract

This research aimed to evaluate the gelation process of ferulated pectin (FP) and ferulated arabinoxylan (AXF) in a new mixed hydrogel and determine its microstructural characteristics. FP from sugar beet (Beta vulgaris) and arabinoxylan from maize (Zea mays) bran [...] Read more.

This research aimed to evaluate the gelation process of ferulated pectin (FP) and ferulated arabinoxylan (AXF) in a new mixed hydrogel and determine its microstructural characteristics. FP from sugar beet (Beta vulgaris) and arabinoxylan from maize (Zea mays) bran were gelled via oxidative coupling using laccase as a crosslinking agent. The dynamic oscillatory rheology of the mixed hydrogel revealed a maximum storage modulus of 768 Pa after 60 min. The scanning electron microscopy images showed that mixed hydrogels possess a microstructure of imperfect honeycomb. The ferulic acid content of the mixed hydrogel was 3.73 mg/g, and ferulic acid dimer 8-5′ was the most abundant. The presence of a trimer was also detected. This study reports the distribution and concentration of ferulic acid dimers, and the rheological and microstructural properties of a mixed hydrogel based on FP and AXF, which has promising features as a new covalent biopolymeric material. Full article

(This article belongs to the Special Issue State-of-the-Art Polymer Science and Technology in Mexico)

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20 pages, 2087 KiB

Open AccessReview

Cutting-Edge Applications of Cellulose-Based Membranes in Drug and Organic Contaminant Removal: Recent Advances and Innovations

by Bandana Padhan, Wanki Ryoo, Madhumita Patel, Jatis Kumar Dash and Rajkumar Patel

Polymers 2024, 16(20), 2938; https://doi.org/10.3390/polym16202938 - 20 Oct 2024

Viewed by 1293

Abstract

The increasing environmental challenges caused by pharmaceutical waste, especially antibiotics and contaminants, necessitate sustainable solutions. Cellulose-based membranes are considered advanced tools and show great potential as effective materials for the removal of drugs and organic contaminants. This review introduces an environmentally friendly composite [...] Read more.

The increasing environmental challenges caused by pharmaceutical waste, especially antibiotics and contaminants, necessitate sustainable solutions. Cellulose-based membranes are considered advanced tools and show great potential as effective materials for the removal of drugs and organic contaminants. This review introduces an environmentally friendly composite membrane for the elimination of antibiotics and dye contaminants from water and food, without the use of toxic additives. The potential of cellulose-based membranes in reducing the impact on water quality and promoting environmental sustainability is emphasized. Additionally, the benefits of using biobased cellulose membranes in membrane biological reactors for the removal of antibiotics from pharmaceutical waste and milk are explored, presenting an innovative approach to achieving a circular economy. This review provides recent and comprehensive insights into membrane bioreactor technology, making it a valuable resource for researchers seeking efficient methods to break down antibiotics in industrial wastewater, particularly in the pharmaceutical and dairy industries. Full article

(This article belongs to the Special Issue Biobased Polymer Membranes for Energy and Environmental Applications)

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16 pages, 6089 KiB

Open AccessArticle

Performance of Combined Woven Roving and Mat Glass-Fiber Reinforced Polymer Composites Under Absorption Tower Lifting Loads

by Víctor Tuninetti and Matías Mariqueo

Polymers 2024, 16(20), 2937; https://doi.org/10.3390/polym16202937 - 19 Oct 2024

Cited by 1 | Viewed by 807

Abstract

This study investigates the structural integrity of a glass-fiber reinforced polymer absorption tower during lifting operations, evaluating factors of safety and stress distribution for both horizontal and vertical scenarios. A key focus is the comparative analysis of surface and volumetric meshing techniques in [...] Read more.

This study investigates the structural integrity of a glass-fiber reinforced polymer absorption tower during lifting operations, evaluating factors of safety and stress distribution for both horizontal and vertical scenarios. A key focus is the comparative analysis of surface and volumetric meshing techniques in finite element modeling. Results demonstrate that surface models achieve comparable stress predictions to computationally intensive volumetric models, significantly reducing computational demands without compromising accuracy. For instance, stress at the flange edge with holes was accurately captured using a surface model with 5675 elements (12.79 MPa), yielding similar results to a volumetric model requiring over 94,000 elements (13.37 MPa). Similar computational efficiency and agreement between modeling approaches were observed at the packing support ring-shell joint. Finite element analysis employing Hashin’s failure criterion, informed by industry-standard experimental data, revealed safety factors ranging from 1.9 to 2.5 for horizontal lifting and four for vertical lifting. These safety factors indicate sufficient margins for safe operation. While these findings support the feasibility of both lifting methods, further investigation is recommended to address the lower safety factors observed in specific horizontal lifting scenarios. A comprehensive assessment incorporating industry standards, dynamic load effects, and potential mitigation strategies is crucial to ensure the long-term structural integrity of the GFRP absorption tower. Full article

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

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16 pages, 1159 KiB

Open AccessArticle

AI-Driven Insight into Polycarbonate Synthesis from CO₂: Database Construction and Beyond

by Aritz D. Martinez, Adriana Navajas-Guerrero, Harbil Bediaga-Bañeres, Julia Sánchez-Bodón, Pablo Ortiz, Jose Luis Vilas-Vilela, Isabel Moreno-Benitez and Sergio Gil-Lopez

Polymers 2024, 16(20), 2936; https://doi.org/10.3390/polym16202936 - 19 Oct 2024

Cited by 1 | Viewed by 1023

Abstract

Recent advancements in materials science have garnered significant attention within the research community. Over the past decade, substantial efforts have been directed towards the exploration of innovative methodologies for developing new materials. These efforts encompass enhancements to existing products or processes and the [...] Read more.

Recent advancements in materials science have garnered significant attention within the research community. Over the past decade, substantial efforts have been directed towards the exploration of innovative methodologies for developing new materials. These efforts encompass enhancements to existing products or processes and the design of novel materials. Of particular significance is the synthesis of specific polymers through the copolymerization of epoxides with CO₂. However, several uncertainties emerge in this chemical process, including challenges associated with successful polymerization and the properties of the resulting materials. These uncertainties render the design of new polymers a trial-and-error endeavor, often resulting in failed outcomes that entail significant financial, human resource, and time investments due to unsuccessful experimentation. Artificial Intelligence (AI) emerges as a promising technology to mitigate these drawbacks during the experimental phase. Nonetheless, the availability of high-quality data remains crucial, posing particular challenges in the context of polymeric materials, mainly because of the stochastic nature of polymers, which impedes their homogeneous representation, and the variation in their properties based on their processing. In this study, the first dataset linking the structure of the epoxy comonomer, the catalyst employed, and the experimental conditions of polymerization to the reaction’s success is described. A novel analytical pipeline based on ML to effectively exploit the constructed database is introduced. The initial results underscore the importance of addressing the dimensionality problem. The outcomes derived from the proposed analytical pipeline, which infer the molecular weight, polydispersity index, and conversion rate, demonstrate promising adjustment values for all target parameters. The best results are measured in terms of the (Determination Coefficient)

R^{2}

between real and predicted values for all three target magnitudes. The best proposed solution provides a

R^{2}

equal to

0.79

,

0.86

, and

0.93

for the molecular weight, polydispersity index, and conversion rate, respectively. The proposed analytical pipeline is automatized (including AutoML techniques for ML models hyperparameter tuning), allowing easy scalability as the database grows, laying the foundation for future research. Full article

(This article belongs to the Section Polymer Chemistry)

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16 pages, 3398 KiB

Open AccessArticle

Efficient Extraction and Analysis of Wheat Straw Lignin by Response Surface Methodology

by Yongke Wang, Xiao-Feng Sun, Jiayi Chen, Sihai Hu and Ran Sun

Polymers 2024, 16(20), 2935; https://doi.org/10.3390/polym16202935 - 19 Oct 2024

Viewed by 711

Abstract

To enhance the high-value utilization of straw waste and achieve efficient lignin extraction, wheat straw was selected as the feedstock for investigating the effects of reaction temperature, reaction time, solid–liquid ratio, and formic acid concentration on lignin yield using a formic acid/acetic acid [...] Read more.

To enhance the high-value utilization of straw waste and achieve efficient lignin extraction, wheat straw was selected as the feedstock for investigating the effects of reaction temperature, reaction time, solid–liquid ratio, and formic acid concentration on lignin yield using a formic acid/acetic acid solvent system. A single-factor experimental design was initially employed, followed by optimization using the response surface methodology. Additionally, a kinetic model was developed to describe lignin extraction kinetics in the formic acid/acetic acid system. The structural characteristics and thermal stability of the extracted lignin were analyzed via FTIR, UV spectroscopy, and TGA. The findings indicate that increasing reaction temperature, reaction time, solid–liquid ratio, and formic acid content all significantly enhanced lignin extraction yield from wheat straw, with the primary influencing factors being reaction temperature > solid–liquid ratio > reaction time > formic acid content. The optimal extraction conditions were identified at a reaction temperature of 90 °C, a reaction time of 3.5 h, a solid–liquid ratio of 1:16.5, and a formic acid content of 86.2 wt.%, yielding a lignin content of 79.83%. The analytical results demonstrated that the extracted lignin preserved the structural integrity of the original lignin and exhibited good thermal stability. Full article

(This article belongs to the Special Issue Advances in Natural Polymers and Active Compounds: Extraction Methods and Applications)

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20 pages, 5742 KiB

Open AccessArticle

Effect of Material Extrusion Process Parameters to Enhance Water Vapour Adsorption Capacity of PLA/Wood Composite Printed Parts

by José A. Martínez-Sánchez, Pablo E. Romero, Francisco Comino, Esther Molero and Manuel Ruiz de Adana

Polymers 2024, 16(20), 2934; https://doi.org/10.3390/polym16202934 - 19 Oct 2024

Viewed by 769

Abstract

This study aims to optimise the water vapour adsorption capacity of polylactic acid (PLA) and wood composite materials for application in dehumidification systems through material extrusion additive manufacturing. By analysing key process parameters, including nozzle diameter, layer height, and temperature, the research evaluates [...] Read more.

This study aims to optimise the water vapour adsorption capacity of polylactic acid (PLA) and wood composite materials for application in dehumidification systems through material extrusion additive manufacturing. By analysing key process parameters, including nozzle diameter, layer height, and temperature, the research evaluates their impact on the porosity and adsorption performance of the composite. Additionally, the influence of different infill densities on moisture absorption is investigated. The results show that increasing wood content significantly enhances water vapour adsorption, with nozzle diameter and layer height identified as the most critical factors. These findings confirm that composite materials, especially those with higher wood content and optimised printing parameters, offer promising solutions for improving dehumidification efficiency. Potential applications include heating, ventilation, and air conditioning systems or environmental control. This work introduces an innovative approach to using composite materials in desiccant-based dehumidification and provides a solid foundation for future research. Further studies could focus on optimising material formulations and scaling this approach for broader industrial applications. Full article

(This article belongs to the Special Issue 3D Printing of Polymer Composites)

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13 pages, 3547 KiB

Open AccessArticle

Application of Biomass-Based Triboelectrification for Particulate Matter Removal

by Hui Chen, Yabo Wu, Zheng Ma, Yefei Wu, Zhaodong Ding and Lianghong Yin

Polymers 2024, 16(20), 2933; https://doi.org/10.3390/polym16202933 - 18 Oct 2024

Viewed by 1115

Abstract

Electrostatic fields are crucial for achieving the highly efficient filtration of airborne pollutants. However, the dissipation of static charges over time, especially under humid conditions, limits their practical application. In this study, we present a self-charging air filter (SAF) powered by a triboelectric [...] Read more.

Electrostatic fields are crucial for achieving the highly efficient filtration of airborne pollutants. However, the dissipation of static charges over time, especially under humid conditions, limits their practical application. In this study, we present a self-charging air filter (SAF) powered by a triboelectric nanogenerator (TENG). This SAF is integrated into a commercial mask, termed SAFM, which can effectively capture and degrade airborne pollutants without requiring an external power source. By leveraging the triboelectric effect during breathing, the TENG within the SAFM continuously replenishes static charges, maintaining the triboelectric field. The system employs a cellulose aerogel/Ti₃C₂T_x composite as the electron donor and an esterified cellulose-based electrospun nanofiber as the electron acceptor. Remarkably, the triboelectric field significantly enhances filtration performance, with the SAF achieving up to 95.7% filtration efficiency for particulate matter as small as 0.3 μm. This work underscores the potential of TENG-powered triboelectric fields in the development of multifunctional, human-machine interactive facemasks. Full article

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

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17 pages, 1696 KiB

Open AccessArticle

Comparative Study of Polymer of Intrinsic Microporosity-Derivative Polymers in Pervaporation and Water Vapor Permeance Applications

by Esra Caliskan, Sergey Shishatskiy and Volkan Filiz

Polymers 2024, 16(20), 2932; https://doi.org/10.3390/polym16202932 - 18 Oct 2024

Viewed by 939

Abstract

This study assesses the gas and water vapor permeance of PIM-derivative thin-film composite (TFC) membranes using pervaporation and “pressure increase” methods, and provides a comparative view of “time lag” measurements of thick films obtained from our previous work. In this study, TFC membranes [...] Read more.

This study assesses the gas and water vapor permeance of PIM-derivative thin-film composite (TFC) membranes using pervaporation and “pressure increase” methods, and provides a comparative view of “time lag” measurements of thick films obtained from our previous work. In this study, TFC membranes were prepared using PIM-1 and homopolymers that were modified with different side groups to explore their effects on gas and water vapor transport. Rigid and bulky aliphatic groups were used to increase the polymer’s free volume and were evaluated for their impact on both gas and water transport. Aromatic side groups were specifically employed to assess water affinity. The permeance of CO₂, H₂, CH₄ and water vapor through these membranes was analyzed using the ‘pressure increase’ method to determine the modifications’ influence on transport efficiency and interaction with water molecules. Over a 20 h period, the aging and the permeance of the TFC membranes were analyzed using this method. In parallel, pervaporation experiments were conducted on samples taken independently from the same membrane roll to assess water flux, with particular attention paid to the liquid form on the feed side. The significantly higher water vapor transport rates observed in pervaporation experiments compared to those using the “pressure increase” method underline the efficiency of pervaporation. This efficiency suggests that membranes designed for pervaporation can serve as effective alternatives to conventional porous membranes used in distillation applications. Additionally, incorporating “time lag” results from a pioneering study into the comparison revealed that the trends observed in “time lag” and pervaporation results exhibited similar trends, whereas “pressure increase” data showed a different development. This discrepancy is attributed to the state of the polymer, which varies significantly depending on the operating conditions. Full article

(This article belongs to the Section Polymer Applications)

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11 pages, 1882 KiB

Open AccessArticle

Hot-Pressing Process of Flat-Pressed Wood–Polymer Composites: Theory and Experiment

by Pavlo Lyutyy, Pavlo Bekhta, Yurii Protsyk and Vladimír Gryc

Polymers 2024, 16(20), 2931; https://doi.org/10.3390/polym16202931 - 18 Oct 2024

Viewed by 645

Abstract

The objective of this research was to develop a mathematical model of the hot-pressing process for making flat-pressed wood–polymer composites (FPWPCs). This model was used to calculate and predict the temperature and time required for FPWPC pressing. The model’s performance was analysed using [...] Read more.

The objective of this research was to develop a mathematical model of the hot-pressing process for making flat-pressed wood–polymer composites (FPWPCs). This model was used to calculate and predict the temperature and time required for FPWPC pressing. The model’s performance was analysed using the experimental results of hot pressing FPWPCs. It was found that an increase in the content of wood particles led to a rapid increase in the pressing time. The model and experiment showed that the core temperature of the wood–polymer mat remained nearly constant for the first 20–30 s of the hot-pressing process. After this period, this temperature increased rapidly until it reached 100 °C, after which the rate of increase began to decelerate sharply. This transition was more distinct in FPWPCs with a high wood-particle content, while in those with a high thermoplastic-polymer content, it was smoother. Increasing the pressing temperature contributed to a reduction in the time required to heat the FPWPC, as confirmed by both experimental data and the modelling of the hot-pressing process. A decrease in the predicted density of the FPWPC resulted in a directly proportional increase in the time required to heat the mat. Validation of the mathematical model revealed a mean absolute percentage error (MAPE) of only 2.5%, confirming its high precision and reliability. The developed mathematical model exhibited a high degree of accuracy and can be used for further calculations of the time required for FPWPC pressing, considering variable parameters such as pressing temperature, wood–polymer ratio, mat thickness, and density. Full article

(This article belongs to the Special Issue New Challenges in Wood and Wood-Based Materials III)

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19 pages, 4206 KiB

Open AccessArticle

Alpha-Tocopherol-Infused Flexible Liposomal Nanocomposite Pressure-Sensitive Adhesive: Enhancing Skin Permeation of Retinaldehyde

by Kanokwan Singpanna, Puchapong Jiratananan, Santipharp Paiboonwasin, Nawinda Petcharawuttikrai, Prin Chaksmithanont, Chaiyakarn Pornpitchanarong and Prasopchai Patrojanasophon

Polymers 2024, 16(20), 2930; https://doi.org/10.3390/polym16202930 - 18 Oct 2024

Viewed by 761

Abstract

Retinaldehyde (RAL), or retinal, is a vitamin A derivative that is widely used for several skin conditions. However, it is light sensitive and has low water solubility, limiting its efficiency in transdermal delivery. This study developed a novel delivery system for retinal (RAL) [...] Read more.

Retinaldehyde (RAL), or retinal, is a vitamin A derivative that is widely used for several skin conditions. However, it is light sensitive and has low water solubility, limiting its efficiency in transdermal delivery. This study developed a novel delivery system for retinal (RAL) using flexible liposomes (FLPs) infused with α-tocopherol succinate (α-TS) to improve stability, and enhance skin permeability. The RAL-FLPs were embedded in pressure-sensitive adhesive (PSA) hydrogels, creating a delivery platform that supports prolonged skin residence and efficient permeation of RAL. The stability and skin permeation as well as human skin irritation and adhesion capabilities were assessed to determine the formulation’s safety and efficacy. Our findings suggested that the addition of α-TS could improve liposomal stability and RAL chemical stability. Moreover, the skin permeation and fluorescence microscopic-based studies suggested that the addition of α-TS could enhance skin permeability of RAL through hair follicles. The RAL-FLP was embedded in PSA hydrogels fabricated from 25% Gantrez^TM S-97 (GT) and 1% hyaluronic acid (Hya) with aluminum as a crosslinker. The PSA hydrogel exhibited desirable peeling and tacking strengths. The developed hydrogels also demonstrated greater skin deposition of RAL compared with its aqueous formulation. Additionally, the RAL-FLP-embedded PSA hydrogels showed no skin irritation and maintained better adhesion for up to 24 h compared to commercial patches. Hence, the developed hydrogels could serve as a beneficial platform for delivering RAL in treating skin conditions. Full article

(This article belongs to the Special Issue Biopolymer Composites for Biomedicine Applications)

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14 pages, 5376 KiB

Open AccessArticle

Highly Filled Waste Polyester Fiber/Low-Density Polyethylene Composites with a Better Fiber Length Retention Fabricated by a Two-Rotor Continuous Mixer

by Junrong Chen, Zhijie Pan, Songwei Yang, Changlin Cao, Weiming Zhou, Yidu Xie, Yilin Yang, Qingrong Qian and Qinghua Chen

Polymers 2024, 16(20), 2929; https://doi.org/10.3390/polym16202929 - 18 Oct 2024

Viewed by 515

Abstract

A key challenge in the utilization of waste polyester fibers (PET fibers) is the development of fiber-reinforced composites with high filler content and the improvement of fiber length retention. Herein, the effects of a two-rotor continuous mixer and a twin-screw extruder on the [...] Read more.

A key challenge in the utilization of waste polyester fibers (PET fibers) is the development of fiber-reinforced composites with high filler content and the improvement of fiber length retention. Herein, the effects of a two-rotor continuous mixer and a twin-screw extruder on the structure and properties of waste polyester fiber composites were evaluated. The results revealed that the mechanical properties of the composites were improved significantly with increasing fiber content, especially when processed using the twin-rotor continuous mixer. This mixer facilitated the formation of a robust fiber network structure, leading to substantial enhancements in tensile strength, flexural strength, and heat resistance. Specifically, compared to those processed by the twin-screw extruder, with 60 wt% fibers content, the tensile and flexural strengths of specimens processed by the twin-rotor continuous mixer increase by 21% and 13%, respectively. The average fiber length in specimens processed by the twin-rotor continuous mixer was 32% longer than that in specimens processed by the twin-screw extruder, attributable to the lower shear frequency and the higher tensile ratio of the former. This blending technique emerges as an effective strategy, contributing significantly to promoting the development and practical application of waste textile fiber-reinforced polymer composites. Full article

(This article belongs to the Special Issue Fiber Reinforced Polymers: Manufacture, Properties and Applications)

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17 pages, 1983 KiB

Open AccessArticle

Kinetics of Polyampholyte Dimerization: Influence of Charge Sequences

by Seowon Kim, Nam-Kyung Lee, Youngkyun Jung and Albert Johner

Polymers 2024, 16(20), 2928; https://doi.org/10.3390/polym16202928 - 18 Oct 2024

Viewed by 632

Abstract

Polyampholytes (PAs) exhibit complex behaviors in various environments influenced by their charge distribution. This study focuses on the kinetics of dimerization of PAs, aiming to elucidate the underlying mechanisms and clarify relevant characteristics of the charge sequence. We focus on PAs with non-zero [...] Read more.

Polyampholytes (PAs) exhibit complex behaviors in various environments influenced by their charge distribution. This study focuses on the kinetics of dimerization of PAs, aiming to elucidate the underlying mechanisms and clarify relevant characteristics of the charge sequence. We focus on PAs with non-zero net charges, employing molecular dynamics simulations and theoretical analyses to examine how charge sequences influence the rates of dimer formation and dissociation. Our findings reveal that the charge sequence of tails and the blockiness of the minority charge group markedly influence the kinetics of dimerization: large blockiness and tails with a high number of majority-type charges slow down the dissociation of dimers. Additionally, the presence of an extended (central) block of the majority charge promotes structural diversity. Within dimer states, blocks alternate between intra- and inter-chain contacts. The duration times in the dimer states are significantly longer than the typical dwell times of block inter-contacts, with a notable extension when multiple blocks are engaged. Intrinsically disordered proteins (IDPs) play crucial roles in cellular functions, primarily due to their ability to undergo rapid conformational changes and form transient complexes. These properties largely depend on the sequence of charged residues. We provide insights into the fundamental principles governing the structural and dynamical properties of polyampholytic IDP, emphasizing the importance of sequence-specific effects on both aggregation and dissociation. Full article

(This article belongs to the Special Issue Polymer Electrolyte: Recent Progress and Applications)

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21 pages, 16390 KiB

Open AccessArticle

Surface Quality Evaluation of 3D-Printed Carbon-Fiber-Reinforced PETG Polymer During Turning: Experimental Analysis, ANN Modeling and Optimization

by Anastasios Tzotzis, Dumitru Nedelcu, Simona-Nicoleta Mazurchevici and Panagiotis Kyratsis

Polymers 2024, 16(20), 2927; https://doi.org/10.3390/polym16202927 - 18 Oct 2024

Viewed by 1035

Abstract

This work presents an experimental analysis related to 3D-printed carbon-fiber-reinforced-polymer (CFRP) machining. A polyethylene-terephthalate-glycol (PETG)-based composite, reinforced with 20% carbon fibers, was selected as the test material. The aim of the study was to evaluate the influence of cutting conditions used in light [...] Read more.

This work presents an experimental analysis related to 3D-printed carbon-fiber-reinforced-polymer (CFRP) machining. A polyethylene-terephthalate-glycol (PETG)-based composite, reinforced with 20% carbon fibers, was selected as the test material. The aim of the study was to evaluate the influence of cutting conditions used in light operations on the generated surface quality of the 3D-printed specimens. For this purpose, nine specimens were fabricated and machined under a wide range of cutting parameters, including cutting speed, feed, and depth of cut. The generated surface roughness was measured with a mechanical gauge and the acquired data were used to develop a shallow artificial neural network (ANN) for prediction purposes, showing that a 3-6-1 structure is the best solution. Following this, a genetic algorithm (GA) was utilized to minimize the response, revealing that the optimal combination is 205 m/min speed, 0.0578 mm/rev feed, and 0.523 mm depth of cut, contributing to the fabrication of low friction parts and shafts with a high quality surface, as well as to the reduction of resource waste. A validation study supported the accuracy of the developed model, by exhibiting errors below 10%. Finally, a set of enhanced images were taken to assess the machined surfaces. It was found that 1.50 mm depth of cut is responsible for the generation of defects across the circumference of the specimens. Especially, combined with 150 m/min cutting speed and 0.11 mm/rev feed, more flaws are produced. Full article

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

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13 pages, 5928 KiB

Open AccessArticle

An Exploration of Alkaline Degumming in the Printing and Dyeing Process of Silk Georgette

by Huihui Wu, Jiali Zhou, Panpan Zhu, Jing Li and Yufeng Li

Polymers 2024, 16(20), 2926; https://doi.org/10.3390/polym16202926 - 18 Oct 2024

Viewed by 585

Abstract

Alkali printing was one of the traditional techniques employed for printing on silk georgette in ancient China. This study investigates two degumming methods in alkaline printing processes, namely alkaline boiling and alkaline steaming, based on the principles of Tang Dynasty alkaline printing techniques. [...] Read more.

Alkali printing was one of the traditional techniques employed for printing on silk georgette in ancient China. This study investigates two degumming methods in alkaline printing processes, namely alkaline boiling and alkaline steaming, based on the principles of Tang Dynasty alkaline printing techniques. The effects of slaked lime concentration, steam temperature, and steam duration on the degumming rate of silk georgette are studied. Alkaline boiling is found to be rapid and effective, achieving a degumming rate of 27% at 80 °C in 30 min, whereas alkaline steaming requires a prolonged process with a maximum degumming rate of less than 20% before the water reaches its boiling point. Additionally, the differences in dyeing effects at various degumming rates, and the variations in pattern clarity and detail under alkaline steaming, were compared. Although both degumming methods can achieve the desired amount of degumming rate through process control, alkaline steaming allows for integration with methods like screen printing and rotary printing, offering better control over pattern freedom and detail. The combination of these two processes can further expand the artistic expression and application of traditional alkaline printing techniques in contemporary silk degumming printing. Full article

(This article belongs to the Special Issue Progress on Advanced Fibrous Materials)

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21 pages, 3616 KiB

Open AccessReview

A Review of the Biomimetic Structural Design of Sandwich Composite Materials

by Shanlong Che, Guangliang Qu, Guochen Wang, Yunyan Hao, Jiao Sun and Jin Ding

Polymers 2024, 16(20), 2925; https://doi.org/10.3390/polym16202925 - 18 Oct 2024

Viewed by 1492

Abstract

Sandwich composites are widely used in engineering due to their excellent mechanical properties. Accordingly, the problem of interface bonding between their panels and core layers has always been a hot research topic. The emergence of biomimetic technology has enabled the integration of the [...] Read more.

Sandwich composites are widely used in engineering due to their excellent mechanical properties. Accordingly, the problem of interface bonding between their panels and core layers has always been a hot research topic. The emergence of biomimetic technology has enabled the integration of the structure and function of biological materials from living organisms or nature into the design of sandwich composites, greatly improving the interface bonding and overall performance of heterogeneous materials. In this paper, we review the most commonly used biomimetic structures and the fusion design of multi-biomimetic structures in the engineering field. They are analyzed with respect to their mechanical properties, and several biomimetic structures derived from abstraction in plants and animals are highlighted. Their structural advantages are further discussed specifically. Regarding the optimization of different interface combinations of multilayer composites, this paper explores the optimization of simulations and the contributions of molecular dynamics, machine learning, and other techniques used for optimization. Additionally, the latest molding methods for sandwich composites based on biomimetic structural design are introduced, and the materials applicable to different processes, as well as their advantages and disadvantages, are briefly analyzed. Our research results can help improve the mechanical properties of sandwich composites and promote the application of biomimetic structures in engineering. Full article

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

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19 pages, 4892 KiB

Open AccessArticle

Mechanistic Study on the Optimization of Asphalt-Based Material Properties by Physicochemical Interaction and Synergistic Modification of Molecular Structure

by Jiashuo Cao and Lifeng Wang

Polymers 2024, 16(20), 2924; https://doi.org/10.3390/polym16202924 - 18 Oct 2024

Viewed by 548

Abstract

In order to investigate the relationship between the molecular structure of fibers and the differences in physicochemical interactions between fibers and asphalt on the performance of fiber-modified asphalt, this paper chose two types of fibers with different chemical structures: straw fiber and polyester [...] Read more.

In order to investigate the relationship between the molecular structure of fibers and the differences in physicochemical interactions between fibers and asphalt on the performance of fiber-modified asphalt, this paper chose two types of fibers with different chemical structures: straw fiber and polyester fiber. First, the differences in molecular interactions between the two fibers and asphalt were explored using molecular dynamics, then the differences in the adsorption capacity of the two fibers on asphalt components were tested by attenuated total reflection infrared spectroscopy experiments, and finally, the differences in the rheological properties of the two fiber-modified asphalts were tested by dynamic shear rheology and low-temperature creep experiments. The molecular dynamics simulation findings reveal that polyester fibers may intersperse into asphalt molecules and interact with them via structures such as aromatic rings, whereas straw fibers are merely adsorbed on the asphalt’s surface. Straw fibers and asphalt exhibit hydrogen bonding, whereas polyester fibers and asphalt display van der Waals interactions. The results of attenuated total reflectance infrared spectroscopy indicated that polyester fiber absorbed asphalt components better than straw fiber. The rheological tests revealed that the polyester fiber had the highest complex shear modulus in the temperature range of 46–82 °C, and at 64 °C, the phase angle was 4.289° lower than that of the straw fiber-treated bitumen. Polyester fiber-modified asphalt had a 32.48%, 15.72%, and 6.09% lower creep modulus than straw fiber-modified asphalt at three low-temperature conditions: −6 °C, −12 °C, and −18 °C. It is clear that fibers with aromatic rings as a chemical structure outperform lignin-based fibers in terms of improving asphalt characteristics. The research findings can serve as a theoretical foundation for the selection of fibers to produce fiber-modified asphalt. Full article

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

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36 pages, 13579 KiB

Open AccessEditor’s ChoiceReview

Exploring the Possibilities of Using Recovered Collagen for Contaminants Removal—A Sustainable Approach for Wastewater Treatment

by Annette Madelene Dancila and Magdalena Bosomoiu

Polymers 2024, 16(20), 2923; https://doi.org/10.3390/polym16202923 - 18 Oct 2024

Viewed by 1532

Abstract

Collagen is a non-toxic polymer that is generated as a residual product by several industries (e.g., leather manufacturing, meat and fish processing). It has been reported to be resistant to bacteria and have excellent retention capacity. However, the recovered collagen does not meet [...] Read more.

Collagen is a non-toxic polymer that is generated as a residual product by several industries (e.g., leather manufacturing, meat and fish processing). It has been reported to be resistant to bacteria and have excellent retention capacity. However, the recovered collagen does not meet the requirements to be used for pharmaceutical and medical purposes. Due to the scarcity of water resources now affecting all continents, water pollution is a major concern. Another major field that could integrate the collagen generated as a by-product is wastewater treatment. Applications of collagen-based materials in wastewater treatment have been discussed in detail, and comparisons with already frequently used materials have been made. Over the last years, collagen-based materials have been tested for removal of both organic (e.g., pharmaceutical substances, dyes) and inorganic compounds (e.g., heavy metals, noble metals, uranium). They have also been tested for the manufacture of oil-water separation materials; therefore, they could be used for the separation of emulsified oily wastewater. Because they have been analysed for a wide range of substances, collagen-based materials could be good candidates for removing contaminants from wastewater streams that have seasonal variations in composition and concentration. The use of recovered collagen in wastewater treatment makes the method eco-friendly and cost efficient. This paper also discusses some of the challenges related to wastewater treatment: material stability, reuse and disposal. The results showed that collagen-based materials are renewable and reusable without significant loss of initial properties. In the sorption processes, the incorporation of experiments with real wastewater has demonstrated that there is a significant competition among the substances present in the sample. Full article

(This article belongs to the Special Issue Advanced Polymers for Wastewater Treatment and Toxicant Removal)

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14 pages, 5184 KiB

Open AccessArticle

Sustainable Composites from Waste Polypropylene Added with Thermoset Composite Waste or Recovered Carbon Fibres

by Ehsan Zolfaghari, Giulia Infurna, Sabina Alessi, Clelia Dispenza and Nadka Tz. Dintcheva

Polymers 2024, 16(20), 2922; https://doi.org/10.3390/polym16202922 - 18 Oct 2024

Viewed by 822

Abstract

In order to limit the ever-increasing consumption of new resources for material formulations, regulations and legislation require us to move from a linear to a circular economy and to find efficient ways to recycle, reuse and recover materials. Taking into account the principles [...] Read more.

In order to limit the ever-increasing consumption of new resources for material formulations, regulations and legislation require us to move from a linear to a circular economy and to find efficient ways to recycle, reuse and recover materials. Taking into account the principles of material circularity and waste reuse, this research study aims to produce thermoplastic composites using two types of industrial waste from neighbouring companies, namely waste polypropylene (wPP) from household production and carbon-fibre-reinforced epoxy composite scrap from a pultrusion company. The industrial scrap of the carbon-fibre-reinforced epoxy composites was either machined/ground to powder (pCFRC) and used directly as a reinforcement agent or subjected to a chemical digestion process to recover the carbon fibres (rCFs). Both pCFRC and rCF, at different weight ratios, were melt-blended with wPP. Prior to melt blending, both pCFRC and rCF were analysed for morphology by scanning electron microscopy (SEM). The pCFRC powder contains epoxy resin fragments with spherical to ellipsoidal shape and carbon fibre fragments. The rCFs are clean from the matrix, but they are slightly thicker and corrugated after the matrix digestion. Further, the morphologies of wPP/pCFRC and wPP/rCF were also investigated by SEM, while the thermal behaviour, i.e., transitions and changes in crystallinity, and thermal resistance were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The strength of the interaction between the filler (i.e., pCFRC or rCF) and the wPP matrix and the processability of these composites were assessed by rheological studies. Finally, the mechanical properties of the systems were characterised by tensile tests, and as found, both pCFRC and rCF exert reinforcement effects, although better results were obtained using rCF. The wPP/pCFRC results are more heterogeneous than those of the wPP/rCF due to the presence of epoxy and carbon fibre fragments, and this heterogeneity could be considered responsible for the mechanical behaviour. Further, the presence of both pCFRC and rCF leads to a restriction of polymer chain mobility, which leads to an overall reduction in ductility. All the results obtained suggest that both pCFRC and rCF are good candidates as reinforcing fillers for wPP and that these complex systems could potentially be processed by injection or compression moulding. Full article

(This article belongs to the Special Issue Progress in Recycling of (Bio)Polymers and Composites, 2nd Edition)

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