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Polymers
Volume 14
Issue 9
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Polymers, Volume 14, Issue 9 (May-1 2022) – 297 articles

Cover Story (view full-size image): Molecular dynamics simulations were performed to study the ability of hyperbranched poly(imines) and poly(glycerol) molecules to associate with terpenoid essential-oil ingredients, found in species of the Greek endemic flora. Both cationic poly(imines) and the electrically neutral poly(glycerols) were found to associate in an aqueous environment with biologically active terpenoids, preferably at lower concentrations. The morphology of the polymer/terpenoid complexes depended on the properties of the hyperbranched molecules. The terpenoids formed polymer-covered nanodroplets with the poly(glycerols) and a mesh-like network with the poly(imines), indicating that both polymers are promising candidates for complexation and delivery purposes of the terpenoid moieties. View this paper.
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17 pages, 37036 KiB  
Article
Effect of Embedded Thin-Plies on the Charpy Impact Properties of CFRP Composites
by Hassan Alshahrani and Tamer A. Sebaey
Polymers 2022, 14(9), 1929; https://doi.org/10.3390/polym14091929 - 09 May 2022
Cited by 4 | Viewed by 1751
Abstract
In this study, different configurations of epoxy composite laminates that contained thin plies were prepared and characterised for sudden impact load bearing applications. The primary aim of this investigation was to develop a hybrid epoxy-based thin ply composite for aerospace and automotive applications [...] Read more.
In this study, different configurations of epoxy composite laminates that contained thin plies were prepared and characterised for sudden impact load bearing applications. The primary aim of this investigation was to develop a hybrid epoxy-based thin ply composite for aerospace and automotive applications that would be tolerant of high impacts. The impact properties of the selected configurations were investigated both experimentally and numerically under low-velocity Charpy impact loading conditions. Furthermore, any damage to the laminates was evaluated with an emphasis on the identification of dominant damage mechanisms and locations. This included a comparison between the laminates that were made from traditional plies and the thin ply laminates in terms of their absorbed energy and failure modes. The results revealed that the integration of thin plies into normal ply had a major effect on the amount of absorbed energy under flatwise conditions: up to 8.7 J at a cut-off angle of 90°. However, edgewise conditions produced a maximum observed energy of 10.0 J for the thin plies that were surrounded by normal plies (Plate 3). The damage assessments showed the increased damage resistance of the hybrid thin ply composites due to their uniform stress distribution. The traditional ply composites incurred large deformations from the impact loads. Moreover, it was noted that delamination formed in the middle regions of the traditional plies. The FEM model analysis revealed that it was capable of accurately predicting the absorbed energy for different configurations of composites, which were prepared and analysed experimentally. Both the experimental and numerical values were very similar to each other. These impact damage assessments improved the thin ply composites so that they could be used as working materials for applications that are prone to high loads, such as the aerospace, defence, automotive and structural industries. Full article
(This article belongs to the Special Issue Fiber Reinforced Polymer Materials)
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22 pages, 5948 KiB  
Review
Review of Soil Quality Improvement Using Biopolymers from Leather Waste
by Daniela Simina Stefan, Magdalena Bosomoiu, Annette Madelene Dancila and Mircea Stefan
Polymers 2022, 14(9), 1928; https://doi.org/10.3390/polym14091928 - 09 May 2022
Cited by 5 | Viewed by 2621
Abstract
This paper reviews the advantages and disadvantages of the use of fertilizers obtained from leather waste, to ameliorate the agricultural soil quality. The use of leather waste (hides and skins) as raw materials to obtain biopolymer-based fertilizers is an excellent example of a [...] Read more.
This paper reviews the advantages and disadvantages of the use of fertilizers obtained from leather waste, to ameliorate the agricultural soil quality. The use of leather waste (hides and skins) as raw materials to obtain biopolymer-based fertilizers is an excellent example of a circular economy. This allows the recovery of a large quantity of the tanning agent in the case of tanned wastes, as well as the valorization of significant quantities of waste that would be otherwise disposed of by landfilling. The composition of organic biopolymers obtained from leather waste is a rich source of macronutrients (nitrogen, calcium, magnesium, sodium, potassium), and micronutrients (boron, chloride, copper, iron, manganese, molybdenum, nickel and zinc), necessary to improve the composition of agricultural soils, and to remediate the degraded soils. This enhances plant growth ensuring better crops. The nutrient release tests have demonstrated that, by using the biofertilizers with collagen or with collagen cross-linked with synthetic polymers, the nutrient release can be controlled and slowed. In this case, the loss of nutrients by leaching into the inferior layers of the soil and ground water is minimized, avoiding groundwater contamination, especially with nitrate. Full article
(This article belongs to the Special Issue Recycling and Resource Recovery from Polymers II)
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10 pages, 3338 KiB  
Article
Effect of Cyclic Shear Fatigue under Magnetic Field on Natural Rubber Composite as Anisotropic Magnetorheological Elastomers
by Jeong-Hwan Yoon, Seung-Won Lee, Seok-Hu Bae, Nam-Il Kim, Ju-Ho Yun, Jae-Hum Jung and Young-Gil Kim
Polymers 2022, 14(9), 1927; https://doi.org/10.3390/polym14091927 - 09 May 2022
Cited by 7 | Viewed by 1474
Abstract
With the development and wide applicability of rubber materials, it is imperative to determine their performance under various conditions. In this study, the effect of cyclic shear fatigue on natural-rubber-based anisotropic magnetorheological elastomer (MRE) with carbonyl iron particles (CIPs) was investigated under a [...] Read more.
With the development and wide applicability of rubber materials, it is imperative to determine their performance under various conditions. In this study, the effect of cyclic shear fatigue on natural-rubber-based anisotropic magnetorheological elastomer (MRE) with carbonyl iron particles (CIPs) was investigated under a magnetic field. An anisotropic MRE sample was prepared by moulding under a magnetic field. Cyclic shear fatigue tests were performed using a modified electromechanical fatigue system with an electromagnet. The storage modulus (G′) and loss factor in the absence or presence of a magnetic field were measured using a modified dynamic mechanical analysis system. Under a magnetic field, fatigue exhibited considerable effects to the MRE, such as migration and loss of magnetised CIPs and suppressed increase in stiffness by reducing the energy loss in the strain cycle. Therefore, the G′ of the MRE after fatigue under a magnetic field was lower than that after fatigue in the zero field. The performance of the MRE, such as absolute and relative magnetorheological effects, decreased after subjecting to cyclic shear fatigue. In addition, all measured results exhibited strain-dependent behaviour owing to the Payne effect. Full article
(This article belongs to the Special Issue RubberCon 2021: Innovative Pioneers for Smart and Sustainable Rubber Technology)
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17 pages, 4536 KiB  
Article
Effects of Non-Ionic Micelles on the Acid-Base Equilibria of a Weak Polyelectrolyte
by Evgenee Yekymov, David Attia, Yael Levi-Kalisman, Ronit Bitton and Rachel Yerushalmi-Rozen
Polymers 2022, 14(9), 1926; https://doi.org/10.3390/polym14091926 - 09 May 2022
Cited by 3 | Viewed by 1862
Abstract
Weak polyelectrolytes (WPEs) are widely used as pH-responsive materials, pH modulators and charge regulators in biomedical and technological applications that involve multi-component fluid environments. In these complex fluids, coupling between (often weak) interactions induced by micelles, nanoparticles and molecular aggregates modify the pKa [...] Read more.
Weak polyelectrolytes (WPEs) are widely used as pH-responsive materials, pH modulators and charge regulators in biomedical and technological applications that involve multi-component fluid environments. In these complex fluids, coupling between (often weak) interactions induced by micelles, nanoparticles and molecular aggregates modify the pKa as compared to that measured in single component solutions. Here we investigated the effect of coupling between hydrogen bonding and excluded volume interactions on the titration curves and pKa of polyacrylic acid (PAA) in solutions comprising PEO-based micelles (Pluronics and Brij-S20) of different size and volume fraction. Titration experiments of dilute, salt-free solutions of PAA (5 kDa, 30 kDa and 100 kDa) at low degree of polymer ionization (α < 0.25) drive spatial re-organization of the system, reduce the degree of ionization and consequentially increase the pKa by up to ~0.7 units. These findings indicate that the actual degree of ionization of WPEs measured in complex fluids is significantly lower (at a given pH) than that measured in single-component solutions. Full article
(This article belongs to the Section Polymer Analysis and Characterization)
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15 pages, 7776 KiB  
Article
Molecular Dynamics Study of Cellulose Nanofiber Alignment under an Electric Field
by Ruth M. Muthoka, Pooja S. Panicker and Jaehwan Kim
Polymers 2022, 14(9), 1925; https://doi.org/10.3390/polym14091925 - 09 May 2022
Cited by 2 | Viewed by 2163
Abstract
The alignment of cellulose by an electric field is an interesting subject for cellulose material processing and its applications. This paper reports an atomistic molecular dynamics simulation of the crystalline cellulose nanofiber (CNF) model in varying electric field directions and strengths. GROMACS software [...] Read more.
The alignment of cellulose by an electric field is an interesting subject for cellulose material processing and its applications. This paper reports an atomistic molecular dynamics simulation of the crystalline cellulose nanofiber (CNF) model in varying electric field directions and strengths. GROMACS software was used to study crystalline cellulose 1β consisting of 18 chains in an aqueous environment at room temperature, and an electric field was applied along the cellulose chain direction and the perpendicular direction with varying field strength. The root-mean-square displacement, radius of gyration, end-to-end length, and hydrogen bond population of the crystalline CNF model were analyzed to determine the effects of the applied electric field on the structure of the CNF model. The results suggest that the nanosecond electric field can induce the orientation of the CNF along the applied electric field direction. The alignment rate and ability to maintain the alignment depend on the electric field strength. Analysis of the radius of gyration, end-to-end length, and bond lengths for intrachain and interchain hydrogen bonds revealed no significant effect on the cellulose structure. Cellulose alignment in an electric field has the potential to broaden the design of electric field-induced processing techniques for cellulose filaments, thin films, and electro-active cellulose composites. Full article
(This article belongs to the Topic Computational Materials Science for Polymers)
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10 pages, 5059 KiB  
Article
Self-Assembly of Ultrafine Fibers with Micropores via Cryogenic Electrospinning and Its Potential Application in Esophagus Repair
by Wenqing Tian, Xinghuang Liu, Xianglin Zhang, Tao Bai and Bin Wu
Polymers 2022, 14(9), 1924; https://doi.org/10.3390/polym14091924 - 09 May 2022
Cited by 2 | Viewed by 1387
Abstract
Electrospinning (e-spinning) has been widely applied to fabricate flat films accumulated by microfibers for tissue engineering. In order to acquire an uneven surface morphology, two methods have been applied traditionally. The first uses a designed receiving substrate, which is stable, but suppresses the [...] Read more.
Electrospinning (e-spinning) has been widely applied to fabricate flat films accumulated by microfibers for tissue engineering. In order to acquire an uneven surface morphology, two methods have been applied traditionally. The first uses a designed receiving substrate, which is stable, but suppresses the flexibility. The second uses dual solvents to achieve bimodal distribution of the fiber diameter. However, the bimodal fiber diameter causes inhomogeneity. To solve these challenges, cryogenic electrospinning, using a flat substrate and a single solvent, was performed in this study to obtain uneven films. By applying a low temperature to the flat receiving substrate, uneven e-spun films with wall-like structures were achieved through the self-assembly of uniform filaments. In addition, the wall-like structures enhanced the mechanical properties of the e-spun films. Moreover, the cryogenic e-spinning produced micropores on the fiber surface, which have the potential to promote esophageal epithelial cell adhesion, proliferation and differentiation. Full article
(This article belongs to the Section Biomacromolecules, Biobased and Biodegradable Polymers)
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13 pages, 2613 KiB  
Article
A Preliminary Investigation of Embedding In Vitro HepaRG Spheroids into Recombinant Human Collagen Type I for the Promotion of Liver Differentiation
by Fang-Chun Liao, Yang-Kao Wang, Ming-Yang Cheng and Ting-Yuan Tu
Polymers 2022, 14(9), 1923; https://doi.org/10.3390/polym14091923 - 09 May 2022
Cited by 2 | Viewed by 2671
Abstract
Background: In vitro three-dimensional (3D) hepatic spheroid culture has shown great promise in toxicity testing because it better mimics the cell–cell and cell–matrix interactions found in in vivo conditions than that of the traditional two-dimensional (2D) culture. Despite embedding HepaRG spheroids with collagen [...] Read more.
Background: In vitro three-dimensional (3D) hepatic spheroid culture has shown great promise in toxicity testing because it better mimics the cell–cell and cell–matrix interactions found in in vivo conditions than that of the traditional two-dimensional (2D) culture. Despite embedding HepaRG spheroids with collagen type I (collagen I) extracellular matrix (ECM) revealed a much better differentiation capability, almost all the collagen utilized in in vitro hepatocytes cultures is animal-derived collagen that may limit its use in human toxicity testing. Method: Here, a preliminary investigation of HepaRG cells cultured in different dimensionalities and with the addition of ECM was performed. Comparisons of conventional 2D culture with 3D spheroid culture were performed based on their functional or structural differences over 7 days. Rat tail collagen (rtCollagen) I and recombinant human collagen (rhCollagen) I were investigated for their ability in promoting HepaRG spheroid differentiation. Results: An immunofluorescence analysis of the hepatocyte-specific functional protein albumin suggested that HepaRG spheroids demonstrated better hepatic function than spheroids from 2D culture, and the function of HepaRG spheroids improved in a time-dependent manner. The fluorescence intensities per unit area of spheroids formed by 1000 cells on days 7 and 10 were 25.41 and 45.38, respectively, whereas almost undetectable fluorescence was obtained with 2D cells. In addition, the embedding of HepaRG spheroids into rtCollagen and rhCollagen I showed that HepaRG differentiation can be accelerated relative to the differentiation of spheroids grown in suspension, demonstrating the great promise of HepaRG spheroids. Conclusions: The culture conditions established in this study provide a potentially novel alternative for promoting the differentiation of HepaRG spheroids into mature hepatocytes through a collagen-embedded in vitro liver spheroid model. This culture method is envisioned to provide insights for future drug toxicology. Full article
(This article belongs to the Topic Hydrogel-Based Platforms for Advanced Therapy and Theranostics)
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18 pages, 3123 KiB  
Article
Lornoxicam-Loaded Chitosan-Decorated Nanoemulsion: Preparation and In Vitro Evaluation for Enhanced Transdermal Delivery
by Rahman Ullah Khan, Shefaat Ullah Shah, Sheikh Abdur Rashid, Faiza Naseem, Kifayat Ullah Shah, Arshad Farid, Khalid Rehman Hakeem, Majid Rasool Kamli, Eman Hillal Althubaiti and Soha A. Alamoudi
Polymers 2022, 14(9), 1922; https://doi.org/10.3390/polym14091922 - 09 May 2022
Cited by 13 | Viewed by 2245
Abstract
Nanoemulsions are promising drug delivery systems for the administration of poorly soluble drugs like lornoxicam (LRX) by oral or parenteral routes. Such formulations work perfectly for transdermal delivery of lornoxicam-type drugs. It has also been established that formulating such a delivery system is [...] Read more.
Nanoemulsions are promising drug delivery systems for the administration of poorly soluble drugs like lornoxicam (LRX) by oral or parenteral routes. Such formulations work perfectly for transdermal delivery of lornoxicam-type drugs. It has also been established that formulating such a delivery system is highly dependent on the presence, type, and concentration of excipients taking part in the formulation. The inherent characteristics of nanoemulsion (NE), i.e., smaller globule size and excipient nature, facilitate the drug’s passage through skin. The current study was aimed at the development of an NE-based formulation of LRX to improve the drug solubility in vitro as well as to enhance drug skin permeation to promote therapeutic outcome in appropriate time. Spontaneous self-emulsification technique was utilized to develop optimized LRX-encapsulated NE-based formulations. ATR-FTIR spectra of the pure drug and various formulations did not show any interaction between the drug and various formulation excipients showing compatibility. Globule size for stable formulations ranged between 63–168 nm. These formulations were characterized for viscosity, surface tension, pH, drug encapsulation efficiency, in vitro drug release, and drug skin permeation studies. Chitosan-decorated optimized NE formulation of LRX showed about 58.82% cumulative drug release, showing an anomalous non-Fickian diffusion mechanism of drug release. Drug encapsulation efficiency, in vitro drug release, and skin permeation studies exhibited promising results. An appreciable drug entrapment efficiency was exhibited by optimized NE formulations LRX-6, 71.91 ± 3.17% and C-LRX, 65.25 ± 4.89%. Permeability parameters like enhancement ratio (Er), permeability constant (Kp), and steady state flux (Jss) showed higher values and exhibited good results based on formulation type. The selected promising formulation type “LRX-6” showed significantly different results as compared to other formulations (LRX-4, 5, and 7). The skin permeation property of the LRX-6 formulation was compared to similar chitosan-based formulations and was found to have better skin permeation results than chitosan-based formulations. This study clearly exhibited that an LRX-containing NE-based formulation can be formulated to form a stable drug delivery system. Such formulations are promising in terms of physicochemical characteristics, improved solubility, and high skin permeation potential. Full article
(This article belongs to the Special Issue Chitosan and Chitosan Derivatives in Biomedical Applications)
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20 pages, 2932 KiB  
Article
Application of Sulfur and Peroxide Curing Systems for Cross-Linking of Rubber Composites Filled with Calcium Lignosulfonate
by Ján Kruželák, Klaudia Hložeková, Andrea Kvasničáková, Katarína Tomanová and Ivan Hudec
Polymers 2022, 14(9), 1921; https://doi.org/10.3390/polym14091921 - 09 May 2022
Cited by 13 | Viewed by 2525
Abstract
Calcium lignosulfonate in different loadings was applied to the rubber matrix based on EPDM. A sulfur curing system, organic peroxide, and a combination of organic peroxide with two coagent types were used for cross-linking of rubber compounds. The work was focused on the [...] Read more.
Calcium lignosulfonate in different loadings was applied to the rubber matrix based on EPDM. A sulfur curing system, organic peroxide, and a combination of organic peroxide with two coagent types were used for cross-linking of rubber compounds. The work was focused on the investigation of filler content and curing system composition in the curing process, cross-link density, morphology, and physical–mechanical properties of composites. The achieved results demonstrated that the curing parameters of rubber compounds cured with the sulfur system were significantly different from those cured with peroxide systems. There was also an observed different influence of curing systems composition on cross link density, though in all cases, the degree of cross-linking showed a decreasing trend with increasing content of lignosulfonate. The tensile strength of the composites cured with sulfur system and organic peroxide was comparable, regardless of lignosulfonate loading. This points to the application of both curing systems in cross-linking of rubber compounds with biopolymer filler. However, the introduction of coagents in peroxide vulcanization led to the improvement of adhesion and compatibility between the rubber and the filler on the filler–rubber interface. This subsequently resulted in the improvement of the tensile characteristics of composites. The introduction of organic peroxide in combination with coagent seems to be a very simple and efficient way for the preparation of biopolymer-filled composites with applicable physical–mechanical properties. Full article
(This article belongs to the Special Issue Rubber Materials: Processes, Structures and Applications)
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15 pages, 1220 KiB  
Review
Biopolymers Produced by Sphingomonas Strains and Their Potential Applications in Petroleum Production
by Haolin Huang, Junzhang Lin, Weidong Wang and Shuang Li
Polymers 2022, 14(9), 1920; https://doi.org/10.3390/polym14091920 - 09 May 2022
Cited by 17 | Viewed by 2586
Abstract
The genus Sphingomonas was established by Yabuuchi et al. in 1990, and has attracted much attention in recent years due to its unique ability to degrade environmental pollutants. Some Sphingomonas species can secrete high-molecular-weight extracellular polymers called sphingans, most of which are acidic [...] Read more.
The genus Sphingomonas was established by Yabuuchi et al. in 1990, and has attracted much attention in recent years due to its unique ability to degrade environmental pollutants. Some Sphingomonas species can secrete high-molecular-weight extracellular polymers called sphingans, most of which are acidic heteropolysaccharides. Typical sphingans include welan gum, gellan gum, and diutan gum. Most sphingans have a typical, conserved main chain structure, and differences of side chain groups lead to different rheological characteristics, such as shear thinning, temperature or salt resistance, and viscoelasticity. In petroleum production applications, sphingans, and their structurally modified derivatives can replace partially hydrolyzed polyacrylamide (HPAM) for enhanced oil recovery (EOR) in high-temperature and high-salt reservoirs, while also being able to replace guar gum as a fracturing fluid thickener. This paper focuses on the applications of sphingans and their derivatives in EOR. Full article
(This article belongs to the Section Biomacromolecules, Biobased and Biodegradable Polymers)
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20 pages, 2106 KiB  
Article
Inherent Flame-Retardant, Humid Environment Stable and Blue Luminescent Polyamide Elastomer Regulated by Siloxane Moiety
by Qianqian Qi, Zhe Xiao, Yaowei Wang, Xinjin Yan, Peng Fu, Xiaomeng Zhang, Wei Zhao, Xinchang Pang, Minying Liu, Qingxiang Zhao and Zhe Cui
Polymers 2022, 14(9), 1919; https://doi.org/10.3390/polym14091919 - 09 May 2022
Cited by 3 | Viewed by 1915
Abstract
The rapid development of the polymeric materials market has created an urgent demand for the thermoplastic polyamide elastomer (TPAE) owing to its greater functionality, and ability to be synthesized via a facile and industrial route. In this work, a series of novel silicone-containing [...] Read more.
The rapid development of the polymeric materials market has created an urgent demand for the thermoplastic polyamide elastomer (TPAE) owing to its greater functionality, and ability to be synthesized via a facile and industrial route. In this work, a series of novel silicone-containing polyamides (PA1212/Si12) were successfully synthesized from 1,12-dodecarboxylic acid (LA), 1,12-dodecarbondiamine (DMDA), and 1,3-bis (amino-propyl) tetramethyldisiloxane (BATS), via a one-pot melt polycondensation method in the absence of a catalyst. FTIR, 1H-NMR, GPC and inherent viscosity results cohesively prove that the polymerization of monomers was well conducted, and the chemical structure was in high accordance with the design. As expected, the Si12 unit-content of the copolymers regulate the properties of the series. As the feeding ratio of BATS in the diamines increases from 5 mol% to 40 mol%, the thermal transition temperatures, Tg and Tm, decline steadily before finally stabilizing at ~6 °C and 160 °C, respectively, indicating that the co-polyamides possess improved chain flexibility but restricted crystallization ability. The conspicuous evolution in crystalline morphology of the series was observed by XRD and AFM. The increased PA Si12 phase induces the crystallized PA 1212 phase to transit from a thermally-favorable large and rigid crystal structure (α phase) to a kinetically-favorable small and ductile crystal structure (γ phase). Reflected in their stress–strain behavior, PA1212/Si12 copolymers are successfully tailored from rigid plastic to ductile elastomer. The tensile strength mildly drops from above 40 MPa to ~30 MPa while the reversible elongation increases from ~50% to approximately 350%. Accordingly, the moderate surface tension differences in the monomers facilitate the efficient conduction of the co-polymerization process, and the distributed short siloxane unit in the backbone fulfills the copolymer with desirable elasticity. Interestingly, the novel silicone-containing polyamides also display Si12 unit-content dependent flame retardancy, humidity stability, and unconventional solid-state fluorescence properties. The elastomers exhibit a low bibulous rate and anti-fouling characteristics to dye droplets and mud contamination, pass the V–1 rating (UL 94) with a constantly declining PHRR value, and emit blue luminescence under a 365 nm light source. Herein, we propose a new facile strategy for developing a high-performance and multifunctional silicone-modified polyamide, which bears promising industrialization potential. In addition, this first reported silicone-containing thermoplastic polyamide elastomer, which is self-extinguishing, anti-fouling and blue-luminescent, will further broaden the application potential of thermoplastic polyamide elastomers. Full article
(This article belongs to the Section Polymer Applications)
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15 pages, 2814 KiB  
Review
The Physics of DNA Folding: Polymer Models and Phase-Separation
by Andrea Esposito, Alex Abraham, Mattia Conte, Francesca Vercellone, Antonella Prisco, Simona Bianco and Andrea M. Chiariello
Polymers 2022, 14(9), 1918; https://doi.org/10.3390/polym14091918 - 09 May 2022
Cited by 5 | Viewed by 2679
Abstract
Within cell nuclei, several biophysical processes occur in order to allow the correct activities of the genome such as transcription and gene regulation. To quantitatively investigate such processes, polymer physics models have been developed to unveil the molecular mechanisms underlying genome functions. Among [...] Read more.
Within cell nuclei, several biophysical processes occur in order to allow the correct activities of the genome such as transcription and gene regulation. To quantitatively investigate such processes, polymer physics models have been developed to unveil the molecular mechanisms underlying genome functions. Among these, phase-separation plays a key role since it controls gene activity and shapes chromatin spatial structure. In this paper, we review some recent experimental and theoretical progress in the field and show that polymer physics in synergy with numerical simulations can be helpful for several purposes, including the study of molecular condensates, gene-enhancer dynamics, and the three-dimensional reconstruction of real genomic regions. Full article
(This article belongs to the Special Issue Models of Polymer Physics for Biological System)
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19 pages, 7828 KiB  
Article
Comparative Study on Macro-Tribological Properties of PLL-g-PEG and PSPMA Polymer Brushes
by Fue Ren, Shuyan Yang, Yang Wu, Feng Guo and Feng Zhou
Polymers 2022, 14(9), 1917; https://doi.org/10.3390/polym14091917 - 08 May 2022
Cited by 7 | Viewed by 2417
Abstract
An ultra-low friction and high load capacity could be obtained on the surfaces grafted by a polymer brush even at relatively slow friction speeds in aqueous lubrication environments, which has attracted widespread attention to study the lubrication mechanism of polymer brushes; however, it [...] Read more.
An ultra-low friction and high load capacity could be obtained on the surfaces grafted by a polymer brush even at relatively slow friction speeds in aqueous lubrication environments, which has attracted widespread attention to study the lubrication mechanism of polymer brushes; however, it has yet to be fully understood. The macroscopic tribological performance of two different polymer brushes, which were prepared by the method of “grafting to” and “grafting from” and named as PLL-g-PEG and PSPMA, respectively, were investigated. The friction results demonstrated that PLL-g-PEG obtained a lower friction coefficient than polymer brush PSPMA, which was ascribed to its unique “self-healing” behavior. The lubrication film was in situ observed and the film thickness induced by the polymer brush was measured using a laboratory set for film thickness measurement apparatus based on interference technology. It was found that PSPMA exhibited excellent lubrication performance not found in PLL-g-PEG, and two film-forming mechanisms highly dependent on velocity were revealed, which may be important to interpret the lubrication mechanism of polymer brushes in aqueous lubricants. Full article
(This article belongs to the Section Polymer Analysis and Characterization)
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11 pages, 5998 KiB  
Article
Effect of Braiding Architectures on the Mechanical and Failure Behavior of 3D Braided Composites: Experimental Investigation
by Di Zhang, Xitao Zheng, Jin Zhou, Xinyi Song, Pu Jia, Haibao Liu and Xiaochuan Liu
Polymers 2022, 14(9), 1916; https://doi.org/10.3390/polym14091916 - 08 May 2022
Cited by 7 | Viewed by 1871
Abstract
Benefiting from the multi-directional load-bearing capability, the three-dimensional braided composites (3DBC) have found a wide application in primary structures. It is therefore of great importance to fully understand their mechanical behavior and failure modes. In the present paper, the tensile and compressive tests [...] Read more.
Benefiting from the multi-directional load-bearing capability, the three-dimensional braided composites (3DBC) have found a wide application in primary structures. It is therefore of great importance to fully understand their mechanical behavior and failure modes. In the present paper, the tensile and compressive tests were carried out, according to standardized testing methods, for eight types of 3DBC, which were manufactured by resin transfer molding (RTM). It was found that the mechanical properties of the 3DBCs decreased with an increasing braiding angle. When the braiding angle was 20°, 3D 5-directional braided composite (3D5dBC) exhibited the best mechanical properties, while for the braiding angle of 40°, the mechanical properties of 3D6dBC were the most prominent. Moreover, the tensile strength of the 3DBCs is approximately two times as much as the compressive strength; however, the compressive modulus is always 10% higher than the tensile modulus. The failure modes of the 3DBCs with a braiding angle of 20°greatly depended on the braiding structures. However, they tend to be consistent when the braiding angle increases to 40°. Full article
(This article belongs to the Special Issue Polymer-Based Three-Dimensional (3D) Textile Composites)
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13 pages, 8206 KiB  
Article
Simultaneous Effects of Carboxyl Group-Containing Hyperbranched Polymers on Glass Fiber-Reinforced Polyamide 6/Hollow Glass Microsphere Syntactic Foams
by Jincheol Kim, Jaewon Lee, Sosan Hwang, Kyungjun Park, Sanghyun Hong, Seojin Lee, Sang Eun Shim and Yingjie Qian
Polymers 2022, 14(9), 1915; https://doi.org/10.3390/polym14091915 - 07 May 2022
Viewed by 1871
Abstract
The hollow glass microsphere (HGM) containing polymer materials, which are named as syntactic foams, have been applied as lightweight materials in various fields. In this study, carboxyl group-containing hyperbranched polymer (HBP) was added to a glass fiber (GF)-reinforced syntactic foam (RSF) composite for [...] Read more.
The hollow glass microsphere (HGM) containing polymer materials, which are named as syntactic foams, have been applied as lightweight materials in various fields. In this study, carboxyl group-containing hyperbranched polymer (HBP) was added to a glass fiber (GF)-reinforced syntactic foam (RSF) composite for the simultaneous enhancement of mechanical and rheological properties. HBP was mixed in various concentrations (0.5–2.0 phr) with RSF, which contains 23 wt% of HGM and 5 wt% of GF, and the rheological, thermal, and mechanical properties were characterized systematically. As a result of the lubricating effect of the HBP molecule, which comes from its dendritic architecture, the viscosity, storage modulus, loss modulus, and the shear stress of the composite decreased as the HBP content increased. At the same time, because of the hydrogen bonding among the polymer, filler, and HBP, the compatibility between filler and the polymer matrix was enhanced. As a result, by adding a small amount (0.5–2.0 phr) of HBP to the RSF composite, the tensile strength and flexural modulus were increased by 24.3 and 9.7%, respectively, and the specific gravity of the composite was decreased from 0.948 to 0.917. With these simultaneous effects on the polymer composite, HBP could be potentially utilized further in the field of lightweight materials. Full article
(This article belongs to the Special Issue Smart Composites and Processing)
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14 pages, 2890 KiB  
Article
Relevance between Cassava Starch Liquefied by Phenol and Modification of Phenol-Formaldehyde Resin Wood Adhesive
by Jinming Liu, Jianlin Fang, Enjun Xie and Weixing Gan
Polymers 2022, 14(9), 1914; https://doi.org/10.3390/polym14091914 - 07 May 2022
Cited by 5 | Viewed by 1823
Abstract
A novel type of phenol-formaldehyde (PF) resin was prepared by utilizing the liquefaction products liquefied by phenol under acidic conditions and then reacted with formaldehyde under alkaline conditions. The relationship between the liquefaction behavior of cassava starch and the properties of modified PF [...] Read more.
A novel type of phenol-formaldehyde (PF) resin was prepared by utilizing the liquefaction products liquefied by phenol under acidic conditions and then reacted with formaldehyde under alkaline conditions. The relationship between the liquefaction behavior of cassava starch and the properties of modified PF resin wood adhesive was studied. The effects of the liquid–solid ratio of phenol to cassava starch, sulfuric acid usage, and liquefaction time on the liquefaction residue rate and relative crystallinity of cassava starch were determined. The results showed that the bonding strength of modified PF resin decreased gradually with the decrease of the liquid–solid ratio. It was a great surprise that bonding strength still met the requirement of the national standard of 0.7 MPa when the liquid–solid ratio was 1.0. The detailed contents were analyzed through FT-IR, SEM, and XRD. In terms of the utilization of bio-materials for liquefaction to synthesize wood adhesive, cassava starch may be superior to the others. Full article
(This article belongs to the Section Polymer Chemistry)
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33 pages, 3516 KiB  
Review
Recent Advances in Fluorescence Recovery after Photobleaching for Decoupling Transport and Kinetics of Biomacromolecules in Cellular Physiology
by Ning Cai, Alvin Chi-Keung Lai, Kin Liao, Peter R. Corridon, David J. Graves and Vincent Chan
Polymers 2022, 14(9), 1913; https://doi.org/10.3390/polym14091913 - 07 May 2022
Cited by 18 | Viewed by 3048
Abstract
Among the new molecular tools available to scientists and engineers, some of the most useful include fluorescently tagged biomolecules. Tools, such as green fluorescence protein (GFP), have been applied to perform semi-quantitative studies on biological signal transduction and cellular structural dynamics involved in [...] Read more.
Among the new molecular tools available to scientists and engineers, some of the most useful include fluorescently tagged biomolecules. Tools, such as green fluorescence protein (GFP), have been applied to perform semi-quantitative studies on biological signal transduction and cellular structural dynamics involved in the physiology of healthy and disease states. Such studies focus on drug pharmacokinetics, receptor-mediated endocytosis, nuclear mechanobiology, viral infections, and cancer metastasis. In 1976, fluorescence recovery after photobleaching (FRAP), which involves the monitoring of fluorescence emission recovery within a photobleached spot, was developed. FRAP allowed investigators to probe two-dimensional (2D) diffusion of fluorescently-labelled biomolecules. Since then, FRAP has been refined through the advancements of optics, charged-coupled-device (CCD) cameras, confocal microscopes, and molecular probes. FRAP is now a highly quantitative tool used for transport and kinetic studies in the cytosol, organelles, and membrane of a cell. In this work, the authors intend to provide a review of recent advances in FRAP. The authors include epifluorescence spot FRAP, total internal reflection (TIR)/FRAP, and confocal microscope-based FRAP. The underlying mathematical models are also described. Finally, our understanding of coupled transport and kinetics as determined by FRAP will be discussed and the potential for future advances suggested. Full article
(This article belongs to the Special Issue Advances in Bio-Based Polymeric Materials)
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16 pages, 2738 KiB  
Article
Tailoring of Geranium Oil-Based Nanoemulsion Loaded with Pravastatin as a Nanoplatform for Wound Healing
by Waleed Y. Rizg, Khaled M. Hosny, Bayan A. Eshmawi, Abdulmohsin J. Alamoudi, Awaji Y. Safhi, Samar S. A. Murshid, Fahad Y. Sabei and Adel Al Fatease
Polymers 2022, 14(9), 1912; https://doi.org/10.3390/polym14091912 - 07 May 2022
Cited by 6 | Viewed by 1942
Abstract
The healing of a burn wound is a complex process that includes the re-formation of injured tissues and the control of infection to minimize discomfort, scarring, and inconvenience. The current investigation’s objective was to develop and optimize a geranium oil–based self-nanoemulsifying drug delivery [...] Read more.
The healing of a burn wound is a complex process that includes the re-formation of injured tissues and the control of infection to minimize discomfort, scarring, and inconvenience. The current investigation’s objective was to develop and optimize a geranium oil–based self-nanoemulsifying drug delivery system loaded with pravastatin (Gr-PV-NE). The geranium oil and pravastatin were both used due to their valuable anti-inflammatory and antibacterial activities. The Box–Behnken design was chosen for the development and optimization of the Gr-PV-NE. The fabricated formulations were assessed for their droplet size and their effects on the burn wound diameter in experimental animals. Further, the optimal formulation was examined for its wound healing properties, antimicrobial activities, and ex-vivo permeation characteristics. The produced nanoemulsion had a droplet size of 61 to 138 nm. The experimental design affirmed the important synergistic influence of the geranium oil and pravastatin for the healing of burn wounds; it showed enhanced wound closure and improved anti-inflammatory and antimicrobial actions. The optimal formulation led to a 4-fold decrease in the mean burn wound diameter, a 3.81-fold lowering of the interleukin-6 serum level compared to negative control, a 4-fold increase in the inhibition zone against Staphylococcus aureus compared to NE with Gr oil, and a 7.6-fold increase in the skin permeation of pravastatin compared to PV dispersion. Therefore, the devised nanoemulsions containing the combination of geranium oil and pravastatin could be considered a fruitful paradigm for the treatment of severe burn wounds. Full article
(This article belongs to the Special Issue Polymer Materials for Drug Delivery and Tissue Engineering)
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15 pages, 4860 KiB  
Article
A Green Approach for the Synthesis of Silver Nanoparticle-Embedded Chitosan Bionanocomposite as a Potential Device for the Sustained Release of the Itraconazole Drug and Its Antibacterial Characteristics
by Saruchi, Manpreet Kaur, Vaneet Kumar, Ayman A. Ghfar and Sadanand Pandey
Polymers 2022, 14(9), 1911; https://doi.org/10.3390/polym14091911 - 07 May 2022
Cited by 13 | Viewed by 1832
Abstract
The present research work intended to demonstrate the green synthesis of silver nanoparticles (AgNPs) using the plant extract Saccharum officinarum, and then the development of chitosan–silver (CH-Ag) bionanocomposite. The synthesized AgNPs were characterized using UV spectroscopy, Fourier transform infrared (FTIR), and transmission [...] Read more.
The present research work intended to demonstrate the green synthesis of silver nanoparticles (AgNPs) using the plant extract Saccharum officinarum, and then the development of chitosan–silver (CH-Ag) bionanocomposite. The synthesized AgNPs were characterized using UV spectroscopy, Fourier transform infrared (FTIR), and transmission electron microscopy (TEM). The maximum absorption spectrum peak was observed at 420 nm, revealing the formation of AgNPs by the stem extract of S. officinarum. The AgNPs sizes were in the range of 10–50 nm. Itraconazole is an antifungal that is used as a novel drug to study its release through synthesized bionanocomposite. Different kinetic models, such as zero order, first order, Korsmeyer–Peppas, Hixson–Crowell and Higuchi, were used to study the drug release profile from the synthesized CH-Ag bionanocomposite. The first-order kinetic model showed the best fit for the drug release with the maximum regression coefficient value. The antibacterial activity of the synthesized CH-Ag bionanocomposite was examined against Bacillus cereus, Staphylococcus, and Escherichia coli, and it was shown to be efficient against these strains. Full article
(This article belongs to the Special Issue Recent Developments in Biodegradable and Biobased Polymers)
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34 pages, 22113 KiB  
Review
Hybrid Time-Dependent Ginzburg–Landau Simulations of Block Copolymer Nanocomposites: Nanoparticle Anisotropy
by Javier Diaz, Marco Pinna, Andrei V. Zvelindovsky and Ignacio Pagonabarraga
Polymers 2022, 14(9), 1910; https://doi.org/10.3390/polym14091910 - 07 May 2022
Cited by 2 | Viewed by 2241
Abstract
Block copolymer melts are perfect candidates to template the position of colloidal nanoparticles in the nanoscale, on top of their well-known suitability for lithography applications. This is due to their ability to self-assemble into periodic ordered structures, in which nanoparticles can segregate depending [...] Read more.
Block copolymer melts are perfect candidates to template the position of colloidal nanoparticles in the nanoscale, on top of their well-known suitability for lithography applications. This is due to their ability to self-assemble into periodic ordered structures, in which nanoparticles can segregate depending on the polymer–particle interactions, size and shape. The resulting coassembled structure can be highly ordered as a combination of both the polymeric and colloidal properties. The time-dependent Ginzburg–Landau model for the block copolymer was combined with Brownian dynamics for nanoparticles, resulting in an efficient mesoscopic model to study the complex behaviour of block copolymer nanocomposites. This review covers recent developments of the time-dependent Ginzburg–Landau/Brownian dynamics scheme. This includes efforts to parallelise the numerical scheme and applications of the model. The validity of the model is studied by comparing simulation and experimental results for isotropic nanoparticles. Extensions to simulate nonspherical and inhomogeneous nanoparticles are discussed and simulation results are discussed. The time-dependent Ginzburg–Landau/Brownian dynamics scheme is shown to be a flexible method which can account for the relatively large system sizes required to study block copolymer nanocomposite systems, while being easily extensible to simulate nonspherical nanoparticles. Full article
(This article belongs to the Special Issue Simulation Methods of Polymers Involving Field Theory)
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21 pages, 3344 KiB  
Article
Defining the Collapse Point in Colloidal Unimolecular Polymer (CUP) Formation
by Ashish Zore, Peng Geng, Yuwei Zhang and Michael R. Van De Mark
Polymers 2022, 14(9), 1909; https://doi.org/10.3390/polym14091909 - 07 May 2022
Cited by 1 | Viewed by 1702
Abstract
Colloidal unimolecular polymer (CUP) particles were made using polymers with different ratios of hydrophobic and hydrophilic monomers via a self-organization process known as water reduction. The water-reduction process and the collapse of the polymer chain to form a CUP were tracked using viscosity [...] Read more.
Colloidal unimolecular polymer (CUP) particles were made using polymers with different ratios of hydrophobic and hydrophilic monomers via a self-organization process known as water reduction. The water-reduction process and the collapse of the polymer chain to form a CUP were tracked using viscosity measurements as a function of composition. A vibration viscometer, which allowed for viscosity measurement as the water was being added during the water-reduction process, was utilized. The protocol was optimized and tested for factors such as temperature control, loss of material, measurement stability while stirring, and changes in the solution volume with the addition of water. The resulting viscosity curve provided the composition of Tetrahydrofuran (THF)/water mixture that triggers the collapse of a polymer chain into a particle. Hansen as well as dielectric parameters were related to the polymer composition and percentage v/v of THF/water mixture at the collapse point. It was observed that the collapse of the polymer chain occurred when the water/THF composition was at a water volume of between 53.8 to 59.3% in the solvent mixture. Full article
(This article belongs to the Special Issue Phase Behavior in Polymers: Morphology and Self-Assembly)
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15 pages, 8204 KiB  
Article
Functionalization of PEG-AgNPs Hybrid Material to Alleviate Biofouling Tendency of Polyethersulfone Membrane
by Afrillia Fahrina, Nasrul Arahman, Sri Aprilia, Muhammad Roil Bilad, Silmina Silmina, Widia Puspita Sari, Indah Maulana Sari, Poernomo Gunawan, Mehmet Emin Pasaoglu, Vahid Vatanpour, Ismail Koyuncu and Saeid Rajabzadeh
Polymers 2022, 14(9), 1908; https://doi.org/10.3390/polym14091908 - 07 May 2022
Cited by 10 | Viewed by 2200
Abstract
Membrane-based processes are a promising technology in water and wastewater treatments, to supply clean and secure water. However, during membrane filtration, biofouling phenomena severely hamper the performance, leading to permanent detrimental impacts. Moreover, regular chemical cleaning is ineffective in the long-run for overcoming [...] Read more.
Membrane-based processes are a promising technology in water and wastewater treatments, to supply clean and secure water. However, during membrane filtration, biofouling phenomena severely hamper the performance, leading to permanent detrimental impacts. Moreover, regular chemical cleaning is ineffective in the long-run for overcoming biofouling, because it weakens the membrane structure. Therefore, the development of a membrane material with superior anti-biofouling performance is seen as an attractive option. Hydrophilic-anti-bacterial precursor polyethylene glycol-silver nanoparticles (PEG-AgNPs) were synthesized in this study, using a sol-gel method, to mitigate biofouling on the polyethersulfone (PES) membrane surface. The functionalization of the PEG-AgNP hybrid material on a PES membrane was achieved through a simple blending technique. The PES/PEG-AgNP membrane was manufactured via the non-solvent induced phase separation method. The anti-biofouling performance was experimentally measured as the flux recovery ratio (FRR) of the prepared membrane, before and after incubation in E. coli culture for 48 h. Nanomaterial characterization confirmed that the PEG-AgNPs had hydrophilic-anti-bacterial properties. The substantial improvements in membrane performance after adding PEG-AgNPs were evaluated in terms of the water flux and FRR after the membranes experienced biofouling. The results showed that the PEG-AgNPs significantly increased the water flux of the PES membrane, from 2.87 L·m−2·h−1 to 172.84 L·m−2·h−1. The anti-biofouling performance of the PES pristine membrane used as a benchmark showed only 1% FRR, due to severe biofouling. In contrast, the incorporation of PEG-AgNPs in the PES membrane decreased live bacteria by 98%. It enhanced the FRR of anti-biofouling up to 79%, higher than the PES/PEG and PES/Ag membranes. Full article
(This article belongs to the Special Issue Novel Polymeric Blend/Composites and Functional Membranes)
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25 pages, 8652 KiB  
Article
The Microencapsulation of Tung Oil with a Natural Hydrocolloid Emulsifier for Extrinsic Self-Healing Applications
by Abdullah Naseer Mustapha, Maitha AlMheiri, Nujood AlShehhi, Nitul Rajput, Sachin Joshi, Ana Antunes and Mohamed AlTeneiji
Polymers 2022, 14(9), 1907; https://doi.org/10.3390/polym14091907 - 07 May 2022
Cited by 3 | Viewed by 2453
Abstract
In this work, tung oil was utilised as a catalyst-free self-healing agent, and an in-situ polymerization process was applied to encapsulate the tung oil core with a poly(urea-formaldehyde) (PUF) shell. The conventional poly(ethylene-alt-maleic-anhydride) (PEMA) polymer was compared to a more naturally abundant gelatin [...] Read more.
In this work, tung oil was utilised as a catalyst-free self-healing agent, and an in-situ polymerization process was applied to encapsulate the tung oil core with a poly(urea-formaldehyde) (PUF) shell. The conventional poly(ethylene-alt-maleic-anhydride) (PEMA) polymer was compared to a more naturally abundant gelatin (GEL) emulsifier to compare the microcapsules’ barrier, morphological, thermal, and chemical properties, and the crystalline nature of the shell material. GEL emulsifiers produced microcapsules with a higher payload (96.5%), yield (28.9%), and encapsulation efficiency (61.7%) compared to PEMA (90.8%, 28.6% and 52.6%, respectively). Optical and electron microscopy imaging indicated a more uniform morphology for the GEL samples. The thermal decomposition measurements indicated that GEL decomposed to a value 7% lower than that of PEMA, which was suggested to be attributed to the much thinner shell materials that the GEL samples produced. An innovative and novel focused ion beam (FIB) milling method was exerted on the GEL sample, confirming the storage and release of the active tung oil material upon rupturing. The samples with GEL conveyed a higher healing efficiency of 91%, compared to PEMA’s 63%, and the GEL samples also conveyed higher levels of corrosion resistance. Full article
(This article belongs to the Special Issue Polymer-Based Nano/Microparticles)
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16 pages, 4691 KiB  
Article
Fabrication of a Nickel Ferrite/Nanocellulose-Based Nanocomposite as an Active Sensing Material for the Detection of Chlorine Gas
by Nurjahirah Janudin, Noor Azilah Mohd Kasim, Victor Feizal Knight, Mohd Nor Faiz Norrrahim, Mas Amira Idayu Abdul Razak, Norhana Abdul Halim, Siti Aminah Mohd Noor, Keat Khim Ong, Mohd Hanif Yaacob, Muhammad Zamharir Ahmad and Wan Md Zin Wan Yunus
Polymers 2022, 14(9), 1906; https://doi.org/10.3390/polym14091906 - 06 May 2022
Cited by 11 | Viewed by 2217
Abstract
Chlorine gas is extensively utilised in industries as both a disinfectant and for wastewater treatment. It has a pungent and irritating odour that is comparable with that of bleach and can cause serious health issues such as headaches and breathing difficulties. Hence, efficiently, [...] Read more.
Chlorine gas is extensively utilised in industries as both a disinfectant and for wastewater treatment. It has a pungent and irritating odour that is comparable with that of bleach and can cause serious health issues such as headaches and breathing difficulties. Hence, efficiently, and accurately monitoring chlorine gas is critical to ensure that no undesirable incidents occur. Due to its remarkable characteristics, numerous researchers have explored the potential of ferrite nanoparticles as a sensing material for chlorine gas detection. Among several ferrite nanoparticles, nickel ferrite (NiFe2O4) is extensively studied as an inverse spinel structured magnetic material that may be ideal for sensing applications. However, the magnetic characteristics of NiFe2O4 cause agglomeration, which necessitates the use of a substrate for stabilisation. Therefore, nanocellulose (NC), as a green and eco-friendly substrate, is ideal for stabilising bare nickel ferrite nanoparticles. In a novel experiment, nickel ferrite was loaded onto NC as a substrate using in situ deposition. The structure was confirmed by X-ray Diffraction (XRD) analysis, while elemental composition was verified by Energy dispersive X-ray (EDX) analysis. Gas sensing properties were determined by evaluating sensitivity as a function of various regulating factors, such as the amount of nickel ferrite, gas concentration, repeatability, and reusability. In the evaluation, 0.3 g nickel ferrite showed superior response and sensitivity than those of other samples. The achieved response time was around 40 s, while recovery time was about 50 s. This study demonstrates the potential of a nickel ferrite/nanocellulose-based nanocomposite to efficiently monitor chlorine gas. Full article
(This article belongs to the Section Smart and Functional Polymers)
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16 pages, 3247 KiB  
Article
Experimental Investigation of the High-Temperature Rheological and Aging Resistance Properties of Activated Crumb Rubber Powder/SBS Composite-Modified Asphalt
by Zhizhong Zhao, Longlin Wang, Wensheng Wang and Xuanhao Shangguan
Polymers 2022, 14(9), 1905; https://doi.org/10.3390/polym14091905 - 06 May 2022
Cited by 9 | Viewed by 1679
Abstract
Crumb rubber could form the active groups on the surface by interrupting the crosslinking bond to improve the compatibility with asphalt. While styrene-butadiene-styrene block copolymer (SBS)-modified asphalt has excellent comprehensive properties, it has poor anti-aging performance and a high cost. To explore the [...] Read more.
Crumb rubber could form the active groups on the surface by interrupting the crosslinking bond to improve the compatibility with asphalt. While styrene-butadiene-styrene block copolymer (SBS)-modified asphalt has excellent comprehensive properties, it has poor anti-aging performance and a high cost. To explore the influence of composite modification of activated crumb rubber powder (ACR) and SBS on asphalt, modified asphalt samples with different modifiers and SBS contents were prepared. Conventional physical properties tests, a dynamic shear rheometer (DSR), and the thin-film oven test (TFOT) were used to study the conventional physical properties, high-temperature rheological properties, and aging resistance of asphalt. In addition, the action forms and distribution of modifiers in asphalt were observed by an optical microscope to characterize the micro-morphology of ACR/SBS composite-modified asphalt. Test results showed that after adding SBS, the softening point, ductility, and elastic recovery of ACR/SBS asphalt could be significantly improved, but the viscosity and softening point difference were also larger. At the same time, according to the complex shear modulus, phase angle, and rutting factor, SBS can effectively improve the high-temperature deformation resistance of ACR/SBS asphalt. The modified asphalt (ACR/SBS-2) had good high- and low- temperature performances, as well as an appropriate viscosity and low softening point difference, as a research object of aging. After short-term aging, the changes in the high- and low-temperature performances and workability of ACR/SBS asphalt were reduced. Taking the softening point as the target performance, the softening point of ACR/SBS asphalt was less affected by aging time and temperature, indicating that ACR/SBS asphalt was not sensitive to aging temperature and had good stability and aging resistance. From the micrograph by microscope, it was found that ACR/SBS asphalt could maintain a relatively stable polyphase structure for aging resistance. Full article
(This article belongs to the Special Issue Polymeric Composites in Road and Bridge Engineering: Characterization, Production and Application)
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16 pages, 3254 KiB  
Article
Extraction Optimization of Mucilage from Seeds of Mimosa pudica by Response Surface Methodology
by Syed Nasir Abbas Bukhari, Arshad Ali, Muhammad Ajaz Hussain, Muhammad Tayyab, Nasser F. Alotaibi, Mervat A. Elsherif, Kashaf Junaid and Hasan Ejaz
Polymers 2022, 14(9), 1904; https://doi.org/10.3390/polym14091904 - 06 May 2022
Cited by 6 | Viewed by 2307
Abstract
Mimosa pudica seed mucilage (MPM) is composed of glucuronoxylan, which is a swellable, pH-responsive and non-toxic biomaterial. Herein, we aimed to extract MPM from M. pudica seeds (MP seeds) to ascertain optimization of extraction conditions to get highest yield by response surface methodology, [...] Read more.
Mimosa pudica seed mucilage (MPM) is composed of glucuronoxylan, which is a swellable, pH-responsive and non-toxic biomaterial. Herein, we aimed to extract MPM from M. pudica seeds (MP seeds) to ascertain optimization of extraction conditions to get highest yield by response surface methodology, via Box-Behnken design (RSM-BBD). MPM was extracted from MP seeds by a hot water extraction method. The effects of four different parameters on the extraction yield of MPM were evaluated: pH of the extraction medium (1–10), seed/water contact time (1–12 h), the temperature of extraction medium (30–90 °C), and seed/water ratio (1:5–1:35 w/v). The maximum yield of MPM obtained by Design-Expert software was 10.66% (10.66 g/100 g) at pH 7, seed/water contact time of 6 h, extraction temperature of 50 °C, and seed/water ratio of 1:20 w/v. The p values of ANOVA were found to be less than 0.0001, which indicated that the extraction yield of MPM was significantly affected by all the study parameters. The results revealed that pH and extraction temperature were the most significant factors affecting the yield of MPM. MPM in compressed tablet form showed pH-responsive on–off switching behavior at pH 7.4 and 1.2 in a reversible manner. MPM in compressed tablet form sustained the release of itopride for 16 h following a super case-II transport mechanism and zero-order release kinetics. Full article
(This article belongs to the Special Issue Functional Natural-Based Polymers)
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24 pages, 10863 KiB  
Article
Multi-Functional 3D-Printed Vat Photopolymerization Biomedical-Grade Resin Reinforced with Binary Nano Inclusions: The Effect of Cellulose Nanofibers and Antimicrobial Nanoparticle Agents
by Nectarios Vidakis, Markos Petousis, Nikolaos Michailidis, Vassilis Papadakis, Apostolos Korlos, Nikolaos Mountakis and Apostolos Argyros
Polymers 2022, 14(9), 1903; https://doi.org/10.3390/polym14091903 - 06 May 2022
Cited by 12 | Viewed by 2612
Abstract
This study introduced binary nanoparticle (NP) inclusions into a biomedical-grade photosensitive resin (Biomed Clear-BC). Multi-functional, three-dimensional (3D) printed objects were manufactured via the vat photopolymerization additive manufacturing (AM) technique. Cellulose nanofibers (CNFs) as one dimensional (1D) nanomaterial have been utilized for the mechanical [...] Read more.
This study introduced binary nanoparticle (NP) inclusions into a biomedical-grade photosensitive resin (Biomed Clear-BC). Multi-functional, three-dimensional (3D) printed objects were manufactured via the vat photopolymerization additive manufacturing (AM) technique. Cellulose nanofibers (CNFs) as one dimensional (1D) nanomaterial have been utilized for the mechanical reinforcement of the resin, while three different spherical NPs, namely copper NPs (nCu), copper oxide NPs (nCuO), and a commercial antimicrobial powder (nAP), endowed the antimicrobial character. The nanoparticle loading was kept constant at 1.0 wt.% to elucidate any synergistic effects as a function of the filler loading. Raman, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) revealed the chemical/spectroscopic and thermal properties of the different manufactured samples. Scanning electron microscopy and Atomic Force Microscopy (AFM) revealed the morphology of the samples. Mechanical properties revealed the reinforcement mechanisms, namely that BC/CNF (1.0 wt.%) exhibited a 102% and 154% enhancement in strength and modulus, respectively, while BC/CNF(1.0 wt.%)/AP(1.0 wt.%) exhibited a 95% and 101% enhancement, as well as an antibacterial property, which was studied using a screening agar well diffusion method. This study opens the route towards novel, multi-functional materials for vat photopolymerization 3D printing biomedical applications, where mechanical reinforcement and antibacterial performance are typically required in the operational environment. Full article
(This article belongs to the Special Issue High-Performance Polymer-Based 3D Printing Composites)
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11 pages, 16356 KiB  
Article
A Highly Sensitive, Ultra-Durable, Eco-Friendly Ionic Skin for Human Motion Monitoring
by Zhaoxin Li, Haoyan Xu, Na Jia, Yifei Li, Liangkuan Zhu and Zhuangzhi Sun
Polymers 2022, 14(9), 1902; https://doi.org/10.3390/polym14091902 - 06 May 2022
Cited by 4 | Viewed by 1630
Abstract
Ionic conductive hydrogels have shown great potential in areas such as wearable devices and electronic skins. Aiming at the sensitivity and biodegradability of the traditional flexible hydrogel electronic skin, this paper developed an ionic skin (S−iSkin) based on edible starch–sodium alginate (starch–SA), which [...] Read more.
Ionic conductive hydrogels have shown great potential in areas such as wearable devices and electronic skins. Aiming at the sensitivity and biodegradability of the traditional flexible hydrogel electronic skin, this paper developed an ionic skin (S−iSkin) based on edible starch–sodium alginate (starch–SA), which can convert the external strain stimulus into a voltage signal without an external power supply. As an excellent ion conductive polymer, S−iSkin exhibited good stretchability, low hydrophilicity and outstanding electrochemical and sensing properties. Driven by sodium ions, the ion charge transfer resistance of S−iSkin is reduced by 4 times, the capacitance value is increased by 2 times and its conductivity is increased by 7 times. Additionally, S−iSkin has excellent sensitivity and linearity (R2 = 0.998), a long service life and good biocompatibility. Under the action of micro-stress, it can produce a voltage change ratio of 2.6 times, and its sensitivity is 52.04. The service life test showed that it can work stably for 2000 s and work more than 200 stress–voltage response cycles. These findings provide a foundation for the development of health monitoring systems and micro-stress sensing devices based on renewable biomass materials. Full article
(This article belongs to the Special Issue Bio-Inspired Functional Polymers: Design, Manufacture and Application)
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5 pages, 212 KiB  
Editorial
Metal Nanoparticles–Polymers Hybrid Materials II
by Iole Venditti
Polymers 2022, 14(9), 1901; https://doi.org/10.3390/polym14091901 - 06 May 2022
Cited by 2 | Viewed by 1198
Abstract
Despite the pandemic, the last five years have been marked by an extraordinary development of new advanced technologies, based not only on new materials but also on modeling, information technology and artificial intelligence, which have allowed for great leaps forward in various research [...] Read more.
Despite the pandemic, the last five years have been marked by an extraordinary development of new advanced technologies, based not only on new materials but also on modeling, information technology and artificial intelligence, which have allowed for great leaps forward in various research fields [...] Full article
(This article belongs to the Special Issue Metal Nanoparticles–Polymers Hybrid Materials II)
8 pages, 3411 KiB  
Communication
Facile Synthesis of Microporous Ferrocenyl Polymers Photocatalyst for Degradation of Cationic Dye
by Bing Zhang, Zhiqiang Tan, Yinhu Zhang, Qingquan Liu, Qianxia Li and Gen Li
Polymers 2022, 14(9), 1900; https://doi.org/10.3390/polym14091900 - 06 May 2022
Cited by 2 | Viewed by 1633
Abstract
Microporous organic polymers (MOPs) were prepared by condensation reactions from substituent-group-free carbazole and pyrrole with 1,1′-ferrocenedicarboxaldehyde without adding any catalysts. The resultant MOPs were insoluble in common solvent and characterized by FTIR, XPS, TGA and SEM. An N2 adsorption test showed that [...] Read more.
Microporous organic polymers (MOPs) were prepared by condensation reactions from substituent-group-free carbazole and pyrrole with 1,1′-ferrocenedicarboxaldehyde without adding any catalysts. The resultant MOPs were insoluble in common solvent and characterized by FTIR, XPS, TGA and SEM. An N2 adsorption test showed that the obtained polymers PFcMOP and CFcMOP exhibited Brunauer–Emmett–Teller (BET) surface areas of 48 and 105 m2 g−1, respectively, and both polymers possessed abundant micropores. The MOPs with a nitrogen and ferrocene unit could be potentially applied in degrading dye with high efficiency. Full article
(This article belongs to the Special Issue Porous Polymeric Materials: Design and Applications)
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