Research

11 pages, 1945 KiB

Open AccessArticle

Ethylene Vinyl Alcohol Copolymer Nanofibrous Cation Exchange Chromatographic Membranes with a Gradient Porous Structure for Lysozyme Separation

by Tianzhi Tang, Jinping Gan, Zhanrui Cao, Pan Cheng, Qin Cheng, Tao Mei, Liping Zhu, Feng Zhou, Ke Liu and Dong Wang

Polymers 2024, 16(8), 1112; https://doi.org/10.3390/polym16081112 - 16 Apr 2024

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Abstract

Lysozyme, a common antimicrobial agent, is widely used in the food, biopharmaceutical, chemical, and medicine fields. Rapid and effective isolation of lysozymes is an everlasting topic. In this work, ethylene vinyl alcohol (EVOH) copolymer nanofibrous membranes with a gradient porous structure used for [...] Read more.

Lysozyme, a common antimicrobial agent, is widely used in the food, biopharmaceutical, chemical, and medicine fields. Rapid and effective isolation of lysozymes is an everlasting topic. In this work, ethylene vinyl alcohol (EVOH) copolymer nanofibrous membranes with a gradient porous structure used for lysozyme adsorption were prepared through layer-by-layer nanofiber wet-laying and a cost-efficient ultraviolet (UV)-assisted graft-modification method, where benzophenone was used as an initiator and 2-acrylamide-2-methylpropanesulfonic acid as a modifying monomer. As indicated in the Fourier Transform Infrared (FTIR) and X-ray photoelectric energy spectrometer (XPS) investigation, sulfonic acid groups were introduced on the surface of the modified nanofibrous membrane, which possessed the ability to adsorb lysozyme. Compared with membranes with homogenous porous structures, membranes with a gradient porous structure present higher static (335 mg/g) and dynamic adsorption capacities (216.3 mg/g). Meanwhile, the adsorption capacity remained high after five cycles of the adsorption–desorption process. The results can be attributed to the gradient porous structure rather than the highest porosity and specific surface area. This suggests that the membrane with comprehensive separation performance can be designed from the view of the transmembrane porous structure, which is of significance for the development of next-generation advanced chromatographic membranes. Full article

(This article belongs to the Special Issue Advanced Polymer Nanocomposites III)

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13 pages, 3259 KiB

Open AccessArticle

Encapsulation of Methanotrophs within a Polymeric Matrix Containing Copper- and Iron-Based Nanoparticles to Enhance Methanol Production from a Simulated Biogas

by Sanjay K. S. Patel, Rahul K. Gupta, In-Won Kim and Jung-Kul Lee

Polymers 2023, 15(18), 3667; https://doi.org/10.3390/polym15183667 - 06 Sep 2023

Cited by 1 | Viewed by 862

Abstract

The production of renewable energy or biochemicals is gaining more attention to minimize the emissions of greenhouse gases such as methane (CH₄) and carbon dioxide for sustainable development. In the present study, the influence of copper (Cu)- and iron (Fe)-based nanoparticles [...] Read more.

The production of renewable energy or biochemicals is gaining more attention to minimize the emissions of greenhouse gases such as methane (CH₄) and carbon dioxide for sustainable development. In the present study, the influence of copper (Cu)- and iron (Fe)-based nanoparticles (NPs), such as Cu, Fe₃O₄, and CuFe₂O₄, was evaluated during the growth of methanotrophs for inoculum preparation and on the development of a polymeric-matrix-based encapsulation system to enhance methanol production from simulated biogas (CH₄ and CO₂). The use of simulated biogas feed and the presence of NP-derived inoculums produce a remarkable enhancement in methanol production up to 149% and 167% for Methyloferula stellata and Methylocystis bryophila free-cells-based bioconversion, respectively, compared with the use of pure CH₄ as a control feed during the growth stage. Furthermore, these methanotrophs encapsulated within a polymeric matrix and NPs-based systems exhibited high methanol production of up to 156%, with a maximum methanol accumulation of 12.8 mmol/L over free cells. Furthermore, after encapsulation, the methanotrophs improved the stability of residual methanol production and retained up to 62.5-fold higher production potential than free cells under repeated batch reusability of 10 cycles. In the presence of CH₄ vectors, methanol production by M. bryophila improved up to 16.4 mmol/L and retained 20% higher recycling stability for methanol production in paraffin oil. These findings suggest that Cu and Fe NPs can be beneficially employed with a polymeric matrix to encapsulate methanotrophs and improve methanol production. Full article

(This article belongs to the Special Issue Advanced Polymer Nanocomposites III)

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13 pages, 1399 KiB

Open AccessArticle

The Role of Virgin Coconut Oil in Corn Starch/NCC-Based Nanocomposite Film Matrix: Physical, Mechanical, and Water Vapor Transmission Characteristics

by Heni Radiani Arifin, Fitriana Utaminingsih, Mohamad Djali, Bambang Nurhadi, Elazmanawati Lembong and Herlina Marta

Polymers 2023, 15(15), 3239; https://doi.org/10.3390/polym15153239 - 29 Jul 2023

Cited by 2 | Viewed by 1065

Abstract

Corn starch-based nanocomposite films usually have low moisture barrier properties. Adding virgin coconut oil (VCO) as a hydrophobic component can improve the nanocomposite film’s characteristics, especially the film’s permeability and elongation properties. This study aimed to determine the role of VCO with various [...] Read more.

Corn starch-based nanocomposite films usually have low moisture barrier properties. Adding virgin coconut oil (VCO) as a hydrophobic component can improve the nanocomposite film’s characteristics, especially the film’s permeability and elongation properties. This study aimed to determine the role of VCO with various concentrations (0, 3, 5 wt%) on the physical, mechanical, and water vapor transmission characteristics of corn starch/NCC-based nanocomposite films. Adding 3% VCO to the film showed the lowest WVTR value by 4.721 g/m².h. At the same time, the value of tensile strength was 4.243 MPa, elongation 69.28%, modulus of elasticity 0.062 MPa, thickness 0.219 mm, lightness 98.77, and water solubility 40.51%. However, adding 5 wt% VCO to the film increased the film’s elongation properties by 83.87%. The SEM test showed that adding VCO formed a finer structure with pores in several areas. The FTIR films showed that adding VCO caused a slightly higher absorption peak shift at the O–H groups and new absorption peaks at wave numbers 1741 cm⁻¹ and 1742 cm⁻¹. The results of this study may provide opportunities for the development of nanocomposite films as biodegradable packaging in the future. Full article

(This article belongs to the Special Issue Advanced Polymer Nanocomposites III)

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13 pages, 6486 KiB

Open AccessArticle

Reinforcement of Aminopropyl-Terminated Siloxane-Treated Carbon Nanotubes in Epoxy Thermosets: Mechanical and Thermal Properties

by Yuxin Sun, Xiwen Zhang and Dongyu Zhao

Polymers 2023, 15(15), 3184; https://doi.org/10.3390/polym15153184 - 27 Jul 2023

Cited by 2 | Viewed by 1083

Abstract

The synthesis and characterization of aminopropyl-terminated polydimethylsiloxane- treated carbon nanotube (AFCNT)-reinforced epoxy nanocomposites are reported in the current study. The amine functionalization of the CNTs was performed with a reaction to PDMS-NH₂. The AFCNTs were homogeneously dispersed in epoxy resin by [...] Read more.

The synthesis and characterization of aminopropyl-terminated polydimethylsiloxane- treated carbon nanotube (AFCNT)-reinforced epoxy nanocomposites are reported in the current study. The amine functionalization of the CNTs was performed with a reaction to PDMS-NH₂. The AFCNTs were homogeneously dispersed in epoxy resin by using an emulsifier and a three-roller mill. The AFCNTs were characterized using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The curing behavior of the epoxy/AFCNT was studied using a differential scanning calorimeter (DSC). The tensile and impact strengths of the 2.0 wt.% AFCNT-reinforced epoxy nanocomposite were enhanced by 43.2% and 370%, respectively. Moreover, the glass transition temperature (T_g) was also enhanced by 21 °C. Furthermore, significant enhancements were observed in the initial degradation and char yield values. SEM results confirmed that the AFCNTs were highly dispersed in the polymeric matrix. Full article

(This article belongs to the Special Issue Advanced Polymer Nanocomposites III)

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18 pages, 5856 KiB

Open AccessArticle

Multi-Walled Carbon-Nanotube-Reinforced PMMA Nanocomposites: An Experimental Study of Their Friction and Wear Properties

by Vijay Patel, Unnati Joshi, Anand Joshi, Blessing Kudzai Matanda, Kamlesh Chauhan, Ankit D. Oza, Diana-Petronela Burduhos-Nergis and Dumitru-Doru Burduhos-Nergis

Polymers 2023, 15(13), 2785; https://doi.org/10.3390/polym15132785 - 22 Jun 2023

Cited by 2 | Viewed by 1118

Abstract

This manuscript presents an experimental investigation of the friction and wear properties of poly (methyl methacrylate) (PMMA) nanocomposites reinforced with functionalized multi-walled carbon nanotubes (MWCNTs). The aim of this study is to evaluate the potential of MWCNTs as a reinforcement material for enhancing [...] Read more.

This manuscript presents an experimental investigation of the friction and wear properties of poly (methyl methacrylate) (PMMA) nanocomposites reinforced with functionalized multi-walled carbon nanotubes (MWCNTs). The aim of this study is to evaluate the potential of MWCNTs as a reinforcement material for enhancing the tribological performance of PMMA. Three types of multi-walled carbon nanotubes, i.e., pristine, hydroxyl functionalized, and carboxyl functionalized, were utilized in this study. The nanocomposite samples were prepared by dispersing varying concentrations of MWCNTs (0.1 wt.%, 0.5 wt.%, and 1 wt.%) within the PMMA matrix via a 3D mixing approach, followed by injection molding/compression molding. The resulting nanocomposite films were characterized using scanning electron microscopy (SEM) to observe the dispersion of MWCNTs within the PMMA matrix. The friction and wear tests were conducted using a pin-on-disk tribometer under dry sliding conditions. The effects of functionalization and MWCNT content on the tribological behaviors of the nanocomposites were analyzed. The nanocomposites exhibited lower friction coefficients and reduced wear rates compared to pure PMMA. The lowest friction coefficient and wear rate were achieved at an optimum MWCNT loading of 0.5 wt.%. It was further revealed that the amount of MWCNT reinforcement, average load, and track diameter significantly affect the coefficient of friction (COF) and rate of wear. The COF and wear rate are best at a filler loading of 0.5 wt.%, a 20 Kg load, and 90 mm. The improved tribological performance of the MWCNT-reinforced PMMA nanocomposites can be attributed to the effective transfer of load between the MWCNTs and the PMMA matrix, as well as the reinforcement effect of the MWCNTs. The MWCNTs acted as reinforcing agents, enhancing the mechanical properties and wear resistance of the nanocomposites. Full article

(This article belongs to the Special Issue Advanced Polymer Nanocomposites III)

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17 pages, 2727 KiB

Open AccessArticle

One-Pot Synthesis of Colloidal Hybrid Au (Ag)/ZnO Nanostructures with the Participation of Maleic Acid Copolymers

by Nadezhda A. Samoilova, Maria A. Krayukhina, Alexander A. Korlyukov, Zinaida S. Klemenkova, Alexander V. Naumkin and Yaroslav O. Mezhuev

Polymers 2023, 15(7), 1670; https://doi.org/10.3390/polym15071670 - 27 Mar 2023

Cited by 1 | Viewed by 1146

Abstract

One-pot synthesis of colloidal Au/ZnO and Ag/ZnO nanohybrid structures was carried out. The copolymers of maleic acid—poly(N-vinyl-2-pyrrolidone-alt-maleic acid), poly(ethylene-alt-maleic acid), or poly(styrene-alt-maleic acid) were used as templates for the sorption of cations of metals-precursors and stabilization of [...] Read more.

One-pot synthesis of colloidal Au/ZnO and Ag/ZnO nanohybrid structures was carried out. The copolymers of maleic acid—poly(N-vinyl-2-pyrrolidone-alt-maleic acid), poly(ethylene-alt-maleic acid), or poly(styrene-alt-maleic acid) were used as templates for the sorption of cations of metals-precursors and stabilization of the resulting nanoheterostructures. Simultaneous production of two types of nanoparticles has been implemented under mild conditions in an aqueous alkaline medium and without additional reagents. Equimolar ratios of the metal cations and appropriate load on all copolymers were used: molar ratio of maleic acid monomeric units of copolymer/gold (silver)cations/zinc cations was 1/0.15/0.23 (1/0.3/0.15). The process of obtaining the heterostructures was studied using UV-Vis spectroscopy. The kinetics of the formation of heterostructures was influenced by the nature of the maleic acid copolymer and noble metal cations used. A high reaction rate was observed in the case of using zinc and gold cations-precursors and a copolymer of maleic acid with N-vinylpyrrolidone as a stabilizer of nanoparticles. The structure of the synthesized polymer-stabilized heterostructures was studied using instrumental methods of analysis—XPS, FTIR, PXRD, and TEM. Under the conditions used, stable colloidal solutions of heterodimers were obtained, and such structure can be converted to a solid state and back without loss of properties. Full article

(This article belongs to the Special Issue Advanced Polymer Nanocomposites III)

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18 pages, 6639 KiB

Open AccessArticle

The β Form in PVDF Nanocomposites with Carbon Nanotubes: Structural Features and Properties

by María L. Cerrada, Javier Arranz-Andrés, Alicia Caballero-González, Enrique Blázquez-Blázquez and Ernesto Pérez

Polymers 2023, 15(6), 1491; https://doi.org/10.3390/polym15061491 - 16 Mar 2023

Cited by 4 | Viewed by 1673

Abstract

Different amounts of carbon nanotubes (CNT) have been incorporated in materials based on poly(vinylidene fluoride) (PVDF) by solvent blending followed by their further precipitation. Final processing was performed by compression molding. The morphological aspects and crystalline characteristics have been examined, additionally exploring in [...] Read more.

Different amounts of carbon nanotubes (CNT) have been incorporated in materials based on poly(vinylidene fluoride) (PVDF) by solvent blending followed by their further precipitation. Final processing was performed by compression molding. The morphological aspects and crystalline characteristics have been examined, additionally exploring in these nanocomposites the common routes described in the pristine PVDF to induce the β polymorph. This polar β phase has been found to be promoted by the simple inclusion of CNT. Therefore, coexistence of the α and β lattices occurs for the analyzed materials. The real-time variable-temperature X-ray diffraction measurements with synchrotron radiation at a wide angle have undoubtedly allowed us to observe the presence of the two polymorphs and determine the melting temperature of both crystalline modifications. Furthermore, the CNT plays a nucleating role in the PVDF crystallization, and also acts as reinforcement, increasing the stiffness of the nanocomposites. Moreover, the mobility within the amorphous and crystalline PVDF regions is found to change with the CNT content. Finally, the presence of CNT leads to a very remarkable increase in the conductivity parameter, in such a way that the transition from insulator to electrical conductor is reached in these nanocomposites at a percolation threshold ranging from 1 to 2 wt.%, leading to the excellent value of conductivity of 0.05 S/cm in the material with the highest content in CNT (8 wt.%). Full article

(This article belongs to the Special Issue Advanced Polymer Nanocomposites III)

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14 pages, 3324 KiB

Open AccessArticle

Porous Membranes of Polysulfone and Graphene Oxide Nanohybrids for Vanadium Redox Flow Battery

by Chien-Hong Lin, Ming-Yen Chien, Yi-Cih Chuang, Chao-Chi Lai, Yi-Ming Sun and Ting-Yu Liu

Polymers 2022, 14(24), 5405; https://doi.org/10.3390/polym14245405 - 09 Dec 2022

Viewed by 1471

Abstract

Porous nanohybrid membranes of polysulfone (PSF) with graphene oxide (GO) nanosheets (PSF/GO membrane) were developed to serve as proton exchange membranes in a vanadium redox flow battery (VRFB). Various ratios of PSF/GO and thickness were investigated to evaluate the optimal voltage efficiency (VE), [...] Read more.

Porous nanohybrid membranes of polysulfone (PSF) with graphene oxide (GO) nanosheets (PSF/GO membrane) were developed to serve as proton exchange membranes in a vanadium redox flow battery (VRFB). Various ratios of PSF/GO and thickness were investigated to evaluate the optimal voltage efficiency (VE), coulombic efficiency (CE), and energy efficiency (EE) of the VRFB. The pore size, distribution, and hydrophilicity of PSF/GO membranes were studied using scanning electron microscopy (SEM) images and contact angles. Functional groups of GO were evaluated using Raman spectroscopy. The mechanical properties and thermal stability of PSF/GO membranes were analyzed using a tensile tester and thermogravimetric analysis (TGA), respectively. The results show that the mechanical properties of the PSF porous membrane with GO nanosheets were significantly improved, indicating that the addition of graphene oxide nanosheets consolidated the internal structure of the PSF membrane. Cyclic voltammetry revealed an obviously different curve after the addition of GO nanosheets. The CE of the VRFB in the PSF/GO membrane was significantly higher than that in the pristine PSF membrane, increasing from 80% to 95% at 0.6 wt.% GO addition. Moreover, PSF/GO membranes displayed great chemical stability during long-term operation; thus, they can evolve as potential porous membranes for application in VRFBs for green energy storage. Full article

(This article belongs to the Special Issue Advanced Polymer Nanocomposites III)

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