Artykuły w czasopismach: „Viscoelastic Properties - Graphene/(poly)vinyl Alcohol(PVA) Nanocomposite”

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Tomić, Nataša Z., Myriam Ghodhbane, Zineb Matouk, Nujood AlShehhi i Chiara Busà. "Enhancement of Self-Healing Efficacy of Conductive Nanocomposite Hydrogels by Polysaccharide Modifiers". Polymers 15, nr 3 (18.01.2023): 516. http://dx.doi.org/10.3390/polym15030516.

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The proper design of a polysaccharide/hydrocolloid modifier significantly affects the conductivity, self-healing, and viscoelastic properties of nanocomposite hydrogels. Due to the presence of different functional groups, these hydrogels can participate in the covalent, hydrogen and dynamic bonding of a system. The improvement of interactions in this system can lead to the development of high-performance nanocomposite hydrogels. In this study, resilient, self-healing and self-adhesive conductive nanocomposite hydrogels were produced by multiple and diverse coordination connections between various polysaccharide-based modifiers (Arabic gum, sodium carboxymethyl cellulose, and xanthan), the poly(vinyl alcohol) (PVA) network and different graphene-based fillers. Graphene nanoplatelets (GNP), activated carbon black (ACB), and reduced graphene oxide (rGO) have distinct functionalized surfaces, which were analyzed by X-ray photoelectron spectroscopy (XPS). Furthermore, the introduction of fillers balanced the hydrogels’ viscoelastic properties and electrical conductivity, providing the hydrogels with resilience, improved electrical conductivity, and extreme stretchability (5000%). The self-healing properties were analyzed using time-dependent measurements in a shear strain mode using an RSO Rheometer. The improvement in electrochemical and conductivity properties was confirmed by electrochemical impedance spectroscopy (EIS). The obtained conductive nanocomposite hydrogels design opens new possibilities for developing high-performance polysaccharide-based hydrogels with wearable electrical sensors and healthcare monitoring applications.

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Lee, Min Eui, i Hyoung-Joon Jin. "Nanocomposite Films of Poly(vinyl alcohol)-Grafted Graphene Oxide/Poly(vinyl alcohol) for Gas Barrier Film Applications". Journal of Nanoscience and Nanotechnology 15, nr 10 (1.10.2015): 8348–52. http://dx.doi.org/10.1166/jnn.2015.11257.

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Poly(vinyl alcohol) (PVA) composites containing graphene oxide (GO) functionalized with PVA were synthesized via the esterification of the carboxylic groups of GO. The presence of PVA-grafted GO (PVA-g-GO) in the PVA matrix induced strong interactions between the chains of the PVA matrix and allowed the PVA-g-GO to be uniformly dispersed throughout the matrix. The grafting of PVA to GO increased the gas barrier properties of the GO/PVA composites because of the increased compatibility between GO and PVA. The PVA-g-GO/PVA composites were used to coat the surface of poly(ethylene terephthalate) films. These coated films exhibited excellent gas barrier properties; the film containing 0.3 wt% of PVA-g-GO had an oxygen transmission rate (OTR) of 0.025 cc/(m2 · day) and an optical transmittance of 83.8%. As a result, PVA-g-GO/PVA composites that exhibited enhanced gas barrier properties were prepared with a solution mixing method.

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Luo, Qiaomei, Yangyang Shan, Xia Zuo i Jiaqi Liu. "Anisotropic tough poly(vinyl alcohol)/graphene oxide nanocomposite hydrogels for potential biomedical applications". RSC Advances 8, nr 24 (2018): 13284–91. http://dx.doi.org/10.1039/c8ra00340h.

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Yilmaz Dogan, Hazal, Yasin Altin i Ayşe Çelik Bedeloğlu. "Fabrication and properties of graphene oxide and reduced graphene oxide reinforced Poly(Vinyl alcohol) nanocomposite films for packaging applications". Polymers and Polymer Composites 30 (styczeń 2022): 096739112211133. http://dx.doi.org/10.1177/09673911221113328.

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Petroleum-based polymers have a wide range of uses in the packaging industry, including films, food packaging, rigid containers, foamed containers, medical products, etc. This study focuses on improving the properties of polyvinyl alcohol (PVA) based material systems, one of the most popular water-soluble biopolymers, to reduce the waste of petroleum-based plastics, which are widely used. Polyvinyl alcohol (PVA) nanocomposite films containing low concentrations (0.05–1%) of graphene oxide (GO) and reduced graphene oxide (rGO) were produced via the solution casting method. When electrical properties of nanocomposite films were evaluated, the addition of 1 wt% GO and rGO resulted in a 36% and 45% decrease in the volumetric resistance of the films as well as a decrease in surface resistance of 24.5% and 34.9%, respectively. The maximum tensile strength of 1% GO and rGO-reinforced PVA nanocomposites was found to be ∼59 MPa and ∼68 MPa with an increase of 20% and 38% compared to neat PVA films, respectively. The average Young’s modulus of 1% GO and rGO-reinforced PVA nanocomposites also increased from 2561 MPa to 3515 MPa and 4219 MPa with an increase of 37% and 65%, respectively. As a result, the electrical conductivity, Young’s modulus, maximum tensile strength, thermal properties, and optical absorption of nanocomposite films increased by adding GO and rGO to PVA. The results show that the produced nanocomposite film may be a promising material for packaging applications.

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Makharza, Sami, Maryam Faroun, Mohammad Bawwab i Ibrahim Afaneh. "GRAPHENE OXIDE REINFORCED POLY (VINYL ALCOHOL) NANOCOMPOSITE: FABRICATION AND CHARACTERIZATION FOR THERMAL AND MECHANICAL PROPERTIES INVESTIGATIONS". Engineering Structures and Technologies 11, nr 4 (31.12.2019): 125–29. http://dx.doi.org/10.3846/est.2019.12473.

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We reported the fabrication of poly (vinyl alcohol) incorporated with two different sizes of graphene oxide particles. Scanning electron microscopy (SEM) revealed two sizes of graphene oxide, the first size is as prepared GO_300 nm and the second size is 100nm after hard sonication. The alteration in thermal and mechanical properties of PVA/ GO (5, 10, 15, 20%) nanocomposite compering with PVA are mainly due to the uniform dispersion of GO particles in the polymer matrix and huge interfacial interaction between PVA and GO sheets. Differential scanning calorimetry shows obvious changes in thermal characteristics of PVA after mixing with GO particles. The composite samples exhibit a significant finding at different concentrations and size distribution of GO.

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Frounchi, Masoud, Susan Dadbin i Sara Haddadi. "Poly (vinyl alcohol)/nano-diamond composite films and hydrogels prepared by gamma ray". Journal of Polymer Engineering 38, nr 9 (25.10.2018): 857–62. http://dx.doi.org/10.1515/polyeng-2017-0290.

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Abstract Poly (vinyl alcohol) and nano-diamond, PVA/ND, hydrogels were prepared and assessed as prosthetic material suitable for replacement of the nucleus pulposus. The hydrogels were prepared by gamma irradiation at various doses (15 kGy, 25 kGy, 35 kGy, 45 kGy) and at various ND concentrations ranging from 0.25 wt.% to 3 wt.%. Extent of gelation, equilibrium water content, and viscoelastic properties of swelled hydrogels at definite water contents were measured and examined as a function of ND concentration as well as gamma dose. According to viscoelastic measurements, the strength of hydrogels increased considerably over that of pure PVA at a low concentration of ND. By increasing irradiation dose, gel percent and strength of hydrogels increased. Hydrogel water content was in a range of 80 wt.% to 90 wt.% similar to that of natural nucleus pulposus. The G″ values of hydrogels were much smaller than G′ values indicating elastic behavior. Also PVA/ND nanocomposite films were prepared at various ND concentrations by solution casting. The ND particles were uniformly distributed within PVA films. Tensile modulus and strength of the films increased over pure PVA.

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Cho, Beom-Gon, Shalik Ram Joshi, Seongjin Lee, Shin-Kwan Kim, Young-Bin Park i Gun-Ho Kim. "Enhanced Mechanical and Antibacterial Properties of Nanocomposites Based on Poly(vinyl Alcohol) and Biopolymer-Derived Reduced Graphene Oxide". Polymers 13, nr 4 (18.02.2021): 615. http://dx.doi.org/10.3390/polym13040615.

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Functionalized graphene–polymer nanocomposites have gained significant attention for their enhanced mechanical, thermal, and antibacterial properties, but the requirement of multi-step processes or hazardous reducing agents to functionalize graphene limits their current applications. Here, we present a single-step synthesis of thermally reduced graphene oxide (TrGO) based on shellac, which is a low-cost biopolymer that can be employed to produce poly(vinyl alcohol) (PVA)/TrGO nanocomposites (PVA–TrGO). The concentration of TrGO varied from 0.1 to 2.0 wt.%, and the critical concentration of homogeneous TrGO dispersion was observed to be 1.5 wt.%, below which strong interfacial molecular interactions between the TrGO and the PVA matrix resulted in improved thermal and mechanical properties. At 1.5 wt.% filler loading, the tensile strength and modulus of the PVA–TrGO nanocomposite were increased by 98.7% and 97.4%, respectively, while the storage modulus was increased by 69%. Furthermore, the nanocomposite was 96% more effective in preventing bacterial colonization relative to the neat PVA matrix. The present findings indicate that TrGO can be considered a promising material for potential applications in biomedical devices.

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Cobos, Mónica, M. Fernández i M. Fernández. "Graphene Based Poly(Vinyl Alcohol) Nanocomposites Prepared by In Situ Green Reduction of Graphene Oxide by Ascorbic Acid: Influence of Graphene Content and Glycerol Plasticizer on Properties". Nanomaterials 8, nr 12 (6.12.2018): 1013. http://dx.doi.org/10.3390/nano8121013.

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The enhanced properties of polymer nanocomposites as compared with pure polymers are only achieved in the presence of well-dispersed nanofillers and strong interfacial adhesion. In this study, we report the preparation of nanocomposite films based on poly(vinyl alcohol) (PVA) filled with well dispersed graphene sheets (GS) by in situ reduction of graphene oxide (GO) dispersed in PVA solution using ascorbic acid (L-AA) as environmentally friendly reductant. The combined effect of GS content and glycerol as plasticizer on the structure, thermal, mechanical, water absorption, and water barrier properties of PVA/GS nanocomposite films is studied for the first time. Higher glass transition temperature, lower crystallinity, melting, and crystallization temperature, higher mechanical properties, and remarkable improvement in the thermal stability compared to neat PVA are obtained as a result of strong interfacial interactions between GS and PVA by hydrogen bonding. PVA/GS composite film prepared by ex situ process is more brittle than its in situ prepared counterpart. The presence of GS improves the water barrier and water resistance properties of nanocomposite films by decreasing water vapor permeability and water absorption of PVA. This work demonstrates that the tailoring of PVA/GS nanocomposite properties is enabled by controlling GS and glycerol content. The new developed materials, particularly those containing plasticizer, could be potential carriers for transdermal drug delivery.

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Cobos, Mónica, Iker De-La-Pinta, Guillermo Quindós, María Jesús Fernández i María Dolores Fernández. "Synthesis, Physical, Mechanical and Antibacterial Properties of Nanocomposites Based on Poly(vinyl alcohol)/Graphene Oxide–Silver Nanoparticles". Polymers 12, nr 3 (24.03.2020): 723. http://dx.doi.org/10.3390/polym12030723.

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The design of new materials with antimicrobial properties has emerged in response to the need for preventing and controlling the growth of pathogenic microorganisms without the use of antibiotics. In this study, partially reduced graphene oxide decorated with silver nanoparticles (GO–AgNPs) was incorporated as a reinforcing filler with antibacterial properties to poly(vinyl alcohol) (PVA) for preparation of poly(vinyl alcohol)/graphene oxide-silver nanoparticles nanocomposites (PVA/GO–AgNPs). AgNPs, spherical in shape and with an average size of 3.1 nm, were uniformly anchored on the partially reduced GO surface. PVA/GO–AgNPs nanocomposites showed exfoliated structures with improved thermal stability, tensile properties and water resistance compared to neat PVA. The glass transition and crystallization temperatures of the polymer matrix increased with the incorporation of the hybrid. The nanocomposites displayed antibacterial activity against Staphylococcus aureus and Escherichia coli in a filler content- and time-dependent manner. S. aureus showed higher susceptibility to PVA/GO–AgNPs films than E. coli. Inhibitory activity was higher when bacterial cells were in contact with nanocomposite films than when in contact with leachates coming out of the films. GO–AgNPs based PVA nanocomposites could find application as wound dressings for wound healing and infection prevention.

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Sharma, S. K., J. Prakash i P. K. Pujari. "Effects of the molecular level dispersion of graphene oxide on the free volume characteristics of poly(vinyl alcohol) and its impact on the thermal and mechanical properties of their nanocomposites". Physical Chemistry Chemical Physics 17, nr 43 (2015): 29201–9. http://dx.doi.org/10.1039/c5cp05278e.

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The effects of the molecular dispersion of graphene oxide on (A) the crystallinity of PVA–GO nanocomposite films and (B) nanohole size distribution in the amorphous region of PVA–GO nanocomposite films.

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Jing, Zhanxin, Xueying Xian, Qiuhong Huang, Qiurong Chen, Pengzhi Hong, Yong Li i Aihua Shi. "Biocompatible double network poly(acrylamide-co-acrylic acid)–Al3+/poly(vinyl alcohol)/graphene oxide nanocomposite hydrogels with excellent mechanical properties, self-recovery and self-healing ability". New Journal of Chemistry 44, nr 25 (2020): 10390–403. http://dx.doi.org/10.1039/d0nj01725f.

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Biocompatible double network PAmAA–Al³⁺/PVA/GO nanocomposite hydrogels based on non-covalent interactions were synthesized, and the non-covalent interactions endow the materials with good self-recovery and self-healing performances.

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Falqi, Fahad H., Osamah A. Bin-Dahman, M. Hussain i Mamdouh A. Al-Harthi. "Preparation of Miscible PVA/PEG Blends and Effect of Graphene Concentration on Thermal, Crystallization, Morphological, and Mechanical Properties of PVA/PEG (10 wt%) Blend". International Journal of Polymer Science 2018 (12.09.2018): 1–10. http://dx.doi.org/10.1155/2018/8527693.

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Water-soluble polymers such as poly(vinyl alcohol) (PVA) and poly(ethylene glycol) (PEG) and their nanocomposites with graphene were prepared by using a solution mixing and casting technique. The effect of different PEG loadings was investigated to determine the optimum blend ratio. The films were characterized using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA) methods. Also, the mechanical properties including tensile strength and elongation at break were measured using a universal tensile testing machine. FTIR results confirmed the formation of the H-bond between PEG and PVA. DSC studies revealed that PEG has a significant plasticization effect on PVA as seen by the drop in the glass transition temperature (Tg). The blend with 10 wt% PEG loading was found to be the optimum blend because of good compatibility as shown by FTIR and SEM results and improved thermal properties. PVA/PEG (10%) nanocomposites were prepared using graphene as a nanofiller. It was found that the elongation at break increased by 62% from 147% for the PVA/PEG (10%) blend to 209% for the nanocomposite with graphene loading of 0.2 wt%. The experimental values of tensile strength were compared using the predictive model of Nicolais and Narkis.

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Badrinezhad, Lida, Çigdem Bilkan, Yashar Azizian-Kalandaragh, Ali Nematollahzadeh, İkram Orak i Şemsettin Altindal. "Preparation and characterization of cross-linked poly (vinyl alcohol)-graphene oxide nanocomposites as an interlayer for Schottky barrier diodes". International Journal of Modern Physics B 32, nr 01 (8.01.2018): 1750276. http://dx.doi.org/10.1142/s0217979217502769.

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Cross-linked polyvinyl alcohol (PVA) graphene oxide (GO) nanocomposites were prepared by simple solution-mixing route and characterized by Raman, UV–visible and fourier transform infrared (FT-IR) spectroscopy analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The XRD pattern and SEM analysis showed significant changes in the nanocomposite structures, and the FT-IR spectroscopy results confirmed the chemical interaction between the GO filler and the PVA matrix. After these morphological characterizations, PVA-GO-based diodes were fabricated and their electrical properties were characterized using current–voltage (I–V) and impedance-voltage-frequency (Z-V-f) measurements at room temperature. Semilogarithmic I–V characteristics of diode showed a good rectifier behavior. The values of C and G/[Formula: see text] increased with decreasing frequency due to the surface/interface states (N[Formula: see text]) which depend on the relaxation time and the frequency of the signal. The voltage, dependent profiles of N[Formula: see text] and series resistance (R[Formula: see text]) were obtained from the methods of high-low frequency capacitance and Nicollian and Brews, respectively. The obtained values of N[Formula: see text] and R[Formula: see text] were attributed to the use of cross-linked PVA-GO interlayer at the Au/n-Si interface.

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Chang, Jin-Hae. "Comparative Analysis of Properties of PVA Composites with Various Nanofillers: Pristine Clay, Organoclay, and Functionalized Graphene". Nanomaterials 9, nr 3 (1.03.2019): 323. http://dx.doi.org/10.3390/nano9030323.

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Poly(vinyl alcohol) (PVA) nanocomposites containing three different nanofillers are prepared and compared in terms of their thermal properties, morphologies, and oxygen permeabilities. Specifically, pristine saponite (SPT) clay, hydrophilic organically modified bentonite (OMB), and hexadecylamine-functionalized graphene sheets (HDA-GSs) are utilized as nanofillers to fabricate PVA nanocomposite films. The hybrid films are fabricated from blended solutions of PVA and the three different nanofillers. The content of each filler with respect to PVA is varied from 0 to 10 wt%, and the changes in the properties of the PVA matrices as a function of the filler content are discussed. With respect to the hybrid containing 5 wt% of SPT, OMB, and HDA-GS, each layer in the polymer matrix consists of well-dispersed individual nanofiller layers. However, the fillers are mainly aggregated in the polymer matrix in a manner similar to the case for the hybrid material containing 10 wt% of fillers. In the thermal properties, SPT and OMB are most effective when the filler corresponds to 5 wt% and 7 wt% for HDA-GS, respectively, and the gas barrier is most effective with respect to 5 wt% content in all fillers. Among the three types of nanofillers that are investigated, OMB exhibits optimal results in terms of thermal stability and the gas barrier effect.

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Grande Tovar, Carlos, Jorge Castro, Carlos Valencia, Diana Navia Porras, José Mina Hernandez, Mayra Valencia, José Velásquez i Manuel Chaur. "Preparation of Chitosan/Poly(Vinyl Alcohol) Nanocomposite Films Incorporated with Oxidized Carbon Nano-Onions (Multi-Layer Fullerenes) for Tissue-Engineering Applications". Biomolecules 9, nr 11 (1.11.2019): 684. http://dx.doi.org/10.3390/biom9110684.

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Recently, tissue engineering became a very important medical alternative in patients who need to regenerate damaged or lost tissues through the use of scaffolds that support cell adhesion and proliferation. Carbon nanomaterials (carbon nanotubes, fullerenes, multi-wall fullerenes, and graphene) became a very important alternative to reinforce the mechanical, thermal, and antimicrobial properties of several biopolymers. In this work, five different formulations of chitosan/poly(vinyl alcohol)/oxidized carbon nano-onions (CS/PVA/ox-CNO) were used to prepare biodegradable scaffolds with potential biomedical applications. Film characterization consisted of Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tension strength, Young’s modulus, X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). The degradation in a simulated body fluid (FBS) demonstrated that all the formulations lost between 75% and 80% of their weight after 15 days of treatment, but the degradation decreased with the ox-CNO content. In vivo tests after 90 days of subdermal implantation of the nanocomposite films in Wistar rats’ tissue demonstrated good biocompatibility without allergenic reactions or pus formation. There was a good correlation between FBS hydrolytic degradation and degradation in vivo for all the samples, since the ox-CNO content increased the stability of the material. All these results indicate the potential of the CS/PVA/ox-CNO nanocomposite films in tissue engineering, especially for long-term applications.

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Saeedi, Fariba, Arash Montazeri, Yaser Bahari, Malihe Pishvaei i Behrooz Jannat. "A study on the viscoelastic behavior of chitosan-polyvinyl alcohol-graphene oxide nanocomposite films as a wound dressing". Polymers and Polymer Composites, 16.10.2020, 096739112096237. http://dx.doi.org/10.1177/0967391120962375.

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The nanocomposites of Chitosan (CS)-poly vinyl alcohol (PVA) reinforced with graphene oxide (GO) were fabricated by casting in a mold. The nanocomposite films were characterized by various techniques. The viscoelastic properties of the wound dressings were evaluated by dynamic mechanical thermal analysis (DMTA) since the healing quality of a wound dressing depends on such properties. DMTA results also were modeled by the Cole-Cole diagram. Finally, the effects of GO on antimicrobial and biological properties of films were studied. It has been shown that nanocomposite films support the initial attachment, proliferation, and growth of mouse fibroblast cells.

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Hussein, Seenaa, Alaa Abd-Elnaiem i Nadia Ali. "Enhanced Thermo-Mechanical Properties of Poly(vinyl alcohol)/Poly(vinyl pyrrolidone) Polymer Blended with Nanographene". Current Nanoscience 16 (10.03.2020). http://dx.doi.org/10.2174/1573413716666200310121947.

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Background: The addition of nanofillers to polymers for enhanced performance is delivering more interesting applications for aerospace, aeronautic industries, and other numerous nano-technical applications. Objective: The aim was therefore to examine the role of graphene nanopowder on the thermal stability and conductivity of the poly(vinyl alcohol)/poly(vinyl pyrrolidone) (PVA/PVP) polymer nanocomposites. Methods: In this work, graphene nanofillers were incorporated into the PVA/PVP polymer blended by solution mixing for the preparation of nanocomposite films. Results: Results showed that; increasing graphene ratio improved thermal conductivity up to 330%, moreover enhancing hardness shore A up to 16.3% compared to pure PVA/PVP blend polymer. TGA analysis confirmed that the PVA/PVP and graphene network showed good thermal stability. Conclusion: From the present findings, it is proved that PVA/PVP blends have profound effects on thermal stability that cannot be attained by using individual counterparts. The property of the nanocomposite depends on the host blend, morphology, and interfacial characteristics.

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Sharma, Swati, Akanksha Adaval, Shiva Singh, Pradip Kumar Maji, Cherumannil Karumuthil Subash, V. H. Shafeeq i Arup Bhattacharyya. "Influence of Graphene Oxide on Rheology, Mechanical, Dielectric, and Triboelectric Properties of Poly (vinyl alcohol) Nanocomposite Hydrogels Prepared via Facile One Step Process". Soft Matter, 2023. http://dx.doi.org/10.1039/d2sm01599d.

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The present investigation aims to develop hydrogels with higher mechanical stability for triboelectric application by adopting a simple method to fabricate graphene oxide (GO) incorporated poly (vinyl alcohol) (PVA) nanocomposite...

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Ma, Jun, Changhua Liu, Rui Li i Jia Wang. "Properties and structural characterization of chitosan/poly(vinyl alcohol)/graphene oxide nano composites". e-Polymers 12, nr 1 (1.12.2012). http://dx.doi.org/10.1515/epoly.2012.12.1.386.

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AbstractChitosan (CS)/poly(vinyl alcohol) (PVA)/graphene oxide (GO) nanocomposites in the form of films are prepared in a casting and solvent evaporation method. Fourier-transform infrared spectroscopy (FTIR), X-ray diffractions (XRD), atomic force microscopy (AFM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile testing and moisture uptake were used to study the structure and properties of these chitosan/poly(vinyl alcohol) /graphene oxide (PCS/GO-n) nanocomposites. The result from tensile testing indicated that the nanocomposite containing 2 wt% GO exhibits high tensile strength (71.21 MPa) with a large elongation at break (51.8%). The high mechanical properties of the nanocomposite films are mainly due to uniform dispersion of GO sheets in the polymer matrix and strong interfacial interactions among components.

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Majeed, Abdulwahhab H., Emaad T. Bakir Al-Tikrity i Dhia H. Hussain. "Dielectric properties of synthesized ternary hybrid nanocomposite embedded in poly (vinyl alcohol) matrix films". Polymers and Polymer Composites, 25.08.2020, 096739112095140. http://dx.doi.org/10.1177/0967391120951406.

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This research involves preparation and characterization of ternary hybrid nanocomposites; reduced graphene oxide rGO nanosheets, manganese dioxide MnO2 nanorods and poly (anthranilic acid) hollow sphere PANA (rGO-MnO2-PANA). The synthesis follows bi-step chemical reaction. Initially, rGO and MnO2 were prepared separately, then mixed together ultrasonically to form a binary hybrid of rGO-MnO2. Second step includes in situ polymerization of anthranilic acid monomer with the prepared rGO-MnO2. All the prepared compounds were characterized by different techniques: FT-IR, XRD, SEM, EDX and TEM. Incorporation of the ternary hybrid in different weight ratios with PVA afforded the required nanocomposites (rGO-MnO2-PANA/PVA) films. The electrical properties of the nanocomposite films were investigated at frequency of 10 kHz-2 MHz. It was found that, at low frequency, the dielectric (real) permittivity (ε’) and imaginary permittivity (ε”) approached to higher values in all cases, while these values decreased gradually with increasing frequency. It was also confirmed that the alternating current conductivity of the composites increased with increasing frequency. These findings underline the potential employing of rGO-MnO2-PANA/PVA composites as a flexible dielectric material for enhancing polymer electrical conductivity and in energy storage applications.

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Priya, V. Shanmuga, S. Khaleel Basha i V. Sugantha Kumari. "Kinetics and adsorption performance of biosorbent starch/poly(vinyl alcohol)/graphene oxide nanocomposite for the removal of dyes". Journal of Umm Al-Qura University for Applied Sciences, 10.07.2023. http://dx.doi.org/10.1007/s43994-023-00063-4.

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AbstractThe present work reports an efficient removal of a cationic dye, methylene blue (MB), and an anionic dye, methyl orange (MO) dye from an aqueous solution using graphene oxide (GO)–based nanocomposite as an adsorbent. GO was investigated as a potential nano-reinforcing filler in starch/poly(vinyl alcohol) (PVA) biopolymer matrix. Bio-nanocomposite based on starch/PVA matrix and GO were prepared by an aqueous casting method. The fabricated nanocomposites were characterized using FT-IR, XRD, Raman, TEM, FE-SEM, tensile study, Brunauer–Emmett–Teller (BET) method, Barrett–Joyner–Halenda (BJH) method, zeta potential, and swelling study. The effect of the various compositions of GO nanofiller in the starch/PVA matrix was highlighted and the impact of GO nanosheets on the properties of the nanocomposites was revealed. The results demonstrated that the starch/PVA matrix with 3 g of GO was found to be the optimal concentration of GO. Batch adsorption experiments were conducted to optimize the operational factors, including adsorbent dosage, pH, and contact time, which were systematically investigated. The kinetics of adsorption followed a pseudo-second-order model, while the Langmuir isotherm model described the equilibrium adsorption capacity. The prepared nanocomposite exhibited a maximum monolayer adsorption capacity of 382 mg g−1 for MB dye and 293.3 mg g−1 for MO dye. Based on the calculated thermodynamic parameters for the adsorption of MB (∆H° = − 16.37 kJ mol−1, ∆S° = − 37.99 J K−1 mol−1 and ∆G° from − 4.39 to − 5.13 kJ mol−1) and MO (∆H° = − 13.72 kJ mol−1, ∆S° = − 31.78 J K−1 mol−1 and ∆G° from − 3.72 to − 4.39 kJ mol−1) dyes onto the nanocomposite material was feasible, exothermic, and spontaneous. A plausible adsorption mechanism was proposed, involving electrostatic attraction, H-bonding, and π-π interactions, which collectively governed the adsorption process. The nanocomposite showed good stability and reusability up to five cycles for the uptake of MB and MO dyes. These findings confirmed the effectiveness of the proposed approach to produce bionanocomposite with enhanced properties, which may be used in water purification technology.

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Artykuły w czasopismach na temat „Viscoelastic Properties - Graphene/(poly)vinyl Alcohol(PVA) Nanocomposite”

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