scholarly journals Structure, Mechanical and Electrochemical Properties of Thermally Reduced Graphene Oxide-poly (Vinyl Alcohol) Foams

2017 ◽  
Author(s):  
Wenxiu Wang ◽  
Hui Xu ◽  
Jian Chen ◽  
Yuanfang Shen ◽  
Imre Bertóti ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Vinyl Alcohol ◽  
Lithium Ion ◽  
Thermal Reduction ◽  
Poly Vinyl Alcohol ◽  
Structure Stability ◽  
X Ray ◽  
Wide Range

Graphene oxide foams with a wide range of poly (vinyl alcohol) contents were synthesized by freeze casting, and then thermally reduced at 300ºC in argon atmosphere. Their thermal stability, microstructure, composition and chemical states of constituents, mechanical and electrical properties were investigated by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry, compressive testing and electrochemical analysis. The results indicated that the PVA content highly influenced the crystallinity and microstructure, resulting in different mechanical properties. After thermal reduction, not only graphene oxide was reduced to graphene, but also PVA was subjected to partial pyrolysis. With the increase of the PVA content, the intensity of the sp2 C-C bond decreased while the sp3 C-C bond increased. Although the mechanical properties decreased after thermal reduction, the composite foams still showed high cyclic structure stability up to 18 % compression strain. Meanwhile, the reduced foams exhibited high electrical conductivity. Applying as anodes in lithium ion battery, the initial discharge capacity for the foams can reach 1822 mA h g-1 and it remained more than 330 mA h g-1 after 50 cycles.

Fabrication and Characterization of Poly(vinyl Alcohol)/Functionalized Graphene Oxide Nanofibers Produced by Electrospinning Method

2013 ◽  
Vol 747 ◽  
pp. 405-408
Author(s):  
Yuan Hsiang Yu ◽  
Chih Jie Jan
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Functionalized Graphene ◽  
Sem Images ◽  
Functionalized Graphene Oxide ◽  
X Ray ◽  
Electrospinning Method

A series of poly (vinyl alcohol) (PVA)/functionalized graphene oxide (FGO) nanofibers with low feeding ratios of FGO to PVA were fabricated by electrospinning method. In this study, the prepared PVA/FGO nanocomposites were dispersed in water phase followed by electrospinning treatment under different operational parameters (i.e., applied voltage, feeding rate and FGO contents) to give nanofibers of various diameters and morphologies. The morphology, diameter and structure of electrospun nanofibers and FGO were investigated by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), (TGA) and differential scanning calorimetry (DSC). SEM images showed that the morphologies of the nanofibers were improved by the incorporation of FGO at a low loading content (e.g., 0.1~0.5 wt %) as compared to pure electrospun PVA. The crystallinity and thermal stability of PVA/FGO nanofibers were also studied.

scholarly journals Regulation Mechanism of Graphene Oxide on the Structure and Mechanical Properties of Bio-Based Gel-Spun Lignin/Poly (Vinyl Alcohol) Fibers

2021 ◽  
Author(s):  
Yanhong Jin ◽  
Yuanyuan Jing ◽  
Wenxin Hu ◽  
Jiaxian Lin ◽  
Yu Cheng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Graphene Oxide ◽  
Young’S Modulus ◽  
Vinyl Alcohol ◽  
Young's Modulus ◽  
Lignin Content ◽  
Poly Vinyl Alcohol ◽  
Regulation Mechanism ◽  
Composite Fibers

Abstract Lignin has been used as a sustainable and eco-friendly filler in composite fibers. However, lignin aggregation occurred at high lignin content, which significantly hindered the further enhancement of fiber performance. The incorporation of graphene oxide (GO) enhanced the mechanical properties of the lignin/poly(vinyl alcohol) (PVA) fibers and affected their structure. With the GO content increasing from 0 to 0.2%, the tensile strength of 5% lignin/PVA fibers increased from 491 MPa to 631 MPa, and Young's modulus increased from 5.91 GPa to 6.61 GPa. GO reinforced 30% lignin/PVA fibers also showed the same trend. The tensile strength increased from 455 MPa to 553 MPa, and Young's modulus increased from 5.39 GPa to 7 GPa. The best mechanical performance was observed in PVA fibers containing 5% lignin and 0.2% GO, which had an average tensile strength of 631 MPa and a Young’s modulus of 6.61 GPa. The toughness values of these fibers are between 9.9-15.6 J/g, and the fibrillar and ductile fracture microstructure were observed. Structure analysis of fibers showed that GO reinforced 5% lignin/PVA fibers had higher crystallinity, and evidence of hydrogen bonding among GO, lignin, and PVA in the gel fibers was revealed. Further, water resistance and swelling behavior of composite PVA fibers were studied to further evidence the structure change of composite fibers.

Characterisation by X-ray photoelectron spectroscopy of surface layers of poly(vinyl alcohol) on particles formed by dispersion polymerisation of divinylbenzene

2005 ◽  
Vol 283 (10) ◽  
pp. 1108-1115
Author(s):  
Luke Alger ◽  
Claire E. Madden ◽  
Ian Sutherland ◽  
John V. Dawkins
Keyword(s):  
Photoelectron Spectroscopy ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Surface Layers ◽  
X Ray

Physico-mechanical properties of graphene oxide/poly(vinyl alcohol) composites

2019 ◽  
Vol 297 (3) ◽  
pp. 485-491 ◽  
Author(s):  
Tatiana V. Panova ◽  
Anna A. Efimova ◽  
Aleksandr V. Efimov ◽  
Anna K. Berkovich
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol

scholarly journals Fabrication of photothermally active poly(vinyl alcohol) films with gold nanostars for antibacterial applications

2018 ◽  
Vol 9 ◽  
pp. 2040-2048 ◽  
Author(s):  
Mykola Borzenkov ◽  
Maria Moros ◽  
Claudia Tortiglione ◽  
Serena Bertoldi ◽  
Nicola Contessi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vinyl Alcohol ◽  
Near Infrared ◽  
Polymeric Materials ◽  
Photothermal Effect ◽  
Poly Vinyl Alcohol ◽  
Broad Application ◽  
Gold Nanostars ◽  
Wide Range ◽  
Spherical Gold Nanoparticles

The unique photothermal properties of non-spherical gold nanoparticles under near-infrared (NIR) irradiation find broad application in nanotechnology and nanomedicine. The combination of their plasmonic features with widely used biocompatible poly(vinyl alcohol) (PVA) films can lead to novel hybrid polymeric materials with tunable photothermal properties and a wide range of applications. In this study, thin PVA films containing highly photothermally efficient gold nanostars (GNSs) were fabricated and their properties were studied. The resulting films displayed good mechanical properties and a pronounced photothermal effect under NIR irradiation. The local photothermal effect triggered by NIR irradiation of the PVA-GNS films is highly efficient at killing bacteria, therefore providing an opportunity to develop new types of protective antibacterial films and coatings.

Fabrication of Nickel Sulfide/Nitrogen-Doped Reduced Graphene Oxide Nanocomposite as Anode Material for Lithium-Ion Batteries and Its Electrochemical Performance

2020 ◽  
Vol 20 (11) ◽  
pp. 6782-6787
Author(s):  
Yeon-Ju Lee ◽  
Tae-Hyun Ha ◽  
Gyu-Bong Cho ◽  
Ki-Won Kim ◽  
Jou-Hyeon Ahn ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Lithium Ion ◽  
Treatment Method ◽  
Retention Capacity ◽  
Graphene Nanocomposites ◽  
X Ray ◽  
Nitrogen Doped ◽  
Reduced Graphene

In this study, NiS/graphene nanocomposites were synthesized by simple heat treatment method of three graphene materials (graphene oxide (GO), reduced graphene oxide (rGO) and nitrogen-doped graphene oxide (N-rGO)) and NiS precursor. The morphology and crystal structure of NiS/graphene nanocomposites were characterized using field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Electrochemical properties were also investigated. NiS/graphene nanocomposites homogeneously wrapped by graphene materials have been successfully manufactured. Among the three nanocomposites, NiS/N-rGO nanocomposite exhibited the highest initial and retention capacity in discharge, respectively, of 1240 mAh/g and 467 mAh/g up to 100 cycles at 0.5 C.

The influence of dehydration on the interfacial bonding, microstructure and mechanical properties of poly(vinyl alcohol)/graphene oxide nanocomposites

Carbon ◽  
2015 ◽  
Vol 94 ◽  
pp. 845-855 ◽  
Author(s):  
Jian Chen ◽  
Ying Gao ◽  
Wenlin Liu ◽  
Xiangru Shi ◽  
Linqi Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Vinyl Alcohol ◽  
Interfacial Bonding ◽  
Poly Vinyl Alcohol ◽  
Microstructure And Mechanical Properties
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