scholarly journals Synthesis and Characterization of Graphene Oxide/Chitosan Composite Aerogels with High Mechanical Performance

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 777 ◽  
Author(s):  
Yang Gong ◽  
Yingchun Yu ◽  
Huixuan Kang ◽  
Xiaohong Chen ◽  
Hao Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Mechanical Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composite Aerogels ◽  
Mercury Porosimeter ◽  
Chitosan Composite

Chitosan, a semi-crystalline biomolecule, has attracted wide attention due to its high synthesis flexibility. In this study, to improve the mechanical properties of chitosan aerogels (CSAs), graphene oxide (GO) was extracted and introduced into chitosan aerogels as fillers. The porous CSAs/GO composite aerogels were fabricated by an environmentally friendly freeze-drying process with different GO contents (0, 0.5, 1.0, 1.5, wt.%). The characteristics of the CSAs/GO were investigated by scanning electron microscopy (SEM), mechanical measurements and mercury porosimeter. The crystallinity of samples was characterized by X-ray diffraction (XRD). The mechanism of the effect of graphene oxide on chitosan was studied by Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results show that the microstructure of the samples is developed in the network structure. The porosity of CSAs/GO aerogels is as high as 87.6%, and the tensile strength of the films increased from 6.60 MPa to 10.56 MPa with the recombination of graphene oxide. The crystallinity (CrI) of composite aerogels increased from 27% to 81%, which indicates that graphene oxide improves the mechanical properties of chitosan by chemical crosslinking.

scholarly journals Copper Containing Glass-Based Bone Adhesives for Orthopaedic Applications: Glass Characterization and Advanced Mechanical Evaluation

2020 ◽  
Author(s):  
Sahar. Mokhtari ◽  
Anthony.W. Wren
Keyword(s):  
Mechanical Properties ◽  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Viscoelastic Behavior ◽  
Polymer Chains ◽  
Nano Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compression Data

AbstractThis study addresses issues with currently used bone adhesives, by producing novel glass based skeletal adhesives through modification of the base glass composition to include copper (Cu) and by characterizing each glass with respect to structural changes. Bioactive glasses have found applications in fields such as orthopedics and dentistry, where they have been utilized for the restoration of bone and teeth. The present work outlines the formation of flexible organic-inorganic polyacrylic acid (PAA) – glass hybrids, commercial forms are known as glass ionomer cements (GICs). Initial stages of this research will involve characterization of the Cu-glasses, significant to evaluate the properties of the resulting adhesives. Scanning electron microscopy (SEM) of annealed Cu glasses indicates the presence of partial crystallization in the glass. The structural analysis of the glass using Raman suggests the formation of CuO nanocrystals on the surface. X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS) further confirmed the formation of crystalline CuO phases on the surface of the annealed Cu-glass. The setting reaction was studied using Fourier transform infrared spectroscopy (ATR-FTIR). The mechanical properties of the Cu containing adhesives exhibited gel viscoelastic behavior and enhanced mechanical properties when compared to the control composition. Compression data indicated the Cu glass adhesives were efficient at energy dissipation due to the reversible interactions between CuO nano particles and PAA polymer chains.

scholarly journals Covalent Functionalization of Graphene Oxide with Fructose, Starch, and Micro-Cellulose by Sonochemistry

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 490
Author(s):  
María Montserrat Cruz-Benítez ◽  
Pablo Gónzalez-Morones ◽  
Ernesto Hernández-Hernández ◽  
José Roberto Villagómez-Ibarra ◽  
Javier Castro-Rosas ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Organic Molecules ◽  
Chemical Characterization ◽  
Covalent Bond ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultrasound Waves ◽  
Short Time

In this work, we report the synthesis of graphene oxide (GO) nanohybrids with starch, fructose, and micro-cellulose molecules by sonication in an aqueous medium at 90 °C and a short reaction time (30 min). The final product was washed with solvents to extract the nanohybrids and separate them from the organic molecules not grafted onto the GO surface. Nanohybrids were chemically characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy and analyzed by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and X-ray diffraction (XRD). These results indicate that the ultrasound energy promoted a chemical reaction between GO and the organic molecules in a short time (30 min). The chemical characterization of these nanohybrids confirms their covalent bond, obtaining a grafting percentage above 40% the weight in these nanohybrids. This hybridization creates nanometric and millimetric nanohybrid particles. In addition, the grafted organic molecules can be crystallized on GO films. Interference in the ultrasound waves of starch hybrids is due to the increase in viscosity, leading to a partial hybridization of GO with starch.

scholarly journals Free-Standing Graphene Oxide and Carbon Nanotube Hybrid Papers with Enhanced Electrical and Mechanical Performance and Their Synergy in Polymer Laminates

2020 ◽  
Vol 21 (22) ◽  
pp. 8585
Author(s):  
Manoj Tripathi ◽  
Luca Valentini ◽  
Yuanyang Rong ◽  
Silvia Bittolo Bon ◽  
Maria F. Pantano ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Mechanical Performance ◽  
Hybrid Structure ◽  
Free Standing ◽  
Hybrid Filler ◽  
X Ray ◽  
The Individual

Hybrid nanomaterials fabricated by the heterogeneous integration of 1D (carbon nanotubes) and 2D (graphene oxide) nanomaterials showed synergy in electrical and mechanical properties. Here, we reported the infiltration of carboxylic functionalized single-walled carbon nanotubes (C-SWNT) into free-standing graphene oxide (GO) paper for better electrical and mechanical properties than native GO. The stacking arrangement of GO sheets and its alteration in the presence of C-SWNT were comprehensively explored through scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. The C-SWNTs bridges between different GO sheets produce a pathway for the flow of electrical charges and provide a tougher hybrid system. The nanoscopic surface potential map reveals a higher work function of the individual functionalised SWNTs than surrounded GO sheets showing efficient charge exchange. We observed the enhanced conductivity up to 50 times and capacitance up to 3.5 times of the hybrid structure than the GO-paper. The laminate of polystyrene composites provided higher elastic modulus and mechanical strength when hybrid paper is used, thus paving the way for the exploitation of hybrid filler formulation in designing polymer composites.

scholarly journals Comparison of Gas Sensing Properties of Reduced Graphene Oxide Obtained by Two Different Methods

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3175
Author(s):  
Sabina Drewniak ◽  
Marcin Procek ◽  
Roksana Muzyka ◽  
Tadeusz Pustelny
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sorption Method ◽  
Reduced Graphene ◽  
Gaseous Atmospheres

In this study, the sensitivity of reduced graphene oxide structures (rGO) to the action of selected gases (especially hydrogen, but also nitrogen dioxide and ammonia) was examined. Two sensing structures, based on rGO structures, obtained by different methods of oxidation (the modified Hummers, and the modified Tour’s method respectively), were investigated. We show here that the method used for the oxidation of rGO influences the sensitivity of the sensing structure during contact with various gaseous atmospheres. We performed our experiments in the atmosphere, containing hydrogen in a concentration range from 0 to 4% in nitrogen or synthetic air, both in dry and wet conditions. The temperature range was from 50 °C to 190 °C. Finally, we checked how the resistance of the samples changes when the other gases (NO2, NH3) appear in tested gas mixtures. The gas investigations were supplemented by the characterization of rGOs materials using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and N2 sorption method.

Photocatalytic Degradation of 2-chlorophenol under γ-Bi2MoO6/Graphene Oxide

MRS Advances ◽  
2019 ◽  
Vol 5 (11) ◽  
pp. 581-589 ◽  
Author(s):  
J. Rodríguez-López ◽  
R. Rangel ◽  
P. Bartolo-Pérez ◽  
J.J. Alvarado-Gil ◽  
J. L. Cervantes-López ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Energy Gap ◽  
Physicochemical Characterization ◽  
Catalytic Performance ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
Bismuth Molybdate ◽  
X Ray

ABSTRACTThe present research was aimed to study the degradation of 2-Chlorophenol through the use of bismuth molybdate (γ-Bi2MoO6) structures supported on graphene oxide (GO) which is intended to control the recombination of charge carriers. γ-Bi2MoO6/GO systems were doped with nitrogen via chemical reaction, to reduce their energy gap, improving their photocatalytic activity. Structural and physicochemical characterization of the resulting catalysts were performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis. The obtained compounds show good photo catalytic performance when using visible energy to degrade 2-Chlorophenol, obtaining 80% of degradation in 65 min.

scholarly journals Functional Bionanocomposite Fibers of Chitosan Filled with Cellulose Nanofibers Obtained by Gel Spinning

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1563
Author(s):  
Sofia Marquez-Bravo ◽  
Ingo Doench ◽  
Pamela Molina ◽  
Flor Estefany Bentley ◽  
Arnaud Kamdem Tamo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Cellulose Nanofibers ◽  
Microstructural Characterization ◽  
Fiber Formation ◽  
Fiber Direction ◽  
Composite Fibers ◽  
X Ray Diffraction ◽  
Gel Spinning ◽  
X Ray

Extremely high mechanical performance spun bionanocomposite fibers of chitosan (CHI), and cellulose nanofibers (CNFs) were successfully achieved by gel spinning of CHI aqueous viscous formulations filled with CNFs. The microstructural characterization of the fibers by X-ray diffraction revealed the crystallization of the CHI polymer chains into anhydrous chitosan allomorph. The spinning process combining acidic–basic–neutralization–stretching–drying steps allowed obtaining CHI/CNF composite fibers of high crystallinity, with enhanced effect at incorporating the CNFs. Chitosan crystallization seems to be promoted by the presence of cellulose nanofibers, serving as nucleation sites for the growing of CHI crystals. Moreover, the preferential orientation of both CNFs and CHI crystals along the spun fiber direction was revealed in the two-dimensional X-ray diffraction patterns. By increasing the CNF amount up to the optimum concentration of 0.4 wt % in the viscous CHI/CNF collodion, Young’s modulus of the spun fibers significantly increased up to 8 GPa. Similarly, the stress at break and the yield stress drastically increased from 115 to 163 MPa, and from 67 to 119 MPa, respectively, by adding only 0.4 wt % of CNFs into a collodion solution containing 4 wt % of chitosan. The toughness of the CHI-based fibers thereby increased from 5 to 9 MJ.m−3. For higher CNFs contents like 0.5 wt %, the high mechanical performance of the CHI/CNF composite fibers was still observed, but with a slight worsening of the mechanical parameters, which may be related to a minor disruption of the CHI matrix hydrogel network constituting the collodion and gel fiber, as precursor state for the dry fiber formation. Finally, the rheological behavior observed for the different CHI/CNF viscous collodions and the obtained structural, thermal and mechanical properties results revealed an optimum matrix/filler compatibility and interface when adding 0.4 wt % of nanofibrillated cellulose (CNF) into 4 wt % CHI formulations, yielding functional bionanocomposite fibers of outstanding mechanical properties.

scholarly journals Fabrication and Characterization of Al/NiO Energetic Nanomultilayers

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
YiChao Yan ◽  
Wei Shi ◽  
HongChuan Jiang ◽  
Jie Xiong ◽  
WanLi Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Total Thickness ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Metallic Oxide ◽  
Promising Candidate ◽  
X Ray ◽  
Thermal Boundary Conductance ◽  
Fabrication And Characterization

The redox reaction between Al and metallic oxide has its advantage compared with intermetallic reaction and Al/NiO nanomutlilayers are a promising candidate for enhancing the performance of energetic igniter. Al/NiO nanomutlilayers with different modulation periods are prepared on alumina substrate by direct current (DC) magnetron sputtering. The thicknesses of each period are 250 nm, 500 nm, 750 nm, 1000 nm, and 1500 nm, respectively, and the total thickness is 3 μm. The X-ray diffraction (XRD) and scanning electron microscope (SEM) results of the as-deposited Al/NiO nanomutlilayers show that the NiO films are amorphous and the layered structures are clearly distinguished. The X-ray photoelectron spectroscopy (XPS) demonstrates that the thickness of Al2O3increases on the side of Al monolayer after annealing at 450°C. The thermal diffusion time becomes greater significantly as the amount of thermal boundary conductance across the interfaces increases with relatively smaller modulation period. Differential scanning calorimeter (DSC) curve suggests that the energy release per unit mass is below the theoretical heat of the reaction due to the nonstoichiometric ratio between Al and NiO and the presence of impurities.

Preparation and Characterization of γ-Fe2O3-ZnFe2O4 Composite Nanoparticles

2013 ◽  
Vol 873 ◽  
pp. 152-157
Author(s):  
Long Long Chen ◽  
Jun Ming Li ◽  
Xiao Min Gong ◽  
Jian Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Species ◽  
Composite Nanoparticles ◽  
X Ray Diffraction ◽  
Ferrite Core ◽  
Phase Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
Chemically Induced

Using a chemically induced transition in an FeCl2 solution, γ-Fe2O3 nanoparticles can be prepared from an amorphous precursor composed of FeOOH and Mg (OH)2. Surface modification by adding ZnCl2 during liquid-phase synthesis was attempted. The magnetization, morphology, crystal structure, and chemical species of as-prepared samples were characterized by vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray energy-dispersive spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). The experimental results showed that the surface of the γ-Fe2O3 nanoparticles can be modified by adding ZnCl2 to form composite nanoparticles with a γ-Fe2O3/ZnFe2O4 ferrite core coated with Zn (OH)2 and absorbed FeCl36H2O; this modification can be enhanced by additional NaOH.

Characterization of X-ray irradiated graphene oxide coatings using X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy

2013 ◽  
Vol 28 (2) ◽  
pp. 68-71 ◽  
Author(s):  
Thomas N. Blanton ◽  
Debasis Majumdar
Keyword(s):  
Atomic Force Microscopy ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
High Energy ◽  
X Ray Diffraction ◽  
Carbon Phase ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After

In an effort to study an alternative approach to make graphene from graphene oxide (GO), exposure of GO to high-energy X-ray radiation has been performed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize GO before and after irradiation. Results indicate that GO exposed to high-energy radiation is converted to an amorphous carbon phase that is conductive.

Synthesis and characterization of homogeneous lead-substituted tin oxide with the (110) face of rutile structure

2000 ◽  
Vol 15 (10) ◽  
pp. 2076-2079
Author(s):  
Chika Nozaki ◽  
Takashi Yamada ◽  
Kenji Tabata ◽  
Eiji Suzuki
Keyword(s):  
Electron Microscopy ◽  
Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Rutile Structure ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Synthesis of a rutile-type lead-substituted tin oxide with (110) face was investigated. The characterization was performed by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, infrared spectroscopy, x-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller surface area measurements. The homogeneous rutile-type lead-substituted tin oxide was obtained until 4.1 mol% of tin was substituted with lead. The surface of obtained oxide had a homogeneously lead-substituted (110) face.

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