Enhancement of X-ray Shielding Properties of PVDF/BaSO4 Nanocomposites Filled with Graphene Oxide

MRS Advances ◽  
2019 ◽  
Vol 4 (3-4) ◽  
pp. 169-175
Author(s):  
Liliane A. Silva ◽  
Adriana M. S. Batista ◽  
Tiago Serodre ◽  
Annibal T. B. Neto ◽  
Clascidia A. Furtado ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Vinylidene Fluoride ◽  
Negative Thermal Expansion ◽  
Graphene Sheets ◽  
Scanning Calorimetry ◽  
Bending Vibration ◽  
Attenuation Coefficients ◽  
X Ray ◽  
Poly Vinylidene Fluoride ◽  
Dispersion State

ABSTRACTIn this work, we report evidences of the improvement of X-ray attenuation efficiency by the addition of a very small amount of Graphene Oxide (GO) in polymer-based nanocomposite. Poly(vinylidene fluoride) (PVDF) homopolymer and barium sulfate (BaSO4) nanoparticles were mixed. PVDF/BaSO4 nanocomposite was found to attenuate 9.14% of a 20 kV X-ray beam. The addition of only 4.0 wt % of GO nanosheets to the nanocomposite improved this X-Ray attenuation efficiency to 24.56%. The respective linear attenuation coefficients (μ) were 39.9 cm-1 and 54.4 cm-1, respectively. The X-ray attenuation gradually decreases until 6.71% and 17.62%, respectively, for the X-ray beam with higher energy (100 kV). Fourier transform infrared data revealed that, due to the lack of the bending vibration modes of CF2 molecule at 656 cm-1, 688 cm-1, 723 cm-1, 776 cm-1and 796 cm-1, characteristics of the γ-crystalline phase of PVDF, the nanocomposites casted from solution are mostly in the β-ferroelectric phase of PVDF, besides the γ-paraelectric phase. SEM micrographs were used to evaluate the dispersion state of graphene sheets and the BaSO4 nanoparticles into the polymeric matrix. UV-Vis spectrometry and Differential Scanning Calorimetry (DSC) were also performed in order to complement the structural analysis. The results confirm that the addition of graphene sheets in PVDF polymer-based nanocomposites enhances the X-ray shielding efficiency. The phenomenon is discussed in terms of the reported anomalous negative thermal expansion coefficient of graphene sheets

SURFACE MODIFICATION OF POLYANILINE ONTO PVDF MEMBRANE VIA RADIATION INDUCED GRAFTING

2015 ◽  
Vol 77 (1) ◽  
Author(s):  
Nadiah Khairul Zaman ◽  
Rosiah Rohani ◽  
Abdul Wahab Mohamad
Keyword(s):  
Vinylidene Fluoride ◽  
Conductive Polymer ◽  
Monomer Concentration ◽  
Scanning Calorimetry ◽  
Pvdf Membrane ◽  
X Ray ◽  
Poly Vinylidene Fluoride ◽  
Radiation Induced ◽  
Conductive Properties ◽  
Radiation Induced Grafting

A conductive polymer, polyaniline (PANI) has been grafted onto a poly (vinylidene fluoride) (PVDF) based polymer using simultaneous radiation induced grafting (RIG), which is a new approached in introducing the conductive properties into a preformed polymer for potential selective separation ability during filtration process. The possibility of coating PVDF membrane with PANI was investigated by looking at the effect of monomer concentration, radiation dose, and aniline in emulsion form on the degree of grafting (DOG). The DOG were obtained at 4.44 and 5.43 % for aniline concentration and its emulsion respectively, and increases with the increase in concentration. The PANI-grafted-PVDF membrane was also characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDX) and differential scanning calorimetry (DSC) techniques. The FTIR and SEM results show that PANI was successfully grafted onto PVDF membrane. EDX analysis also confirmed the grafting by the presence of NH2 representing aniline in the PANI-grafted-PVDF membranes. The modification was found to have not change the overall properties of PVDF, still retaining its intrinsic properties.

scholarly journals Phase Transitions in Poly(vinylidene fluoride)/Polymethylene-Based Diblock Copolymers and Blends

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2442
Author(s):  
Nicolás María ◽  
Jon Maiz ◽  
Daniel E. Martínez-Tong ◽  
Angel Alegria ◽  
Fatimah Algarni ◽  
...  
Keyword(s):  
Diblock Copolymers ◽  
Vinylidene Fluoride ◽  
Polarized Light ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Preparation Conditions ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Poly Vinylidene Fluoride ◽  
Ray Scattering

The crystallization and morphology of two linear diblock copolymers based on polymethylene (PM) and poly(vinylidene fluoride) (PVDF) with compositions PM23-b-PVDF77 and PM38-b-PVDF62 (where the subscripts indicate the relative compositions in wt%) were compared with blends of neat components with identical compositions. The samples were studied by SAXS (Small Angle X-ray Scattering), WAXS (Wide Angle X-ray Scattering), PLOM (Polarized Light Optical Microscopy), TEM (Transmission Electron Microscopy), DSC (Differential Scanning Calorimetry), BDS (broadband dielectric spectroscopy), and FTIR (Fourier Transform Infrared Spectroscopy). The results showed that the blends are immiscible, while the diblock copolymers are miscible in the melt state (or very weakly segregated). The PVDF component crystallization was studied in detail. It was found that the polymorphic structure of PVDF was a strong function of its environment. The number of polymorphs and their amount depended on whether it was on its own as a homopolymer, as a block component in the diblock copolymers or as an immiscible phase in the blends. The cooling rate in non-isothermal crystallization or the crystallization temperature in isothermal tests also induced different polymorphic compositions in the PVDF crystals. As a result, we were able to produce samples with exclusive ferroelectric phases at specific preparation conditions, while others with mixtures of paraelectric and ferroelectric phases.

Temperature-dependent small-angle x-ray scattering from poly(vinylidene fluoride)

1980 ◽  
Vol 51 (10) ◽  
pp. 5508 ◽  
Author(s):  
J. M. Schultz ◽  
J. S. Lin ◽  
R. W. Hendricks ◽  
R. R. Lagasse ◽  
R. G. Kepler
Keyword(s):  
Small Angle ◽  
Vinylidene Fluoride ◽  
Temperature Dependent ◽  
X Ray ◽  
X Ray Scattering ◽  
Poly Vinylidene Fluoride ◽  
Ray Scattering

Kinetic of poly(vinylidene fluoride) defluorination under X-ray irradiation

2010 ◽  
Vol 4 (1) ◽  
pp. 122-127 ◽  
Author(s):  
A. M. Kuvshinov ◽  
S. S. Chebotaryov ◽  
L. A. Pesin ◽  
I. V. Gribov ◽  
N. A. Moskvina ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
X Ray ◽  
Poly Vinylidene Fluoride

Simulations of High-Strain Electrostrictive Chlorinated Terpolymers

2003 ◽  
Vol 785 ◽  
Author(s):  
George J. Kavarnos ◽  
Thomas Ramotowski
Keyword(s):  
Vinylidene Fluoride ◽  
High Strain ◽  
Polymer Chains ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lamellar Structures ◽  
Annealing Conditions ◽  
Poly Vinylidene Fluoride ◽  
Electromechanical Responses ◽  
Kinetics Of

ABSTRACTChlorinated poly(vinylidene fluoride/trifluoroethylene) terpolymers are remarkable examples of high strain electrostrictive materials. These polymers are synthesized by copolymerizing vinylidene fluoride and trifluoroethylene with small levels of a third chlorinated monomer. The electromechanical responses of these materials are believed to originate from the chlorine atom, which, by its presence in the polymer chains and by virtue of its large van der Waals radius, destroys the long-range crystalline polar macro-domains and transforms the polymer from a normal to a high-strain relaxor ferroelectric. To exploit the strain properties of the terpolymer, it is desirable to understand the structural implications resulting from the presence of the chlorinated monomer. To this end, computations have been performed on model superlattices of terpolymers using quantum-mechanical based force fields. The focus has been on determining the energetics and kinetics of crystallization of the various polymorphs that have been identified by x-ray diffraction and fourier transform infrared spectroscopy. The chlorinated monomer is shown to act as a defect that can be incorporated into the lamellar structures of annealed terpolymer without a high cost in energy. The degree of incorporation of the chlorinated monomer into the crystal lattice is controlled by annealing conditions and ultimately determines the ferroelectric behavior of the terpolymers.

The Synthesis and Characterization of the Graphene Oxide Covalent Modified Phenolic Resin Nanocomposites

2011 ◽  
Vol 327 ◽  
pp. 115-119 ◽  
Author(s):  
Duo Wang ◽  
Jie Gao ◽  
Wei Fang Xu ◽  
Feng Bao ◽  
Rui Ma ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Phenolic Resin ◽  
Synthesis And Characterization ◽  
Infrared Spectrometry ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hummers Method ◽  
Modified Hummers Method ◽  
Thermal Stability Of

Graphene oxide (GO) was made by a modified Hummers method. Graphene oxide modified phenolic resin nanocomposites (GO/PF) were prepared by Steglich esterification, catalyzed by dicyclohexyl carbodiimide and 4-dimethylaminopyridine. The composites were characterized by Fourier transform infrared spectrometry, differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. The result revealed that the graphene oxide was absolutely exfoliated and covalent linked GO/PF composite was obtained. The thermal stability of PF is remarkably improved by modification with GO.

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