Structure and electrophysical properties of polyvinylidene fluoride (PVDF)/magnetite nanocomposites

2018 ◽  
Vol 33 (1) ◽  
pp. 138-149 ◽  
Author(s):  
MA Ramazanov ◽  
AM Maharramov ◽  
HA Shirinova ◽  
Luca Di Palma
Keyword(s):  
Dielectric Permittivity ◽  
Polyvinylidene Fluoride ◽  
Vinylidene Fluoride ◽  
Theoretical Calculations ◽  
Threshold Value ◽  
Electrophysical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Subsequent Decrease ◽  
Poly Vinylidene Fluoride

In the present study, the effect of magnetite (Fe3O4) nanoparticles on the structural and dielectric properties of poly(vinylidene fluoride) (PVDF) matrix was investigated. Distribution of Fe3O4 nanoparticles in the polymer matrix has been studied by scanning electron microscopy (JEOL JSM-7600 F). The structure of the nanocomposite samples was investigated by the X-ray diffraction and Fourier-transform infrared spectroscopy. It was shown that the dielectric permittivity of PVDF + Fe3O4 nanocomposite samples was gradually increased up to 7 wt% of Fe3O4 content. Further increase in the concentration of the filler leads to decrease in the dielectric permittivity. The subsequent decrease in dielectric permittivity at higher Fe3O4 content can be explained by the increase in defects in the structure of the nanocomposite. The comparison of experimental data and the results of theoretical calculations show that the reduction in the empirical value of dielectric permittivity of the nanocomposite is obviously linked with the threshold value of filler. While calculating the theoretical value of the dielectric permittivity for the higher content of the filler, defects in the nanocomposite structure should be considered.

scholarly journals STRUCTURE AND ELECTROPHYSICAL PROPERTIES OF PVDF+PbS/CdS NANOCOMPOSITES

2021 ◽  
pp. 53-56
Author(s):  
A. A. Novruzova
Keyword(s):  
Dielectric Permittivity ◽  
Cds Nanoparticles ◽  
Electrophysical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Subsequent Decrease ◽  
The Given ◽  
Cds Nanocomposites ◽  
Small Nanoparticles ◽  
Scanning Electron

In the given paper were investigated structure and electrophysical properties of PVDF+PbS/CdS nanocomposites. Distribution and the size of PbS and CdS nanoparticles in the polymer matrix has been studied by scanning electron microscopy (JEOL JSM-7600 F). The structure of the nanocomposite samples was investigated by the X-ray diffraction spectroscopy. The dependence of dielectric permittivity at frequency and temperature was investigated. It was shown that the dielectric permittivity of PVDF+PbS/CdS nanocomposite samples was increase in small nanoparticles content. Further increase in the concentration of the filler leads to decrease in the dielectric permittivity. The subsequent decrease in dielectric permittivity at higher nanoparticles content can be explained by the increase in defects in the structure of the nanocomposite.

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.

Structures and Physical Properties of Multi-Walled Carbon Nanotube-Filled PVDF Thermoplastic Composites

2007 ◽  
Vol 124-126 ◽  
pp. 1117-1120 ◽  
Author(s):  
Dong Wook Chae ◽  
Young Wan Nam ◽  
Seung Sangh Wang ◽  
S.M. Hong
Keyword(s):  
Carbon Nanotube ◽  
Vinylidene Fluoride ◽  
Thermoplastic Composites ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Loading Level ◽  
Multi Walled Carbon Nanotube ◽  
Poly Vinylidene Fluoride ◽  
Internal Mixer

Poly(vinylidene fluoride) (PVDF) / multi-walled carbon nanotube (MWNT) thermoplastic composites was melt compounded in an internal mixer. The percolation level for this system in electrical conductivity clearly occured between 2 and 2.5 wt%. PVDF/MWNT thermoplastic composites exhibited an increased crystallization temperature with the loading level, at 10 wt% loading by ca. 6. In addition, they presented a shoulder posterior to the main melting peak and an increased endpoint of the peak. In the Wide Angle X-ray Diffraction (WAXD) patterns, the incorporation of MWNT produced a larger shoulder at 2θ =20.7° with increasing the loading level, corresponding to the β-form crystal of PVDF.

scholarly journals Influence of molecular weight on dielectric properties and piezoelectric constant of poly(vinylidene fluoride) membranes obtained by electrospinning

Polimery ◽  
2021 ◽  
Vol 66 (10) ◽  
pp. 532
Author(s):  
Aminatul Sobirah Zahari ◽  
Muhammad Hafiz Mazwir ◽  
Izan Izwan Misnon
Keyword(s):  
Molecular Weight ◽  
Dielectric Properties ◽  
Vinylidene Fluoride ◽  
Electrochemical Impedance ◽  
Piezoelectric Constant ◽  
Phase Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Poly Vinylidene Fluoride

A significant influence of the molecular weight on the dielectric properties and piezoelectric constant of poly(vinylidene fluoride) (PVDF) membranes obtained by electrospinning was demonstrated. Electrochemical impedance spectroscopy and d33 meter were used to evaluate dielectric properties and piezoelectric constant respectively. The presence of the β-phase was determined by Fourier transform infrared spectroscopy (FTIR) and X-Ray diffraction (XRD). The membranes with the lowest molecular weight (180,000 g/mol) possessed the best dielectric properties. They also had the highest piezoelectric constant (21 pC/N) and dielectric constant (2.9 at 50 Hz) as well as the highest β-phase content (80.25%).

Effect of Thermal Treatment on the Physical Properties of Electrospun PVDF Membrane

2012 ◽  
Vol 591-593 ◽  
pp. 1113-1116
Author(s):  
Si Chen Cheng ◽  
Yin Zheng Liang ◽  
Yi Ping Qiu
Keyword(s):  
Thermal Treatment ◽  
Tensile Property ◽  
Tensile Testing ◽  
Vinylidene Fluoride ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Pvdf Membrane ◽  
X Ray ◽  
Before And After ◽  
Poly Vinylidene Fluoride

The electrospinning technique was used to produce poly (vinylidene fluoride) (PVDF) membrane. Thermal treatment was introduced to improve the mechanical property and dimensional stability. In this paper, the PVDF membranes before and after thermal treatment were characterized by Scanning electron microscope (SEM), differential scanning calorimeter (DSC) and wide angle X-ray diffraction (WAXD), tensile testing. The crystallinity, tensile property, as well as melting temperature changed with the treated temperature. The results hows that thermal treatment could notably increase the tensile property of electrospun PVDF membrane and 160°C is a proper temperature for thermal treating

Stretching Induced Crystalline-Phase Transition in Energy-Conversion Poly(Vinylidene Fluoride) (PVDF) Films

2014 ◽  
Vol 1070-1072 ◽  
pp. 589-593
Author(s):  
Fei Peng Wang ◽  
Zheng Yong Huang ◽  
Jian Li
Keyword(s):  
Phase Transition ◽  
Crystalline Phase ◽  
High Speed ◽  
Vinylidene Fluoride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase ◽  
Poly Vinylidene Fluoride ◽  
Crystalline Phase Transition

Commercial poly (vinylidene fluoride) (PVDF) films are uniaxially stretched with varying rates at 110 °C in order to endow PVDF piezo-and pyroelectric by crystalline-phase transition from α to β during the stretching. The crystalline phases are determined by infrared spectroscopy. The β-phase content and its fraction in films increase as a result of stretching with high rates. In addition, higher stretching rates yield a slight increase of γ phase. The crystallite size is evaluated by means of X-ray diffraction. It is found that the β-phase crystallites become smaller with fast stretching, whereas the α-phase crystallites are cracked and disappear at high-speed stretching of 2.5 /min.

INFLUENCE OF THE SUBSTRATE ON THE CRYSTALLINE PHASE AND MORPHOLOGY OF POLY (VINYLIDENE FLUORIDE) (PVDF) THIN FILM

2016 ◽  
Vol 23 (03) ◽  
pp. 1650005 ◽  
Author(s):  
IBTISAM YAHYA ABDULLAH ◽  
MUHAMMAD YAHAYA ◽  
MOHAMMAD HAFIZUDDIN HJ JUMALI ◽  
HAIDER MOHAMMED SHANSHOOL
Keyword(s):  
Thin Film ◽  
Indium Tin Oxide ◽  
Crystalline Phase ◽  
Vinylidene Fluoride ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coated Glass ◽  
Poly Vinylidene Fluoride ◽  
Hexamethyl Phosphoramide

The effect of substrate on the crystalline phase and morphology of the poly (vinylidene fluoride) (PVDF) thin film has been investigated. The solution of PVDF/Hexamethyl phosphoramide (HMPA) was deposited on four different substrates, namely, silicon (Si), glass (SiO2), indium tin oxide (ITO) coated glass and silver (Ag) coated glass respectively by using the spin coating technique. The crystalline structure was investigated using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) techniques. The morphology was determined using scanning electron microscopy (SEM). XRD demonstrated that the structure of PVDF thin films on each substrate is [Formula: see text]-phase with different orientations of the molecular chains. FTIR results confirmed XRD that the samples contain [Formula: see text]-phase. SEM shows spherulites structure, which is rough and porous, besides, the size of spherulites and the porosity are different for each sample. The size of spherulites is in average diameter range (1–6[Formula: see text][Formula: see text]m) and this range is attributed to the [Formula: see text]-phase. The nucleation process of [Formula: see text]-phase on the various substrates attributed either to the match of polymer-substrate or to the electrostatic interaction. Among the substrates used, the ITO substrate exhibited a greater tendency for [Formula: see text]-phase formation.

Phase Transition in Poly(Vinylidene Fluoride) Investigated with Micro-Raman Spectroscopy

2005 ◽  
Vol 59 (3) ◽  
pp. 275-279 ◽  
Author(s):  
C. J. L. Constantino ◽  
A. E. Job ◽  
R. D. Simões ◽  
J. A. Giacometti ◽  
V. Zucolotto ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
Vinylidene Fluoride ◽  
Raman Band ◽  
X Ray Diffraction ◽  
X Ray ◽  
Micro Raman Spectroscopy ◽  
Β Phase ◽  
Α Phase ◽  
Poly Vinylidene Fluoride

The phase transition from the non-polar α-phase to the polar β-phase of poly(vinylidene fluoride) (PVDF) has been investigated using micro-Raman spectroscopy, which is advantageous because it is a nondestructive technique. Films of α-PVDF were subjected to stretching under controlled rates at 80 °C, while the transition to β-PVDF was monitored by the decrease in the Raman band at 794 cm−1 characteristic of the α-phase, along with the concomitant increase in the 839 cm−1 band characteristic of the β-phase. The α→β transition in our PVDF samples could be achieved even for the sample stretched to twice (2×-stretched) the initial length and it did not depend on the stretching rate in the range between 2.0 and 7.0 mm/min. These conclusions were corroborated by differential scanning calorimetry (DSC) and X-ray diffraction experiments for PVDF samples processed under the same conditions as in the Raman scattering measurements. Poling with negative corona discharge was found to affect the α-PVDF morphology, improving the Raman bands related to this crystalline phase. This effect is minimized for films stretched to higher ratios. Significantly, corona-induced effects could not be observed with the other experimental techniques, i.e., X-ray diffraction and infrared spectroscopy.

Electrically excited oscillation and crystalline structure of a nanoclay/poly(vinylidene fluoride) composite film

2011 ◽  
Vol 22 (18) ◽  
pp. 2103-2112 ◽  
Author(s):  
Go Murasawa ◽  
Akihiro Nishioka ◽  
Ken Miyata ◽  
Tomonori Koda ◽  
Hideo Cho
Keyword(s):  
Composite Film ◽  
Crystalline Structure ◽  
Vinylidene Fluoride ◽  
Composite Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Impedance Characteristics ◽  
Poly Vinylidene Fluoride ◽  
Excited Oscillation

This study was conducted to investigate electrically excited oscillation and crystalline structure of nanoclay/poly(vinylidene fluoride) (PVDF) composite films. First, nanoclay/PVDF composite films are fabricated by solvent casting. Second, their PVDF crystalline structure and nanoclay orientation are analyzed using x-ray diffraction. The impedance characteristics of films are then measured. Third, the oscillation excited from films as a result of applied voltage is measured. Thereby, we confirmed the presence of unoriented β-phase PVDF crystals and exfoliated-type nanoclay structure in a composite film. The output oscillation showed monotonic component corresponding to the input sinusoidal voltage at a high frequency range, although its amplitude is low.

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