Preparation of PVDF/PAR Composites with Piezoelectric Properties by Post-Treatment

Thermoplastic composites were prepared using poly (vinylidene fluoride) (PVDF) as the matrix with piezoelectric properties and aromatic polyarylate (PAR) as the reinforcing component. The PVDF/PAR conjugate fibers were prepared by melt conjugate spinning. The PVDF/PAR composites were prepared by compression molding of the PVDF/PAR conjugate fiber laminates at various molding temperatures. Drawing and poling post-treatments of the PVDF/PAR composites were performed to increase the β crystalline phase content of the PVDF. The morphologies of the PVDF/PAR composites were observed by scanning electron microscopy, and the tensile properties were tested using an universal testing machine. The crystal structure of the PVDF/PAR composites was confirmed by Fourier transform infrared spectroscopy and X-ray diffraction. The piezoelectric properties were tested using voltmeters and multimeters. The post-treatments enhanced the content of the β crystalline phase of the PVDF matrix, thereby improving the piezoelectric properties of the composites. A molding temperature of 180 °C, drawing temperature of 90 °C, and poling voltage of 12 kV were identified as the optimal conditions for the preparation of the PVDF/PAR composite.

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Fabrication of Piezoelectric PVDF/PAR Composites Using a Sheath-Core Fiber Method

Polymers ◽

10.3390/polym12102214 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2214

Author(s):

Min Hong Jeon ◽

Yu Rim Lee ◽

Hyeon Soo Lim ◽

Jong Sung Won ◽

Seung Goo Lee

Keyword(s):

Vinylidene Fluoride ◽

Piezoelectric Properties ◽

Testing Machine ◽

X Ray Diffraction ◽

Composite Surface ◽

Fiber Assembly ◽

Universal Testing ◽

Poly Vinylidene Fluoride ◽

Core Fiber ◽

Growing Conditions

We report the preparation of sheath-core type fibers made from poly(vinylidene fluoride) (PVDF) and polyarylate (PAR) using melt conjugate spinning to fabricate piezolectric composites. The morphology of this sheath-core fiber was determined through scanning electron microscopy. Subsequently, by the compression molding of the PVDF/PAR sheath-core fiber assembly, we fabricated PVDF/PAR composites exhibiting piezoelectric properties. For enhancing the piezoelectric properties, we increased the concentration of PVDF β-crystalline phase in the PVDF/PAR composite through poling post-treatments. The resulting crystal structure of PVDF was confirmed through infrared spectroscopy and X-ray diffraction. A universal testing machine was employed to measure the tensile properties of the PVDF/PAR composites. Finally, through a hydrothermal growing method, ZnO was coated on the composite surface to enhance the piezoelectric properties, which were subsequently optimized by varying the hydrothermal growing conditions.

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

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.1117 ◽

2007 ◽

Vol 124-126 ◽

pp. 1117-1120 ◽

Cited By ~ 1

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.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1070-1072.589 ◽

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.

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

Surface Review and Letters ◽

10.1142/s0218625x16500050 ◽

2016 ◽

Vol 23 (03) ◽

pp. 1650005 ◽

Cited By ~ 2

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.

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The Effects of Hydrothermal Ageing on the Crushing Behavior of Glass/Epoxy Composite Pipes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.819.411 ◽

2015 ◽

Vol 819 ◽

pp. 411-416

Author(s):

S.N. Fitriah ◽

M.S. Abdul Majid ◽

R. Daud ◽

M. Afendi ◽

Z.S. Nazirah

Keyword(s):

Composite Laminates ◽

Testing Machine ◽

Hydrothermal Condition ◽

Compression Tests ◽

Universal Testing ◽

Failure Region ◽

The Matrix ◽

Glass Fibre Reinforced ◽

Crushing Behavior ◽

Composite Pipes

The paper discusses the crushing behavior of glass fibre reinforced epoxy (GRE) pipes under hydrothermal ageing condition. This study determines the behavior of the GRE pipes when subjected to different ageing periods and temperatures. Hydrothermal ageing has been found to cause degradation between resin and fibre interface thus causing the reduction in the strength of composite laminates. The pipes were subjected to hydrothermal condition to simulate and precipitate ageing by immersing the pipe samples in water at 80°C for 250, 500, and 1000 hours. Compression tests were carried out using Universal Testing Machine (UTM) for virgin condition and aged samples in accordance with ASTM D695 standard. The maximum force at the initial failure region is observed for each of the conditioned pipes. The results show that the strength of the matrix systems was considerably degraded due to the plasticization of the matrix system.

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Simulations of High-Strain Electrostrictive Chlorinated Terpolymers

MRS Proceedings ◽

10.1557/proc-785-d3.7 ◽

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.

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Development of self-poled PVDF/MWNT flexible nanocomposites with a boosted electroactive β-phase

New Journal of Chemistry ◽

10.1039/d0nj02003f ◽

2020 ◽

Vol 44 (34) ◽

pp. 14578-14591

Author(s):

Akash M. Chandran ◽

S. Varun ◽

Prasanna Kumar S. Mural

Keyword(s):

Vinylidene Fluoride ◽

Piezoelectric Properties ◽

Nanocomposite Films ◽

Fabrication Method ◽

Β Phase ◽

Poly Vinylidene Fluoride ◽

Dielectric And Piezoelectric Properties

In the present study, we report a simple fabrication method for poly(vinylidene fluoride) PVDF/MWCNT flexible nanocomposite films with a boosted electroactive phase that enhanced the dielectric and piezoelectric properties.

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