scholarly journals Enhanced Piezoelectric Behavior of PVDF Nanocomposite by AC Dielectrophoresis Alignment of ZnO Nanowires

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Kyungwho Choi ◽  
Woongchul Choi ◽  
Choongho Yu ◽  
Yong Tae Park
Keyword(s):  
Dielectric Constant ◽  
Polymer Matrix ◽  
Polyvinylidene Fluoride ◽  
Zno Nanowires ◽  
Lead Free ◽  
Poling Process ◽  
Piezoelectric Polymer ◽  
The Matrix ◽  
Pvdf Matrix ◽  
Piezoelectric Behavior

In contrast to commercial piezoelectric ceramics, lead-free materials such as ZnO and a polymer matrix are proper candidates for use in ecofriendly applications. In this article, the authors represent a technique using ZnO nanowires with a polyvinylidene fluoride (PVDF) matrix in a piezoelectric polymer composite. By aligning the nanowires in the matrix in a desired direction by AC dielectrophoresis, the piezoelectric behavior was enhanced. The dielectric constant of the composite was improved by increasing the concentration of the ZnO nanowires as well. Specifically, the resulting dielectric constant shows an improvement of 400% with aligned ZnO nanowires by increasing the poling effect compared to that of a randomly oriented nanowire composite without a poling process.

Enhancement of dielectric permittivity and ferroelectricity of a modified cobalt nanoparticle and polyvinylidene fluoride based composite

RSC Advances ◽  
2015 ◽  
Vol 5 (12) ◽  
pp. 8591-8597 ◽  
Author(s):  
K. Vasundhara ◽  
B. P. Mandal ◽  
A. K. Tyagi
Keyword(s):  
Dielectric Constant ◽  
Dielectric Permittivity ◽  
Polyvinylidene Fluoride ◽  
Cobalt Nanoparticles ◽  
Remarkable Increase ◽  
Β Phase ◽  
Pvdf Matrix ◽  
Cobalt Nanoparticle

A remarkable increase in the amount of polar β phase has been observed upon dispersion of cobalt nanoparticles in the PVDF matrix. A significant improvement in the dielectric constant of PVDF has been achieved.

scholarly journals Development of Lead-Free Nanowire Composites for Energy Storage Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Miguel Mendoza ◽  
Md Ashiqur Rahaman Khan ◽  
Mohammad Arif Ishtiaque Shuvo ◽  
Alberto Guerrero ◽  
Yirong Lin
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Polymer Matrix ◽  
Polyvinylidene Fluoride ◽  
Breakdown Strength ◽  
Environmental Safety ◽  
High Energy ◽  
High Energy Density ◽  
Lead Free ◽  
High Dielectric

There is an increasing demand to improve the energy density of dielectric capacitors for satisfying the next generation material systems. One effective approach is to embed high dielectric constant inclusions such as lead zirconia titanate in polymer matrix. However, with the increasing concerns on environmental safety and biocompatibility, the need to expel lead (Pb) from modern electronics has been receiving more attention. Using high aspect ratio dielectric inclusions such as nanowires could lead to further enhancement of energy density. Therefore, this paper focuses on the development of a lead-free nanowire reinforced polymer matrix capacitor for energy storage application. Lead-free sodium niobate nanowires (NaNbO3) were synthesized using hydrothermal method, followed by mixing them with polyvinylidene fluoride (PVDF) matrix using a solution-casting method for nanocomposites fabrication. Capacitance and breakdown strength of the samples were measured to determine the energy density. The energy density of NaNbO3/PVDF composites was also compared with that of lead-containing (PbTiO3/PVDF) nanocomposites and previously developed Pb()O3/PVDF composites to show the feasibility of replacing lead-containing materials. The energy density of NaNbO3/PVDF capacitor is comparable to those of lead-containing ones, indicating the possibility of expelling lead from high-energy density dielectric capacitors.

scholarly journals Determining the effect of dispersed aluminum particles on the functional properties of polymeric composites based on polyvinylidene fluoride

2021 ◽  
Vol 3 (12 (111)) ◽  
pp. 59-66
Author(s):  
Eduard Lysenkov ◽  
Leonid Klymenko
Keyword(s):  
Polymer Matrix ◽  
Polyvinylidene Fluoride ◽  
Polymeric Materials ◽  
Mechanical Analysis ◽  
Degree Of Crystallinity ◽  
Functional Characteristics ◽  
Aluminum Particles ◽  
Ultrasound Propagation ◽  
The Matrix ◽  
Dispersed Aluminum

Polymeric materials that contain inorganic fillers demonstrate a unique set of physical properties due to the combination of matrix elasticity and filler strength. This paper reports determining the effect of dispersed aluminum particles on the properties of polyvinylidene fluoride-based materials. This study result is the fabrication of a series of composite materials using a piston extruder. Their functional characteristics have been explored using the methods of thermophysical and mechanical analysis, dilatometry, and acoustic spectroscopy. It was established that the introduction of dispersed aluminum particles leads to the loosening of the matrix, which may indicate the transition of macro macromolecules from the crystalline phase to the boundary layer around the filler. This feature of structure formation and the uniform distribution of filler particles ensured the improvement of the functional characteristics of the materials obtained. It has been shown that with an increase in the content of filler in the system to 5 % the thermal conductivity increases from 0.17 W/(m·K) to 1.55 W/(m·K). The introduction of the filler leads to an improvement in the heat resistance of the materials obtained, by 17 K. The increase in both melting point and destructiveness is explained by the formation of a more perfect polymer structure with a higher degree of crystallinity. An increase in the speed of ultrasound propagation was identified, by 67 %, as well as in the tensile strength, by 36 %, in the materials obtained, which can be explained by contributions from the filler, which has greater sound conductivity and mechanical strength than the polymer matrix. Such systems show the reinforcing effect of aluminum particles on the polymer matrix, so they could be used as structural materials with improved functional characteristics

Multifunctional Lead-Free K0.5Bi0.5TiO3-based Ceramic Reinforced PVDF Matrix Composites

2021 ◽  
pp. 159616
Author(s):  
Sushmita Dwivedi ◽  
Manish Badole ◽  
Tanvi Pareek ◽  
Sunil Kumar
Keyword(s):  
Lead Free ◽  
Matrix Composites ◽  
Pvdf Matrix

scholarly journals A mechanism for fire retardancy realized by a combination of biofillers and ammonium polyphosphate in various polymer systems

Cellulose ◽  
2021 ◽  
Author(s):  
Koki Matsumoto ◽  
Tatsuya Tanaka ◽  
Masahiro Sasada ◽  
Noriyuki Sano ◽  
Kenta Masuyama
Keyword(s):  
Polymer Matrix ◽  
Synergetic Effect ◽  
Polymer System ◽  
Ammonium Polyphosphate ◽  
Fire Retardancy ◽  
Polymer Systems ◽  
Thermal Decomposition Behavior ◽  
Burning Behavior ◽  
The Matrix ◽  
Decomposition Behavior

AbstractThis study focused on realizing fire retardancy for polymer composites by using a cellulosic biofiller and ammonium polyphosphate (APP). The motivation of this study was based on revealing the mechanism of the synergetic effect of a cellulosic biofiller and APP and determining the parameters required for achieving a V-0 rating in UL94 standard regardless of the kind of polymer system used. As for the polymer matrix, polypropylene and polylactic acid were used. The flammability, burning behavior and thermal decomposition behavior of the composites were investigated through a burning test according to the UL-94 standard, cone calorimetric test and thermogravimetric analysis. As a result, the incorporation of a high amount of cellulose enabled a V-0 rating to be achieved with only a small amount of APP despite the variation of the optimum cellulose loading between the matrix polymers. Through analysis, the results indicated that APP decreased the dehydration temperature of cellulose. Furthermore, APP promoted the generation of enough water as a nonflammable gas and formed enough char until the degradation of the polymer matrix was complete. The conditions required to achieve the V-0 rating were suggested against composites incorporating APP and biofillers. Furthermore, the suggested conditions were validated by using polyoxymethylene as a highly flammable polymer.

scholarly journals Comparison of the Dielectric Properties of Ecoflex® with L,D-Poly(Lactic Acid) or Polycaprolactone in the Presence of SWCN or 5CB

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1719
Author(s):  
Patryk Fryń ◽  
Sebastian Lalik ◽  
Natalia Górska ◽  
Agnieszka Iwan ◽  
Monika Marzec
Keyword(s):  
Oleic Acid ◽  
Dielectric Properties ◽  
Polymer Matrix ◽  
Liquid Crystalline ◽  
Weight Ratio ◽  
Poly Lactic Acid ◽  
Relaxation Processes ◽  
The Matrix ◽  
Walled Carbon Nanotubes ◽  
Hybrid Layers

The main goal of this paper was to study the dielectric properties of hybrid binary and ternary composites based on biodegradable polymer Ecoflex®, single walled carbon nanotubes (SWCN), and liquid crystalline 4′-pentyl-4-biphenylcarbonitrile (5CB) compound. The obtained results were compared with other created analogically to Ecoflex®, hybrid layers based on biodegradable polymers such as L,D-polylactide (L,D-PLA) and polycaprolactone (PCL). Frequency domain dielectric spectroscopy (FDDS) results were analyzed taking into consideration the amount of SWCN, frequency, and temperature. For pure Ecoflex®, two relaxation processes (α and β) were identified. It was shown that the SWCN admixture (in the weight ratio 10:0.01) did not change the properties of the Ecoflex® layer, while in the case of PCL and L,D-PLA, the layers became conductive. The dielectric constant increased with an increase in the content of SWCN in the Ecoflex® matrix and the conductive behavior was not visible, even for the greatest concentration (10:0.06 weight ratio). In the case of the Ecoflex® polymer matrix, the conduction relaxation process at a frequency ca. several kilohertz appeared and became stronger with an increase in the SWCN admixture in the matrix. Addition of oleic acid to the polymer matrix had a smaller effect on the increase in the dielectric response than the addition of liquid crystal 5CB. Fourier transform infrared (FTIR) results revealed that the molecular structure and chemical character of the Ecoflex® and PCL matrixes remained unchanged upon the addition of SWCN or 5CB in a weight ratio of 10:0.01 and 10:1, respectively, while molecular interactions appeared between L,D-PLA and 5CB. Moreover, adding oleic acid to pure Ecoflex® as well as the binary and ternary hybrid layers with SWCN and/or 5CB in a weight ratio of Ecoflex®:oleic acid equal to 10:0.3 did not have an influence on the chemical bonding of these materials.

The Research on the Piezoelectric and Dielectric Properties of Bi0.5(Nak)0.5-BaTiO3 Lead-Free Ceramics

2014 ◽  
Vol 1035 ◽  
pp. 422-425
Author(s):  
Jian Yong Guo ◽  
Tao Sheng Zhou ◽  
Ji Hong Liao
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Perovskite Structure ◽  
Relative Dielectric Constant ◽  
Lead Free ◽  
Reactive Sintering ◽  
Lead Free Ceramics ◽  
Xrd Patterns ◽  
Sintering Method

The Bi0.5(Na1-xKx)0.5-yBaTiO3(BNK-BT) lead-free ceramics have been prepared by the solild reactive sintering method. XRD patterns show the BNK-BT ceramics had a perovskite structure. Piezoelectric and dielectric properties of the ceramics also have been studied. The results show that the samples had the best piezoelectric and dielectric properties when x=0.20, y=0.10. And the maximum of d33is 149 pC/N, while the relative dielectric constant is 1087.

scholarly journals Characterization of percolation behavior in conductor–dielectric 0-3 composites

2014 ◽  
Vol 04 (04) ◽  
pp. 1450035 ◽  
Author(s):  
Lin Zhang ◽  
Patrick Bass ◽  
Zhi-Min Dang ◽  
Z.-Y. Cheng
Keyword(s):  
Dielectric Constant ◽  
Percolation Threshold ◽  
Frequency Dependence ◽  
Experimental Results ◽  
Effective Dielectric Constant ◽  
Filler Concentration ◽  
Percolation Behavior ◽  
The Matrix ◽  
The Relationship

The equation ε eff ∝ (ϕc - ϕ)-s which shows the relationship between effective dielectric constant (εeff) and the filler concentration (φ), is widely used to determine the percolation behavior and obtain parameters, such as percolation threshold φc and the power constant s in conductor–dielectric composites (CDCs). Six different systems of CDCs were used to check the expression by fitting experimental results. It is found that the equation can fit the experimental results at any frequency. However, it is found that the fitting constants do not reflect the real percolation behavior of the composites. It is found that the dielectric constant is strongly dependent on the frequency, which is mainly due to the fact that the frequency dependence of the dielectric constant for the composites close to φc is almost independent of the matrix.

Properties of a Dielectric Elastomer Actuator Modified by Dispersion of Functionalised Carbon Nanotubes

2012 ◽  
Vol 79 ◽  
pp. 41-46 ◽  
Author(s):  
Fabia Galantini ◽  
Sabrina Bianchi ◽  
Valter Castelvetro ◽  
Irene Anguillesi ◽  
Giuseppe Gallone
Keyword(s):  
Carbon Nanotubes ◽  
Dielectric Constant ◽  
Mechanical Performance ◽  
Broad Class ◽  
Dielectric Elastomer ◽  
Low Dielectric ◽  
Dielectric Elastomer Actuators ◽  
Electromechanical Transduction ◽  
The Matrix ◽  
Simple Matrix

Among the broad class of electro-active polymers, dielectric elastomer actuators represent a rapidly growing technology for electromechanical transduction. In order to further develop this applied science, the high driving voltages currently needed must be reduced. For this purpose, one of the most promising and adopted approach is to increase the dielectric constant while maintaining both low dielectric losses and high mechanical compliance. In this work, a dielectric elastomer was prepared by dispersing functionalised carbon nanotubes into a polyurethane matrix and the effects of filler dispersion into the matrix were studied in terms of dielectric, mechanical and electro-mechanical performance. An interesting increment of the dielectric constant was observed throughout the collected spectrum while the loss factor remained almost unchanged with respect to the simple matrix, indicating that conductive percolation paths did not arise in such a system. Consequences of the chemical functionalisation of carbon nanotubes with respect to the use of unmodified filler were also studied and discussed along with rising benefits and drawbacks for the whole composite material.

Nanocomposites in Drug Delivery and Imaging Applications

2021 ◽  
pp. 1539-1554
Author(s):  
Dimple Sethi Chopra
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Thermal Analysis ◽  
Cancer Treatment ◽  
Polymer Matrix ◽  
Cell Imaging ◽  
Xrd Pattern ◽  
Chemical Functionalization ◽  
Disease Biomarkers ◽  
The Matrix

Nanocomposites are a class of materials in which one or more phases with nanoscale dimensions are embedded in a metal, ceramic, or polymer matrix. The properties of nanocomposites depend on matrix, loading, degree of dispersion, size, shape, and orientation of the nanoscale phase and interaction between the matrix and the nanoscale phase. Nanocomposites are generally prepared using direct melt intercalation. The formation of nanocomposite is ascertained by XRD pattern, FTIR spectra, electron microscopy, and thermal analysis like DSC and TGA. Nanocomposites have properties of nanoparticles, multifunctional capabilities, chemical functionalization, huge interphase zone. Novel nanomaterials offer a new chemotherapeutic route for cancer treatment by combining cell imaging and hyperthermia in a synergistic way. In spite of toxicity and safety concerns, multifunctional nanocomposite still interest the researchers because of emergence of versatile properties, better understanding of disease biomarkers, and quest for ways to improve biocompatibility.

Sign in / Sign up

Export Citation Format

Share Document