Isothermal Dielectric Relaxations of Poly(vinylidene Fluoride) Filled with Silicon Carbide Nanoparticles

2011 ◽  
Vol 279 ◽  
pp. 49-53
Author(s):  
Yu Сhao Li ◽  
Xiang Сai Ge ◽  
Sie Chin Tjong
Keyword(s):  
Activation Energy ◽  
Silicon Carbide ◽  
Vinylidene Fluoride ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Modulus Formalism ◽  
Dielectric Relaxations ◽  
Silicon Carbide Nanoparticles ◽  
Poly Vinylidene Fluoride ◽  
Dielectric Relaxation Behavior

The dielectric relaxation behavior of poly (vinylidene fluoride) based composites filled with beta silicon carbide nanoparticles were investigated over a wide frequency range and temperature intervals. The composites exhibited dielectric relaxations in the tested frequency range and the relaxations of composites can be well described via the modulus formalism of dielectric spectroscopy. Further, activation energy determined from the isothermal dielectric relaxations tended to decrease with increasing SiC indicating the promotion of SiC to the dipole relaxations of PVDF.

Dielectric Properties of Graphite Nanosheets Doped Poly(vinylidene Fluoride)/Silicon Carbide Hybrid

2011 ◽  
Vol 279 ◽  
pp. 3-9
Author(s):  
Yu Сhao Li ◽  
Xiang Сai Ge ◽  
Sie Chin Tjong
Keyword(s):  
Silicon Carbide ◽  
Dielectric Constant ◽  
Vinylidene Fluoride ◽  
Wide Frequency Range ◽  
Dielectric Behavior ◽  
Frequency Range ◽  
Molding Process ◽  
Graphite Nanosheets ◽  
Poly Vinylidene Fluoride ◽  
Sic Composites

Binary poly(vinylidene fluoride)/silicon carbide (PVDF/SiC) composites and its graphite nanosheets (GN) doped ternary hybrids were fabricated using simple solution mixing and hot compression molding process. The dielectric behavior of such hybrids was studied over a wide frequency range. Additions of graphite nanosheets with their concentrations close to the percolation threshold were found to be very effective to enhance the dielectric permittivity of PVDF/SiC system. The dielectric constant for PVDF/SiC/GN 80/20/2 system was ~ 200, being twenty times higher than that of neat PVDF. Furthermore, the dielectric behavior of such hybrid displayed strong frequency dependence.

Wide-Frequency Range Dielectric Relaxations in Sr 1−1.5x Bi x TiO 3 Ceramics

2002 ◽  
Vol 272 (1) ◽  
pp. 357-362 ◽  
Author(s):  
Viktor Bovtun ◽  
Viktor Porokhonskyy ◽  
Maxim Savinov ◽  
Tetyana Ostapchuk ◽  
Polina Samoukhina ◽  
...  
Keyword(s):  
Wide Frequency Range ◽  
Frequency Range ◽  
Dielectric Relaxations

Exploring the Structural and Dielectric Properties of Polymer Films Incorporating Carbon-Based Nanomaterials

2021 ◽  
Vol 20 (02) ◽  
pp. 2150019
Author(s):  
A. Deepak ◽  
Pheba Cherian ◽  
D. F. L. Jenkins
Keyword(s):  
Vinylidene Fluoride ◽  
Tunneling Current ◽  
Polymer Nanocomposite ◽  
Wide Frequency Range ◽  
Nanocomposite Films ◽  
Host Matrix ◽  
Weight Percentage ◽  
Poly Vinylidene Fluoride ◽  
Electrical Permittivity ◽  
Carbon Based Nanomaterials

This work explores the electrical, dielectric and physical characteristics of multi-walled carbon nanotube (MWCNT) and graphene reinforced Poly vinylidene fluoride (PVDF) polymer nanocomposite films, over a wide frequency range, ranging from 1 Hz to 1 MHz. Films are prepared with different weight percentage of MWCNTs or graphene powder within a PVDF host matrix and its intrinsic properties are compared with pure PVDF films. As the weight percentage increases, the material properties such as conductivity (electrical), permittivity (dielectric) and capacitance (dielectric) will change. PVDF is a dielectric and the fillers are conductors, and this gives rise to the phenomenon of percolation, as the weight percentage of conducting fillers increases. This paper explores film’s properties for different weight percentage of MWCNTs and graphene fillers. Tunneling current of graphene–PVDF films are also compared with MWCNT–PVDF films.

Molecular relaxation in Chitosan films in GHz frequency range

2014 ◽  
Vol 1613 ◽  
pp. 83-88
Author(s):  
Siva Kumar-Krishnan ◽  
Evgen Prokhorov ◽  
Gabriel Luna-Barcenas
Keyword(s):  
Activation Energy ◽  
Low Frequency ◽  
Bound Water ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Temperature Range ◽  
A Value ◽  
Chitosan Films ◽  
First Time

ABSTRACTThe molecular relaxations behavior of chitosan (CS) films in the wide frequency range of 0.1-3x109 Hz (by using three different impedance analyzers) have been investigated in the temperature range of -100C to 120°C using Dielectric Spectroscopy (DS). Additionally to the low frequency molecular relaxations such as α and β relaxations, for the first time, high frequency (1-3 GHz) relaxation process has been observed in the chitosan films. This relaxation exhibits Arrhenius-type dependence in the temperature range of -100 C to 54°C with negative activation energy -2.7 kJ/mol. At temperatures above 54°C, the activation energy changes from -2.7 kJ/mol to +4.4 kJ/mol. Upon cooling, the activation energy becomes negative again with a value of -1.2 kJ/mol. The bound water between chitosan molecules strongly modifies molecular motion and the relaxation spectrum, giving rise to a new relaxation at the frequency at ca. 1 GHz. In situ FTIR analysis has shown that this relaxation related to the changes in vibration of the –OH, NH and –CO functional groups.

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