Improving dielectric properties and thermal conductivity of polymer composites with CaCu3Ti4O12 and β-SiC hybrid fillers

2015 ◽  
Vol 08 (03) ◽  
pp. 1540011 ◽  
Author(s):  
Xin Ouyang ◽  
Peng Cao ◽  
Weijun Zhang ◽  
Zhaohui Huang ◽  
Wei Gao
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Response ◽  
Interfacial Polarization ◽  
Melt Blending ◽  
Hybrid Fillers ◽  
Different Types ◽  
Thermally Conductive ◽  
Sic Whiskers

In this paper, we report a series of homogeneous polymeric composites with enhanced dielectric properties and thermal conductivity. The composites were constituted of polyvinylidene fluorides (PVDFs) matrix and CaCu 3 Ti 4 O 12 (CCTO) monolithic or CCTO/β- SiC hybrid fillers, and prepared by simple melt blending and hot moulding technique. The influence of different types of fillers and their composition on the dielectric response and thermal conductivity of the obtained composites was studied. Results show that hybrid loading is preferred and a reasonable combination of thermal conductivity (0.80 W⋅m-1⋅K-1), dielectric constant (∼50) and dielectric loss (∼0.07) at 103 Hz was achieved in the PVDF composite containing 40 vol.% CCTO and 10 vol.% β- SiC . The strong dipolar and interfacial polarization derived from the fillers are responsible for the enhancement of the dielectric constant, while the formation of thermally conductive networks/chains by β- SiC whiskers contributes to the improved thermal conductivity.

CaCu3Ti4O12–PVDF polymeric composites with enhanced capacitive energy density

2015 ◽  
Vol 29 (10n11) ◽  
pp. 1540003 ◽  
Author(s):  
Xin Ouyang ◽  
Peng Cao ◽  
Weijun Zhang ◽  
Zhuofeng Liu ◽  
Zhaohui Huang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Melting Point ◽  
Energy Density ◽  
Vinylidene Fluoride ◽  
Dielectric Breakdown ◽  
Melt Blending ◽  
Capacitive Energy Storage ◽  
Poly Vinylidene Fluoride

CaCu 3 Ti 4 O 12 (CCTO)–poly(vinylidene fluoride (PVDF)) composites were prepared by melt blending and hot molding techniques. The addition of CCTO remarkably enhanced the dielectric properties and the thermal conductivity of PVDF composites, while the melting point of the PVDF composites (~170°C) was almost independent of the CCTO concentration. Based on the results of dielectric constant and dielectric breakdown voltage, the PVDF composite containing 40 vol.% CCTO fillers shows the optimized capacitive energy storage potential (7.81 J/cm3).

scholarly journals Crystallization and Dielectric Properties of MWCNT /Poly(1-Butene) Composite Films by a Solution Casting Method

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 755
Author(s):  
Lingfei Li ◽  
Qiu Sun ◽  
Xiangqun Chen ◽  
Yongjun Xu ◽  
Zhaohua Jiang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Breakdown Strength ◽  
Composite Films ◽  
Conductive Filler ◽  
Interfacial Polarization ◽  
Solution Casting ◽  
Casting Method ◽  
Solution Casting Method

In this work, poly(1-butene) (PB-1) composite films with multi-walled carbon nanotubes (MWCNT) were prepared by a solution casting method. The relationship between the dielectric properties and the crystal transformation process of the films was investigated. It was indicated that there were two crystal forms of I and II of PB-1 during the solution crystallization process. With the prolongation of the phase transition time, form II was converted into form I. The addition of the conductive filler (MWCNT) accelerated the rate of phase transformation and changed the nucleation mode of PB-1. The presence of crystal form I in the system increased the breakdown strength and the dielectric constant of the films and reduced the dielectric loss, with better stability. In addition, the dielectric constant and the dielectric loss of the MWCNT/PB-1 composite films increased with the addition of MWCNT, due to the interfacial polarization between MWCNT and PB-1 matrix. When the mass fraction of the MWCNT was 1.0%, the composite film had a dielectric constant of 43.9 at 25 °C and 103 Hz, which was 20 times that of the original film.

scholarly journals Stable dielectric response of low-loss aromatic polythiourea thin films on Pt/SiO2 substrate

2016 ◽  
Vol 06 (01) ◽  
pp. 1650003 ◽  
Author(s):  
A. Eršte ◽  
L. Fulanović ◽  
L. Čoga ◽  
M. Lin ◽  
Y. Thakur ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Response ◽  
High Density Polyethylene ◽  
Dielectric Losses ◽  
Low Loss ◽  
Promising Candidate ◽  
Sio2 Substrate ◽  
Polar Polymer

We have investigated dielectric properties of aromatic polythiourea (ArPTU, a polar polymer containing high dipolar moments with very low defect levels) thin films that were developed on Pt/SiO2 substrate. The detected response is compared to the response of commercially available polymers, such as high density polyethylene (HDPE) and polypropylene (PP), which are at present used in foil capacitors. Stable values of the dielectric constant [Formula: see text] (being twice higher than in HDPE and PP) over broad temperature and frequency ranges and dielectric losses as low as in commercial systems suggest ArPTU as a promising candidate for future use in a variety of applications.

scholarly journals The Dielectric Properties and Thermal Conductivities of Epoxy Composites Reinforced by Titanium Dioxide

2021 ◽  
Author(s):  
Yuan Jia ◽  
Juxiang Yang ◽  
Weijie Dong ◽  
Beibei Li ◽  
Zhen Liu
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Titanium Dioxide ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Hydrothermal Process ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Ep Matrix ◽  
Thermal Conductivities

Abstract To improve the dielectric properties and thermal conductivities of epoxy resins (EP), titanium dioxide superfine powders with microspheres structure (S-TiO2) were prepared via a hydrothermal process based on the sodium dodecyl benzene sulfonate and hydroxyl silicate. The different content of S-TiO2 was then employed as modifiers to add into EP resin to prepare the S-TiO2/EP composites. The structure and morphology of the prepared S-TiO2 was observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and influences of different addition of S-TiO2 on the thermal conductivity of S-TiO2/EP composites are researched, while their dielectric constant and dielectric loss are also studied. The results suggested that the reasonable content of S-TiO2 can endow the S-TiO2/EP composites with higher dielectric constant without excessive increase their dielectric loss even under the high frequency. Furthermore, the thermal conductivity of S-TiO2/EP are also be improved, which can be attributed to the good thermal conductivity of S-TiO2 itself and the thermal conductivity path formed by S-TiO2 inside the EP matrix.

Preparation and Dielectric Properties of Cu/PVDF Composite Films

2014 ◽  
Vol 1035 ◽  
pp. 417-421 ◽  
Author(s):  
Jian Wen Zhai ◽  
Ya Jun Wang ◽  
Jian Lou Deng ◽  
Chang Gen Feng
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Volume Fraction ◽  
Composite Films ◽  
Interfacial Polarization ◽  
Dielectric Constants ◽  
Pvdf Film ◽  
Continuous Increase ◽  
Better Than

nanoand micro size Cu were employed separately and investigated comparatively. Different volume fraction of Cu was added into PVDF film in order to investigate the content of filler effect on the dielectric properties of polymer composites. XRD and SEM were used to analyze the crystalline phase and microstructure of the films. The results show that two sizes of Cu have the same peak features, and with the continuous increase of the content of Cu, it disperse better in PVDF. The dielectric constant (ε) of the composite containing 16 vol% micro-CCTO filler is 16 at 100 Hz and room temperature, and its dielectric loss (tanδ) is only 0.15, which is substantially better than others. Besides, for 18 vol% nanoCu/PVDF composite tanδis 0.25 andεis 18 at 100 Hz. Moreover,εand tanδof nanoCu/PVDF composite are both higher than those of micro-Cu/PVDF. Analysis shows that the composites with nanoCu have higher dielectric constants, which is mainly from the interfacial polarization.

Dielectric properties of normal, reduced, and specially reduced rutile (TiO2) single crystals at room temperature

1969 ◽  
Vol 47 (1) ◽  
pp. 3-6 ◽  
Author(s):  
H. B. Lal ◽  
K. G. Srivastava
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Oxygen Vacancy ◽  
Single Crystals ◽  
Room Temperature ◽  
Interfacial Polarization ◽  
Absorption Peak ◽  
Single Relaxation Time

The variation of the dielectric constant (ε′) and the dielectric loss (ε″) have been studied as a function of frequency (102 to 1010 c.p.s.) for normal (as grown), reduced (heated in vacuum), and specially reduced (heated in vacuum in presence of an asymmetric d.c. field) rutile single crystals parallel to c-axis at room temperature. Dispersions in ε′ have been observed in the frequency ranges 102 to 103 and 107 to 109 c.p.s. for all the samples with absorption peaks in ε″ at 2 × 102 and 6 × 107 c.p.s. Also an extra absorption peak in ε″ has been found at 2 × 104 c.p.s. for the specially reduced sample. The absorption peak at 2 × 102 c.p.s. has been observed by many workers and is typical for interfacial polarization. The peak at 6 × 107 c.p.s. appears to be due to a dipole rotation process with a single relaxation time and is identified as due to relaxation of dipoles formed between Ti3+ and a neighboring oxygen vacancy. The possible mechanism of relaxation for the 2 × 104 c.p.s. absorption peak is also discussed.

scholarly journals The combination of Al2O3 and BN for enhancing the thermal conductivity of PA12 composites prepared by selective laser sintering

RSC Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1984-1991
Author(s):  
Yue Yuan ◽  
Wei Wu ◽  
Huanbo Hu ◽  
Dongmei Liu ◽  
Hui Shen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Polymer Composites ◽  
Selective Laser Sintering ◽  
Conductive Polymer ◽  
High Thermal Conductivity ◽  
Complex Structures ◽  
Conductive Polymer Composites ◽  
Hybrid Fillers ◽  
Thermally Conductive

The introduction of hybrid fillers in SLS technology is an effective method for the manufacture of thermally conductive polymer composites with high thermal conductivity, complex structures and good mechanical properties.

scholarly journals The Effect of Ca Dopant on the Electrical and Dielectric Properties of BaTi4O9 Sintered Ceramics

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5375
Author(s):  
Asad Ali ◽  
Muhammad Hasnain Jameel ◽  
Sarir Uddin ◽  
Abid Zaman ◽  
Zafar Iqbal ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Energy Storage ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Impedance Spectroscopy ◽  
Energy Loss ◽  
Interfacial Polarization ◽  
Storage Material ◽  
Energy Storage Material ◽  
The Impact

The current research examines the impact of Ca2+ substitution on the phase and electrical properties of (Ba1−xCax)Ti4O9, (x = 0.0, 0.3, 0.6, and 0.9) sintered pellets synthesized by solid-state reaction method. The as-synthesized samples were analyzed using X-ray diffraction (XRD) and impedance spectroscopy. The emergence of orthorhombic phase fit into space group Pnmm was revealed by XRD, and the addition of Ca resulted in a considerable shift in grain size. Dielectric properties were determined using an impedance spectroscopy in a wide frequency range from 1MHz to 3 GHz. The dielectric properties i.e., dielectric constant (εr) and dielectric loss (tanσ), were measured at 3 GHz frequency. The frequency-dependent parameters such as conductivity, dielectric constant, and dielectric loss indicated that the relaxation process is a Maxwell–Wagner type of interfacial polarization. The improved dielectric properties and low energy loss have made (Ba1−xCax)Ti4O9 a prominent energy storage material. This study provides the possibility to improve its dielectric properties and reduce energy loss, making it an excellent energy storage material.

scholarly journals Effect of Transition Metal on Structural and Dielectric Properties of Mg0.5Tm0.5Fe2O4 (Tm = Zn and Cu) System

2021 ◽  
Author(s):  
Pallavi Saxena ◽  
Anand Yadav
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Interfacial Polarization ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
High Frequencies ◽  
X Ray ◽  
Cubic Structure ◽  
High Dielectric

This study explored the structural and dielectric features of Mg0.5Tm0.5Fe2O4 (Tm = Zn and Cu) that were synthesized by the Solid-state reaction (SSR) method. The X-ray powder diffraction (XRD) analysis reveals that the prepared samples are single-phase cubic structure without any impurity. Rietveld-refined X-ray diffraction results reveal the formation of cubic structure and all the peaks of Mg0.5Zn0.5Fe2O4 and Mg0.5Cu0.5Fe2O4 are perfectly indexed in the cubic (Fd-3 m) structure. Dielectric constant and dielectric loss variation with frequency were also explored. Both decrease when the relevant alternating field is increasing and become constant at high frequencies which reflects the important role of interfacial polarization. Furthermore, the Mg0.5Cu0.5Fe2O4 having the smallest crystallite size (~ 44.73 nm) has a high dielectric constant (~ 4.41 × 104) value as compare to Mg0.5Zn0.5Fe2O4.

Effect of clay modification on the dynamic mechanical and dielectric properties of PMMA nanocomposites via melt blending

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Yeh Wang ◽  
Wei-C. Chen
Keyword(s):  
Dielectric Properties ◽  
Ionic Conduction ◽  
Interfacial Polarization ◽  
Ionic Species ◽  
Space Charge Polarization ◽  
Melt Blending ◽  
Dynamic Mechanical ◽  
Clay Modification ◽  
Β Relaxation ◽  
Clay Layers

AbstractThe dynamic mechanical and dielectric properties of poly(methyl methacrylate)/ clay nanocomposites (PCNs) prepared with melt blending was studied in terms of clay modification and nanoscale dispersion. The pristine clay was modified via various routes, including PMMA concentrates from in situ polymerization and POP-diamine intercalation. Partially exfoliated clay layers were uniformly dispersed in the nanocomposites as evidenced from x-ray diffraction study. The subglass β relaxation, the segmental α relaxation, and the α β-merging process above Tg were observed in the nanocomposites from the dielectric analysis. Compared to neat PMMA, with only 5 wt% clay loading, the modified PCN materials exhibit higher glass-transition temperatures and higher dynamic storage moduli, which was attributed to the polymer chain tethering and confinement effect. Significant increase in dielectric permittivity’s and losses due to interfacial polarization and ionic conduction were observed for the PCNs. The intensity of the interfacial polarization process increases with the dispersion degree of clay layers and hence the relaxation process can be assigned to the space charge polarization of the ionic species in the clay intergalleries.

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