Research on Thermal Conductive and Insulating Material Based on Phosphoric Acid Adhesive

2011 ◽  
Vol 399-401 ◽  
pp. 1184-1187
Author(s):  
Yong De Hao ◽  
Hao Kun Liu ◽  
Xuan Xiong
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Dielectric Property ◽  
Thermal Conduction ◽  
Relative Dielectric Constant ◽  
Material Research ◽  
Insulating Material ◽  
Conducting Property ◽  
Thermal Conducting ◽  
Auxiliary Material

A thermal conductive and insulating material with H3PO4 as the adhesive, AlN as the principal material of thermal conduction and Al2O3 as auxiliary material, was researched and developed in this paper. The paper explores the influences of components on density, thermal conducting property and dielectric property of the material. Research results show that as to the block sample of (mol)AlN: (mol)Al2O3=90:10, ω(H3PO4)=12% in the research, its density is 2.51 g/cm3, thermal conductivity is 5.655 W/(m•K), and relative dielectric constant under 10 kHz is 6.207.

The study on effective thermal conductivity of carbon foam based on fractal theory

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Wang Yong ◽  
An Qingqing ◽  
Cao Lingling ◽  
Si Xiaojuan ◽  
Liu Donghui ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Theoretical Basis ◽  
Fractal Theory ◽  
Carbon Foam ◽  
Conducting Property ◽  
Thermal Conductivity Model ◽  
Thermal Conducting ◽  
Temperature And Pressure ◽  
The Relationship

AbstractNovel carbon foam with high thermal conductivity is prepared by thermal treating of mesophase pitch under certain temperature and pressure condition. With fractal theory, the thermal conducting property of this novel porous material is discussed. Then we deduce the area fractal dimension of carbon foam. A thermal conductivity model of carbon foam is proposed. The relationship formula of effective thermal conductivity is presented by using thermal resistance method. Through computation, the effective thermal conductivity of carbon foam is acquired. The value of model forecast is consistent with that of the actual observed for carbon foam. This method has provided the theoretical basis for better using its fine heat conduction performance.

Fabrication and Properties of Aluminum Nitide Ceramics Doped Carbon Nanotubes

2009 ◽  
Vol 610-613 ◽  
pp. 559-562 ◽  
Author(s):  
Bao Ping Li ◽  
Ben Niu ◽  
Jie Qiang Wang ◽  
Ping Li ◽  
Sun Hao Wang
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Dielectric Constant ◽  
Relative Dielectric Constant ◽  
Linear Shrinkage ◽  
Electric Resistance ◽  
Nitride Ceramics ◽  
Apparent Decrease ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Aluminum nitride ceramics doped carbon nanotubes were fabricated by dispersed multi-walled carbon nanotubes (MWNTs) into AlN powders homogenously. The densification, electric resistance, thermal conductivity and relative dielectric constant of AlN ceramics were investigated. It was found that MWNTs additives could purify the grain boundaries. Furthermore, it induced the increase of the thermal conductivity and the decrease of the relative dielectric constant. However, the linear shrinkage and electric resistance decreased with increasing MWNTs amount. AlN ceramics with high thermal conductivity and low relative dielectric constant were obtained without apparent decrease of electric resistivity.

Effect of CNTs Content on Properties of AlN-CNTs Composite Ceramic

2013 ◽  
Vol 634-638 ◽  
pp. 2406-2410 ◽  
Author(s):  
Qiu Xiang Liu ◽  
Gui Xia Dong ◽  
Jiang Yuan Wang
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Electrical Resistivity ◽  
Electron Microscope ◽  
Dielectric Property ◽  
Dielectric Loss ◽  
Scanning Electron Microscope ◽  
Percolation Theory ◽  
Composite Ceramic ◽  
Scanning Electron

AlN-CNTs composites were prepared by using hot pressed sintering. The microstructure of AlN-CNTs composites was observed by scanning electron microscope (SEM), and the dielectric property and thermal conductivity were measured using LCR and other specialized instruments. The experimental results showed that the variation of the electrical resistivity was consistent with the percolation theory, with the percolation threshold of the samples at about 1.4% CNTs, and that with increase of CNTs content both the dielectric constant and dielectric loss rise up, whereas the thermal conductivity goes down

Study of the Dielectric, Magnetic and Resistive Properties of Various Substances

2010 ◽  
Vol 305-306 ◽  
pp. 105-108
Author(s):  
Amitava Ghorai ◽  
Rabindranath Singh ◽  
Mrinal Kanti Hota ◽  
Dhananjay Bej
Keyword(s):  
Dielectric Constant ◽  
Dielectric Property ◽  
Binary Mixture ◽  
Black Carbon ◽  
Magnetic Permeability ◽  
Random Network ◽  
Paraffin Wax ◽  
Conducting Property ◽  
Resistive Property

The value of dielectric constant of paraffin wax doped with different concentrations of lamp black carbon decreases with the increase in the concentration of lamp black carbon in it. It is a case of loss of dielectric property and gain in conducting property and the specimen behaves as a random binary mixture of conductors and insulators, more specifically, a random network of resistors and capacitors. Anderson Bridge is used to investigate the magnetic permeability and susceptibility of different media inside a solenoid. The resistive property of manganin wire is studied using Kelvin double Bridge.

Dielectric and thermal properties of epoxy/boron nitride nanotube composites

2010 ◽  
Vol 82 (11) ◽  
pp. 2175-2183 ◽  
Author(s):  
Chunyi Y. Zhi ◽  
Yoshio Bando ◽  
Takeshi Terao ◽  
Chengchun Tang ◽  
Dmitri Golberg
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Thermal Properties ◽  
Dielectric Property ◽  
Boron Nitride ◽  
Boron Nitride Nanotube ◽  
Nanotube Composites ◽  
And Control ◽  
Dielectric And Thermal Properties

We report the fabrication of and investigations into the dielectric and thermal properties of epoxy/boron nitride nanotube (BNNT) composites. It was found that BNNT fillers can effectively adjust the dielectric constant of epoxy. Moreover, the thermal conductivity of epoxy was improved by up to 69 % with 5 wt % BNNTs. Our studies indicate that BNNTs are promising nanofillers for polymers, to obtain and control an adjustable dielectric property and improved thermal conductivity.

A Study of Some Mechanical and Physical Properties for Palm Fiber/Polyester Composite

2020 ◽  
Vol 38 (3B) ◽  
pp. 104-114
Author(s):  
Samah M. Hussein
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Date Palm ◽  
Volume Fraction ◽  
Unsaturated Polyester ◽  
Dielectric Strength ◽  
Palm Fiber ◽  
Mechanical And Physical Properties ◽  
Polyester Composite

This research has been done by reinforcing the matrix (unsaturated polyester) resin with natural material (date palm fiber (DPF)). The fibers were exposure to alkali treatment before reinforcement. The samples have been prepared by using hand lay-up technique with fiber volume fraction of (10%, 20% and 30%). After preparation of the mechanical and physical properties have been studied such as, compression, flexural, impact strength, thermal conductivity, Dielectric constant and dielectric strength. The polyester composite reinforced with date palm fiber at volume fraction (10% and 20%) has good mechanical properties rather than pure unsaturated polyester material, while the composite reinforced with 30% Vf present poor mechanical properties. Thermal conductivity results indicated insulator composite behavior. The effect of present fiber polar group induces of decreasing in dielectric strength, and increasing dielectric constant. The reinforcement composite 20% Vf showed the best results in mechanical, thermal and electrical properties.

A Novel Poly(Ionic Liquid) as the Thermal Insulating Material

2020 ◽  
Vol 13 (3) ◽  
pp. 241-247
Author(s):  
Wenxin Wei ◽  
Guifeng Ma ◽  
Hongtao Wang ◽  
Jun Li
Keyword(s):  
Thermal Conductivity ◽  
Ionic Liquid ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Flame Resistance ◽  
Insulating Material ◽  
Low Thermal Conductivity ◽  
Thermal Insulating ◽  
Poly Ionic Liquid

Objective: A new poly(ionic liquid)(PIL), poly(p-vinylbenzyltriphenylphosphine hexafluorophosphate) (P[VBTPP][PF6]), was synthesized by quaternization, anion exchange reaction, and free radical polymerization. Then a series of the PIL were synthesized at different conditions. Methods: The specific heat capacity, glass-transition temperature and melting temperature of the synthesized PILs were measured by differential scanning calorimeter. The thermal conductivities of the PILs were measured by the laser flash analysis method. Results: Results showed that, under optimized synthesis conditions, P[VBTPP][PF6] as the thermal insulator had a high glass-transition temperature of 210.1°C, high melting point of 421.6°C, and a low thermal conductivity of 0.0920 W m-1 K-1 at 40.0°C (it was 0.105 W m-1 K-1 even at 180.0°C). The foamed sample exhibited much low thermal conductivity λ=0.0340 W m-1 K-1 at room temperature, which was comparable to a commercial polyurethane thermal insulating material although the latter had a much lower density. Conclusion: In addition, mixing the P[VBTPP][PF6] sample into polypropylene could obviously increase the Oxygen Index, revealing its efficient flame resistance. Therefore, P[VBTPP][PF6] is a potential thermal insulating material.

Influence of the Material and Thickness of the Specimen on an Infrared Stress Image

2004 ◽  
Vol 261-263 ◽  
pp. 1641-1646
Author(s):  
Kenji Machida ◽  
Mamtimin Gheni
Keyword(s):  
Thermal Conductivity ◽  
Hybrid Method ◽  
Thermal Conduction ◽  
Crack Problem ◽  
High Stress ◽  
High Accuracy ◽  
Problem Analysis ◽  
Principal Stresses ◽  
Distribution Form ◽  
Stress Components

The thickness dependency of the temperature image obtained by an infrared thermography was investigated using specimens with three kinds of materials and four kinds of the thickness of the specimen. Only the sum of the principal stresses which is the first invariant of stress tensor is measured, and it is impossible to measure individual stress components directly. Then, the infrared hybrid method was developed to separate individual stress components. Although the form of the contour line of low stress side differs greatly, the distribution form of high stress side was considerably alike. The stress intensity factor of material with low thermal conductivity can be estimated with high accuracy by the infrared hybrid method. On the crack problem, it was elucidated that the influence of thermal conduction is large and an inverse problem analysis is required.

Effect Of Moisture On The Physical Properties Of Polyimide Films

1991 ◽  
Vol 227 ◽  
Author(s):  
Rajeevi Subramanian ◽  
Michael T. Pottiger ◽  
Jacqueline H. Morris ◽  
Joseph P. Curilla
Keyword(s):  
Dielectric Constant ◽  
Steady State ◽  
Electrical Properties ◽  
Relative Humidity ◽  
Quartz Crystal ◽  
Moisture Absorption ◽  
Relative Dielectric Constant ◽  
Moisture Uptake ◽  
Polyimide Films ◽  
Effect Of Moisture

ABSTRACTMoisture absorption and its effect on electrical properties were measured for several polyimides. A Quartz Crystal Microbalance (QCM) was used to investigate the moisture absorption in BPDA/PPD, PMDA/ODA, and BTDA//ODA/MPD polyimides. The steady-state moisture uptake in polyimides as a function of relative humidity (RH) was determined by exposing film samples to successively higher RH values ranging from 10 to 85% at 25°C. The isothermal moisture absorption as a function of percent RH was found to be nearly linear for all of the polyimides studied. The effect of moisture on the electrical properties of a BPDA/PPD polyimide was also investigated. The relative dielectric constant at 25 °C was found to be a linear function of the moisture absorbed.

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.

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