scholarly journals Dielectric and Thermal Conductivity of Epoxy Resin Impregnated Nano-h-BN Modified Insulating Paper

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1359 ◽  
Author(s):  
Hongda Yang ◽  
Qingguo Chen ◽  
Xinyu Wang ◽  
Minghe Chi ◽  
Heqian Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Properties ◽  
Space Charge ◽  
Epoxy Resin ◽  
Direct Current ◽  
Heat Conductivity ◽  
Power Transmission ◽  
Breakdown Strength ◽  
Hexagonal Boron Nitride ◽  
Insulating Paper

Epoxy resin-impregnated insulation paper (RIP) composites are used as the inner insulation of dry condenser bushing in the ultra-high voltage direct current (UHVDC) power transmission system. To improve the dielectric properties and heat conductivity of RIP, hexagonal boron nitride (h-BN) nano-flakes are added to the insulation paper at concentrations of 0–50 wt % before impregnation with pure epoxy resin. X-ray diffraction (XRD), scanning electron microscopy (SEM) observations, thermal conductivity as well as the typical dielectric properties of direct current (DC) volume conductivity. DC breakdown strength and space charge characteristics were obtained. The maximum of nano-h-BN modified heat conductivity reach 0.478 W/(m·K), increased by 139% compared with unmodified RIP. The DC breakdown electric field strength of the nano-h-BN modified RIP does not reduce much. The conductivity of nano-h-BN modified is less sensitive to temperature. As well, the space charge is suppressed when the content is 50 wt %. Therefore, the nano-h-BN modified RIP is potentially useful in practical dry DC bushing application.

scholarly journals Dielectric and Thermal Conductivity Characteristics of Epoxy Resin-Impregnated H-BN/CNF-Modified Insulating Paper

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2080
Author(s):  
Hongda Yang ◽  
Qingguo Chen ◽  
Xinyu Wang ◽  
Minghe Chi ◽  
Jinfeng Zhang
Keyword(s):  
Thermal Conductivity ◽  
Space Charge ◽  
Epoxy Resin ◽  
Breakdown Strength ◽  
Hexagonal Boron Nitride ◽  
Cellulose Fiber ◽  
High Voltage Direct Current ◽  
Insulating Paper ◽  
Nano Cellulose ◽  
Scanning Electron

High-voltage direct-current (HVDC) dry bushing capacitor-core insulation is composed of epoxy resin-impregnated insulating paper (RIP). To improve the thermal conductivity, breakdown strength, and space charge characteristics of RIP, 0.1 wt % nano-cellulose fiber (CNF)-modified RIP (CNF/RIP), 2.5–30 wt % hexagonal boron nitride (h-BN)-modified RIP (h-BN/RIP), and 2.5–30 wt % h-BN + 0.1 wt % CNF-modified RIP (h-BN + 0.1 wt % CNF/RIP) were prepared. Scanning electron microscopy (SEM) was implemented; the thermal conductivity, DC conductivity, DC breakdown strength, and space charge characteristics were tested. The maximum thermal conductivity of h-BN + 0.1 wt % CNF/RIP was 0.376 W/m.K with a h-BN content of 30 wt %. The thermal conductivity was 85.2% higher than that of unmodified RIP. The breakdown strength and charge suppression were the best in the case of 10 wt % h-BN + 0.1 wt % CNF/RIP. The maximum breakdown strength was 11.2% higher than that of unmodified RIP. These results can play a significant role in the research and development of insulation materials for HVDC dry bushing.

scholarly journals Enhanced Thermal Conductivity and Dielectric Properties of h-BN/LDPE Composites

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4738
Author(s):  
Lijuan He ◽  
Junji Zeng ◽  
Yuewu Huang ◽  
Xiong Yang ◽  
Dawei Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Space Charge ◽  
Direct Current ◽  
Breakdown Strength ◽  
Hexagonal Boron Nitride ◽  
Electrical Equipment ◽  
Electrical Performance ◽  
Suppression Effect ◽  
Thermally Conductive ◽  
Ldpe Composites

Low-density polyethylene (LDPE), as an excellent dielectric insulating material, is widely used in electrical equipment insulation, whereas its low thermal conductivity limits its further development and application. Hexagonal boron nitride (h-BN) filler was introduced into LDPE to tailor the properties of LDPE to make it more suitable for high-voltage direct current (HVDC) cable insulation application. We employed melt blending to prepare h-BN/LDPE thermally conductive composite insulation materials with different contents. We focused on investigating the micromorphology and structure, thermal properties, and electrical properties of h-BN/LDPE composites, and explained the space charge characteristics. The scanning electron microscope (SEM) results indicate that the h-BN filler has good dispersibility in the LDPE at a low loading (less than 3 phr (3 g of micron h-BN particles filled in 100g of LDPE)), as well as no heterogeneous phase formation. The results of thermal conductivity analysis show that the introduction of h-BN filler can significantly improve the thermal conductivity of composites. The thermal conductivity of the composite samples with 10 phr h-BN particles is as high as 0.51 W/(m·K), which is 57% higher than that of pure LDPE. The electrical performance illustrates that h-BN filler doping can significantly inhibit space charge injection and reduce space charge accumulation in LDPE. The interface effect between h-BN and the substrate reduces the carrier mobility, thereby suppressing the injection of charges of the same polarity and increasing the direct-current (DC) breakdown strength. h-BN/LDPE composite doped with 3 phr h-BN particles has excellent space charge suppression effect and high DC breakdown strength, which is 14.3% higher than that of pure LDPE.

scholarly journals Characterization of Polypropylene Modified by Blending Elastomer and Nano-Silica

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1321 ◽  
Author(s):  
Xiaohong Chi ◽  
Lu Cheng ◽  
Wenfeng Liu ◽  
Xiaohong Zhang ◽  
Shengtao Li
Keyword(s):  
Dielectric Properties ◽  
Space Charge ◽  
Power Transmission ◽  
Breakdown Strength ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Insulation Material ◽  
Nano Silica ◽  
Scanning Calorimetry ◽  
High Voltage Direct Current

Polypropylene (PP) contains promising application prospects in thermoplastic cables for high voltage direct current (HVDC) power transmission because of its outstanding thermal and dielectric properties. However, the problem of poor toughness and space charge has restricted the application of pure PP in HVDC cables. In this paper, polyolefin elastomer (POE) and nano-silica were blended thoroughly and added into a PP mixture by a melting method. Scanning electron microscopy (SEM) was employed to observe the dispersion of POE and nanoparticles. Thermal properties were characterized by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Mechanical properties were evaluated by tensile tests. The elastomeric properties of composites were improved as the dispersed POE could transfer and homogenize external mechanical forces. DC breakdown results showed that the fail strength of composite with 10 phr POE and 1 phr nano-silica was obviously enhanced. The pulsed electro-acoustic (PEA) results showed that the injection and accumulation of space charge was increased by the introduction of POE, while it was restrained by the collective effect caused by nano-silica filling. X-ray diffraction (XRD) spectrograms showed that secondary ordered structures existed in the composites of PP, POE, and nano-silica, and that the ordered structure around the nanoparticles contributed to the enhancement of breakdown strength. The mechanical and dielectric properties were modified synergistically, which made the modified PP a propitious insulation material for HVDC cables.

Thermal and dielectric properties of epoxy-based composites filled with flake and whisker type hexagonal boron nitride materials

2020 ◽  
pp. 095400832095941
Author(s):  
Rongkun Yang ◽  
Mingming Sheng ◽  
Yujun Zhang ◽  
Hongyu Gong ◽  
Xiao Lin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Properties ◽  
Boron Nitride ◽  
Epoxy Resin ◽  
Heat Dissipation ◽  
Hexagonal Boron Nitride ◽  
Transmission Efficiency ◽  
Pure Epoxy ◽  
The Matrix ◽  
Properties Of Composites

In this work, the epoxy-based composites filled with 3-Aminopropyltriethoxysilane (KH-550) modified binary filler of hexagonal boron nitride (h-BN) flakes and h-BN whiskers were fabricated, and the thermal and dielectric properties of composites were systematically investigated. Adding h-BN whiskers to the filler could effectively form heat conduction paths and improve the phonon transmission efficiency, thereby improving the thermal conductivity of the composites. According to our results, the thermal conductivity of composite with 27 wt% h-BN flakes and 3 wt% h-BN whiskers reached up to 0.819 W·m−1·K−1, which was 3.9 times that of pure epoxy resin. At the same time, the dielectric loss value and dielectric constant of this composite at 1 MHz were 0.02678 and 4.55, respectively, while pure epoxy resin were 0.03602 and 4.33. In addition, introducing h-BN whiskers into the matrix could effectively improve the thermal stability and heat dissipation performance of composites.

Thermal stable honokiol-derived epoxy resin with reinforced thermal conductivity, dielectric properties and flame resistance

2021 ◽  
Vol 412 ◽  
pp. 128647
Author(s):  
Jingjing Meng ◽  
Pengfei Chen ◽  
Rui Yang ◽  
Linli Dai ◽  
Cheng Yao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Properties ◽  
Epoxy Resin ◽  
Flame Resistance ◽  
Thermal Stable

Dielectric properties and thermal conductivity of epoxy resin composite modified by Zn/ZnO/Al2O3 core–shell particles

2018 ◽  
Vol 76 (8) ◽  
pp. 3957-3970 ◽  
Author(s):  
Yang Wang ◽  
Lingjie Zhu ◽  
Jun Zhou ◽  
Beibei Jia ◽  
Yingye Jiang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Properties ◽  
Epoxy Resin ◽  
Resin Composite ◽  
Core Shell ◽  
Epoxy Resin Composite ◽  
Shell Particles

scholarly journals Acetylated SEBS Enhanced DC Insulation Performances of Polyethylene

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1033 ◽  
Author(s):  
Wei Dong ◽  
Xuan Wang ◽  
Zaixing Jiang ◽  
Bo Tian ◽  
Yuguang Liu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Field Strength ◽  
Space Charge ◽  
Aromatic Compounds ◽  
Breakdown Strength ◽  
Charge Accumulation ◽  
New Approach ◽  
Functional Units ◽  
Poly Ethylene ◽  
Accumulation Characteristics

Acetophenone can significantly improve the dielectric properties of polyethylene (PE) insulation materials. However, it easily migrates from the PE due to its poor compatibility with the material, which limits its application. In this paper, the functional units of acetophenone were modified in polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) by an acetylation reaction, and SEBS was used as the carrier to inhibit the migration of acetophenone. The number of functional units in the acetylated SEBS (Ac-SEBS) was measured by 1H NMR and the effect of the acetylation degree of SEBS on its compatibility with PE was studied. Meanwhile, the effects of Ac-SEBS on PE’s direct current (DC) breakdown strength and space charge accumulation characteristics were investigated. It is demonstrated that Ac-SEBS can significantly improve the field strength of the DC breakdown and inhibit the accumulation of space charge in the PE matrix. This work provides a new approach for the application of aromatic compounds as voltage stabilizers in DC insulation cable materials.

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