Effect of Hydrophilic and Hydrophobic SiO2 Particles on Performances of PI/Al2O3 Composite Films

2015 ◽  
Vol 645-646 ◽  
pp. 26-31 ◽  
Author(s):  
Yuan Yuan Li ◽  
Li Zhu Liu ◽  
Hui Shi ◽  
Ling Weng ◽  
Wie Wei Cui
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Field Strength ◽  
In Situ Polymerization ◽  
Composite Films ◽  
Breakdown Field ◽  
Inorganic Particles ◽  
Transmission Electron ◽  
Breakdown Field Strength ◽  
Corona Resistance

In this paper, we mainly analyzed the different influence of hydrophilic SiO2 particles and hydrophobic SiO2 particles on the properties of PI/Al2O3 films. PI/Al2O3/SiO2(hydrophilic) films and PI/Al2O3/SiO2(hydrophobic) films with 16 wt% content of Al2O3 and 3 wt‰, 5 wt‰, 7 wt‰ content of SiO2 respectively were prepared by in-situ polymerization method. Firstly, the hydrophilic SiO2 particles and hydrophobic SiO2 particles were investigated by transmission electron microscopy (TEM), infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results showed that the average sizes and infrared characteristic peaks of two kinds of SiO2 particles were similar, and two kinds of SiO2 particles were amorphous inorganic particles. Then the morphology of the composite films was characterized by scanning electron microscopy (SEM), and the mechanical properties, the breakdown field strength and corona resistant time were tested and analyzed. Results indicated that inorganic particles added to PI/Al2O3/SiO2(hydrophilic) films dispersed better than that of PI/Al2O3/SiO2(hydrophobic) films. When the content of SiO2 particles was 5 wt‰, the mechanical properties and corona resistance of PI/Al2O3/SiO2(hydrophilic) films were best, the tensile strength, elongation at break and corona resistance times of the films were: 132.44 MPa, 12.64%, 378 min, respectively. The breakdown field strength of PI/Al2O3/SiO2(hydrophilic) films was only 211.15 kV/mm, and inferior to that of PI/Al2O3/SiO2(hydrophobic) films (232.08 kV/mm).

scholarly journals Effect of Acetylated SEBS/PP for Potential HVDC Cable Insulation

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1596
Author(s):  
Peng Zhang ◽  
Yongqi Zhang ◽  
Xuan Wang ◽  
Jiaming Yang ◽  
Wenbin Han
Keyword(s):  
Mechanical Properties ◽  
Field Strength ◽  
Thermoplastic Elastomer ◽  
High Energy ◽  
Thermoplastic Elastomers ◽  
Electrical Strength ◽  
Voltage Stabilizer ◽  
Breakdown Field ◽  
Cable Insulation ◽  
Breakdown Field Strength

Blending thermoplastic elastomers into polypropylene (PP) can make it have great potential for high-voltage direct current (HVDC) cable insulation by improving its toughness. However, when a large amount of thermoplastic elastomer is blended, the electrical strength of PP will be decreased consequently, which cannot meet the electrical requirements of HVDC cables. To solve this problem, in this paper, the inherent structure of thermoplastic elastomer SEBS was used to construct acetophenone structural units on its benzene ring through Friedel–Crafts acylation, making it a voltage stabilizer that can enhance the electrical strength of the polymer. The DC electrical insulation properties and mechanical properties of acetylated SEBS (Ac-SEBS)/PP were investigated in this paper. The results showed that by doping 30% Ac-SEBS into PP, the acetophenone structural unit on Ac-SEBS remarkably increased the DC breakdown field strength of SEBS/PP by absorbing high-energy electrons. When the degree of acetylation reached 4.6%, the DC breakdown field strength of Ac-SEBS/ PP increased by 22.4% and was a little higher than that of PP. Ac-SEBS, with high electron affinity, is also able to reduce carrier mobility through electron capture, resulting in lower conductivity currents in SEBS/PP and suppressing space charge accumulation to a certain extent, which enhances the insulation properties. Besides, the highly flexible Ac-SEBS can maintain the toughening effect of SEBS, resulting in a remarkable increase in the tensile strength and elongation at the break of PP. Therefore, Ac-SEBS/PP blends possess excellent insulation properties and mechanical properties simultaneously, which are promising as insulation materials for HVDC cables.

scholarly journals The Research of Conductivity and Dielectric Properties of ZnO/LDPE Composites with Different Particles Size

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4136 ◽  
Author(s):  
Yujia Cheng ◽  
Guang Yu ◽  
Boyang Yu ◽  
Xiaohong Zhang
Keyword(s):  
Dielectric Constant ◽  
Field Strength ◽  
Interfacial Polarization ◽  
Breakdown Field ◽  
Test Results ◽  
Nano Zno ◽  
Inorganic Particles ◽  
Zno Particles ◽  
Ldpe Composites ◽  
Breakdown Field Strength

Nanocomposites exhibit a high dielectric strength, whereas microcomposites exhibit a high thermal conductivity. In this study, good insulating materials were developed on the basis of the synergetic effect of micro- and nanoparticles, which were used as inorganic fillers. With a double-melting blend, nano-ZnO/low density polyethylene (LDPE), micro-ZnO/LDPE, and micro-nano-ZnO/LDPE composites were prepared, according to the scanning electron microscope test, polarization microscope test, conductivity test, breakdown test, and dielectric spectrum test, the dielectric property of micro-nano-ZnO/LDPE was explored. The SEM test results showed that by adding a suitable proportion of ZnO particles, the inorganic particles could disperse uniformly without reuniting. The PLM test results showed that the micro- and nano-ZnO particles adding decreased the crystal size. The arrangement was regular and tight. The macroscopic results showed that the mass fraction of nanoparticles and microparticles were 3% and 2%, the samples conductivity was the lowest. The breakdown field strength of the nanocomposites increased. The breakdown field strength of nanocomposites with 1%, 3%, and 5% nanoparticle contents were 5%, 15%, and 10% higher than that of pure LDPE. The addition of inorganic particles resulted in new polarization modes: Ionic displacement polarization and interfacial polarization. The ZnO/LDPE composites exhibited a higher dielectric constant and dielectric loss factor than pure LDPE. However, with the increasing frequency, it took considerable time to attain interfacial polarization in the nanocomposite and micro-nanocomposite, thus decreasing the dielectric constant.

Effects of interface bonding on the corona resistance of the polyimide/nano-Al2O3 three-layer composite films

2017 ◽  
Vol 30 (10) ◽  
pp. 1240-1246 ◽  
Author(s):  
Xinyu Ma ◽  
Lizhu Liu ◽  
Hongju He ◽  
Ling Weng
Keyword(s):  
Composite Film ◽  
Breakdown Strength ◽  
In Situ Polymerization ◽  
Electrical Breakdown ◽  
Layer Structure ◽  
Composite Films ◽  
Raw Material ◽  
Breakdown Field ◽  
Layer Composite ◽  
Corona Resistance

Polyimides (PIs) are widely used in many fields including aerospace and microelectronics. Due to their poor corona resistance, their practical applications were limited, especially in the field of variable frequency motors. In this study, we have achieved for the first time to increase the corona resistance by controlling the preparation process of the three-layered PI composite. A series of PI/nano-Al2O3 composite films with novel three-layer structure were prepared by in situ polymerization employing pyromellitic dianhydride and 4,4-diaminodiphenyl as raw material, N, N-dimethylacetamide as solvent, and doping of nano-Al2O3. The first layer of the PI/Al2O3 composite film was characterized by Fourier transform infrared spectroscopy, and the imidization rate under different processes was calculated. The interface structures and bonding conditions of the composite films were characterized by scanning electron microscope, and the surface morphologies of the composite films treated by different corona-resistance times were investigated. X-ray diffraction analysis was also used to study the effect of nano-Al2O3 on PIs with different imidization ratios. The corona-resistance time and breakdown field strength of the composite films prepared by different processes were also tested. The results indicated that the combination of the three-layer composite film and the corona-resistance abilities of the composite membrane surface was enhanced by increasing the imidization rate. Meanwhile, the corona-resistance time and the electrical breakdown strength of composite films were also improved by increasing the imidization rate.

scholarly journals Dielectric and AC Breakdown Properties of SiO2/MMT/LDPE Micro–Nano Composites

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1235
Author(s):  
Hongtao Jiang ◽  
Xiaohong Zhang ◽  
Junguo Gao ◽  
Ning Guo
Keyword(s):  
Experimental Data ◽  
Field Strength ◽  
Dielectric Constants ◽  
Low Density Polyethylene ◽  
Breakdown Field ◽  
Nano Composites ◽  
Low Density ◽  
Inorganic Particles ◽  
The Matrix ◽  
Breakdown Field Strength

Low-density polyethylene (LDPE) is an important thermoplastic material which can be made into films, containers, wires, cables, etc. It is highly valued in the fields of packaging, medicine, and health, as well as cables. The method of improving the dielectric property of materials by blending LDPE with inorganic particles as filler has been paid much attention by researchers. In this paper, low-density polyethylene is used as the matrix, and montmorillonite (MMT) particles and silica (SiO2) particles are selected as micro and nano fillers, respectively. In changing the order of adding two kinds of particles, a total of five composite materials were prepared. The crystallization behavior and crystallinity of five kinds of composites were observed, the εr and tanδ changes of each material were investigated with frequency and temperature, and the power frequency (50 Hz) AC breakdown performance of materials were measured. The differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results show that the crystallinity of the composites is higher than that of LDPE. Experimental data of dielectric frequency spectra show that the dielectric constants of micro–nano composites and composites with added MMT particles are lower than LDPE, the dielectric loss of composites can be improved by adding MMT particles. The experimental data of dielectric temperature spectra show that the permittivity of SiO2-MMT/LDPE is still at a low level under the condition of 20~100 °C. In terms of breakdown field strength, the SiO2/LDPE composite material increased by about 17% compared with the matrix LDPE, and the breakdown field strength of the materials SiO2-MMT/LDPE and MMT-SiO2/LDPE increased by about 6.8% and 4.6%, respectively.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Microstructure Evolution and Mechanical Properties of an Al-Cu-Mg Alloy at Elevated Temperature

2014 ◽  
Vol 1004-1005 ◽  
pp. 148-153
Author(s):  
Min Hao ◽  
Ji Gang Ru ◽  
Ming Liu ◽  
Kun Zhang ◽  
Liang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Shear Fracture ◽  
S Phase ◽  
Mg Alloy ◽  
Transmission Electron ◽  
Fracture Features ◽  
Scanning Electron

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to study the microstructure and mechanical behavior of an Al-Cu-Mg alloy after tensile test at 125°C, 150°C, 175°C and 200 °C, respectively. The yield strength and ultimate tensile strength decreased with the increase of temperature, while the elongation increased firstly and then decreased. The S and S′ precipitate after tension at elevated temperatures. When the temperature was higher than 175°C, the precipitate coarsens rapidly. The alloys displayed a shear fracture features at elevated temperature. The larger S′ and S phase coarsened and dropped which forming crack in the grain boundaries and precipitate interfaces, resulting in the decrease of the elongation of the alloy.

Effect of Coupled Conditions of Thermal Cycle and Dump Environment on Conductivity of 5mol% Yttria Stabilized Zirconia

2013 ◽  
Vol 591 ◽  
pp. 245-248 ◽  
Author(s):  
Jin Feng Xia ◽  
Hong Qiang Nian ◽  
Tao Feng ◽  
Hai Fang Xu ◽  
Dan Yu Jiang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
Thermal Cycle ◽  
Oxygen Sensor ◽  
Yttria Stabilized Zirconia ◽  
Cyclic Change ◽  
Stabilized Zirconia ◽  
Transmission Electron

In some applications such as automotive oxygen sensor, 5mol% Y2O3stabilized zirconia (5YSZ) is generally used because it has both excellent ionic conductivity and mechanical properties. The automotive oxygen sensor would experience a cyclic change from high temperature (engine running) environment to the low temperature damp environment (in the tail pipe when vehicle stops). The conductivity change with coupled conditions of thermal cycle and dump environment in the 5mol%Y2O3ZrO2(5YSZ) system was examined by XRD,Impedance spectroscopy and transmission electron microscopy (SEM) in this paper.

Application and Study of Reactive Polyacrylate Microgel in Pigment Paint of Printed Fabric

2011 ◽  
Vol 311-313 ◽  
pp. 1044-1048
Author(s):  
Hong Long Xing ◽  
Shui Lin Chen
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Sodium Dodecyl ◽  
Ammonium Persulfate ◽  
Color Fastness ◽  
Adhesive Film ◽  
Transmission Electron ◽  
Divinyl Benzene

Polyacrylate microgel emulsion was prepared by emulsion polymerization using styrene, α-n-butyl acrylate and methyl methacrylate as monomer, polyoxyethylene octylphenol ether (TX-30) and sodium dodecyl sulfate(SDS) as combine emulsifier, divinyl benzene and ammonium persulfate (APS) as initiator，respectively. The prepared microgel was analyzed by a variety of measurment methods, such as Fourier transform infrared spectroscopy and transmission electron microscopy. The effect of microgel on the rheological properties of adhesives, leveling, mechanical properties and pigment printing performance was studied. The rhelogy and the color fastness of the pigment printing binder of printed fabrics were measured by rheometer and friction color fastness test instruments, respectively. At the same time, the mechanical properties of the adhesive film was measured by strength tester. The results show that the thixotropy, leveling and mechanical properties of adhesive printing binder and pringting quality of coating fabrics were improved when the microgel was added.

Mechanical Properties and Microstructure Evolution of Typical Over-Aging State Al-Zn-Mg-Cu Alloy during Thermal Exposure

2021 ◽  
Vol 1026 ◽  
pp. 84-92
Author(s):  
Tao Qian Cheng ◽  
Zhi Hui Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Electrical Conductivity ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Thermal Exposure ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Thermal Stability Of

Al-Zn-Mg-Cu alloy have been widely used in aerospace industry. However, there is still a lack of research on thermal stability of Al-Zn-Mg-Cu alloy products. In the present work, an Al-Zn-Mg-Cu alloy with T79 and T74 states was placed in the corresponding environment for thermal exposure experiments. Performance was measured by tensile strength, hardness and electrical conductivity. In this paper, precipitation observation was analyzed by transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HREM). The precipitations of T79 state alloy were GPⅡ zone, η' phase and η phase while the ultimate tensile strength, hardness and electrical conductivity were 571MPa, 188.2HV and 22.2MS×m-1, respectively. The mechanical property of T79 state alloy decreased to 530MPa and 168.5HV after thermal exposure. The diameter of precipitate increased and the precipitations become η' and η phase at the same time. During the entire thermal exposure, T74 state alloy had the same mechanical property trend as T79 state alloy. The precipitate diameter also increased while the types of precipitate did not change under thermal exposure. The size of precipitates affected the choice of dislocation passing through the particles to affect the mechanical properties.

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