The Effects of Coupling Agents on the Electrical Properties of Polyimide/TiO2 Hybrid Films

2014 ◽  
Vol 556-562 ◽  
pp. 371-374
Author(s):  
Kai Yan ◽  
Xiao Xu Liu
Keyword(s):  
Composite Film ◽  
Breakdown Strength ◽  
In Situ Polymerization ◽  
Composite Films ◽  
Electric Breakdown ◽  
Future Application ◽  
Breakdown Field ◽  
Coupling Agents ◽  
Hybrid Films ◽  
Simple Method

Polyamides (PI)-matrix composite films with inorganic nanoTiO2 have been fabricated by employing in situ polymerization. Before addition, TiO2 particles were firstly modified with coupling agents (KH550). The electric breakdown strength and micromorphology of hybrid films were characterized and investigated. Results indicated that nanoTiO2 particles were homogeneously dispersed in the PI matrix for the addition of coupling agents and the electric breakdown strength of PI/TiO2 composite films with KH550 were better than unmodified PI composite film. The breakdown field strength and tensile modulus of PI composite film with the inorganic content of 5 wt% were 200.1 (KV/mm). So the using coupling agent can effectively improve the compatibility and the homogenous dispersion of nanoTiO2 particles in PI matrix. Meanwhile, the procedure described here offers an effective and simple method to produce PI/TiO2 with excellent electrical needed for future application in electrical engineering field.

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 The Effects of Coupling Agents on the Properties of Polyimide/Nano-Al2O3Three-Layer Hybrid Films

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Lizhu Liu ◽  
Ling Weng ◽  
Yuxia Song ◽  
Lin Gao ◽  
Qingquan Lei
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Composite Film ◽  
Breakdown Strength ◽  
Composite Films ◽  
Coupling Agents ◽  
Hybrid Films ◽  
Mechanical Method ◽  
Elongation At Break

PI/nano-Al2O3hybrid films were prepared by ultrasonic-mechanical method. Before addition, nano-Al2O3particles were firstly modified with different coupling agents. The micromorphology, thermal stability, mechanical properties, and electric breakdown strength of hybrid films were characterized and investigated. Results indicated that nano-Al2O3particles were homogeneously dispersed in the PI matrix by the addition of coupling agents. The thermal stability and mechanical properties of PI/nano-Al2O3composite films with KH550 were the best. The tensile strength and elongation at break of PI composite film were 119.1 MPa and 19.1%, which were 14.2% and 78.5% higher than unmodified PI composite film, respectively.

Effect of imidization process on the performance of PI/nano-Al2O3 three layer composite film

2017 ◽  
Vol 46 (4) ◽  
pp. 327-331 ◽  
Author(s):  
Lizhu Liu ◽  
Hongju He ◽  
Ling Weng ◽  
Xiaorui Zhang
Keyword(s):  
Composite Film ◽  
Breakdown Strength ◽  
Electrical Breakdown ◽  
Composite Films ◽  
Inorganic Materials ◽  
Raw Material ◽  
Nanocomposite Films ◽  
Breakdown Field ◽  
Content Type ◽  
The Impact

Purpose The purpose of this paper was to comprehensively understand the effects of imidization process on the structure and properties of polyimide (PI) films through the preparation and characterization of a variety of PI/aluminium oxide (Al2O3) nanocomposite films by using several imidization-based strategies. Design/methodology/approach Poly(amic acid) (PAA) containing different amounts of inorganic materials (namely, 0 Wt.%, 4 Wt.%, 8 Wt.%, 12 Wt.% and 16 Wt.%) was synthesized by using pyromellitic dianhydride and 4,4-diaminodiphenyl ether as raw material and N,N-dimethylacetamide as solvent. Subsequently, the solution obtained was casted on a glass substrate and dried by the means of various curing processes. The micro-structure, Fourier transform–infrared spectral features, breakdown field strength, dielectric properties and the corona-resistant time parameters of films were achieved. Findings The imidization process influences substantially the properties of composite films. Therefore, as the imidization rate is increased, the corona-resistant time and the electrical breakdown strength of composite films are also improved, while the dielectric constant faces a+ decreasing. Research limitations/implications In this paper, the impact of imidization process on the performance of PI/nano-Al2O3 three-layered composite film is reported. However, there are multiple factors governing these systems (such as, interlayer thickness ratio and humidity), which are not discussed herein. Originality/value The current study expounds the relationship between imidization ratios as well as the effect of imidization ratio on the performance of the film.

scholarly journals Bioinspired Dielectric Film with Superior Mechanical Properties and Ultrahigh Electric Breakdown Strength Made from Aramid Nanofibers and Alumina Nanoplates

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3093
Author(s):  
Qiu-Wanyu Qing ◽  
Cheng-Mei Wei ◽  
Qi-Han Li ◽  
Rui Liu ◽  
Zong-Xi Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Hydrogen Bonding ◽  
Composite Film ◽  
Breakdown Strength ◽  
Composite Films ◽  
Electrical Equipment ◽  
Electric Breakdown ◽  
Excellent Thermal Stability ◽  
Practical Applications ◽  
Al2o3 Composite

Materials with excellent thermal stability, mechanical, and insulating properties are highly desirable for electrical equipment with high voltage and high power. However, simultaneously integrating these performance portfolios into a single material remains a great challenge. Here, we describe a new strategy to prepare composite film by combining one-dimensional (1D) rigid aramid nanofiber (ANF) with 2D alumina (Al2O3) nanoplates using the carboxylated chitosan acting as hydrogen bonding donors as well as soft interlocking agent. A biomimetic nacreous ‘brick-and-mortar’ structure with a 3D hydrogen bonding network is constructed in the obtained ANF/chitosan/Al2O3 composite films, which provides the composite films with exceptional mechanical and dielectric properties. The ANF/chitosan/Al2O3 composite film exhibits an ultrahigh electric breakdown strength of 320.1 kV/mm at 15 wt % Al2O3 loading, which is 50.6% higher than that of the neat ANF film. Meanwhile, a large elongation at break of 17.22% is achieved for the composite film, integrated with high tensile strength (~233 MPa), low dielectric loss (<0.02), and remarkable thermal stability. These findings shed new light on the fabrication of multifunctional insulating materials and broaden their practical applications in the field of advanced electrics and electrical devices.

Preparation and Dielectric Property of Al2O3 Surface Coating Modified BaTiO3/Polyimide Composite Film

2014 ◽  
Vol 908 ◽  
pp. 63-66
Author(s):  
Ya Jun Wang ◽  
Xiao Juan Wu ◽  
Chang Gen Feng
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Composite Film ◽  
Breakdown Strength ◽  
In Situ Polymerization ◽  
Chemical Properties ◽  
Dielectric Strength ◽  
Xrd Analysis ◽  
Nanocomposite Films ◽  
The Matrix

Polyimide (PI) was chosen as the matrix of the composite, barium titanate/polyimide (BT/PI) nanocomposite films were prepared by in situ polymerization. In order to improve the dispersion and the physical-chemical properties of BT surface, barium titanate was modified by Al2O3coating and modified BT/PI nanocomposite films were prepared. The prepared modified BT was characterized by X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM), and the dielectric properties of the composites were characterized in detail. It was shown that surface modification with Al2O3is the chemical process and there were new substances forming. When BT was modified by 10 wt% Al2O3, the dielectric constant of the composite film was 18.96 (103Hz), the loss tangent 0.005, breakdown strength 70 MV·m-1, energy storage density 0.41 J·cm-3. The dielectric constant of BT modified by Al2O3is decreased while the dielectric strength of the modified BT/PI composite film is increased.

Fabrication and Ultraviolet Characterization of Potassium Sodium Niobate/Polyimide Hybrid Films

2013 ◽  
Vol 395-396 ◽  
pp. 121-124
Author(s):  
Jia Qi Lin ◽  
Pan Pan Zhang ◽  
Wen Long Yang
Keyword(s):  
In Situ Polymerization ◽  
Composite Films ◽  
Polymerization Process ◽  
Sodium Niobate ◽  
Hybrid Films ◽  
Potassium Sodium Niobate ◽  
Potassium Sodium

A functional potassium sodium niobate/polyimide (KNN/PI) composite films were prepared in this paper. KNN fillers are well dispersed in the PI matrix without any accumulation through in situ polymerization process. The optical band baps of the hybrid films become smaller with the increase of KNN loading. The optical band baps of the films with 0-20 wt% KNN filler are estimated to be 2.61 eV, 2.57 eV, 2.52 eV, 4.29 eV, 2.35 eV respectively.

Dielectric behavior of a flexible three-phase polyimide/BaTiO3/multi-walled carbon nanotube composite film

2016 ◽  
Vol 09 (01) ◽  
pp. 1650006 ◽  
Author(s):  
Junli Wang ◽  
Shengli Qi ◽  
Yiyi Sun ◽  
Guofeng Tian ◽  
Dezhen Wu
Keyword(s):  
Composite Film ◽  
Volume Fraction ◽  
In Situ Polymerization ◽  
Composite Films ◽  
Dielectric Behavior ◽  
Low Dielectric ◽  
Three Phase ◽  
The Matrix ◽  
Multi Walled Carbon Nanotubes ◽  
High Dielectric

A three-phase composite film was produced by inserting multi-walled carbon nanotubes (MWCNTs) and BaTiO3 nanoparticles into polyimide (PI). The combination of in-situ polymerization and water-based preparation involved in the experiment ensured fillers’ homogeneous dispersion in the matrix, which led to flexible shape of the composite films. The dielectric properties of composite films as a function of the frequency and the volume fraction of MWCNTs were studied. Such composite film displayed a high dielectric constant (314.07), low dielectric loss and excellent flexibility at 100[Formula: see text]Hz in the neighborhood of percolation threshold (9.02 vol%) owing to the special microcapacitor structure. The experimental results were highly consistent with the power law of percolation theory.

Fabrication, Morphology and Properties of Polyimide/Al2O3 Nanocomposite Films via Surface Modification and Ion-Exchange Technique

2018 ◽  
Vol 921 ◽  
pp. 91-98
Author(s):  
Ming Yu Zhang ◽  
Li Zhu Liu ◽  
K.S. Hui
Keyword(s):  
Ion Exchange ◽  
Composite Film ◽  
Original Film ◽  
Treatment Time ◽  
Breakdown Strength ◽  
Composite Films ◽  
Nanocomposite Films ◽  
Polyimide Films ◽  
Force Microscopy ◽  
Corona Resistance

Polyimide films with Al2O3composite layers were prepared by KOH solution surface hydrolysis, ion exchange and heat treatment. Scanning electron microscope (SEM), atomic force microscopy (AFM), X-ray diffractometry (XRD), thermo gravimetric analyzer (TGA), breakdown voltage tester, high frequency pulse voltage machine were performed to characterize the micromorphology, thermal stability, mechanical properties, electric breakdown strength, and corona resistance time of composite films. Results indicated that the thermal properties of the composite film are better than the original film. The corona resistance time of the composite film was longer than that of the pristine film. The composite film had the longest corona resistance time and reached 101.2min while the KOH treatment time was 90min.

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).

Mechanical Property and Conductivity of Polyaniline-Poly(Vinyl Alcohol)Composite Films

2012 ◽  
Vol 502 ◽  
pp. 297-301
Author(s):  
Xiao Hua Wang
Keyword(s):  
Tensile Strength ◽  
Reaction Time ◽  
Composite Film ◽  
In Situ Polymerization ◽  
Composite Films ◽  
Ammonium Persulfate ◽  
Poly Vinyl Alcohol ◽  
Dodecylbenzenesulfonic Acid ◽  
Drying Temperature

The polyaniline(PANI)-poly(vinyl alcoho1)(PVA) composite films with the doping of hydrochloride (HCl), dodecylbenzenesulfonic acid (DBSA) or aminosulfonic acid (NH2SO3H ) were prepared by in-situ polymerization. Effects of PVA content, HC1 content, oxidant ammonium persulfate(APS)dosage, reaction time and film drying temperature on tensile strength of the HCl-PANI-PVA composite film were studied. The conductivity of PANI-PVA composite film with the doping of HCl is the highest of 13.2S.cm-1 among them. The tensile strength of the film is improved greatly due to effective mixture of PANI and PVA. The tensile strength of the composite film substantially depended upon the mass fraction of PVA. The tensile strength of the HC1-PANI-PVA composite film reaches the maximum of 60.8 MPa, in case the PVA content is 40%, the C(HC1)=1.0 mol/L，reaction time is 4.0 h, the n(APS/An)=1.0, and film drying temperature is 80°C.

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