Pub Date : 2020-09-09DOI: 10.5772/intechopen.93254
V. Griseri
Polyimide (PI) is an interesting material for space applications as it offers excellent thermal properties. However, due to its dielectric properties, charge storage and release can be at the origin of electrostatic discharges that are hazardous for the surrounding electrical equipment. Depending on the spacecraft orbit, it is necessary to study the impact of specific surrounding environment. In any cases, the effect of vacuum and temperature variations can be combined with electrons and protons’ irradiation, atomic oxygen erosion, and photons impact from UV exposure. On the market, there exist many types of PI, and since several years, composite are also developed. The main properties that are usually observed are the conductivity that is analyzed from surface potential decay, the photoemission and the ability to initiate and propagate surface flashover. Since several years, the space charge storage analysis by the pulse electro-acoustic method has been developed as an interesting complementary tool. It is important to remember that experimental characterization needs to be representative to the space environment especially because it has been observed that PI can recover its original properties in air in a couple of hours depending on the ageing degree.
{"title":"Polyimide Used in Space Applications","authors":"V. Griseri","doi":"10.5772/intechopen.93254","DOIUrl":"https://doi.org/10.5772/intechopen.93254","url":null,"abstract":"Polyimide (PI) is an interesting material for space applications as it offers excellent thermal properties. However, due to its dielectric properties, charge storage and release can be at the origin of electrostatic discharges that are hazardous for the surrounding electrical equipment. Depending on the spacecraft orbit, it is necessary to study the impact of specific surrounding environment. In any cases, the effect of vacuum and temperature variations can be combined with electrons and protons’ irradiation, atomic oxygen erosion, and photons impact from UV exposure. On the market, there exist many types of PI, and since several years, composite are also developed. The main properties that are usually observed are the conductivity that is analyzed from surface potential decay, the photoemission and the ability to initiate and propagate surface flashover. Since several years, the space charge storage analysis by the pulse electro-acoustic method has been developed as an interesting complementary tool. It is important to remember that experimental characterization needs to be representative to the space environment especially because it has been observed that PI can recover its original properties in air in a couple of hours depending on the ageing degree.","PeriodicalId":131194,"journal":{"name":"Polyimide for Electronic and Electrical Engineering Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125479656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-08-20DOI: 10.5772/intechopen.91206
S. Akram, J. Castellon, S. Agnel, J. Habas
Polymer nanocomposite-based dielectric materials are playing a vital role in the area of electrical insulation research and developments. The nanoparticle dispersion and interface region are the crucial parts of these developments. This chapter begins with the description of physical properties and their derived nanoparticles of polyimide (PI) films. Then, the detailed synthesis process of PI/nanocomposite multilayer film and its optimization is discussed in this chapter. Several factors in the synthesis process, which can influence the quality of the film, are discussed. After synthesis, the dielectric properties such as space charge were measured, and the results are compared with single and multilayer PI/nanocomposite films. Simulations and modeling help to shed light on the experimental results and create an understanding of polymer nanocomposite properties. Therefore, the PI/nanocomposite multilayer 3D model based on boundary conditions obtained from SEM/TEM images of synthesized samples was also constructed and simulated in COMSOL multiphysics software. The nanoparticle agglomeration and the impact of nanoparticle dispersion on the electrical properties of the material are described in detail in this model. The results demonstrate that the nanoparticle dispersion is improved by using a thin layer of PI/nanocomposite on PI film. As a result, fewer space charges and low electric fields are observed in multilayer films.
{"title":"Synthesis Process Optimization of Polyimide Nanocomposite Multilayer Films, Their Dielectric Properties, and Modeling","authors":"S. Akram, J. Castellon, S. Agnel, J. Habas","doi":"10.5772/intechopen.91206","DOIUrl":"https://doi.org/10.5772/intechopen.91206","url":null,"abstract":"Polymer nanocomposite-based dielectric materials are playing a vital role in the area of electrical insulation research and developments. The nanoparticle dispersion and interface region are the crucial parts of these developments. This chapter begins with the description of physical properties and their derived nanoparticles of polyimide (PI) films. Then, the detailed synthesis process of PI/nanocomposite multilayer film and its optimization is discussed in this chapter. Several factors in the synthesis process, which can influence the quality of the film, are discussed. After synthesis, the dielectric properties such as space charge were measured, and the results are compared with single and multilayer PI/nanocomposite films. Simulations and modeling help to shed light on the experimental results and create an understanding of polymer nanocomposite properties. Therefore, the PI/nanocomposite multilayer 3D model based on boundary conditions obtained from SEM/TEM images of synthesized samples was also constructed and simulated in COMSOL multiphysics software. The nanoparticle agglomeration and the impact of nanoparticle dispersion on the electrical properties of the material are described in detail in this model. The results demonstrate that the nanoparticle dispersion is improved by using a thin layer of PI/nanocomposite on PI film. As a result, fewer space charges and low electric fields are observed in multilayer films.","PeriodicalId":131194,"journal":{"name":"Polyimide for Electronic and Electrical Engineering Applications","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114571123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-26DOI: 10.5772/intechopen.92260
J. Zha, Xue-Jie Liu, Yaya Tian, Z. Dang, George Chen
The availability of high-temperature dielectrics is key to develop advanced electronics and power systems that operate under extreme environmental conditions. In the past few years, many improvements have been made and many exciting developments have taken place. However, currently available candidate materials and methods still do not meet the applicable standards. Polyimide (PI) was found to be the preferred choice for high-temperature dielectric films development due to its thermal stability, dielectric properties, and flexibility. However, it has disadvantages such as a relatively low dielectric permittivity. This chapter presents an overview of recent progress on PI dielectric materials for high-temperature capacitive energy storage applications. In this way, a new molecular design of the skeleton structure of PI should be performed to balance size and thermal stability and to optimize energy storage property for high-temperature application. The improved performance can be generated via incorporation of inorganic units into polymers to form organic-inorganic hybrid and composite structures.
{"title":"High-Temperature Polyimide Dielectric Materials for Energy Storage","authors":"J. Zha, Xue-Jie Liu, Yaya Tian, Z. Dang, George Chen","doi":"10.5772/intechopen.92260","DOIUrl":"https://doi.org/10.5772/intechopen.92260","url":null,"abstract":"The availability of high-temperature dielectrics is key to develop advanced electronics and power systems that operate under extreme environmental conditions. In the past few years, many improvements have been made and many exciting developments have taken place. However, currently available candidate materials and methods still do not meet the applicable standards. Polyimide (PI) was found to be the preferred choice for high-temperature dielectric films development due to its thermal stability, dielectric properties, and flexibility. However, it has disadvantages such as a relatively low dielectric permittivity. This chapter presents an overview of recent progress on PI dielectric materials for high-temperature capacitive energy storage applications. In this way, a new molecular design of the skeleton structure of PI should be performed to balance size and thermal stability and to optimize energy storage property for high-temperature application. The improved performance can be generated via incorporation of inorganic units into polymers to form organic-inorganic hybrid and composite structures.","PeriodicalId":131194,"journal":{"name":"Polyimide for Electronic and Electrical Engineering Applications","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115641256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-25DOI: 10.5772/intechopen.92643
J. Ho, M. Schroeder
Nearly five decades of effort has focused on identifying and developing new polymer capacitor films for higher-than-ambient temperature applications, but simultaneous demands of processability, dielectric permittivity, thermal conductivity, dielectric breakdown strength, and self-clearing capability limit the number of available materials. Demands on these criteria are even more stringent in growing numbers of applications demanding high power performance. Aromatic polyimides, though not a panacea, are a class of heat-resistant polymers of great interest to researchers as capacitor dielectrics because of good thermal and mechanical stability. In this chapter, the key aspects and advantages of metallized polymer film capacitors are compared to analogous alternative technologies (polymer-film-metal-foil, ceramic, and electrolytic capacitors), followed by a comprehensive review of commercial resin development leading up to recent research on polyimides targeted for operating temperature above 150°C. Finally, this chapter provides a brief discussion on the recent effort on combining computation and synthesis to design polymers with desirable dielectric properties.
{"title":"Polyimides as High Temperature Capacitor Dielectrics","authors":"J. Ho, M. Schroeder","doi":"10.5772/intechopen.92643","DOIUrl":"https://doi.org/10.5772/intechopen.92643","url":null,"abstract":"Nearly five decades of effort has focused on identifying and developing new polymer capacitor films for higher-than-ambient temperature applications, but simultaneous demands of processability, dielectric permittivity, thermal conductivity, dielectric breakdown strength, and self-clearing capability limit the number of available materials. Demands on these criteria are even more stringent in growing numbers of applications demanding high power performance. Aromatic polyimides, though not a panacea, are a class of heat-resistant polymers of great interest to researchers as capacitor dielectrics because of good thermal and mechanical stability. In this chapter, the key aspects and advantages of metallized polymer film capacitors are compared to analogous alternative technologies (polymer-film-metal-foil, ceramic, and electrolytic capacitors), followed by a comprehensive review of commercial resin development leading up to recent research on polyimides targeted for operating temperature above 150°C. Finally, this chapter provides a brief discussion on the recent effort on combining computation and synthesis to design polymers with desirable dielectric properties.","PeriodicalId":131194,"journal":{"name":"Polyimide for Electronic and Electrical Engineering Applications","volume":"483 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123060258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-02DOI: 10.5772/intechopen.91973
Yan Yang, Guangning Wu
Polyimide (PI) is a commonly used insulating material to resist surface discharge, for instance, as turn-to-turn insulating material in inverter-fed motors driven by pulse width modulation (PWM) converters. Under the effect of repetitive impulse voltages, PI is expected to withstand surface partial discharge (PD) during service. However, lifetime under repetitive impulse voltages is much shorter than that under AC voltages due to storage effect of charges. Many approaches have been proposed to improve lifetime of polyimide under repetitive impulse voltages, such as using nanocomposites, surface modification, and structure design. In this chapter, we will discuss the lifetime of polyimide under repetitive impulse voltages and corresponding theoretical mechanism, together with modification approaches and their effects on lifetime improvement.
{"title":"Lifetime of Polyimide under Repetitive Impulse Voltages","authors":"Yan Yang, Guangning Wu","doi":"10.5772/intechopen.91973","DOIUrl":"https://doi.org/10.5772/intechopen.91973","url":null,"abstract":"Polyimide (PI) is a commonly used insulating material to resist surface discharge, for instance, as turn-to-turn insulating material in inverter-fed motors driven by pulse width modulation (PWM) converters. Under the effect of repetitive impulse voltages, PI is expected to withstand surface partial discharge (PD) during service. However, lifetime under repetitive impulse voltages is much shorter than that under AC voltages due to storage effect of charges. Many approaches have been proposed to improve lifetime of polyimide under repetitive impulse voltages, such as using nanocomposites, surface modification, and structure design. In this chapter, we will discuss the lifetime of polyimide under repetitive impulse voltages and corresponding theoretical mechanism, together with modification approaches and their effects on lifetime improvement.","PeriodicalId":131194,"journal":{"name":"Polyimide for Electronic and Electrical Engineering Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116795736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-01DOI: 10.5772/intechopen.92251
Xiaoping Wang, D. Min, Shengtao Li
Polyimide has been widely used as insulating and structural materials in spacecraft due to its excellent electrical, thermal and mechanical properties. However, its charging and discharging problem in harsh space environment has been a major limit to the development of high-voltage and high-power spacecraft. In this chapter, charging and discharging phenomena of dielectric materials under electron irradiation environment were presented. First, the electrical properties of polyimide consisting of dielectric properties, trap properties, conductivity and electrical breakdown properties were investigated, which have great influences on charging and discharging characteristics. Then, a surface charging model under relatively low-energy electron irradiation was proposed for polyimide, based on the synergistic effects of electron movement above surface and charge transport in surface layer. The DC surface flashover of polyimide under electron irradiation with different energies, fluxes and incident angles was investigated. Furthermore, a deep charging model under high-energy electron irradiation with the Fluence Model for Internal Charging (FLUMIC) spectrum was established. The effects of electron flux enhancement and operating voltage on charging characteristics were discussed in different grounding modes. It indicates that the processes of discharging under electron irradiation have a close link with the charge transport characteristics of polyimide.
{"title":"Charging and Discharging Mechanism of Polyimide under Electron Irradiation and High Voltage","authors":"Xiaoping Wang, D. Min, Shengtao Li","doi":"10.5772/intechopen.92251","DOIUrl":"https://doi.org/10.5772/intechopen.92251","url":null,"abstract":"Polyimide has been widely used as insulating and structural materials in spacecraft due to its excellent electrical, thermal and mechanical properties. However, its charging and discharging problem in harsh space environment has been a major limit to the development of high-voltage and high-power spacecraft. In this chapter, charging and discharging phenomena of dielectric materials under electron irradiation environment were presented. First, the electrical properties of polyimide consisting of dielectric properties, trap properties, conductivity and electrical breakdown properties were investigated, which have great influences on charging and discharging characteristics. Then, a surface charging model under relatively low-energy electron irradiation was proposed for polyimide, based on the synergistic effects of electron movement above surface and charge transport in surface layer. The DC surface flashover of polyimide under electron irradiation with different energies, fluxes and incident angles was investigated. Furthermore, a deep charging model under high-energy electron irradiation with the Fluence Model for Internal Charging (FLUMIC) spectrum was established. The effects of electron flux enhancement and operating voltage on charging characteristics were discussed in different grounding modes. It indicates that the processes of discharging under electron irradiation have a close link with the charge transport characteristics of polyimide.","PeriodicalId":131194,"journal":{"name":"Polyimide for Electronic and Electrical Engineering Applications","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117353164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-20DOI: 10.5772/intechopen.92010
S. Kim, T. Byun, J. Kim, I. Chung, S. Kim
Fluorinated polyimides were prepared from the twisted benzidine monomer containing two trifluoromethyl (CF3) groups on one aromatic ring. The diamine monomer having a rigid and nonplanar structure was polymerized with typical dianhydride monomers including BPDA, BTDA, ODPA, 6-FDA, and PMDA, to obtain the corresponding polyimides. Most polyimides are soluble in organic solvents due to their twisted chain structure and can be solution cast into flexible and tough films. These films have a UV-vis absorption cut-off wavelength at 354–398 nm and a light transparency of 34–90% at a wavelength of 550 nm. They also have tensile strengths of 92–145 MPa and coefficients of thermal expansion (CTE) of 6.8–63.1 ppm/°C. The polymers exhibited high thermal stability with 5% weight loss at temperatures ranging from 535 to 605°C in nitrogen and from 523 to 594°C in air, and high glass temperature (Tg) values in the range of 345–366°C. Interestingly, some of the soluble polyimides showed thermo-responsive behaviors in organic solvents presumably due to the multiple hydrogen bondings with unsymmetrically positioned two CF3 groups along the polymer chains.
{"title":"Synthesis and Properties of Fluorinated Polyimides from Rigid and Twisted Bis(Trifluoromethyl)Benzidine for Flexible Electronics","authors":"S. Kim, T. Byun, J. Kim, I. Chung, S. Kim","doi":"10.5772/intechopen.92010","DOIUrl":"https://doi.org/10.5772/intechopen.92010","url":null,"abstract":"Fluorinated polyimides were prepared from the twisted benzidine monomer containing two trifluoromethyl (CF3) groups on one aromatic ring. The diamine monomer having a rigid and nonplanar structure was polymerized with typical dianhydride monomers including BPDA, BTDA, ODPA, 6-FDA, and PMDA, to obtain the corresponding polyimides. Most polyimides are soluble in organic solvents due to their twisted chain structure and can be solution cast into flexible and tough films. These films have a UV-vis absorption cut-off wavelength at 354–398 nm and a light transparency of 34–90% at a wavelength of 550 nm. They also have tensile strengths of 92–145 MPa and coefficients of thermal expansion (CTE) of 6.8–63.1 ppm/°C. The polymers exhibited high thermal stability with 5% weight loss at temperatures ranging from 535 to 605°C in nitrogen and from 523 to 594°C in air, and high glass temperature (Tg) values in the range of 345–366°C. Interestingly, some of the soluble polyimides showed thermo-responsive behaviors in organic solvents presumably due to the multiple hydrogen bondings with unsymmetrically positioned two CF3 groups along the polymer chains.","PeriodicalId":131194,"journal":{"name":"Polyimide for Electronic and Electrical Engineering Applications","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121130823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-11DOI: 10.5772/intechopen.92024
B. Du, R. Xu, J. Xing, Li Jin
Polyimide (PI) is widely employed as winding insulation in high voltage devices, such as extra-high voltage electric reactor and inverter-fed motor. The injection and accumulation of charges on the surface of PI films will lead to electrical field distortion and reduced lifespan of winding insulation, especially for the operation environment of high temperature and high voltage. This chapter focuses on effects of surface molecular modification and nanoparticles on dynamic characteristics of surface charge and space charge of pure PI films, including three sections. The effect of molecular structure on the surface charge dynamics of PI films was studied firstly. The chapter investigated that how molecular structure affects surface charge of polyimide nanocomposite films. Furthermore, the effect of surface molecular modification on space charge characteristics of multilayer PI films was researched. The results illustrate that surface molecular modification and nanoparticles can comprehensively suppress space charge accumulation and improve dielectric property.
{"title":"Effect of Molecular Structure Modification and Nano-Doping on Charge Transportation of Polyimide Films for Winding Insulation","authors":"B. Du, R. Xu, J. Xing, Li Jin","doi":"10.5772/intechopen.92024","DOIUrl":"https://doi.org/10.5772/intechopen.92024","url":null,"abstract":"Polyimide (PI) is widely employed as winding insulation in high voltage devices, such as extra-high voltage electric reactor and inverter-fed motor. The injection and accumulation of charges on the surface of PI films will lead to electrical field distortion and reduced lifespan of winding insulation, especially for the operation environment of high temperature and high voltage. This chapter focuses on effects of surface molecular modification and nanoparticles on dynamic characteristics of surface charge and space charge of pure PI films, including three sections. The effect of molecular structure on the surface charge dynamics of PI films was studied firstly. The chapter investigated that how molecular structure affects surface charge of polyimide nanocomposite films. Furthermore, the effect of surface molecular modification on space charge characteristics of multilayer PI films was researched. The results illustrate that surface molecular modification and nanoparticles can comprehensively suppress space charge accumulation and improve dielectric property.","PeriodicalId":131194,"journal":{"name":"Polyimide for Electronic and Electrical Engineering Applications","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121706520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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