Publicação
Characterization of metallized polymeric films for high thermal performance applications
| Resumo: | A capacitor is an electrical component capable of storing electrical current, conduct alternate current (AC) and block different voltage levels of a direct current (DC) power source. It’s basically composed by electrodes which are separated by a non-conductive material, namely, the dielectric, involved in an epoxy resin while inserted in a plastic case. Ceramic, electrolytic or plastic materials can be used as dielectrics in capacitors. These different materials possess different electric properties such as dielectric constant, dissipation factor and dielectric strength, which influence the capacitor performance and long-term reliability. Due to the good stability towards a large range of frequencies and temperatures, low dissipation factors, high lifetime, high dielectric strength and crystallinity, polymeric films are greatly used as dielectrics. Polypropylene base films are commonly used as a dielectric in metallized film capacitors. The need of subjecting capacitors to higher voltage applications and operating temperatures above 105°C led to the investigation of new base materials to be used as dielectrics in capacitors. Compound X is an amorphous material with good thermal resistance and high dimensional stability and is being increasingly added to polypropylene films to maximize its thermal performance in electrical applications. On the present dissertation, five metallized biaxially oriented films were analysed through various characterization techniques such as Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy – Attenuated Total Reflectance, Atomic Force Microscopy and Scanning electron Microscopy. Additionally, mechanical tests were performed in machine direction as well as temperature shrinkage evaluations in machine and transverse directions. Three of the five films consist in polypropylene modified with compound X while the two remaining films contain polypropylene only. Beyond the base film effect, other factors such as film thickness and metallizer (A and B) are investigated. Compound X presence leads to an overall lower crystallinity and young modulus, a fibre structure morphology, higher roughness and better dimensional stability when exposed to high temperatures, with emphasis in the higher thickness film. Thickness had a negative effect on crystallinity and overall mechanical parameters except for the strain at break. Metallizer B promoted the appearance of a metallization pattern in segmented areas of the film and higher film roughness. |
|---|---|
| Autores principais: | Alvarães, Hugo André Capela |
| Assunto: | Compound X Metallized film capacitors Polypropylene Composto X Condensadores de filme metalizado Polipropileno Ciências Naturais::Outras Ciências Naturais |
| Ano: | 2022 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | A capacitor is an electrical component capable of storing electrical current, conduct alternate current (AC) and block different voltage levels of a direct current (DC) power source. It’s basically composed by electrodes which are separated by a non-conductive material, namely, the dielectric, involved in an epoxy resin while inserted in a plastic case. Ceramic, electrolytic or plastic materials can be used as dielectrics in capacitors. These different materials possess different electric properties such as dielectric constant, dissipation factor and dielectric strength, which influence the capacitor performance and long-term reliability. Due to the good stability towards a large range of frequencies and temperatures, low dissipation factors, high lifetime, high dielectric strength and crystallinity, polymeric films are greatly used as dielectrics. Polypropylene base films are commonly used as a dielectric in metallized film capacitors. The need of subjecting capacitors to higher voltage applications and operating temperatures above 105°C led to the investigation of new base materials to be used as dielectrics in capacitors. Compound X is an amorphous material with good thermal resistance and high dimensional stability and is being increasingly added to polypropylene films to maximize its thermal performance in electrical applications. On the present dissertation, five metallized biaxially oriented films were analysed through various characterization techniques such as Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy – Attenuated Total Reflectance, Atomic Force Microscopy and Scanning electron Microscopy. Additionally, mechanical tests were performed in machine direction as well as temperature shrinkage evaluations in machine and transverse directions. Three of the five films consist in polypropylene modified with compound X while the two remaining films contain polypropylene only. Beyond the base film effect, other factors such as film thickness and metallizer (A and B) are investigated. Compound X presence leads to an overall lower crystallinity and young modulus, a fibre structure morphology, higher roughness and better dimensional stability when exposed to high temperatures, with emphasis in the higher thickness film. Thickness had a negative effect on crystallinity and overall mechanical parameters except for the strain at break. Metallizer B promoted the appearance of a metallization pattern in segmented areas of the film and higher film roughness. |
|---|