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How the biaxially stretching mode influence dielectric and energy storage properties of polypropylene films
Author(s) -
Xiong Jie,
Wang Xin,
Zhang Xiao,
Xie Yunchuan,
Lu Junyong,
Zhang Zhicheng
Publication year - 2021
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.50029
Subject(s) - materials science , composite material , polypropylene , dielectric , capacitor , amorphous solid , extrusion , dielectric loss , polymer , thin film , film capacitor , voltage , optoelectronics , nanotechnology , crystallography , chemistry , quantum mechanics , physics
The most important polymer film used in commercial capacitors is biaxially oriented polypropylene (BOPP), which could be produced by sequentially or simultaneously biaxial orientation after the melt‐extrusion. In order to disclose the influence of the stretching technique on the properties of films, the BOPP films with varied thickness were fabricated by sequential and simultaneous orientation, respectively. Compared to the sequentially biaxially stretched films, the crystal grains in the simultaneously biaxially stretched films are more isotropically dispersed. As temperature increases, all the BOPP films exhibit similar dielectric constant, and the simultaneous films have much lower dielectric loss thanks to the finer blended crystalline and amorphous phases. When the film thickness is smaller than 5 μm, the breakdown field strength, energy density and discharging time of the simultaneous films can be increased by at least 10% comparing to the sequential ones, which is very important for reducing the volume of the film capacitors. All the results suggest the simultaneously biaxial orientation mode shows significant advantages in producing thin BOPP films with better mechanical and electrical properties.