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Carbonization behavior of polyimide films with various chemical structures
Author(s) -
Inagaki M.,
Ibuki T.,
Takeichi T.
Publication year - 1992
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.1992.070440316
Subject(s) - polyimide , carbonization , scanning electron microscope , shrinkage , materials science , pyrolysis , electrical resistivity and conductivity , conductivity , composite material , polymer chemistry , atmospheric temperature range , chemical engineering , chemistry , layer (electronics) , electrical engineering , engineering , physics , meteorology
Six kinds of polyimide films with different molecular structures were synthesized and carbonized up to 1100°C. The carbonization behavior of polyimides was followed by measuring the changes in weight, size, and electrical conductivity. Pyrolysis gases evolved on the way to carbonize up to 1000°C were analyzed by gas chromatography. All films showed appreciable shrinkage and became a black color above 500°C. No cracks and pores were observed on the films heated up to 1100°C, even under the scanning electron microscope. A large weight decrease of 35–50% was observed in a narrow temperature range from 500 to 650°C, which seemed to be due to the departure of CO groups as either CO or CO 2 . An additional weight decrease occurred gradually above 800°C, due to N 2 departure. A remarkable increase of electrical conductivity along the film surface, more than 2 orders, was observed with the increase in heat‐treatment temperature. The polyimide film with a flat molecular structure (PMDA/PPD) gave the highest conductivity: 3.7 × 10 2 S/cm.