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Thermal Imidization of the Precursor of a Liquid Crystalline Polyimide
Author(s) -
Pramoda Kumari P.,
Liu Songlin,
Chung TaiShung
Publication year - 2002
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.200290027
Subject(s) - polyimide , fourier transform infrared spectroscopy , materials science , thermogravimetric analysis , x ray photoelectron spectroscopy , differential scanning calorimetry , isothermal process , polymer chemistry , imide , curing (chemistry) , liquid nitrogen , nitrogen , infrared spectroscopy , chemical engineering , analytical chemistry (journal) , organic chemistry , composite material , chemistry , physics , layer (electronics) , engineering , thermodynamics
Imidization of the precursor of a liquid crystalline polyimide was investigated using modulated differential scanning calorimetry (MDSC), Fourier transform infrared (FTIR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), and thermogravimetric analyzer (TGA) coupled to FTIR (TG‐IR). The FTIR study revealed that the rate and degree of imidization are functions of curing temperature and time. Imidization proceeds in two stages under isothermal condition. The initial weight loss up to 250 °C as observed from TGA was due to thermal cyclization, i.e., imidization process. The XPS analysis shows that the poly(amic acid) has two nitrogen 1s species at 400.3 and 399.2 eV possibly due to the isomerism of the dianhydride carbonyl, while liquid crystalline polyimide shows only a single nitrogen 1s species at 400.8 eV due to imide species.PLM micrograph of PAA (at 280 °C) after imidization.