Premium
Formation of graphite fiber–polyimide prepregs by electrodeposition
Author(s) -
Iroh J. O.,
Yuan W.
Publication year - 1996
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/(sici)1097-4628(19960124)59:4<737::aid-app19>3.0.co;2-m
Subject(s) - pyromellitic dianhydride , polyimide , materials science , graphite , emulsion , solvent , polymer chemistry , faraday efficiency , chemical engineering , fiber , nuclear chemistry , chemistry , composite material , organic chemistry , electrochemistry , layer (electronics) , electrode , engineering
Nonaqueous electrodeposition of polyamic acid of pyromellitic dianhydride and 4,4′‐diaminodiphenyl ether was carried out from an emulsion containing a solvent, precipitant, emulsifier, and the polyamic acid. The amount of polyamic acid deposited onto the graphite fibers was dependent on electrodeposition parameters such as the applied current, the amount of polyamic acid (solid content), precipitant/solvent (P/S) ratio, and the acid/base (COOH/TEA) mole ratio. The weight gain of fibers increased with increased current density, P/S ratio, solid content, and deposition time. A maximum weight gain of fibers of about 95% was obtained from an emulsion composed of 3 wt % solid content, P/S ratio of 3 : 1, and TEA/COOH ratio of 1 : 1. The electrodeposition of polyamic acid onto graphite fibers proceeded in accordance with the Faraday's law of electrolysis and a Coulombic efficiency of about 62.2 mg/C was attained. Thermal analysis shows that the cured polyimide coatings were thermally stable up to 500°C. © 1996 John Wiley & Sons, Inc.