Carbonization and graphitization of polyimide films: Effect of size of leaving group at imidization

✍ Scribed by Tsutomu Takeichi; Yoshinori Endo; Yutaka Kaburagi; Yoshihiro Hishiyama; Michio Inagaki

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 166 KB
• Volume: 68
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19980606)68:10<1613::aid-app10>3.0.co;2-y

✦ Synopsis

Polyamide acid was prepared from pyromellitic dianhydride and p-phenylenediamine and was then reacted with NaH and various kinds of alkyl halides to transform into alkyl esters. The cast films were imidized as fixed on glass substrate to give polyimide films and were then carbonized by heating to 900ЊC. The electrical conductivity of the carbonized films decreased with the increase of the size of the leaving group at the imidization step. The carbonized films were further heated to 2800ЊC for graphitization. Their degrees of graphitization and orientation of the graphite crystallite as a function of weight loss at imidization were studied by X-ray diffraction measurement at room temperature and magnetoresistance measurement at liquid nitrogen temperature. Both measurements clearly indicate that the graphitized films prepared from polyamide acid alkyl ester have high degrees of graphitization. It was also made clear that the orientation of the graphitized films increased with the increase of the size of the leaving group at the imidization step.