Kinetics of thermal degradation of 6FDA based copolyimides - I

P. Santhana Gopala Krishnan, Rohit H. Vora*, S. Veeramani, Suat Hong Goh, Tai Shung Chung

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Two series of linear aromatic copolyimides containing hexafluoro isopropylidine moieties (i.e. 6F) were synthesized by reacting 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) with various mole percents of 2,3,5,6-tetramethyl-1,4-phenylene diamine (Durene diamine) and 2,6-diamino toluene (DAT) or m-phenylene diamine (mPDA) in N-methyl-2-pyrrolidone (NMP). These copolyimides were characterised by GPC, XRD, DSC, TMA, DMA and TGA. Copolymer composition of these copolyimides was determined using 1H-NMR. Tg calculated using Fox equation was compared with experimentally found values. All copolyimides were found to be amorphous. Activation energy was determined for the thermal degradation of these copolyimides using Coats-Redfern and Chang equations and were found to follow first order kinetics in air and in nitrogen. Inherent viscosity and Tg, decreased with decrease in mole ratio of durene diamine whereas activation energy and frequency factor [ln (A)] were found to increase with decrease in mole ratio of durene diamine in [6FDA + Durene diamine + mPDA] and [6FDA + Durene diamine + DAT] copolyimide series. CO2 was the main decomposition product in air and CHF3 in nitrogen atmosphere. Amount of CHF3 evolved increased with increase in durene content in copolyimide series.

Original languageEnglish (US)
Pages (from-to)273-285
Number of pages13
JournalPolymer Degradation and Stability
Issue number2
StatePublished - 2002
Externally publishedYes


  • 6FDA
  • Activation energy
  • Kinetics
  • Polyimide
  • Thermal degradation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Materials Chemistry
  • Polymers and Plastics


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