Preparation and investigations of polyimides III - Thermal investigation of the imidization of polyamide acid powders

J. Varga, T. Meisel, K. Belina, J. Balla

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Polyamide acid powders of pyromellitic dianhydride and 4,4′-diaminodiphenyl ether base were prepared in tetrahydrofuran, in the heterogeneous phase. The imidization of these powders was investigated by thermogravimetric, calorimetric and mass-spectrometric methods. According to the TG and DSC data, the temperatures of the beginning and maximum rate of imidization increase with increasing temperature and duration of imidization. A linear relationship has been found to exist between the weight loss and the reaction heat of the imidization process. The reaction heat corresponding to unit weight loss increases with decreasing molecular weight. Dicarboxylic anhydrides, applied as chain-terminators, do not affect the thermal properties of polyamide acids to an appreciable extent. Imidization has been found to be a complex process, in which decomposition of polyamide acids also takes place besides dehydrocyclization. The kinetics of imidization are satisfactorily described by a first-order dehydrocyclization and a parallel first-order decomposition. The weight loss during imidization is higher than the loss calculated on the basis of dehydrocyclization, which must be due to the release of the decomposition products of the polyamide acid, the release of solvated or complexed tetrahydrofuran, or that of possible oligomeric clusters.

Original languageEnglish
Pages (from-to)407-420
Number of pages14
JournalJournal of Thermal Analysis
Volume16
Issue number2
DOIs
Publication statusPublished - Aug 1979

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Nylons
Polyamides
polyimides
Polyimides
Powders
preparation
acids
Acids
di-(4-aminophenyl)ether
tetrahydrofuran
Decomposition
decomposition
heat
Anhydrides
anhydrides
Ethers
molecular weight
ethers
Thermodynamic properties
thermodynamic properties

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Engineering(all)

Cite this

Preparation and investigations of polyimides III - Thermal investigation of the imidization of polyamide acid powders. / Varga, J.; Meisel, T.; Belina, K.; Balla, J.

In: Journal of Thermal Analysis, Vol. 16, No. 2, 08.1979, p. 407-420.

Research output: Contribution to journalArticle

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