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Kinetics of imidization and crosslinking in PMR-polyimide resinInfrared spectroscopy and differential scanning calorimetry were employed to study the imidization and crosslinking kinetics of norbornenyl-capped, addition-type polyimide resins (designated PMR for polymerization of monomer reactants). The spectral and thermal analyses were performed on resin specimens which had been isothermally aged at temperatures appropriate for imidization (120 to 204 C) and crosslinking (275 to 325 C). Imidization occurs rapidly (approximately 0.01/min) at short times, while at times longer than approximately 0.5 hour, the rate decreases significantly (approximately 0.0001/min). The crosslinking reaction exhibits first order kinetics during the initial portion of the reaction and its rate appears to be limited by the reversion of the norbornenyl Diels-Alder adduct. The total heat evolved per mole of endcap during crosslinking shows an inverse dependence on the molecular weight of the imide prepolymers. This reflects the effect of endcap dilution and decreased mobility of the larger oligomers.
Document ID
19780015288
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Lauver, R. W. (NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 3, 2013
Publication Date
January 1, 1977
Subject Category
Nonmetallic Materials
Report/Patent Number
NASA-TM-78844
E-9561
Meeting Information
Meeting: Central Reg. Meeting of the Am. Chem. Soc.
Location: Charleston, WV
Country: United States
Start Date: October 12, 1977
End Date: October 14, 1977
Accession Number
78N23231
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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