FTIR investigation of cross-linking and isomerization reactions of acetylene-terminated polyimide and polyisoimide oligomers

0887-6266

FTIR spectroscopy ; acetylene-terminated polyisoimide ; acetylene-terminated polyimide ; isoimide-imide isomerization ; cross-linking reaction ; thermal curing process ; flexibility effect ; cross-linking effect ; rate constant ; Chemistry ; Polymer and Materials Science

Wiley InterScience Backfile Collection 1832-2000

Chemistry and Pharmacology

Physics

The interrelationship between the cross-linking and isoimide-imide isomerization reactions of oligomeric isoimides and imides was investigated using FTIR spectroscopy. It was found that cross-linking of the acetylene units of Thermid IP-600 retarded the local rearrangement of the isoimide to imide conversion of Thermid IP-600 compared with an aniline-terminated analog, decreasing the rate constant by a factor of about 2. The increased flexibility of both the isoimide (Thermid IP-600) and imide (Thermid FA-700) oligomers increased the cross-linking rate of the acetylene end groups by a factor of 4 and 2, respectively, over that of the more rigid imide oligomer (MC-600). With increasing conversion of the isoimide to imide linkages in Thermid IP-600, the kinetic parameters, Eα and in A, for the cross-linking reaction of this oligomer became the same as those for the oligomeric imide, Thermid MC-600. © 1994 John Wiley & Sons, Inc.

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