Wx. Huang et Sl. Wunder, A DYNAMIC FT-IR METHOD FOR DETERMINING THE CURING TEMPERATURE RANGES OF AN ACETYLENE-TERMINATED POLYISOIMIDE PREPOLYMER, Journal of applied polymer science, 59(3), 1996, pp. 511-520
A dynamic FT-IR method was used to determine the individual curing tem
perature ranges of the isoimide-imide isomerization and crosslinking r
eactions of an acetylene-terminated polyisoimide prepolymer. The indiv
idual curing temperature ranges of these two types of chemical reactio
ns for the polyisoimide system using differential scanning calorimetry
(DSC) were totally overlapped. Using dynamic FT-IR spectroscopy, the
curing temperature ranges of the isomerization and crosslinking reacti
ons were clearly separated. The isomerization reaction began at lower
temperatures than the crosslinking reaction and was complete when only
half of the crosslinking reaction had occurred. The temperature width
, Delta T-1/2, was twice as great for the crosslinking reaction compar
ed with the isomerization reaction. Activation energies from dynamic F
T-IR spectroscopy can be obtained for the two separate reactions, howe
ver, for the reactions considered here, the activation energies were s
imilar, 26 kcal/mol for the isomerization reaction and 23 kcal/mol for
the crosslinking reaction. (C) 1996 John Wiley & Sons, Inc.