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Online near‐infrared measurements of an epoxy cure process compared to mathematical modeling based on differential scanning calorimetry measurements
Author(s) -
FriisPedersen H.H.,
Houmøller L. P.,
Storm B. K.
Publication year - 2008
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.28407
Subject(s) - differential scanning calorimetry , thermosetting polymer , epoxy , diglycidyl ether , materials science , degree (music) , composite material , amine gas treating , polymer chemistry , bisphenol a , chemistry , organic chemistry , thermodynamics , physics , acoustics
An epoxy resin containing diglycidyl ether of bisphenol A, dicyandiamide, and an accelerator (diurone) was investigated under different cure cycles. The mathematical prediction of the degree of cure in a thermoset as a function of time and temperature was investigated and compared to measured data. Near‐infrared analysis was used to measure the conversion of epoxy and primary amine and the production of hydroxyl. Modulated differential scanning calorimetry was used to measure the changes in the heat capacity during cure. The measurements revealed differences in the primary amine conversion and hydroxyl production, and close relations to the measurements of heat capacity were found. The measurements of the degree of cure revealed that cure cycles initiated at 80°C produced a lower degree of cure than cure cycles initiated at 90°C, although all cure cycles were postcured at 110°C. These findings were to some degree supported by measurements of the primary amine conversion and hydroxyl production. The characteristics found were attributed to differences in the cure mechanisms. The mathematical model did not incorporate these differences, and this may have led to discrepancies between the predicted and actual values of the degree of cure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008