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Glass transition temperature ( T g ) determination of partially cured thermosetting systems
Author(s) -
Lee C. YC.,
Goldfarb I. J.
Publication year - 1981
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760211208
Subject(s) - thermosetting polymer , materials science , epoxy , curing (chemistry) , glass transition , composite material , softening , torsion (gastropod) , calibration curve , modulus , polymer , mathematics , medicine , statistics , surgery , detection limit
Previous experiments have shown that T g of a partially cured thermosetting system can be measured with conventional thermal scan methods only if no appreciable additional cure occurred during the scan. For high temperature performance systems, the partially cured T g is often at a temperature where kinetics rate is very rapid, causing either an observation of a more advanced cured T g , or only the completely cured system's T g [ T g (∞)]. Two methods to interpolate the T g information in spite of additional cure are presented and illustrated with an epoxy resin as a testing material. The Isocure State Curve method is demonstrated with a two‐step curing experiment with the Torsion Impregnated Cloth Analysis (TICA) technique, which is a forced torsion measurement on the Rheometrics mechanical spectrometer, with the resin impregnated on a glass cloth specimen. The calibration method is demonstrated by the post cure experiments of TICA, using the time to loss modulus maximum, and the softening parameter R as the calibration parameters.