Determination of glass transition temperature from viscosity and conductivity measurements for an epoxy–amine system during curing

✍ Scribed by Tsuneo Koike

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 614 KB
• Volume: 50
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1993.070501111

✦ Synopsis

The melt viscosity and the direct current ( d c ) conductivity have been investigated for three bisphenol-A novolac-type epoxide oligomers ( PGEBANs) that have some branching in each molecule in comparison with the diglycidyl ether of bisphenol-A (DGEBA) oligomer without branching. The novolac-type PGEBAN oligomer has an experimental relationship between the melt viscosity (7) and the dc conductivity ( a ) , a -g k = const, which is the same form observed for the DGEBA oligomer. The exponent k has a linear relationship with the glass transition temperature ( T , ) for the two types of oligomers with and without branching. The Tg dependence of k for the epoxide oligomers was used to analyze the T, of a DGEBA-amine system that had some degree of branching in the molecule based on the bisphenol-A structure. The Tg of the DGEBA-amine system, which was calculated from the k that had been nondestructively determined from the viscosity and the conductivity measurements, was consistent with the Tg experimentally measured by differential scanning calorimetry (DSC) .