MACROSCOPIC VOLUME, VAN-DER-WAALS VOLUME AND FREE-VOLUME AFTER CURE VERSUS CHEMICAL CONVERSION FOR A HIGH-T-G EPOXY-AMINE THERMOSETTING SYSTEM

Isothermal glassy-state properties of cured thermosetting materials pa ss through maximum and minimum values with increasing chemical convers ion. In this work a diglycidyl ether of bisphenol A (a diepoxide) and trimethylene glycol di-p-aminobenzoate (a tetra-functional aromatic di -amine) system (DGEBA/TMAB) has been investigated for the purpose of a nalyzing the behavior after cure of the isothermal properties of the g lass with increasing conversion. The glass transition temperature (T-g ) is used as a direct measure of conversion. The density, T-g, modulus , and free volume of the material after cure with increasing conversio n was measured. The specific volume at 25 degrees C after cure passes through a minimum and the modulus passes through a maximum with increa sing conversion (T-g). The fractional free volume at 25 degrees C afte r cure passes through a minimum value with respect to conversion. The specific volume, modulus, and fractional free volume at 25 degrees C v ersus conversion data qualitatively correlate.