DYNAMIC-MECHANICAL ANALYSIS - THERMAL-DEGRADATION OF A DIGLYCIDYL ETHER OF BISPHENOL-A AND 1,3-BISAMINOMETHYLCYCLOHEXANE EPOXY-RESIN SYSTEM

Using dynamic mechanical analysis (DMA) we have studied thermal degrad ation for a system containing a diglycidyl ether of bisphenol A (DGEBA ) and 1,3-bisaminomethylcylohexane (1,3-BAC). The changes of dynamic m echanical properties during thermal degradation indicated a shift of t he glass transition temperature (T-g) to higher temperatures and a dec rease in the peak value of the dynamic loss factor (tan delta) with an increasing of aging time. The value of dynamic storage modulus (E') a t the rubbery state showed an increase with aging lime, while E' at th e glassy state only underwent a moderate change with increased thermal degradation. From these results it can be argued that thermal degrada tion during the stage prior to the onset of the severe degradation inv olves structural changes in the epoxy system, as further crosslinking and loss of dangling chains in the crosslinked network.