Showing papers by "Carmen Ramírez published in 1994"

Determination of the activation energies for α and β transitions of a system containing a diglycidyl ether of bisphenol a (DGEBA) and 1,3-bisaminomethylcyclohexane (1,3-BAC)

Abstract: Using dynamic mechanical analysis (DMA) we have studied the variation with the frequency of the dynamic mechanical properties (storages modulus,E'; loss modulus,E'' and loss tangent or tan σ) for a system containg a diglycidyl ether of bisphenol A (DGEBA) and 1,3-bisaminomethylcyclohexane (1,3-BAC). These properties were measured both in the glass transition and β transition regions. An increase in frequency caused a shift of tan σ peak positions in both regions toward higher temperature. Finally, we report the activation energies of a DGEBA/1,3-BAC expoxy system for α and β transitions.