Influence of sequence of chemical reactions on kinetics and solid state behavior for bisphenol A diglycidyl ether-bisphenol A - sulfanilamide ternaryblends

The kinetics of reaction of ternary blends based on Bisphenol A diglycidyl ether, Bisphenol A and sulfanilamide curing agent was investigated using FT IR, HPLC, SEC following two different synthesis paths. Four the same initia l composition prepolymers differing by the cross-link point distribution an d the chain length between cross-links have been synthesized and their soli d state behavior has been studied. For the formulation DGEBA:SAA:BA = 4.0:1 .25:1.5 mol (catalyst - 0.005 e.e.w. DGEBA), though the schedules have diff erent kinetics, finally the prepolymers with equal conversion of epoxy grou ps and mass-average molar mass were obtained by both schedules. The dynamic mechanical spectroscopy performed in the glass transition region displays the evolution of the viscoelastic characteristics as a function of cross-li nk density. For similar formulations networks obtained by schedule 1 have h igher values of T-g and sigma (y) than networks obtained by schedule 2, per haps due to a higher real cross-link density.