Study of the influence of isomerism on the curing properties of the epoxy system DGEBA(n=0)/1,2-DCH by rheology

摘要

Rheology was used to characterise the curing process of the epoxy system consisting of a diglycidyl ether of bisphenol A [DGEBA(n=0)] and one, or a mixture of the two isomers of the curing agent 1,2-diaminocyclohexane (1,2-DCH). The trans isomer and a mixture cis-trans (30-70% respectively) of 1,2-DCH were used to investigate their different behaviour. In a previous article (L. Nunez et al., Therm Anal Calorim, 2005), it was reported that the values of gel time measured by dielectric analysis for the systems DGEBA(n=0)/trans-1,2-DCH and DGEBA(n=0)/cis-trans -1,2-DCH were very similar, while times to vitrification, as measured by modulated scanning calorimetry differed widely. In the present study, rheometry was used to corroborate the results obtained in the previous article for gel time and activation energy and also to analyse differences in the cure of the two epoxy systems studied by comparing the results reported here with those previously measured by DEA and DSC.