Mechanical relaxation studies of the cure of epoxy resins: 2. Activation energy of the γ-process in amine-cured epoxy resins

摘要: Abstract Measurements are reported of the activation energy for secondary relaxation (γ-relaxation) in amine-cured epoxy resins. Good agreement was found between values determined from area under loss modulus/inverse absolute temperature curve and those derived shift γ-relaxation different measuring frequencies. The to be dependent on degree cure, increasing about 14 kcal/mol during early stages cure higher following post after gelation, eventually levelling out a value characteristic hardener used (23 triethylene tetramine, 26 ethylene diamine). If less than stoichiometric amount is reduced (e.g. 18k cal/mol 11 phr TETA). interpretation as being due ‘crankshaft’ rotation CH2CH(OH)CH2O group with an therefore modified curing become example hindered double potential well, additional barrier steric effects arising increase crosslink density.