Sub-glass transition motions in linear and cross-linked bisphenol-type epoxy resins by deuterium line shape NMR

摘要: Deuterium solid-state echo delay line shapes are used to establish the local motions occurring in linear and cross-linked epoxy systems based on Bisphenol A. Four isotopically labeled samples were prepared:  resins with deuterated methylene units, phenylene units. Two observed all four samples:  trans−gauche isomerization of units π flips The simulated obtain rates motion, amplitudes apparent distribution rates, temperature dependence rates. two jump differ by about an order magnitude rate, flip process being faster two. Both have similar distributions relaxation times given a stretched exponential correlation function exponent 0.6−0.7. activation energy for is 50 kJ/mol trans...