Dynamic mechanical response of model epoxy networks in the glassy state

The dynamic mechanical properties of model epoxy‐amine networks are investigated in the glassy state over a wide range of frequencies, at temperatures between 123 K and 350 K. The effects of crosslink density and network chain flexibility on the β relaxation are examined. Motions responsible for the β process begin to develop at the same temperature, whatever the crosslink density. However, an increase in crosslink density is accompanied by an increase in amplitude and a broadening towards high temperatures of both damping tan δ and loss modulus E ″. This effect is responsible for the decrease of elastic modulus E ′ at room temperature with increasing crosslink density.