| Abstract: | The mechanism of low-temperature mechanical relaxation in epoxide resins cured with various acid anhydrides has been investigated by comparing dynamic mechanical properties and chemical structures of these networks. One mechanical relaxation, denoted as the β relaxation, is observed at about ?70°C. The β relaxation is affected by the chemical structure of the curing agents, but not by that of the epoxide resins. In addition, the strength of the relaxation increases linearly with increasing concentration of diester linkage introduced in the network by reaction with acid anhydrides. From these results, it is concluded that the β relaxation mechanism of the anhydride-cured systems involves the motion of diester segments included in the network structures. |
