Low-temperature relaxations in styrene-crosslinked polyester networks. II. The γ′ relaxation

The low-temperature γ′ relaxation was found to originate in the diol units of a variety of crosslinked polyesters. The results were explained in terms of Boyer's Crankshaft model. As the polyester concentration in the networks increased, the γ′ relaxation shifted to higher temperatures and the intensity of the relaxation increased but not as rapidly as the diol concentration. This behaviour was interpreted in terms of an interaction of the relaxing species with the surrounding matrix.