Influence de la Stereorégularite des Chaînes sur les Transitions du Polyméthacrylate de Méthyle

Dilatométric studies on five PMM samples of different tacticities show generally three transition ranges between −35 and 150°C. The main glass transition temperature depends on the relative proportion of the iso‐ or syndiotactic segments. The secondary transition, located around 60°C., seems to be related to the presence of heterotactic segments. The third transition range, common to all the five samples, located around 0°C., may be attributed tentatively to the freezing in of the ester side groups.