Les effets thermiques associés à la transition vetreuse de films de poly(téearéphatalate d'éthylène)

Abstract

Differential scanning calorimetry and thermomechanical analysis are used for examining the thermal behaviour of amorphous poly(ethy1ene terephthalate) films in the glass-transition range. By variation of the heating rate between 0,2 and 100 K . d n -' , it is possible to obtain either an exotherm associated with a shrinkage, or an endotherm, or both of these phenomena.It is found that very low heating rates not only give rise to a retardation mechanism but also to a molecular rearrangement.