非晶聚对苯二甲酸乙二醇酯薄片在低温退火过程中的声发射现象

ACOUSTIC EMISSION DURING SUB-Tg ANNEALING FOR AMORPHOUS POLY (ETHYLENE TEREPHTHALATE) SHEET

Acoustic emission during sub-Tg annealing fort amorphous polyethylene terephthalate (PET) sheet quenched from melt has been observed. The mechanical properties, texture and glass transition of annealed specimens have been studied. It is shown that some of PET chains change from non-equilibrium state to equilibrium state during sub-Tg annealing, which leads to stress concentration in specimen. When the level of internal stress approaches to the limit, the acoustic waves are emitted due to sudden releasing of stress and the micro-defects are for-med. This is one of the important reasons,the causes the loss of mechanical properties to an-nealed specimens.