• Journal of the Korean Society of Industry Convergence
• /
• v.6 no.4
• /
• pp.387-392
• /
• 2003

The change of crystalline structure and mechanical properties of PET filaments were investigated. Samples were treated by isothermally annealed after elevated heating. Measurements were carried out of density gradient tube for crystallinity and UTM for initial modulus and yield stress. Isothermally heat treatment were carried out $100^{\circ}C$, $120^{\circ}C$, $140^{\circ}C$ for 10min., 30min., 60min, in silicon oil bath. And isothermally heat treatment after elevated heating from $20^{\circ}C$ were carried out $100^{\circ}C$, $120^{\circ}C$, $140^{\circ}C$ for 10min., 30min., 60min., with heating rate of $5^{\circ}C/min$., $10^{\circ}C/min$. From the results of this study, it found the following facts. It was found that the crystallinity, initial modulus and yield stress of samples were increased with increasing of annealed temperature and time. Also crystallinity, initial modulus and yield stress of samples which were isothermally annealed after elevated heating from $20^{\circ}C$ were larger than those of isohtermally annealed samples.