Abstract
The thermal properties and crystallization behaviors of poly(ethylene terephthalate) (PET) were investigated by controlling the annealing conditions of PET sample, such as relative humidity, temperature, and time. The variations of moisture content, glass transition temperature (T g) and cold crystallization temperature (T cc) were examined after annealing the PET sample. Subsequently crystallization process was performed with the annealed PET specimen, and then the degree of crystallinity and heat distortion temperature (HDT) of variously crystallized PET specimen were examined. Residual stress relaxation in the injection molded PET sample after annealing was also observed through polarized films. Moisture content in the PET specimen increased up to 6000 ppm with increasing the relative humidity, temperature, and time of annealing. T g and T cc of the annealed PET specimen decreased with increasing moisture content. The degree of crystallinity increased as increasing moisture content in the PET specimen. However for same moisture content, the degree of crystallinity varied with annealing conditions. The relaxations of residual stress in the PET sample differed from annealing conditions, and the maximum degree of crystallinity increased with decreasing residual stress in the PET sample.
| Original language | English |
|---|---|
| Pages (from-to) | 113-119 |
| Number of pages | 7 |
| Journal | Polymer (Korea) |
| Volume | 27 |
| Issue number | 2 |
| State | Published - Mar 2003 |
Keywords
- Crystallization temperature
- Degree of crystallinity
- Glass transition temperature
- Moisture content
- Poly(ethylene terephthalate)