Table 2.
Activation energy values using the Flynn–Wall–Ozawa, the Capela/Ribeiro and the Friedmann methods. The data were obtained with the arithmetic mean (r is the correlation value and CV is the coefficient of variation).
| Compound and Purge Gas | Capela and Ribeiro Method Ea/kJ mol−1 ± r (CV) |
Ozawa Method Ea/kJ mol−1 ± r (CV) |
Friedman Method Ea/kJ mol−1 ± r (CV) |
|---|---|---|---|
| Virgin PET (synthetic air) | 174.55 ± 0.1 (0.99669) |
177.71 ± 0.11 (0.99632) |
191.24 ± 0.12 (0.9778) |
| Virgin PET (carbonic gas) | 197.55 ± 0.02 (0.99771) |
206.23 ± 0.03 (0.99866) |
220.66 ± 0.07 (0.98491) |
| PET 500 h (synthetic air) | 177.48 ± 0.06 (0.99907) |
188.85 ± 0.08 (0.99426) |
202.47 ± 0.09 (0.98020) |
| PET 500 h (carbonic gas) | 179.42 ± 0.02 (0.99537) |
197.63 ± 0.01 (0.99170) |
211.13 ± 0.07 (0.97288) |
| PET 1000 h (synthetic air) | 175.82 ± 0.09 (0.99618) |
185.99 ± 0.07 (0.98971) |
199.96 ± 0.1 (0.97869) |
| PET 1000 h (carbonic gas) | 182.27 ± 0.04 (0.99963) |
191.27 ± 0.05 (0.99963) |
336.32 ± 0.06 (0.97821) |