TABLE 4.
Effect of 1,3-dioxolane extraction on the molecular weight distribution and thermal and mechanical properties.
| Condition | Purity | Recovery | MW | MN | PDI | TM | Tg | Young’s modulus | Stress at maximum load | Elongation |
|---|---|---|---|---|---|---|---|---|---|---|
| (%) | (%) | (x 105) | (x 105) | (°C) | (°C) | (MPa) | (MPa) | (%) | ||
| Commercial PHB (CAS 26063–00–3 Batch-02925CB, Sigma-Aldrich) | — | — | 4.3 | 2.3 | 1.9 | 172.0 | 3187.3 | 40.3 | 1.4 | |
| Chloroform (80°C, manual vortex every 30 min, 6 h) | ||||||||||
| Dried cells (40 ml) | 98.8 ± 1.7 | 94.5 ± 1.0 | 3.5 | 2.2 | 1.6 | 175.9 | 3.6 | 2315.0 | 14.6 | 1.7 |
| 1,3-Dioxolane (80°C, 150 rpm of shaking speed, 4 h) | ||||||||||
| Dried cells (1,000 ml) | 99.3 ± 0.5 | 94.1 ± 0.4 | 3.7 | 2.4 | 1.5 | 177.1 | 4.2 | 2515.8 | 22.2 | 2.2 |
| Wet cells (1,000 ml) | 90.3 ± 1.5 | 92.6 ± 1.0 | 3.5 | 2.6 | 1.3 | 177.5 | -3.4 | 2629.6 | 21.0 | 4.2 |
| 1,3-Dioxolane (RT, 150 rpm of shaking speed, 36 h) | ||||||||||
| Wet cells (40 ml) | 97.7 ± 1.3 | 93.5 ± 0.7 | 3.1 | 2.7 | 1.1 | 178.2 | -3.2 | 2874.7 | 22.5 | 2.2 |
| Autoclaved wet cells (40 ml) | 97.6 ± 1.5 | 68.8 ± 1.0 | 2.3 | 1.9 | 1.2 | 177.0 | -2.3 | 2904.0 | 30.6 | 1.8 |