Table 4.
Transition temperatures and enthalpies for irradiated PLGA nonwovens obtained in different in vitro degradation times.
| Days | Ter (°C)/ΔHer (J/g) | Tg (°C) | Tcc (°C) | ΔHcc (J/g) | Tm (°C) | ΔHm (J/g) | Xc (%) |
|---|---|---|---|---|---|---|---|
| SBF | |||||||
| 7 | 65.7/6.83 | 45.4 | 94.2 | 15.2 | 156.7 | 17.5 | 2.2 |
| 15 | 64.4/9.25 | 42.0 | 94.7 | 16.1 | 155.7 | 21.4 | 5.0 |
| 30 | 61.2/8.41 | 43.3 | 91.9 | 12.8 | 158.4 | 21.4 | 8.1 |
| DMEM | |||||||
| 7 | 64.4/7.40 | 44.4 | 93.4 | 18.2 | 159.0 | 22.5 | 4.1 |
| 15 | 65.8/7.25 | 43.9 | 94.9 | 16.3 | 159.3 | 19.7 | 3.2 |
| 30 | 61.7/7.61 | ND | 89.9 | 10.6 | 157.9 | 17.8 | 6.8 |
| ARTIFICIAL SALIVA | |||||||
| 7 | 63.8/7.79 | 43.2 | 92.1 | 15.6 | 157.8 | 20.2 | 4.3 |
| 15 | 63.9/16.3 a | 44.7 | 92.4 | 14.5 | 154.9 | 20.6 | 5.8 |
| 30 | 60.8/22.9 a | ND | 89.2 | 8.79 | 155.8 | 16.1 | 6.9 |
Tg, glass transition temperature obtained from the second heating run; Ter, Tm and Tcc, enthalpic relaxation temperature, melting temperature and crystallization temperature on heating (cold crystallization); ΔHer, ΔHm and ΔHcc, enthalpic relaxation, melting and cold crystallization enthalpies and ND, not determined and a bimodal peak. Irradiated PLGA control: Ter = 62.7 °C, ΔHer = 7.06 J/g, Tg = 48.8 °C, Tcc = 94.4 °C, ΔHcc = 16.1 J/g, Tm = 156.6 °C, ΔHm = 16.9 J/g and Xc = 0.8%.