Table 6.
Biodegradation and disintegration of PLA/PBS blends.
| Type | Ratio PLA/PBS | Test Specimen | Degradation Conditions | Degradation Outcomes | Ref |
|---|---|---|---|---|---|
| Disintegration in composting conditions | 80/20 | Films prepared by solvent casting: 15 × 15 × 0.03 mm3 | 4–6 cm depth in boxes with soil: aerobic, 58 °C, 50% RH, 17 days | The disintegration value is reduced as a consequence of higher crystalline nature induced by PBS; surfactant facilitates the disintegration. degree of disintegration >90%, 17 days. | [53] |
| Enzymatic degradation | 80/20/1 (BPO) | Films 30 × 10 × 0.1 mm3 | Incubation: 37 °C, in buffer (pH = 8), proteinase K | Filaments appear on the surface; films became thin; randomly distributed holes form into large ones; degradation rate: 67%, 96 h. | [43] |
| Hydrolytic degradation (Soil burial test) | 80/20 etc. | Compression-molded sheets: at 180 °C, 12 MPa, 0.3 mm thick. | Soil temp.: 29–39 °C; soil moisture: 18–30%, 60 days | Blends with higher content of PBS have higher rate of biodegradation; Mn decreases as a function of degradation time. | [66] |
| Hydrolytic degradation (NaOH solution) |
70/30 | Compression-molded sheets (at 190 °C, 5 MPa, 50 µm thick) | Incubation: 37 °C, NaOH, pH = 13 | Immiscible PBS particles induce gaps in blends, providing channels for water penetration; hydrolytic degradation ↑; weight loss per unit area ↑ when PBS content ↑. | [35] |
Legend: BPO: benzoyl peroxide; RH: relative humidity; Mn: number-average molecular weight.