Table 5.
Mechanical properties of hemp fibre composites after the different treatments
| Treatment | Period | Composite properties (Vf = 50%) | Calculated fibre properties | |||
|---|---|---|---|---|---|---|
| Stiffness Ec (GPa) |
UTSc
(MPa) |
Porosity Vp (%) |
Ef
(GPa) |
Porosity αpf (%) |
||
| Untreated | 0 | 33.8 (0.6) | 294 (14) | 7.9 (0.4) | 64.9 (1.2) | 15.7 (0.8) |
| Field retted | 20 days | 26.9 (0.6) | 248 (17) | 8.1 (0.6) | 51.2 (1.1) | 16.2 (1.2) |
| Fungal retting | 7 days | 32.2 (0.5) | 283 (8) | 6.6 (0.8) | 61.6 (0.9) | 13.1 (1.5) |
| 14 days | 34.5 (0.5) | 300 (9) | 4.9 (0.4) | 66.2 (0.9) | 9.7 (0.7) | |
| 20 days | 34.8 (0.3) | 307 (6) | 5.5 (0.5) | 66.9 (0.6) | 10.9 (0.9) | |
| PectinaseA | 90 min | 35.2 (1.0) | 306 (15) | 6.0 (0.3) | 67.6 (1.9) | 11.9 (0.6) |
| HTT + pectinaseA | 90 min | 38.2 (0.8) | 325 (6) | 4.2 (0.2) | 73.6 (1.6) | 8.4 (0.4) |
Values are means (standard error)
AWith or without autoclave treatment (HTT) at 1 bar (121 °C) for 30 min before the pectinase treatment (Liu et al. 2016b)