Table 2. Summary of Preliminary Test Results.
| test | parameter | BL: baseline | BN: 1 wt % purified (gas phase) BNNTs | BNW: 1 wt % purified (gas phase + solvent-washed) BNNT | BN2: 2 wt % purified (gas phase) BNNT |
|---|---|---|---|---|---|
| fiber volume fraction (%) | 43 ± 1 | 40 ± 2 | 41 ± 1 | 38 ± 1 | |
| 3 point bending | elastic modulus (GPa) | 23.1 ± 0.6 | 24.3 ± 0.9 | 22.5 ± 0.8 | 21.2 ± 0.8 |
| max. stress (MPa) | 478 ± 15 | 602 ± 36 | 517 ± 27 | 520 ± 35 | |
| strain (%) | 2.7 ± 0.2 | 2.8 ± 0.1 | 3.0 ± 0.2 | 2.8 ± 0.2 | |
| DMA | glass transition temperature (°C) | 92 ± 0.1 | 94.1 ± 0.3 | 95.5 ± 0.6 | 97 ± 0.3 |
| modified Charpy | fracture energy per area (kJ/m2) | 112 ± 12 | 132 ± 18 | 122 ± 5 | 114 ± 11 |
| failure stress [max. stress in outside fibers due to bending], (MPa) | 657 ± 44 | 719 ± 79 | 678 ± 17 | 635 ± 34 | |
| max stress [max load/area], (MPa) | 23.3 ± 1.8 | 27.2 ± 2.5 | 24.9 ± 1.0 | 25.4 ± 1.0 |