The limiting oxygen index and UL-94 vertical burning test of PPUFs and NPUFs.
| Sample | LOI (%) | UL-94 | |||
|---|---|---|---|---|---|
| t 1 a (s) | t 2 a (s) | Dripping | Rating | ||
| PPUF-0 | 18.3 | BCb | — | Yes | NRc |
| PPUF-10 | 20.2 | 19.0 | 3.7 | No | V1 |
| PPUF-20 | 21.6 | 12.6 | 3.1 | No | V0 |
| PPUF-30 | 23.2 | 10.5 | 2.9 | No | V0 |
| PPUF-40 | 24.3 | 8.8 | 2.5 | No | V0 |
| PPUF-50 | 25.2 | 7.8 | 2.1 | No | V0 |
| NPUF-0 | 18.7 | 29.3 | 4.0 | Yes | V1 |
| NPUF-10 | 20.8 | 16.7 | 3.3 | No | V1 |
| NPUF-20 | 21.9 | 7.5 | 3.0 | No | V0 |
| NPUF-30 | 23.7 | 5.0 | 2.7 | No | V0 |
| NPUF-40 | 24.6 | 4.3 | 2.3 | No | V0 |
| NPUF-50 | 25.5 | 3.4 | 2.0 | No | V0 |
a
t, average combustion times after the flame.
b
BC, burns to clamp.
c
NR, not rated.