TABLE OF CONTENTS In an explosive reaction, heat and gases are liberated. The volume of gas V and the heat of explosion Q can both be calculated independently but these values can be combined to give the value for the explosive power as shown in Equation 5.12.
The value for the explosive power is then compared with the explosive power of a standard explosive (picric acid) resulting in the power index, as shown in Equation 5.13, where data for Q (picric acid) and V (picric acid) are 3250 kJ kg ?1 and 0.831 dm 3 g ?1, respectively.
The power index values of some primary and secondary explosive substances are presented in Table 5.14.
| Explosive substance | Q v/kJ g ?1 | V/dm 3 g ?1 | Q V 10 4 | Power index/% |
|---|---|---|---|---|
| Primary explosives | ||||
| Mercury fulminate | 1755 | 0.215 | 37.7 | 14 |
| Lead styphnate | 1885 | 0.301 | 56.7 | 21 |
| Lead azide | 1610 | 0.218 | 35.1 | 13 |
| Secondary explosives | ||||
| Nitroglycerine | 6194 | 0.740 | 458.4 | 170 |
| EGDN | 6658 | 0.737 | 490.7 | 182 |
| PETN | 5794 | 0.780 | 451.9 | 167 |
| RDX | 5036 | 0.908 | 457.3 | 169 |
| HMX | 5010 | 0.908 | 454.9 | 169 |
| Nitroguanidine | 2471 | 1.077 | 266.1 | 99 |
| Picric acid | 3249 | 0.831 | 270.0 | 100 |
| Tetryl | 4335 | 0.820 | 355.5 | 132 |
| TATB | 3496 | 0.781 | 273.0 | 101 |
| HNS | 3942 | 0.747 | 294.5 | 109 |
| TNT | 4247 | 0.740 | 314.3 |
