Abstract:
An explosive reaction is an ultra-fast exothermic reaction resulting in high heat ‘Q’ and gaseous ‘V’ output. Heat/energy released by the explosion raises the temperature of product gasses, making them to expand and work on the surroundings, giving a ‘lift and heave’ effect. The rise in temperature of the gasses produced and their succeeding expansion is dependent on the heat of explosion. Hence the power of any explosive is calculated as: Explosive Power = Q x V.
When exactly adequate oxygen is available to the explosive molecule to fully oxidize its intrinsic carbon (C) and hydrogen (H) atoms to carbon dioxide (CO2) and water (H2O), Oxygen balance is considered as zero (Ω = 0) and the effect of explosion is optimal.
To date TNT forms the backbone of military explosives as it has proved its robustness and efficiency over time. Most military explosive formulations contain a considerable portion of TNT, but there is a problem with TNT! It is an oxygen starved molecule (50% deficient in the needed oxygen atoms). TNT (C7H5N3O6) does not have enough oxygen atoms within its structure to completely oxidize its C and H component (fuel element).
To cater for the lack of oxygen in TNT, generally ammonium nitrate (AN) is added as oxidizer; as its cheap, easily available and an excellent oxidizer. The mixture of TNT and AN is called ‘Amatol’. Amatol (80:20) has an oxygen balance, Ω=0 (ideal). By doing so, a high Q value is obtained but the detonation velocity/VOD suffers; being only 5080 m/s for Amatol of density 1.45 g/cm3 vs 6950 m/s for TNT at 1.58 g / cm3.
Nanoparticles (NPs) owing to their high surface to volume ratio are highly reactive and their small quantities bring about large differences in performance/properties. So, if AN in nano form is added to TNT it is likely to improve its performance and overcome low VOD.
Keywords: Explosives, ultra-fast exothermic reaction, heat Q, gaseous output V, Oxygen Balance Ω, Velocity of Detonation VOD; Trinitrotoluene TNT, Ammonium Nitrate AN, Amatol, Nanoparticles NPs.
