Explosive properties of nitrocellulose

The equation of decomposition and the physical constants reported by Kast [83] are quoted below. They refer to guncotton of 13.1% N  

The decomposition equation for the same guncotton containing 16% of water, has the following values  

Guncotton such as the above, in a dry state, compressed to a density of 1.30 g/cm3 demonstrated a detonation rate of 6300 m/sec, and an expansion in the lead block of 375 cm3, while guncotton with 16% of water content detonated with a rate of 6800 m/sec, and produced an expansion in the lead block of 280 cm3. 

Milus [84] investigated the explosive decomposition of nitrocotton with different nitrogen content and obtained experimental data which he used to calculate the values tabulated below (Table 68). 

Taking into account earlier experiments, Roux and Sarrau [85] have estimated the heat of explosion of guncotton to be 1056 kcal/kg, a value compatible with those 

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In 1845, German Swiss chemist C. F. Schonbein accidentally discovered the explosive properties of nitrocellulose fibers when he used his wife s cotton apron to mop up some nitric acid, then hung the apron by a stove to dry. 

T. Urbanski and Magiera [85] have examined the chemical stability and explosive properties of the ester and conclude that neither the substance itself nor a solution of nitrocellulose in it are sufficiently stable for practical application. Its temperature of initiation is 150°C (whereas nitroglycol is initiated at 220°C), and it is considerably more sensitive to impact than nitroglycol. They also found that an impact energy of 0.91 kgm/cm2 is necessary to ensure a 10% probability explosion of nitroglycol, as compared with barely 0.11 kgm/cm2 for the ester. 

Niehaus, M., Compounding of Glycidyl Azide Polymer with Nitrocellulose and its Influence on the Properties of Propellants, Propellants, Explosives, Pyrotechnics, Vol. 25, 2000, pp. 236-240. 

Uses In low-freezing dynamites. As plasticizer for nitrocellulose. In blasting explosives in combination with chlorates or nitrates. Such plastic explosives have the desirable property of completely filling the bore hole by using only a light pressure. The oily... 

All polymers show the relative viscosity of 1% acetone solution between ).l and 1.8 cp. Partial compatibility with nitrocellulose and rubber has been described for polymers lie and lid. The densities of samples II were 1.50-1.64. Polymer Ila showed explosive properties it detonated with the rate of 6200 m/s at d= 1.57,... 

Efforts are being made to find an explosive polymer with properties similar to those of nitrocellulose. Naturally attention was directed towards the nitration of polyvinyl alcohol as the most accessible high molecular poly hydroxyl alcohol. It is described in the chapter dedicated to explosive polymers (Chapter XIV). 

It is pertinent from these structiues that nitro arrd azide groups make plasticizers to have energetic properties. In addition to these plasticizers, also neutral plasticizers such as DOP and other plasticizers are used in these applications. The plasticizers or their combinations are selected to achieve the reqirired effect. Inert plasticizers usrrally lower the energy content of polymers used in explosives (e.g., nitrocellulose). 

Acetone, isopropanol and ethanol are used in the manufacture of nitrocellulose explosives. Again solvency properties are important. The alcohols are also used as damping materials for nitrocellulose resins, making them safe to handle and transport. 

A number of derivatives of cellulose are used commercially. Most of these are compounds in which two or three of the free hydroxyl groups of each glucose unit have been converted to an ester or an ether. This conversion substantially alters the physical properties of the material, making it more soluble in organic solvents and allowing it to be made into fibers and films. Treating cellulose with acetic anhydride produces the triacetate known as Arnel or acetate, used widely in the textile industry. Cellulose trinitrate, also called gun cotton or nitrocellulose, is used in explosives. 

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