Physical properties of nitrocellulose

Newman [22] has estimated indirectly the melting point of nitrocellulose containing 12.6% N by the following method. He determined the melting points of mixtures of nitrocellulose and y-butyrolactone obtaining values from 39 toll2°C. By extrapolation he calculated the melting point of nitrocellulose to be 890°K, i.e. 617°C. 

The calculated heat of fusion is 1350 cal per anhydroglucose unit, and the corresponding entropy of fusion is 1.51 cal/°C. 

Earlier authors Wehrhahn [23] and Mosenthal [24], assumed that the specific gravity of nitrocellulose determined in water is independent on the nitrogen content, and is 1.66. For cellulose in alcohol, Mosenthal reports the value 1.56-1.58. The specific gravity of nitrocelluloses of different nitration degree has been determined by Brunswig [25]. 

Values measured later in the Chemisch-Technische Reichsanstalt [26] are well in line with those reported earlier. The increase of specific gravity accompanying the increase of nitrogen content is extremely small, namely  

For the specific gravity determined in a pycnometer with mercury, a series of diminishing figures has been established  

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Structure of nitrocellulose Physical properties of nitrocellulose Melting points Specific gravity Solubility... 

R.C. Warren, The effect of aging and annealing on the physical properties of nitrocellulose plasticized with nitroglycerine. Polymer 31 (1990) 861-868. 

IFiG. 275. Influence of cross-linking of nitrocellulose on physical properties of cast... 

The physical properties of the nitric esters resemble in a general way the physical properties of the alcohols from which they are derived. Thus, methyl and ethyl nitrate, like methyl and ethyl alcohol, are volatile liquids nitroglycerin is a viscous oil, more viscous and less volatile than glycol dinitrate as glycerin is more viscous and less volatile than glycol. Nitrocellulose from... 

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. 

Trimethylolethane trinitrate (metriol trinitrate) is not satisfactory as a plasticizer for nitrocellulose, and must be used with other plasticizers such as metriol triacetate. Mixtures with nitroglycerin tend to improve the mechanical properties of double-base cast propellants at high and low temperatures. Metriol trinitrate has also been used in combination with triethylene glycol dinitrate as a plasticizer for nitrocellulose. Its physical properties are Hsted in Table 7 (118-122). 

GC material was widely modified with conducting (or nonconducting) polymers in order to obtain an improved surface for DNA adsorption and detection. The initial approaches were performed by the physical attachment of nylon or nitrocellulose membranes on GC electrodes [51]. As explained, these membranes were extensively used in classical DNA analysis due to their well-known adsorption properties [33]. Other approaches were performed by the direct adsorption of the polymeric film on the GC surface. Finally, polymeric films were electrochemically grown on the GC substrate. These conducting polymers are particularly promising for the adsorption, but also for inducing electrical signals obtained from DNA interactions. 

Introduction. Today nitrocellulose is one of most important derivatives of cellulose used in industry and commerce, and a major product of the chemical industry. Its wide and manifold applications are due mainly to its extraordinary physical properties. Thus a protective coating of nitrocellulose varnish, a nitrocellulose film or a tube of smokeless powder — all are characterized by relatively high elasticity and mechanical strength. These properties are a direct consequence of the microstructure of cellulose, which is composed of highly oriented long-chain molecules of polysaccharide. Not only nitrocellulose, but also other derivatives of cellulose, such as other esters and ethers, demonstrate similar characteristics. 

There exists a range of various kinds of nitrocellulose differing from one another in their physical properties according to the application intended. Nitrocellulose for smokeless powder manufacturing (guncotton) represents one type while other properties are demanded from the raw material to be used for making celluloid or artificial fibres (collodion cotton, collodion nitrocotton). 

High explosives may be class d according to their physical properties as powdery, meltable, semi-meltable and plastic. Propellants may be grouped on the basis of chemical composition into gun powder and similar mixtures, nitrocellulose (single base) and nitroglycerine (double base) powders, With respect to their uses and some properties they are divided into black powder, smokeless and flashless powders, and rocket propellants. 

During the Second World War, mixtures of metriol trinitrate with tri-glycol dinitrate (a good gelatinizer of nitrocellulose) were processed together with nitrocellulose to produce tropic-proof propellants. They were also distinguished by high physical properties for employment in rocket motors. 

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