Nitrocellulose preparation

Using the ultracentrifuge sedimenting method, Gralen and Svedberg [40] have determined the molecular weight of nitrocellulose prepared from various types of cellulose. The nitration was carried out at 0°C by means of a mixture composed of 40% of nitric acid, 40% of phosphoric acid, and 20% of phosphorus pentoxide. The results are collected in Table 79. 

In 2003, Ksiqzczak et al. [42] used water TPM for the characterization of nitrocellulose prepared by nitration of natural cellulose. The hydrophobic nature of the membrane made the measurements difficult and only partial conclusions were drawn. Despite this, pore size distributions were measured which showed good consistency and confirmed the value of TPM for such studies. Even more recently, Rohman et al. used water TPM to measure pore size distributions in porous polymers networks [43]. 

Tonite and A nalogous Nitrocellulose Preparations. The sample is held over the rectangular sieve, and sufficient for the tests is scraped... 

Use Stabilizer for nitrocellulose preparations, possible substitute for urea as fertilizer. 

Fig. 4 4. Lines of constant nitrogen for nitrocellulose prepared in mixed acid. The dashed lines are lines of constant degree of nitration, namely, 3, 6, 7, 9, 10, 11, 12, and 13 per cent N. These lines are almost parallel to the lines of constant water concentration except in the regions of high sulfuric acid concentration at the lower right-hand comer. The zone of technical nitration is also indicated. The choice of composition for technical nitration in this concentration area is probably dictated by the economics of the recovery of spent acids. F. D, MileSf Cellulose Nitrate Interscience PublisherSf Inc., p. 66, 1955.)...

The first satisfactory photographic film was produced in 1888 when gelatin-dispersed microcrystals of silver haUde were coated on celluloid sheets (23). Within a year George Eastman prepared and marketed toU films on a base produced by dissolving nitrocellulose with camphor and amyl acetate in methanol (qv). 

New teipolymers of vinyl acetate with ethylene and carbon monoxide have been prepared and their uses as additives to improve the curing and flexibihty of coating resins, eg, nitrocellulose, asphalt, phenoHcs, and polystyrene, have been described (130—132). Vinyl acetate and vinyUdene cyanide form highly alternating copolymers. 

Guanine is obtained fiom various fish including menhaden, herring, and alewives. To prepare the colorant, scales are scraped from the fish, levigated, and washed with water, and then made into one or more commercial forms, depending on the intended use. Typically, guanine is suppHed as a paste or suspension in water, castor oil, or nitrocellulose. Guanine is not a colorant in the strict sense but instead is used to produce iridescence in a product. 

Eor example, the technique of Southern blotting was developed (68) for use with agarose gel electrophoresis of DNA fragments. Southern blots are designed to detect specific sequences of DNA. After electrophoresis is complete, the DNA is denatured and the single stranded DNA transferred to the specially prepared nitrocellulose paper. The nitrocellulose is then incubated with radioactive RNA or DNA complementary to those DNA sequences of interest. After the nitrocellulose has been sufftciendy incubated with the radioactive complementary DNA, autoradiography is used to identify the fragments of interest. 

Use of Sulfur-35 to Characterize the Sulfate Content in Nitrocellulose (NC). Military grades f NC are prepared by nitrating a suitable grade of cellulose, either cotton linters or wood pulp,... 

Preparation o f NitroisobutyIglycerin. Several procedures for the preparation of this compd are given in the literature. Of those tried, that described by Stettbacher [Nitrocellulose 5, 162 (1934)] gave the best results. The method of prepn follows ... 

The membrane is critically important in osomometry. Selection of a membrane involves reconciliation of high permeability toward the solvent with virtual impermeability to the smallest polymer molecules present in the sample. Membranes of cellulose are most widely used. Commercially Regenerated cellulose film is a common source. The undried gel cellophane film is often preferred, but the dry film may be swollen in water (or in aqueous solutions of caustic or zinc chloride ) to satisfactory porosity. Useful cellulose membranes may also be prepared by denitration of nitrocellulose films/ and special advantages have been claimed for bacterial cellulose films. The water in the swollen membrane in any case may be replaced by a succession of miscible organic solvents ending with the one in which osmotic measurements are to be made. Membranes of varying porosity may be... 

Pure PETN is too sensitive to friction and impact for direct application for military purposes. It can usefully be mixed with plasticised nitrocellulose, or with synthetic rubbers to obtain plastic or mouldable explosives. The commonest application, however, is in conjunction with TNT in the form of pentolites. Pentolites are usually obtained by incorporating PETN into molten TNT. A small amount of the PETN goes into solution, but the bulk remains suspended in the liquid and the whole mix can suitably be used in preparing cast charges. Pentolites containing 20-50% PETN are the commonest in practice. 

Nitrocellulose is usually handled wet and containing approximately 30% of water. Under these conditions it can be considered as a nonexplosive material when the nitrogen content does not exceed 12-6%. More highly nitrated cellulose is known as guncotton and is explosive even when moderately wet. When dry, nitrocellulose of all types is an extremely sensitive and dangerous explosive. Dry nitrocellulose is required for use in certain types of explosives and is then prepared by slow drying of the wet material in a current of warm air. 

Nitrocellulose [C6H702(0H)x(0N02)y where x + y = 3] materials prepared from cotton are fluffy white solids that ignite around 180°C and do not melt. This explosive dissolves in organic solvents to form a gel that has good physical properties and is... 

The tests with the 12-kW system in Demo II successfully confirmed that this technology is capable of destroying the components (nitrocellulose and nitroglycerine) of M28 propellant. For tetrytol, the destruction of TNT and tetryl was good. However, recalcitrant intermediate products were formed during the treatment of tetrytol, which AEA was still evaluating at the time the Demo II report was prepared (NRC, 2001b). 

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