Cellulose nitrate solubility

Table 5. Connection between molecular mass of ketone solvents M, degree of solvation (for cellulose nitrate) //, solubility parameter S. hydrogen bond parameter y, and dipole moment p...

Cellulosics. CeUulosic adhesives are obtained by modification of cellulose [9004-34-6] (qv) which comes from cotton linters and wood pulp. Cellulose can be nitrated to provide cellulose nitrate [9004-70-0] which is soluble in organic solvents. When cellulose nitrate is dissolved in amyl acetate [628-63-7] for example, a general purpose solvent-based adhesive which is both waterproof and flexible is formed. Cellulose esterification leads to materials such as cellulose acetate [9004-35-7], which has been used as a pressure-sensitive adhesive tape backing. Cellulose can also be ethoxylated, providing hydroxyethylceUulose which is useful as a thickening agent for poly(vinyl acetate) emulsion adhesives. Etherification leads to materials such as methylceUulose [9004-67-5] which are soluble in water and can be modified with glyceral [56-81-5] to produce adhesives used as wallpaper paste (see Cellulose esters Cellulose ethers). 

Cellulose Deriva.tives, Cellulose can be derivatized to make both water-soluble gums and hydrophobic polymers. The preparation of the hydrophobic cellulose esters (qv), cellulose acetates and cellulose nitrates, has already been mentioned. The water-soluble cellulose derivatives are cellulose ethers (qv). 

Uses. Cellulose nitrates with differing nitrogen contents have various appHcations (Table 3). The largest iadustrial use of CN is protective and decorative lacquer coatings. CN is soluble ia a variety of organic solvents and yields clear, tough films. CN is also compatible with many plasticizers and resias. 

Soluble Cellulose Nitrate, ASTM D301-72, American Society for Testing and Materials, Philadelphia, Pa., 1983. 

Nitration of cellulose followed by plasticisation of the product with camphor has the effect of reducing the orderly close packing of the cellulose molecules. Hence whereas cellulose is insoluble in solvents, except in certain cases where there is chemical reaction, celluloid is soluble in solvents such as acetone and amyl acetate. In addition the camphor present may be dissolved out by chloroform and similar solvents which do not dissolve the cellulose nitrate. 

Cellulose nitrates, 4 724t 5 396-397 solubility, 5 402-403 U.S. production, 5 429t Cellulose palmitate, moisture properties, 5 416t... 

Non-drying oil resins are soluble only in Aromatic hydrocarbons. They are used with amino resins for stoving finishes for appliances. Medium resins are used as plasticisers for cellulose nitrate. Along with natural oils several natural occurring and synthetic acid like resin (abiotic acid) pelargonic acid and isooctanoic acid are added to modify alkye resins. The alkyd resins are obtained by two processes, i.e., (1) Fatty Acid Process and (2) Alcoholysis process. 

As a solvent, acetone is used in varnishes, lacquer, cellulose acetate fiber, cellulose nitrate (an explosive), and as a carrier solvent for acetylene in cylinders. Acetylene is stored at about 225 psi but is so explosively reactive that as an extra precaution the cylinder is filled with asbestos wool soaked in acetone. Acetylene is extremely soluble in acetone, and the asbestos keeps it from sloshing around when the cylinder is half empty. Acetone also is used in smaller volumes for the manufacture of pharmaceuticals and chloroform (the anesthetic). 

The influence of nitrogen content on the solubility of nitrocellulose in ether-alcohol has been known for a long time. Cellulose nitrates of an average nitrogen... 

In water studies it is standard practice to filter the sample soon after collection, usually through a 0.45p,m membrane disc (made of cellulose acetate, cellulose nitrate or polycarbonate). This process arbitrarily divides the sample components into soluble and insoluble fractions, but as shown in Table 2.3, the average size of different chemical species varies widely, and some differentiation between species can be obtained through using filter media of different pore sizes. For example, fully dissolved compounds can be separated from finer colloidal forms by using gel filtration and dialysis, and sub-division of the total content into fractions based on particle or molecular size (see Section 2.3) has been used for speciation of elements in waters. 

Collection of metal complexes of the analytes on suitable adsorbing materials is often employed as an enrichment step in combination with flame methods. In a procedure proposed by Solyak et al. [20], five metals [Co(II), Cu(II), Cr(III), Fe(III), and Pb(II)] were complexed with calmagite 3-hydroxy-4-[(6-hydroxy-m-tolyl)azo]-naphthalenesulfonic acid and subsequently collected on a soluble cellulose nitrate membrane filter. In this way an effective separation from alkaline and alkaline earth metals was achieved, based on the differences in their complex formation constants and those of the transition elements. The experimental parameters were optimized for the quantitative recovery of the elements. After hot dissolution of the filter with HNO3, the analytes were determined by FAAS. Minimum detectable concentrations ranged from 0.06 pg l-1 for Cu to 2.5 pg l-1 for Cr. 

The nitric acid concentration in the nitration acid mixture is usually 20-25%. The degree of nitration can be regulated by changes in the water content. Examples of the solubility and use of cellulose nitrates are given in Table 9-3. As a by-product in the nitration process some cellulose sulfate is also formed (see below). Because this results in instability of the cellulose nitrate, the sulfate groups must be removed by various treatments and the sulfuric acid formed removed by washing. 

For adhesive application, the acid mixture is made up of nitric acid (25%), sulfuric acid (55%), and water (20%). The function of sulfuric acid is to remove the water of reaction so that nitration may be carried to the desired degree more readily. The various products may be characterized by nitrogen content, which corresponds to the degree of substitution. The nitrogen content also determines the solubility of cellulose nitrate. With 11.8 to 12.2% nitrogen content,... 

Because of its wide range of solubility, cellulose nitrate has become a popular household cement. It is a waterproof, clear, flexible adhesive for use with plastics, cloth, wood, paper, china, glass, metal, and leather. A medium or high-viscosity type cellulose nitrate is generally used with solvents that are fairly rapid in evaporation rate. A plasticizer is used to give flexibility. Several commercial grades of cellulose nitrate with characteristic properties are listed in Table III. 

It should be noted that it is not only preparations of mixed polysaccharides which differ from cellulose in solubility, but also esters (acetates, nitrates) do not dissolve com Jetely m solvents of the corresponding cellulose esters. Thus, the nitrate of mixed polysaccharide(III), which contains 42 mol.-% of altrose, dissolves in acetone to 68%, and the triacetate dissolves in methylene chloride to 65 %. 

---