Cellulose dinitrate

It has a low solubility parameter (15.3 MPa ) which differs considerably from that of the cellulose dinitrate (21.8 MPa ). This indicates that compatibility is not simply due to similarities of cohesive forces but also to some form of interaction probably involving the carbonyl group. 

Cellulose dinitrate, 5 396 Cellulose ester hollow fibers, 16 19 Cellulose esters, 4 716 20 558-559. 

Fig. 83. X-Ray diagrams (according to Miles and Craik [13]) (a) ramie cellulose, (b) ramie cellulose dinitrate, (c) ramie cellulose trinitrate.

On the other hand, in the case of cellulose dinitrate or 2i-nitrate, the structure is generally irregular, hence no adhesion between the chains exists. With a small number of irregularly distributed hydroxyl groups there exists little probability that the macro-molecules could be joined together by means of hydrogen bonds (Fig. 89b, see also Figs. 86 and 88). 

According to Trommel [15b] the cellulose dinitrate chains become more irregular after being dissolved in acetone and precipitated with water. Hence the solubility of precipitated cellulose dinitrate is increased [15c]. The proposed relationship between the solubility and regularity of the structure of nitrocellulose has been confirmed by experiments with nitrocellulose at different stages of swelling and... 

On the other hand, numerous observations favour the opinion that the solvent enters into a chemical combination with nitrocellulose to form solvates. Some of those solvates are stable only at low temperatures. For instance, cellulose dinitrate does not dissolve in methyl alcohol at room temperature, though on cooling it does so. The cellulose nitric ester precipitates again when the solution is heated. Similar behaviour is observed with ethyl alcohol a lower temperature causes nitrocellulose to swell or even to dissolve more readily. The solvent seems likely to be bound to free hydroxyl radicals (Highfield [36]). The hypothesis explains why nitrocellulose is soluble in a mixture of ether and alcohol, though neither of these solvents, when used separately, is capable of dissolving it. It is assumed that first an alcohol solvate of nitrocellulose is formed which then dissolves in the ether. 

Hence the O-substituents (NOz groups) are placed in positions 3 and 6, so that the substance is a 3,6-cellulose dinitrate. 

Only half the nitrate groups present in cellulose dinitrate is substituted by amine groups, the other half undergoing hydrolysis. 

Cellulose dinitrate is obtained by treating cotton linters with a mixture of nitric acid, sulphuric acid and water (25 55 20), and treating the product with alcohol. Camphor, a favoured plasticizer, is mixed into the alcohol-wet cake, leading to the product celluloid , for which the most important application is the manufacture of table-tennis balls. 

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