Cellulose trinitrate, viscosity

The classic example of the extended cellulose chain is, of course, cellulose trinitrate, to which we now turn. The most extensive viscosity measurements include those of Immergut, Ranby and Mark 131) and of Harland (5). These data are plotted in Fig. 20. Although the molecular weight ranges from 3 104 to about 106, the points scatter to a considerable extent, as the difficulty of working with this material is well known. 

Figure 8. Effect of nitrate and carbanilate derivatives on the calibration of CED viscosity (--------------) cellulose trinitrate ( - -j cellulose tricarbanilate.

Chain configurational data are oeeasionally given in the first column. The data given in parentheses refer to only one set of viscosity constants listed in the same row, while the data given without parentheses refer to a series of sets listed in the same and succeeding rows. Thus, for example, the data N content, 13.9 wt.% are effective only for the sixth row of cellulose trinitrate, and the data 95%-cis, 1%-trans, 4%-l,2 are effective for the fourth to eighth rows of polybutadiene. 

One of the earlier methods was to treat cellulose with sodium hydroxide and carbon disulfide to obtain xanthate esters which could be dispersed in water and cast into sheets or spun into fibers. Subsequent treatment with acid decomposed the xanthates and gave regenerated cellulose, either in fiber or film form. The fibers were called viscose rayon and the films were named cellophane. Cellophane is still used as a wrapping film and some of it is still manufactured by the xanthate process. By treatment with nitric acid, cellulose was converted to a trinitric acid ester, which could be cast into units which were satisfactory for making gun cotton for a smokeless powder for either artillery shells or shotgun ammunition. It was quite insoluble but it could be converted to a jelly-like mass, which could be shaped into a desired form for ammunition use. Under milder conditions, a lower nitrate... 

As with GPC analyses, the cellulose derivative used for the calibration of CED viscosities has been the trinitrate (16, 17). 

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