8 H. E. Williams — Action of Neutral Salts on Cellulose 



The addition of other salts that will either not affect, or 

 will increase the heat of dilution, and at the same time increase 

 its viscosity, should convert the solution of the sodium salt 

 into a cellulose solvent. In Fig. 3 the viscosities and boiling 

 points are plotted of the sodium thiocyanate solution to which 

 has been added other thiocyanates and compounds, and it will 

 be noticed that in all cases the addition has increased the 

 viscosity of the sodium salt solution, and the curve passes into 

 the area marked "cellulose solvent area." All these solutions 

 represented by the curves that cross into the il solution area " 

 are cellulose solvents, and moreover thev only become solvents 

 when the concentration of the solution rises to the point where 

 the viscosity boiling point curve crosses the " solution area " 

 and above. A very large number of such additions can be 

 made to the concentrated sodium thiocyanate solution besides 

 those given in the figure, such for example as aluminium, 

 chromium, or ferrous thiocyanate, or by dissolving silver, 

 lead, calcium, or cuprous thiocyanate in the solution. All 

 these additions increase the viscosity of the solution, and at 

 the same time convert the sodium thiocyanate solution into 

 a cellulose solvent. 



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