Speciality sulphuric acid polymers

The system styrene-sulphuric acid merits some special discussion. Gandini and Plesch [6, 7] were unable to reproduce the results of Pepper and his collaborators [8]. When a phial containing styrene was broken into a solution of sulphuric acid in methylene or ethylene dichloride at 20 °C only traces of polymer were obtained, apparently very rapidly, and thereafter no further polymerisation and no colour developed. These results are in essential agreement with those of Tsuda [9] who also found the polymerisation to be inhibited by water. 

Geometric effects coupled with diffusion and nucleation usually control the rates of all solids deposition phenomena. Such effects can be put to good use in the production of special products such as cellulose yarn (rayon), by the precipitation of cellulose in filament form as it emerges as sodium cellulose xanthate liquid from the spinnerets into a bath containing sulphuric acid, which extracts the sodium as sodium sulphate, and the carbon disulphide. In a similar manner, the fabrication of aromatic polyimide fibres is performed by dissolving the polymer in concentrated sulphuric acid and forcing the solution through spinnerets into water. 

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