The anionic polymerization of styrene in hexamethylphosphortriamide (HMPA) with sodium as gegenion

The anionic polymerization of styrene with sodium as gegenion was investigated in hexamethylphosphortriamide by the flow technique. The polymerization process corresponds to that observed in other polar solvents with the difference that in this solvent polystyrylsodium prevailingly exists as solvent-separated ion pairs and its free ions. Therefore the rate constants of these species can be directly determined and are found to be practically identical to those found in other ethereal solvents. The dissociation constant of polystyrylsodium is approximately 10^?2 mole/l.