A Step Towards High‐Molecular‐Weight Living/Controlled Polystyrene Using SG1‐Mediated Polymerization

The synthesis of high‐molecular‐weight living/controlled polystyrene by NMP was studied. The combination of Ac2O and alkoxyamines based on nitroxides TEMPO, TIPNO, and SG1 was tested at 130 °C. With TEMPO and TIPNO, dipole/dipole interactions led to a decrease in nitroxide concentration and an acceleration of the reaction. To minimize thermal auto‐initiation and thus obtain high‐M ₙ PS, the temperature was lowered. At 90 °C, the use of BlocBuilder yielded PS of M ₙ = 210 000 g · mol−1 with a living fraction of 60%. Finally, new SG1‐based nitroxides were used to perform the polymerization at 75 °C. Since these nitroxides were too constrained, the decrease in kc caused a loss of control and livingness for high‐M ₙ polymers. magnified image