Chain-Growth Polycondensation for Aromatic Polyethers with Low Polydispersities: Living Polymerization Nature in Polycondensation

Polycondensation normally proceeds in a step-growth reaction manner to give polymers with a wide range of molecular weights. However, the polycondensation of potassium 5-cyano-4-fluoro-2-propylphenolate ( 1 ) proceeded at 150 °C in a chain polymerization manner from an initiator, 4-fluoro-4‘-trifluoromethylbenzophenone ( 2a ), to give aromatic polyethers having controlled molecular weights and low polydispersities ( M w / M n ≤ 1.1). The resulting polycondensation of 1 had all of the characteristics of living polymerization and displayed a linear correlation between molecular weight and monomer conversion, maintaining low polydispersities. The MALDI−TOF mass spectrum of poly 1 revealed that this polycondensation did not include conventional step-growth polycondensation which gave the polymer without initiation unit and macrocycles. The poly 1 with low polydispersity showed higher crystallinity than that with broad molecular weight distribution, obtained by the conventional polycondensation of 1 without 2a .