Chain-growth polycondensation in solid-liquid phase with ammonium salts for well-defined polyesters

Polycondensation of a potassium 4-bromo-methylbenzoate derivative dispersed in organic solvent was carried out with tetrabutylammonium iodide as phase transfer catalyst (PTC) and a reactive benzyl-bro mide as an initiator to yield polyesters having a define molecular weight and a narrow molecular weight distribu tion ((M) over bar (w)/(M) over bar (n) < 1.3). Polymerization involves the transfer of monomer to organic solvent layer with the PTC and the react ion of monomer with the initiator and the polymer end benzyl bromide moiety in a chain polymerization manner, as evidenced by polymerization behavior increase of the molecular weight in proportion to monomer conversion and equal amount of the initiator unit an the end group in polymer irrespective of monomer conversion. Furthermore, the molecule weight increased in proportion to feed ration ([monomer](0)/[initiator](0)), and the polydispersity index (M) over bar (w)/(M) over bar (n) stayed less than 1.3 over the whole range of feed ratio.