Synthesis and molecular weight characterization of end‐functionalized N ‐vinyl‐2‐pyrrolidone oligomers

New oligomers of N ‐vinyl‐2‐pyrrolidone, functionalized at one end with hydroxy functions, were obtained by radical polymerization in the presence of a hydroxylated compound, namely 2‐isopropoxyethanol, acting as chain‐transfer agent. The oligomeric samples obtained were characterized in terms of molecular weight and molecular weight distribution by means of analytical size exclusion chromatography (SEC). To this purpose, a calibration curve for a set of SEC columns had been determined, making use of poly( N ‐vinyl‐2‐pyrrolidone) standards purposely prepared. The chain transfer constant C T of 2‐isopropoxyethanol towards N ‐vinyl‐2‐pyrrolidone was determined from the knowledge of the cumulated number‐average degree of polymerization X̄ n and monomer conversion Y t of the samples during the reaction.