摘要：

Low molecular weight poly(N-vinylpyrrolidone) (PVP) with a hydroxyl group at one end was successfully synthesized by free radical polymerization of N-vinyl-2-pyrrolidone (NVP). Using isopropyl alcohol as solvent and 2-mercaptoethanol as chain transfer agent, a control over molecular weight (MW) profile of PVP was obtained, leading to average-number MW as low as 2500 Da and polydispersity indexes close to 1.5. MALDITOF mass spectrometry indicated that the insertion of hydroxyl group on one chain end was quantitative. Hydroxyl-terminated PVP was used as macroinitiator in ring-opening polymerization of d,l-lactide yielding amphiphilic poly(N-vinylpyrrolidone)-block-poly(d,l-lactide) (PVP-b-PDLLA) diblock copolymer with polydispersity indexes as low as 1.14. PDLLA contents could be tuned according to the feed ratio of DLLA, leading to molar percents up to 47%. The well-defined diblock copolymer self-assembles into micelles in aqueous solution. Polymeric micelles, composed of PVP-b-PDLLA with PVP Mn of 2500 a...

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