Synthesis of poly(L-lactide)-block-linear-polyglycidol

Abstract

Linear polyglycidol-b-poly(L-lactide) or PG-b-PLLA was prepared from ring opening copolymerization of LLA monomers by the hydroxyl chain end of poly(1-ethoxyethyl glycidyl ether) (PEEGE) by using Sn(oct)[subscript 2] catalyst, followed by ethoxy ethyl deprotection. The mole ratio of PEEGE and LLA was varied from 1:10, 1:20, to 1:30. The copolymerization was performed at 110-120℃ for 24 hours. Two types of polymer products with difference in MeOH solubility were obtained. By NMR and MALDI-TOF-MS, the methanol-soluble part were PEEGE-b-PLLA copolymer with structures that matched tert-BuO-PG[subscript p]-b-PLLA[subscript n] และ HO-PG[subscript p]-b-PLLA[subscript n] as well as other polymers with undefined structure. The molecular weight distribution of the methanol-soluble copolymer was rather wide, indicating the non-living nature of the copolymerization process. The methanol-insoluble parts were found to consist of mostly homo PLLA and polymers with undefined structures. Nevertheless the obtained PG-b-PLLA was not completely soluble in water as initially expected.