6533b821fe1ef96bd127c14f

RESEARCH PRODUCT

Double-Hydrophilic Linear-Hyperbranched Block Copolymers Based on Poly(ethylene oxide) and Poly(glycerol)

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A convenient 4-step (2-pot) approach for the synthesis of biocompatible, double hydrophilic linear-hyperbranched block copolymers based on poly(ethylene oxide) (PEO) and poly(glycerol) (PG) is described. The polymers consisting exclusively of an aliphatic polyether structure were prepared from linear PEO-b-(l-PG) precursor block copolymers, obtained via anionic polymerization of ethylene oxide and subsequently ethoxyethyl glycidyl ether (EEGE). In order to generate initiating functionalities for glycidol, the protected hydroxyl groups of the P(EEGE) block were recovered by hydrolysis with hydrochloric acid. Partial deprotonation of the linear poly(glycerol) block with cesium hydroxide permitted hypergrafting of glycidol onto the alkoxide initiating sites, using the slow monomer addition technique. Detailed studies showed that narrow polydispersity was only obtained with Cs counterions, while use of potassium resulted in larger polydispersities. The resulting linear-hyperbranched PEO-b-(hb-PG) block copoly...