Precise synthesis of undecenyl poly(ethylene oxide) macromonomers as heterofunctional building blocks for the synthesis of linear diblocks or of branched materials

摘要

Heterofunctional α-undecenyl-ω-hydroxy poly(ethylene oxide) (PEO) macromonomers could be designed by initiation. For their synthesis via Anionic Ring-Opening Polymerization (AROP) of ethylene oxide, a potassium alcoholate, prepared in situ by reaction of 10-undecene-1-ol with a stoichiometric amount of diphenylmethyl potassium (DPMK), was used. The applicability of the same initiator but in powder form was evaluated for the polymerization of ethylene oxide. This initiator is well-suited for, e.g., automated high-throughput screening approaches by simply weighing in the amount of initiator needed. The macromonomers were characterized by SEC, ~1H NMR, MALDI-TOF MS and light scattering. Independent from the applied approach, well-defined heterobifunctional PEO macromonomers could be obtained. Their solution behavior was investigated in water and methanol by Dynamic Light Scattering (DLS) and in water by critical micelle concentration (cmc) measurements. Chemical modification of the hydroxyl end-group by methyl methacrylate or by propargyl bromide could be achieved leading to heterobifunctional PEO macromonomers. These PEOs offer a great potential as building blocks in macromolecular engineering. PI-b-PEO diblocks or comb-shaped PEOs represent typical examples.