The synthesis of poly (ethylene glycol) (PEG) copolymers with multiple amino functionalities within the chain is described, relying on an epoxide comonomer bearing a protected amino group. N,Ndibenzyl amino glycidol (DBAG) and ethylene oxide (EO) were copolymerized via anionic polymerization, leading to well-defined polymers with varied comonomer content and low polydispersities (Mw/Mn in the range of 1.1 to 1.2). Subsequent hydrogenolysis with Pearlman's catalyst afforded polyethylene glycol-coamino glycerols (PEG-coPAG) with a precisely adjusted number of randomly incorporated amino groups in the range of 2-15%. For the first time, the kinetics of an. EO copolymerizations have has been directly monitored by 1H NMR spectroscopy in real time. Monomer consumption and compositional drift in monomer feed have been studied for various reaction temperatures, revealing a slightly tapered yet random DBAG distribution in the copolymers. The random structure of the copolymers was confirmed by detailed 13C NMR characterization of EO- and DBAG-centered triad sequence distribution and DSC measurements.
|Number of pages||8|
|Publication status||Published - 9 Mar 2010|