Tri-block copolymers of polyethylene glycol and hyperbranched poly-3-ethyl-3-(hydroxymethyl)oxetane through cationic ring opening polymerization.
Journal article, 2009
Tri-block copolymers of linear poly(ethylene glycol) (PEG) and hyperbranched poly-3-ethyl-3-(hydroxymethyl)oxetane (poly-TMPO) are reported. The novel dumb-bell shaped polyethers were synthesized in bulk with cationic ring opening polymn. utilizing BF3OEt2 as initiator, via drop-wise addn. of the oxetane monomer. The thermal properties of the materials were successfully tuned by varying the amt. of poly-TMPO attached to the PEG-chains, ranging from a m.p. of 54 DegC and a degree of crystallinity of 76% for pure PEG, to a m.p. of 35 DegC and a degree of crystallinity of 12% for the polyether copolymer having an av. of 14 TMPO units per PEG chain. The materials are of relatively low polydispersity, with Mn/Mw ranging from 1.2 to 1.4. The materials have been evaluated for usage with the energetic oxidizer ammonium dinitramide. (c) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6191-6200, 2009. [on SciFinder (R)]