Convenient Access to α-Amino-ω-Hydroxyl Heterobifunctional PEG and PPO via a Sacrificial Hexahydro-Triazine Star Strategy.

Abstract

The anionic ring opening polymerizations of ethylene oxide (EO) and propylene oxide (PO) are performed by using 1,3,5-triethanol hexahydro-1,3,5-triazine (TrAz) as a "sacrificial" trifunctional initiator. Well-defined three-arm star polymers are obtained with a narrow molecular weight distribution (M w /M n < 1.1). Molecular weights range from 3-15 kg mol-1 . Since these star polymers possess an acid-labile hexahydro-triazine core, acidic hydrolysis leads to cleavage of the arms. This gives access to well-defined α-amino-ω-hydroxyl heterobifunctional poly(ethylene glycol) (PEG) and poly(propylene oxide) (PPO) in the molecular weight range of 1-5 kg mol-1 and low dispersity M w /M n < 1.1. The α,ω-heterobifunctional polyethers are valuable structures for bioconjugation. Furthermore, an acid-labile triazine star polymer is directly used as a polyol component for the synthesis of a polyurethane network, which is stable under ambient conditions but degrades rapidly under acidic conditions.