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

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 -amino--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 ,-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.