Anionic polymerization of oxirane in the presence of the polyiminophosphazene base t-Bu-P4

The use of the polyiminophosphazene base t-Bu-P₄ (1) for the anionic polymerization of ethylene oxide is described. Polymerization initiated by a monoalkoxide of the protonated base leads to well-defined poly(ethylene oxide)s with low polydispersity (M _w/M _n ≈ 1.1). Furthermore, graft copolymers of polyethylene-co-(vinyl alcohol)] (PEVA) with poly(ethylene oxide) and a star macromolecule were synthesized from multifunctional polyalkoxides in high yields.