Block copolymerization by a cation to anion transformation process: 2. Polymerization of styrene by polyTHF possessing terminal secondary nitranions

A route for preparing block copolymers by a cation to anion transformation is examined. PolyTHF possessing a terminal secondary amine group is prepared by reacting living polymer with excess of the primary amine, then metallated with potassium to create a terminal nitranion. This is then used to initiate the anionic polymerization of styrene, but initiation is relatively slow and, although all the styrene is consumed, only about 30% of polyTHF chains form a block copolymer.