Anionic Synthesis of Macromonomers and Graft Copolymers with Well-Defined Structures

Abstract

Macromonomers are linear macromolecules carrying some polymerizable functional groups at their chain ends; the polymerizable functional groups can be at one chain end or at both chain ends^1–12. Macromonomers are macromolecular monomers, often referred to as “Macromers®”¹. The important feature of macromonomers is that they can undergo copolymerization with other monomers by a variety of mechanisms to form comb-type, graft copolymers^13,14 as shown in Scheme 1. This aspect of macromonomers distinguishes them from telechelic (α,ω-difunctional) polymers^5,8; telechelic polymers undergo step-growth type chain extension reactions with other monomers to form linear macromolecules, not branched structures. The polymerizable functional group at the chain end of a macromonomer is often a vinyl group, 1, but it can also be a heterocyclic ring such as an oxirane (epoxide) functionality, 2. These functional groups participate in chain reaction polymerizations with other vinyl or heterocyclic monomers, respectively. A condensation-type macromonomer has two functional groups at one chain end (3) which can participate in step-growth (condensation) polymerization with other difunctional monomers; for example, the functional group, X, could be hydroxyl, amino, carboxyl or isocyanate^5,9.