Homo‐ and Copolymerization of ω‐Functional Polystyrene Macromonomers via Coordination Polymerization

Macromonomers have been extensively used, as well defined building blocks for various macromolecular architectures via anionic, ROMP and free radical homo‐ or copolymerization processes. The purpose of the present work was to examine the homopolymerization and copolymerization of ω‐allyl, ω‐undecenyl and ω‐vinylbenzyl polystyrene (PS) macromonomers, in the presence of early or late transition metal catalysts. The influence of several parameters (type of catalytic system, nature of polymerizable end‐group and molar mass of the macromonomer) on the homopolymerization was first investigated. Whereas ω‐allyl or ω‐undecenyl PS macromonomers were not very reactive in homopolymerization whatever the catalyst, ω‐vinylbenzyl PS macromonomers gave interesting results with CpTiCl₃/MAO and Cp*TiCl₃/MAO. The copolymerization of these macromonomers with ethylene was also studied in the presence of the following palladium catalyst: (ArN?C(Me)? C(Me)?NAr)Pd(CH₂)₃(COOMe)]⁺BAr₄′^?(VERSIPOL?) (Ar = 2,6‐iPr₂–C₆H₃ and Ar′ = 3,5‐(CF₃)₂? C₆H₃). ω‐vinylbenzyl PS macromonomers could not be incorporated into poly(ethylene) chains. On the contrary, the incorporation of ω‐allyl PS macromonomers was achieved. Moreover, for macromonomers containing an alkyl spacer between the allylic unit and the PS chain, the incorporation rate, the copolymerization yield and the molar masses of the copolymers were increased, giving access to a new type of graft copolymer structure.

Synthesis of polystyrene macromonomers.