Olefin cross-metathesis is introduced as a versatile polymer side-chain modification technique. The reaction of a poly(2-oxazoline) featuring terminal double bonds in the side chains with a variety of functional acrylates has been successfully performed in the presence of Hoveyda-Grubbs second-generation catalyst. Self-metathesis, which would lead to polymer-polymer coupling, can be avoided by using an excess of the cross-metathesis partner and a catalyst loading of 5 mol%. The results suggest that bulky acrylates reduce chain-chain coupling due to self-metathesis. Moreover, different functional groups such as alkyl chains, hydroxyl, and allyl acetate groups, as well as an oligomeric poly(ethylene glycol) and a perfluorinated alkyl chain have been grafted with quantitative conversions. Olefin cross-metathesis (CM) enables an efficient side-chain functionalization of polymers having terminal alkenes as pendant groups. Acrylates and cis-2-butene-1,4-diacetate are used as CM partners to introduce a variety of functional groups. The scope and limitations of this polymer functionalization technique are discussed.
- functionalization of polymers
- graft copolymers