Branched Polymers via ROMP of Termimers

Abstract

Today's olefin metathesis catalysts show high reactivity, selectivity, and functional group tolerance and allow the design of new syntheses of precisely functionalized polymers. Here the synthesis of a new end-capping reagent is investigated allowing the introduction of a highly reactive activated ester end-group at the polymer chain end as well as its prefunctionalization to directly introduce functional moieties. The versatility of this new end-capping reagent is demonstrated by utilizing it to synthesize a so-called termimer (a monomer with termination capabilities). Copolymerization of a norbornene derivative with the termimer leads to hyperbranched ring-opening metathesis polymerization polymers as proven by gel permeation chromatography and MALDI-ToF-(matrix-assisted laser desorption/ionization time of flight) mass spectrometry. A synthetic route to functional cis-vinyl ethers is developed and employed to prepare a so-called termimer (a monomer capable of propagation and functional termination) for the ring opening metathesis polymerization (ROMP). It is demonstrated that this termimer opens up a new way to prepare hyperbranched polymers via ROMP.