A facile two-step route to branched polyisoprenes via ABn-macromonomers

A facile two-step synthesis for branched poly(isoprene)s (PI) based on polyaddition of AB(n)-type macromonomers is described. The synthesis of the macromonomers was achieved by anionic polymerization of isoprene and subsequent end-capping of the polymers by addition of chlorodimethylsilane to the living carbanions. This led to PI-based macromonomers with narrow polydispersity ((M) over bar (w)/(M) over bar (n) < 1.15) and molecular weights in the range of 1700 22 100 g.mol(-1). Synthesis of the branched polymers was carried out by a hydrosilylation-based polymerization of the macromonomers. Characterization via SEC, SEC-MALLS, coupled SEC-viscosimetry and H-1-NMR- spectroscopy supported the formation of branched structures, Interestingly, these branched polymers exhibited a-values that were similar to those reported for hyperbranched polymers based on AB(2)-monomers.