Synthesis of telechelic polyolefins

Telechelic polymers, polymers with two reactive end-groups, are sought after for their role in synthesizing macromolecules with complex structures such as multiblock copolymers and graft polymers. Many strategies for the synthesis of telechelic polymers from vinyl monomers using controlled radical polymerizations and anionic polymerizations exist. However, polyolefins—which account for the major fraction of polymer production—are not easily synthesized with two reactive end-groups. This difficulty is related to the sensitivity of olefin polymerization catalysts and their propensity for intramolecular chain transfer reactions. As a result, the most common strategies to access telechelic polyethylene and polypropylene (the two major polyolefins) do not rely on the insertion polymerization of ethylene nor propylene but rather on the polymerization of dienes or cyclic olefins. Nonetheless, recent advances in insertion polymerization and post-polymerization functionalization have resulted in the emergence of novel synthetic methods to access telechelic polyolefins. We here present a comprehensive review of all of these strategies to synthesize telechelic polyolefins.