Tandem Living Insertion and Controlled Radical Polymerization for Polyolefin-Polyvinyl Block Copolymers.

Practical synthesis of polyolefin-polyvinyl block copolymers remains a challenge for transition-metal catalyzed polymerizations. Common approaches functionalize polyolefins for post-radical polymerization via insertion methods, yet sacrifice the livingness of the olefin polymerization. This work identifies an orthogonal radical/spin coupling technique which affords tandem living insertion and controlled radical polymerization. The broad tolerance of this coupling technique has been demonstrated for diverse radical/spin traps such as 2,2,5-trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO), 1-oxyl-(2,2,6,6-tetramethylpiperidine) -4-yl-α-bromoisobutyrate (TEMPO-Br), and N-tert-butyl-α-phenylnitrone (PBN). Subsequent controlled radical polymerization is demonstrated with nitroxide-mediated polymerization (NMP) and atom transfer radical polymerization (ATRP), yielding polyolefin-polyvinyl di- and triblock copolymers (Đ<1.3) with acrylic, vinylic and styrenic segments. These findings highlight radical trapping as an approach to expand the scope of polyolefin-functionalization techniques to access polyolefin macroinitiators.