Group Transfer Radical Polymerization of Sulfone-Substituted Aliphatic Alkynes.

Radical homopolymerization of aliphatic alkynes remains a formidable challenge, primarily because the high reactivity of propagating vinyl radicals renders inevitable chain transfer via hydrogen atom transfer kinetically more favorable than chain propagation. By harnessing rationally designed distal sulfone-substituted aliphatic alkynes as monomers, here we report an efficient radical homopolymerization of aliphatic alkynes via 1,4-group transfer, affording a series of new polymers with defined ABC-type sequence. DFT calculations reveal that the 1,4-group transfer plays a critical role in facilitating chain propagation. The resulting polymers further exhibit outstanding performance as binders for high-temperature proton-exchange membrane fuel cells. Furthermore, the polymers can be chemically degraded to yield a diversity of valuable crotylamines. This work achieves the elusive radical polymerization of aliphatic alkynes that is inaccessible by traditional methods, providing a promising platform for the development of functional polymers.