Trithiocarbonates in RAFT Polymerization

This chapter provides a review of the synthesis, reactions, and applications of trithiocarbonates, R′SC(S)SR, in radical polymerization with reversible addition–fragmentation chain transfer (RAFT polymerization). Non-symmetric trithiocarbonates, where only R is a good homolytic leaving group, are currently the most popular agents used in implementing both thermally and photochemically initiated RAFT polymerization. With appropriate selection of R and/or R′, good control (i.e. low dispersity, predicted M n , high end-group fidelity) can be achieved in RAFT polymerization of most more activated monomer s ( MAM s; styrenes, acrylates, acrylamides) and some intermediate activated monomer s ( IAM s, N -vinyl aromatics, S -vinylsulfides). For these classes, retardation is generally small or not observable when targeting a degree of polymerization X n > 10. However, trithiocarbonates are generally not suited for less activated monomer s ( LAM s; vinyl esters, vinyl amides) where strong retardation or inhibition is usually observed. The further use of trithiocarbonates in mechanism transformation polymerization and processes for trithiocarbonate-group transformation are considered. The use of trithiocarbonates in heterogeneous polymerization, and the mechanisms for photo- and redox initiation are also briefly mentioned.