The scope for synthesis of macro-RAFT agents by sequential insertion of single monomer units

Chain Transfer in Degenerative RAFT Polymerization Revisited: A Comparative Study of Literature Methods

“…Transfer coeffi cients can then be calculated a posteriori and explicitly. Hitherto, high-level ab initio calculations [ 17,[34][35][36][37] and parameter estimation procedures based on more extensive kinetic modeling results [38][39][40][41][42] have been used to obtain these individual rate coeffi cients. Despite being based on fi rst principles, the former calculations often rely on calculations for smaller compounds to represent the considered system as a compromise between accuracy and computational cost, [ 15,37 ] whereas the parameter estimation methods highly depend on the elementary reactions considered in the kinetic model and the size of the polymerization data set.…”

Living Radical Polymerization by the RAFT Process – A Third Update

“…In RAFT polymerization of St with trithiocarbonate 95, Houshyar et al [109] found that k t (intermediate radical termination) must be ,10 6 M À1 s À1 (it could be zero). Brown et al [134] studied RAFT polymerization of St with a dithiocarbamate 254 which contains a potentially florescent carbazole chromophore to aid the detection of star products from intermediate radical termination; no stars were detected.…”

“…Chen et al [433] have published further examples of the synthesis of RAFT agents (150, 151) or macro-RAFT agents (152, see section on block copolymers below) by insertion of a single monomer unit into an existing RAFT agent. Houshyar et al [109] examined the scope of RAFT single-unit monomer insertion for sequential insertion of St and NIPAm in detail. Critical factors for success were found to be a high transfer constant for the RAFT agent, such that only one monomer unit was added per activation cycle, and a high rate of addition of the radical (R ) to monomer relative to that for further propagation.…”

Recent developments in the synthesis of sequence controlled polymers

“…Moad and coworkers [72] synthesized macro-RAFT agents containing styrene-N-isopropylacrylamide (NIPAM) co-dimer. Junkers and coworkers [73] reported macro-RAFT agents containing four units of acrylates with different side groups.…”