Homolytic substitution chain transfer agents

Group transfer processes are of particular importance in the production of telechelic or di-end functional polymers. 

The following sections detail the chemistry undergone by specific transfer agents that react by atom or group transfer by a homolytic substitution mechanism. Thiols, disulfides, and sulfides arc covered in Sections 6.2.2,1,6.2.2.2 and 6.2.2.3 respectively, halocarbons in Section 6.2.2.4, and solvents and other agents in Section 6.2.2.5. The transfer constant data provided have not been critically 

---

Radical polymerizations that involve a reversible chain transfer step for chain equilibration and that displayed the characteristics of living polymerizations were first reported in 1995. ° The mechanism of the reversible chain transfer step may involve homolytic substitution (Scheme 73) or addition-fragmentation (RAFT) (Scheme 74). An essential feature is that the product of chain transfer is also a chain transfer agent with similar activity to the precursor transfer agent. The process has also been termed degenerate or degenerative chain transfer... 

---