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Living free radical polymerization is a type of living polymerization where the active polymer chain end is a free radical. Several methods exist. Several methods exist. IUPAC recommends [ 1 ] to use the term " reversible-deactivation radical polymerization " instead of "living free radical polymerization", though the two terms are not synonymous.
In polymer chemistry, radical polymerization (RP) is a method of polymerization by which a polymer forms by the successive addition of a radical to building blocks (repeat units). Radicals can be formed by a number of different mechanisms, usually involving separate initiator molecules .
Radical polymerisation of unsaturated monomers is generally propagated by C-radicals. These can be effectively terminated by combining with other radicals to form neutral species and many true inhibitors operate through this mechanism. In the simplest example oxygen can be used as it exists naturally in its triplet state (i.e. it is a diradical).
These techniques involved catalytic chain transfer polymerization, iniferter mediated polymerization, stable free radical mediated polymerization (SFRP), atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer polymerization, and iodine-transfer polymerization. In "living" radical polymerization (or ...
In chain-growth (or chain) polymerization, the only chain-extension reaction step is the addition of a monomer to a growing chain with an active center such as a free radical, cation, or anion. Once the growth of a chain is initiated by formation of an active center, chain propagation is usually rapid by addition of a sequence of monomers.
The distinction between "step-growth polymerization" and "chain-growth polymerization" was introduced by Paul Flory in 1953, and refers to the reaction mechanisms, respectively: [4] by functional groups (step-growth polymerization) by free-radical or ion (chain-growth polymerization)
IUPAC recommends to further simplify "chain-growth polymerization" to "chain polymerization". It is a kind of polymerization where an active center (free radical or ion) is formed, and a plurality of monomers can be polymerized together in a short period of time to form a macromolecule having a large molecular weight.
The nature of chain transfer reactions is currently well understood and is given in standard polymerization textbooks. Since the 1980s, however, a particularly active area of research has been in the various forms of free radical living polymerizations including catalytic chain transfer polymerization, RAFT, and iodine transfer polymerization ...