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Living polymerization of cyclic esters – a route to (bio)degradable polymers. Influence of chain transfer to polymer on livingness
Author(s) -
Penczek Stanislaw,
Szymanski Ryszard,
Duda Andrzej,
Baran Jolanta
Publication year - 2003
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200351129
Subject(s) - macromolecule , chain transfer , polymerization , living polymerization , polymer , disproportionation , polymer chemistry , chemistry , reversible addition−fragmentation chain transfer polymerization , radical polymerization , kinetic chain length , chain (unit) , materials science , organic chemistry , catalysis , physics , astronomy , biochemistry
Polymerization of cyclic esters leads to (bio)degradable polymers of the increasing industrial importance. These polymerizations are of the living nature, although chain transfer to polymer with chain scission may cause deviations from the livingness and introduce structural differences (e.g. in end‐groups), important for physical properties. Two different systems are discussed. In the first one two living macromolecules react one with another and reproduce two living macromolecules, retaining the same reactivities and the same end‐groups. Polymerizations of ϵ‐caprolactone and lactide belong to this category. On the other hand, polymerization of cyclic carbonates proceeds with chain transfer, in which disproportionation of the living chains takes place: from two living macromolecules one “dead” and one “doubly active” can be formed. Conditions of retaining the livingness in terms of the ratios of the rate constants of transfer, reinitiation, and propagation are discussed.