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Polylactones, 56. ABA Triblock Copolymers Derived from ε ‐Caprolactone or L ‐Lactide and a Central Polysiloxane Block
Author(s) -
Kricheldorf Hans R.,
Langanke Dennis
Publication year - 2001
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/1616-5195(20011101)1:8<364::aid-mabi364>3.0.co;2-q
Subject(s) - copolymer , polymer chemistry , monomer , ring opening polymerization , polymerization , caprolactone , polymer , lactide , chemistry , oxetane , materials science , organic chemistry
A commercial oligosiloxane having two γ ‐hydroxypropyl endgroups and a number‐average molecular weight ( M̄ n ) around 1 000 Da was condensed with Bu 2 Sn(OMe) 2 yielding tin‐containing macrocycles but no polymers. These macrocycles reacted with γ ‐thiobutyrolactone by insertion of one thiolactone per Sn—O bond. When ε‐caprolactone was added a ring‐expansion polymerization was initiated, so that the M̄ n could be controlled via the monomer/initiator (M/I) ratio. Triblock copolymers with free OH endgroups were obtained by removal of the Bu 2 Sn group from the cyclic polymers with 1,2‐dimercaptoethane or methanol. Analogous cyclic and linear triblockcopolymers were prepared from L ‐lactide.