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Next Generation of Zinc Bisguanidine Polymerization Catalysts towards Highly Crystalline, Biodegradable Polyesters
Author(s) -
Hermann Alina,
Hill Stephen,
Metz Angela,
Heck Joshua,
Hoffmann Alexander,
Hartmann Laura,
HerresPawlis Sonja
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202008473
Subject(s) - polycaprolactone , polymerization , polyester , crystallinity , ring opening polymerization , biodegradable polymer , polymer , materials science , catalysis , lactide , zinc , caprolactone , polymer chemistry , molar mass , monomer , chemical engineering , chemistry , organic chemistry , composite material , engineering
Polylactide and polycaprolactone are both biodegradable polymers produced through metal‐catalyzed ring‐opening polymerization. For a truly sustainable lifecycle of these polymers it is essential to replace the industrially used cytotoxic catalyst tin(II) bis(2‐ethylhexanoate) [Sn(Oct) 2 ] with non‐toxic alternatives. Here, we report the fastest known robust catalyst in the polymerization of lactide and ϵ‐caprolactone. This zinc guanidine catalyst can polymerize non‐purified technical rac ‐lactide and ϵ‐caprolactone in the melt at different [M]/[I] ratios with fast rate constants, high molar masses, and high yields in a short time, leading to colorless, transparent polymer. Moreover, we report that polylactide and polycaprolactone produced by zinc‐guanidine complexes have favorably high crystallinities. In fact, the obtained polylactide shows a more robust degradation profile than its Sn(Oct) 2 ‐catalysed equivalent due to a higher degree of crystallinity.