SnOct{sub 2}-Catalyzed Syntheses of Cyclic Poly(L-lactide)s with Catechol as Low-Toxic Co-catalyst

Journal Article · Sun Dec 15 04:00:00 EST 2019 · Journal of Polymers and the Environment

DOI:https://doi.org/10.1007/S10924-019-01545-5· OSTI ID:22959272

Weidner, Steffen M. ^[1]

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1. BAM, Federal Institute for Materials Research and Testing (Germany)

Polymerizations of L-lactide in bulk at 160 or 180 °C were performed with 1/1 mixtures of catechol (CA) or 4-tert-butylcatechol (BuCA) and tin(II)-2-ethylhexanoate (SnOct{sub 2}) as catalysts and a variation of the Lac/Cat ratio. Weight average molar masses (Mw) up to 170,000 g mol{sup −1} were obtained with CA and up to 120,000 g mol{sup −1} with BuCA. The cyclic structure of the resulting poly(L-lactide)s was proven by MALDI-TOF mass spectrometry and by comparison of their hydrodynamic volumes with those of commercial linear poly(L-lactide)s. The predominance of even-numbered cycles increased with lower temperatures and shorter polymerization times. This finding indicates that the cyclic architecture is the results of a ring-expansion polymerization mechanism. Addition of silylated BuCA as co-catalyst was less favorable than addition of free BuCA.

• OSTI ID: 22959272
• Journal Information: Journal of Polymers and the Environment, Journal Name: Journal of Polymers and the Environment Journal Issue: 12 Vol. 27; ISSN 1566-2543
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACETATES
CATALYSTS
HYDRODYNAMICS
LACTIC ACID
MASS SPECTROSCOPY
NMR SPECTROMETERS
POLYESTERS
POLYMERIZATION
PYROCATECHOL
SYNTHESIS
TIN COMPOUNDS
TOXICITY