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. 2020 Nov 2;9(12):1224-1228.
doi: 10.1002/open.202000243. eCollection 2020 Dec.

Chemical Recycling of End-of-Life Poly(lactide) via Zinc-Catalyzed Depolymerization and Polymerization

Even Cheung  1 , Christoph Alberti  1 , Stephan Enthaler  1
Affiliations

Chemical Recycling of End-of-Life Poly(lactide) via Zinc-Catalyzed Depolymerization and Polymerization

Even Cheung et al. ChemistryOpen. .

Abstract

The chemical recycling of poly(lactide) was investigated based on depolymerization and polymerization processes. Using methanol as depolymerization reagent and zinc salts as catalyst, poly(lactide) was depolymerized to methyl lactate applying microwave heating. An excellent performance was observed for zinc(II) acetate with turnover frequencies of up to 45000 h-1. In a second step the monomer methyl lactate was converted to (pre)poly(lactide) in the presence of catalytic amounts of zinc salts. Here zinc(II) triflate revealed excellent performance for the polymerization process (yield: 91 %, Mn ∼8970 g/mol). Moreover, the (pre)poly(lactide) was depolymerized to lactide, the industrial relevant molecule for accessing high molecular weight poly(lactide), using zinc(II) acetate as catalyst.

Keywords: catalysis; depolymerization; green chemistry; polymers; recycling.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Scheme 1
Scheme 1
Chemical recycling concept for PLA.
Scheme 2
Scheme 2
Scale‐up of end‐of‐life PLA depolymerization and polymerization of methyl lactate.
See this image and copyright information in PMC

References

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