Efficient chemical recycling of poly(L-lactic acid) via either alcoholysis to alkyl lactate or thermal depolymerization to L-lactide promoted by Zn(II) catalysts
Poly(lactic acid) (PLA), a commercially fully bio-based and biodegradable polymer, stands out as a sustainable alternative to commodity plastics. Its current end-of-life management involves composting, but chemical recycling would be more appropriate for a circular economy model. Here we report two...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-02-01
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| Series: | Polymer Testing |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0142941825000418 |
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| Summary: | Poly(lactic acid) (PLA), a commercially fully bio-based and biodegradable polymer, stands out as a sustainable alternative to commodity plastics. Its current end-of-life management involves composting, but chemical recycling would be more appropriate for a circular economy model. Here we report two very efficient chemical recycling pathways for commercial high molar mass and highly crystalline PLA samples, both ones promoted by different imidazole[1,5-a]pyrid-3-yl)phenolate Zn(II) catalysts: (i) alcoholysis was easily achieved by simply treating the polymer samples in boiling methanol in the presence of 1 % Zn(II) catalyst, resulting in up to 99 % yield and selectivity in methyl lactate; and (ii) chemical recycling to the monomer was achieved by heating the polymer samples at 180 °C under vacuum or in a nitrogen flow in the presence of 0.1 % Zn(II) catalyst and a highly boiling alcohol, resulting in up to 99 % yield of L-lactide, having high chemical and steric purity, which could be repolymerized without any further purification. |
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| ISSN: | 1873-2348 |