Progress in synthesis， depolymerization and recycle of polylactic acid

doi:10.19491/j.issn.1001-9278.2025.10.019

Abstract

Abstract:

The escalating production and application of polylactic acid （PLA） have intensified the need for efficient recycling methods for its post⁃consumer waste. This review comprehensively summarized recent advancements in PLA synthesis， depolymerization， and chemical recycling. Various depolymerization techniques were critically analyzed with a focus on their reaction mechanisms， catalytic systems， and the resulting product streams. Furthermore， the advantages and limitations of each chemical recycling pathway were evaluated， and future research directions and challenges in establishing a circular economy for PLA were discussed.

Key words: polylactic acid, synthesis, depolymerization, recycle

CLC Number:

TQ321

WANG Qiong, XU Fang, WENG Yunxuan. Progress in synthesis， depolymerization and recycle of polylactic acid[J]. China Plastics, 2025, 39(10): 121-128.

Figures/Tables 12

Fig.1. Structural formulas of PLLA， PDLA， and PDLLA

Fig.2. Reaction equation for PLA prepared by direct polycondensation

Fig.3. Catalytic ring⁃opening polymerization of lactide using stannous succinate［19］

Fig.4. Catalytic ring⁃opening polymerization of lactide using methyl trifluoromethanesulfonate （F3CSO3CH3）［23］

Fig.5. Anionic catalyst⁃catalyzed ring⁃opening polymerization of lactide［24］

Fig.6. Hydrolysis of PLA and further conversion products of lactic acid

Fig.7. Hydrolysis and closed⁃loop recycling of PLA catalyzed by diphenyl phosphate［32］

Fig.8. Lactic acid ester obtained from PLA alcoholysis

Fig.9. Catalysis of different PLA products by Zn（HMDS）2 for closed⁃loop recovery by alcoholysis［41］

Fig.10. PLA depolymerization and recycling for the preparation of polyamide［42］

Fig.11. PLA⁃PU produced by one⁃step alcoholysis of PLA［43］

Fig.12. PLA ammonia decomposition to produce alanine［60］

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