Kinetics-Guided Controlled Oligomeric Depolymerization of PET for Tailored High-Performance Polymer Upcycling

Ran Cui; Jie Jiang; Chenyang Li; Man Zhou; Weizhong Zheng; Shicheng Zhao; Ling Zhao; Zhenhao Xi

doi:10.1016/j.eng.2026.02.010

Engineering ›› :202602010 DOI: 10.1016/j.eng.2026.02.010

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Kinetics-Guided Controlled Oligomeric Depolymerization of PET for Tailored High-Performance Polymer Upcycling

Ran Cui ^a^,^#
, Jie Jiang ^a^,^b^,^#
, Chenyang Li ^a^,^c
, Man Zhou ^a
, Weizhong Zheng ^a
, Shicheng Zhao ^a^,^c
, Ling Zhao ^a^,^c^,^*
, Zhenhao Xi ^a^,^c^,^*

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Abstract

Growing concerns over polyethylene terephthalate (PET) waste have underscored the urgent necessity for scalable and sustainable recycling strategies. This study proposes a kinetics-guided depolymerization and repolymerization strategy to upcycle PET into high-performance thermoplastics. PET depolymerization was conducted using 1,4-cyclohexanedimethanol (CHDM) as both solvent and reagent, without external catalysts, leveraging the unique structure of CHDM to facilitate effective transesterification under mild conditions. A population balance equation-based kinetic model was employed to precisely control the oligomer molecular weight distribution. The depolymerization proceeded via a predominantly random chain scission mechanism with an activation energy of 76.08 kJ ∙ mol^-1. The CHDM-derived well-defined oligomers were directly repolymerized into recycled thermoplastic polyester elastomers and recycled glycol-modified PET, which achieved mechanical properties comparable to or surpassing those of commercial virgin materials. Furthermore, the kinetic model was validated in a 15 L reactor, demonstrating its efficacy in guiding scalable process design. By eliminating the esterification and pre-polycondensation steps, the process simplified operation and reduced energy consumption, aligning with existing polycondensation infrastructure. This catalyst-free streamlined route offers both molecular-level tunability and industrial scalability, representing a viable pathway for sustainable PET upcycling for a circular polymer economy.

Keywords

Depolymerization / Kinetics / Population balance equation / PET upcycling / Molecular weight distribution / PET depolymerization kinetics / PET waste recycling / Sustainable recycling

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Ran Cui, Jie Jiang, Chenyang Li, Man Zhou, Weizhong Zheng, Shicheng Zhao, Ling Zhao, Zhenhao Xi. Kinetics-Guided Controlled Oligomeric Depolymerization of PET for Tailored High-Performance Polymer Upcycling. Engineering 202602010 DOI:10.1016/j.eng.2026.02.010

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