Crystallinity regulation for low-energy methanolysis of waste PET to DMT: Implications for polymer aging and stabilization research

Research Background and Core Facts

According to the study published in Polymer Degradation and Stability Volume 254 (December 2026), the author Dieu Minh Ngo、Geonkyo Park、Kyunghan Lee、Changjoon Park、Siyoon Yang、Seongyeong Min A low-energy methanolysis route for waste PET with crystallinity engineering as the core was proposed by Hyun Min Jung, with the target product being dimethyl terephthalate (DMT). This study considers the aggregated structure of PET as a key variable for regulating the depolymerization reaction, rather than relying solely on increasing temperature or catalyst dosage to drive the reaction. From the disclosed information, the research revolves around the structural parameter of “crystallinity”: by changing the crystallization state of PET, it affects the penetration of methanol molecules into the polymer and the attack efficiency of ester bonds, thereby achieving depolymerization under lower energy input conditions. This approach links the rate of depolymerization reaction with the mobility of polymer segments and the distribution of crystalline and amorphous regions, and belongs to typical degradation behavior and structural correlation research.

Relationship with polymer aging mechanism

The aging of PET during service is essentially controlled by the aggregated structure.

. The movement of chain segments in regions with high crystallinity is limited, making it difficult for oxygen, water, and ultraviolet light to penetrate deeply. Degradation often begins in the amorphous region first; The differences in crystallinity, orientation, and spherulite morphology can also alter the sensitivity of materials to thermal and photo oxidative aging. This study uses crystallinity as a lever to regulate the depolymerization rate, suggesting that in polymer aging research, the aggregated structure should not only be regarded as a background parameter, but should be one of the core variables to explain the differences in degradation rate. For weather stability, this logic has direct reference value. The distribution and efficiency of stabilizing agents in the polymer matrix are also affected by the exclusion effect of the crystalline region: if HALS and UVA are difficult to enter the crystalline region, their protective effect mainly occurs in the amorphous region and amorphous interface. Therefore, when evaluating antioxidant systems and photostable systems, combining crystallinity, melting behavior, and morphological characterization can help explain the performance fluctuations of the same formulation under different processing or service conditions.

Implications for the design of stabilization systems

This study did not directly involve the formulation evaluation of antioxidants, HALS, or UVA, but its methodology has two transferable implications for the polymer additive industry.

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• Characterization approach for structure degradation correlation:Analyzing aggregation parameters such as crystallinity in parallel with degradation product generation rate can be used to study the mechanism of antioxidant systems and HALS efficacy, helping to distinguish between “insufficient chemical protection” and “uneven distribution of additives”..
• Evaluation dimensions of composite systems:In weather resistant and stable formulations, the composite effect of UVA and HALS is often influenced by the morphology of the matrix.

. Drawing on the ideas of crystallinity engineering, morphological indicators can be introduced into accelerated aging and detection characterization to make the mechanism of action of the composite system more interpretable.

It should be emphasized that the above correlation is an extension of research ideas, and the source itself focuses on the methanol hydrolysis of waste PET and DMT preparation, without providing specific experimental data on antioxidants, HALS, UVA, or complex systems.

. For the field of polymer aging and stabilization, the value of this work lies in reminding researchers that the degradation rate is not only determined by the chemical structure, but also by the crystalline state and chain accessibility of the material; This understanding also applies to in-depth analysis of the mechanisms of processing stability, thermal oxidative aging, and photo oxidative aging. Source: Polymer Degradation and Stability, Volume 254, December 2026. The research topic is to achieve low-energy methanolysis of waste PET to produce dimethyl terephthalate through crystallinity engineering.

Information source:Sustainable low-energy methanolysis of waste PET to dimethyl terephthalate through crystallinity engineering， Organized by Herun Chemical.