The influence of crystallinity on the depolymerization mechanism of PET fibers

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability Pub Date : 2025-09-13 DOI:10.1016/j.polymdegradstab.2025.111670

Gaozhe Liu, Weiwei Zuo, Meng Hao, Kaiyang Zhu, Fengxing Wang, Long Chen

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引用次数: 0

Abstract

The high-efficiency depolymerization and recycling of polyester (PET) fibers are of great significance for reducing energy consumption, improving resource utilization efficiency, and achieving high-value utilization of by-products. Reaction kinetics is a key factor for enhancing reaction efficiency, lowering energy consumption, and developing high-value products. However, in industrial methods for recycling waste polyester textiles, the diverse degrees of crystallinity of these textiles make the impact of crystallinity on reaction kinetics and the specific reaction mechanisms unclear. In this study, by investigating the glycolysis pathways of PET fibers with different crystallinities and at various reaction temperatures, we established a kinetic model for the glycolysis of PET fibers with different crystallinities and discovered a new depolymerization mechanism. The experimental curves of glycolysis of PET fibers catalyzed by zinc acetate at different reaction temperatures (165 °C - 180 °C) closely match the theoretical curves of the nucleation-controlled model. At low crystallinity (10 %), the glycolysis of PET by ethylene glycol (EG) involves both internal and external depolymerization simultaneously. At higher crystallinities (15 %, 26 %, 33 %, and 43 %), the glycolysis of PET by EG occurs through gradual external depolymerization, layer by layer. These findings are expected to guide the development of more efficient PET depolymerization processes and have significant implications for the low-energy recycling of polyester.

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结晶度对PET纤维解聚机理的影响

聚酯（PET）纤维的高效解聚和回收利用对于降低能耗、提高资源利用效率、实现副产物的高价值利用具有重要意义。反应动力学是提高反应效率、降低能耗和开发高价值产品的关键因素。然而，在工业回收废旧聚酯纺织品的方法中，由于这些纺织品的结晶度不同，结晶度对反应动力学的影响和具体的反应机理尚不清楚。本研究通过研究不同结晶度PET纤维在不同反应温度下的糖酵解途径，建立了不同结晶度PET纤维糖酵解的动力学模型，发现了新的解聚机理。不同反应温度（165℃~ 180℃）下醋酸锌催化PET纤维糖酵解的实验曲线与成核控制模型的理论曲线吻合较好。在低结晶度（10 %）下，乙二醇（EG）对PET的糖酵解同时涉及内部和外部解聚。在较高的结晶度下（15 %,26 %，33 %和43 %），PET的糖酵解是通过逐渐的外部解聚，一层一层地进行的。这些发现有望指导更有效的PET解聚工艺的发展，并对聚酯的低能量回收具有重要意义。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Polymer Degradation and Stability 化学-高分子科学

CiteScore

10.10

自引率

10.20%

发文量

325

审稿时长

23 days

期刊介绍： Polymer Degradation and Stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology. Deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and mechanical stress, and during the useful life of the materials when oxygen and sunlight are the most important degradative agencies. In more specialised applications, degradation may be induced by high energy radiation, ozone, atmospheric pollutants, mechanical stress, biological action, hydrolysis and many other influences. The mechanisms of these reactions and stabilisation processes must be understood if the technology and application of polymers are to continue to advance. The reporting of investigations of this kind is therefore a major function of this journal. However there are also new developments in polymer technology in which degradation processes find positive applications. For example, photodegradable plastics are now available, the recycling of polymeric products will become increasingly important, degradation and combustion studies are involved in the definition of the fire hazards which are associated with polymeric materials and the microelectronics industry is vitally dependent upon polymer degradation in the manufacture of its circuitry. Polymer properties may also be improved by processes like curing and grafting, the chemistry of which can be closely related to that which causes physical deterioration in other circumstances.