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Synergistic Effect of Dual Additive System on Molecular Structure and Foaming Properties of Recycled PET

Cronfa (Swansea University) 2025 1 citation ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Tae Hyeong Park, H. C. Jeon, Ji Eun Choo, Yingfeng Ji, Sung Wook Hwang

Summary

Researchers investigated how dual chain extenders (PMDA and Joncryl ADR4468) improve the melt strength and foamability of recycled PET bottle flakes. The optimized formulation produced uniform low-density foam cells comparable to virgin PET, demonstrating a viable path for upgrading mechanically recycled PET into high-value foam products.

Polymers

ABSTRACT This study investigated the effect of chain extenders on molecular structure and foaming properties of poly (ethylene terephthalate) (PET) bottle flake (BF). To improve the melt strength of BF, two different chain extenders, pyromellitic dianhydride (PMDA) and BASF Joncryl ADR4468, were introduced, and the optimized composition was determined based on the melt viscosity of BF, which resulted in improvements in both the storage modulus and the complex viscosity. The foaming was achieved by applying a chemical blowing agent to the compositions of BF_p and BF_d3 samples which is required for the minimum intrinsic viscosity for the possible chemical foaming process. The formation of small and uniform cells within virgin PET (vPET) and BF was confirmed through the field emission scanning electron microscopy (FE‐SEM). The vPET and BF using recipe R3, optimized chain extender composition, was found to be formed the lower density PET foam. In addition, the formation of a long‐chain branched (LCB) structure was observed from the rheological behavior, therefore, it could be suggested that a dual additive system successfully proved a synergistic effect in PET foaming performance.

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