# Value-Added Products Derived from Poly(ethylene terephthalate) Glycolysis

## TL;DR

This paper presents a method to convert waste PET into valuable products through glycolysis and chemical reactions, offering potential applications in flame retardants and thermal stabilizers.

## Contribution

The study introduces a novel approach to directly use glycolysis products of PET for synthesizing flame retardant additives and thermal stabilizers without purification.

## Key findings

- GP-PET can be valorized via phosphorylation with PPD and TMP to create value-added products.
- The exchange reaction between GP-PET and TMP was confirmed using NMR and GPC analysis.
- The carbon residual from the end products suggests their potential as flame retardants and thermal stabilizers.

## Abstract

Among polymer wastes, poly(ethylene terephthalate) (PET) is the most important commercial thermoplastic polyester. Less than 30% of total PET production is recycled into new products. Therefore, large amounts of waste PET need to be recycled. We describe a feasible approach for the direct application of the glycolysis products of PET (GP-PET), without further purification, for the synthesis of value-added products. It was established that GP-PET is valorized via phosphorylation with phenylphosphonic dichloride (PPD), as well as with trimethyl phosphate (TMP). When PPD is used, a condensation reaction takes place with the evolution of hydrogen chloride. During the interaction between GP-PET and TMP, the following reactions take place simultaneously: a transesterification with the participation of the hydroxyl group of GP-PET and the methoxy group of TMP and an exchange reaction between the ester group of GP-PET and the methyl ester group of TMP. The occurrence of the exchange reaction was confirmed by 1H, 31P, 13C NMR, and GPC analysis. Thermogravimetric analysis (TGA) revealed that the percentage of a carbon residual (CR) implies the possibility of using the end products as flame retardant (FR) additives, especially for polyurethanes as well as thermal stabilizers of polymer materials or Li-ion cells.