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

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Chemistry

Background:

• Poly(ethylene terephthalate) (PET) is a widely used thermoplastic polyester with low recycling rates.
• Large volumes of PET waste necessitate efficient recycling and valorization strategies.
• Direct application of glycolysis products of PET (GP-PET) offers a sustainable route for waste management.

Purpose of the Study:

• To explore the direct valorization of GP-PET without purification.
• To synthesize value-added products from PET waste through phosphorylation.
• To evaluate the potential of the synthesized products as flame retardants and thermal stabilizers.

Main Methods:

• Glycolysis of PET to obtain GP-PET.
• Phosphorylation of GP-PET using phenylphosphonic dichloride (PPD) and trimethyl phosphate (TMP).
• Characterization using NMR (¹H, ³¹P, ¹³C) and GPC analysis.
• Thermogravimetric analysis (TGA) to assess thermal properties.

Main Results:

• Successful phosphorylation of GP-PET with PPD and TMP.
• Confirmation of transesterification and exchange reactions during TMP interaction via NMR and GPC.
• TGA results indicate potential for flame retardant (FR) applications due to high carbon residual (CR).

Conclusions:

• GP-PET can be directly phosphorylated to create functional additives.
• The synthesized products show promise as FR additives for polyurethanes.
• Potential applications include thermal stabilizers for polymers and Li-ion cells, contributing to waste valorization.