# Synthesis of Epoxidized Soybean Oil as a Bio-Based Chain Extender for Recycled Polyethylene Terephthalate and Optimization of the Extrusion Process for Its Performance

## TL;DR

This paper shows how epoxidized soybean oil can improve the strength and quality of recycled plastic used in textiles and packaging.

## Contribution

The study introduces epoxidized soybean oil as a sustainable chain extender for recycled PET and optimizes extrusion parameters for performance.

## Key findings

- 2.0 wt% ESBO with 10 min residence time maximized intrinsic viscosity and mechanical performance of recycled PET.
- ESBO improved thermal stability and molecular weight of recycled PET under optimal conditions.
- Characterization techniques confirmed ESBO's effectiveness in restoring PET properties.

## Abstract

Polyethylene terephthalate
(PET), widely used in textiles
and packaging,
loses its mechanical strength during melt processing and recycling
due to chain scission, resulting in reduced intrinsic viscosity (IV).
Epoxidized soybean oil (ESBO), a biobased and ecofriendly modifier,
offers a sustainable alternative to petroleum-derived chain extenders
(CEs) to recover the IV. This study explores the effect of ESBO on
the IV and mechanical properties of recycled PET (r-PET) via reactive
extrusion using a single screw extruder. Various ESBO concentrations
were tested, and it was found that 2.0 wt % ESBO with a 10 min residence
time (B2–10min) achieved the best enhancement in
IV and mechanical performance of the r-PET. The findings suggest that
optimizing parameters such as CE loading and residence time can further
improve ESBO’s efficiency in restoring PET properties. Characterization
by viscometry, Fourier transform infrared spectroscopy, nuclear magnetic
resonance spectroscopy, thermogravimetric analysis, field emission
scanning electron microscopy, X-ray diffraction, and tensile strength
confirmed that ESBO effectively increased the molecular weight, thermal
stability, and mechanical properties of r-PET under optimal conditions.