Rheological and Molecular Modifications of Recycled PET Induced by Chain Extenders for Enhanced 3D Printing Processability

Nismar Parneam, Siriorn Isarankura Na Ayutthaya, Thanathach Yingshataporn-a-nan, Panachai Thusanaphoom, Kritsana Pokamas, Nathapong Sukhawipat, Jatuphorn Wootthikanokkhan, Wichain Chailad

Abstract

This research investigated the processability of recycled poly(ethylene terephthalate) (rPET) derived from PET bottle waste to form filaments for 3D printing by modifying its molecular structure from linear to branched chains using different types and amounts of epoxide chain extenders. The rheological properties, processability, and morphology of the modified rPET were examined using a rotational rheometer, a twin-screw extruder, and a camera image technique, respectively. The highest filament performance was achieved with the addition of 12.5 parts per hundred (pph) of ethylene/n-butyl acrylate/glycidyl methacrylate copolymer, resulting in improved processability and increased shear viscosity. This material exhibited pseudoplastic flow at low shear rates. Additionally, the incorporation of 0.3 pph of styrene-methacrylate-glycidyl methacrylate copolymer further enhanced shear viscosity at low shear rates, resulting in a filament with a smoother surface. Thermal stability and the completion of interactions between rPET and chain extenders were confirmed using a rheometer in oscillatory time-sweep mode. These findings suggest that optimal modification significantly enhances the suitability of rPET for manufacturing 3D printing filaments in the industrial sector.

Keywords

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