Influence of Different Molecular Weights and Concentrations of Poly(glycidyl methacrylate) on Recycled Poly(ethylene terephthalate): A Thermal, Mechanical, and Rheological Study

Recycled poly(ethylene terephthalate) (r-PET) is a thermoplastic polyester. Repeated heat processing of r-PET may negatively affect physical properties due to thermal degradation. Therefore, to improve the physical properties of r-PET, poly(glycidyl methacrylate) (PGMA) samples with different molecular weights (low, medium, and high) were synthesized using atom transfer radical polymerization. The synthesized PGMA polymer was then subjected to 1 H-NMR characterization and gel permeation chromatography for the analysis of molecular weight and its distribution. The intrinsic viscosity values of the r-PET/PGMA blend were increased from 0.61 to 0.8 dL g − 1 using high-molecular-weight PGMA at 2 wt%, and the glass transition temperature was increased from 71.8 °C for r-PET to 82.2 °C using high-molecular-weight PGMA at 1 wt%. Young’s modulus was increased by 1.1 times using 2 wt% high-molecular-weight PGMA compared with raw r-PET. All r-PET/PGMA blends samples exhibited notable shear thinning behavior and high viscosity compared with raw r-PET, and r-PET/PGMA blends are found with medium-molecular-weight PMGA polymers observing optimal physical properties. With these enhanced properties, the r-PET/PGMA blends can be applied in the recycling of PET, such as in eco-friendly yarn, packaging materials, and melt-brown non-woven fabric applications.