Thermal shrinkage of chemically recycled and virgin poly(ethylene terephthalate) blends

Abstract

Blends of chemically recycled and virgin poly(ethylene terephthalate) (PET) were prepared using a meltblending process. To enhance the physical properties, virgin PET chips were added to the chemically recycled PET in ratios of 20, 40, and 70 wt%. The mechanical and thermal properties, thermal shrinkage, and crystallinity of the blends were investigated. The thermal shrinkage of the blends decreased with increasing chemically recycled PET content. Tensile tests revealed that the tensile strength and elongation at break of the chemically recycled/virgin PET blends were increased by the addition of virgin PET. The melt flow index and melt density of chemically recycled PET were also investigated. The thermal stability of the blends increased as the virgin PET content increased. Their crystallinity depended on the chemically recycled PET content because of the nucleating effect of nanoparticles in that material, such as metal catalysts. The color index of chemically recycled/virgin PET blends showed yellowing by chemically recycled PET.