Study on Polymer Blends from Recycled Polypropylene and Plastic Waste Processed in a Hydrothermal Carbonization Process

: The remaining residues in plastic recycling facilities are incinerated or landfilled. In this study, hydro-char was prepared by hydrothermal carbonization of residue from plastics recycling facilities (RPRF) and the properties of hydro-char were analyzed. Additionally, the physical properties of the hydro-char/recycled polypropylene (PP) blends were stud-ied to evaluate the possibility of physical recycling of the RPRF. The hydro-char thus prepared was regular shaped-fine powder with uniform size, and its bulk density increased compared to the raw material ( i.e. , RPRF), making it easier to handle. The mechanical strength of the hydro-char/recycled PP blend was much higher than expected value, slightly lower than the composition average of the hydro-char and recycled PP. When a small amount of the impact modifier was incorporated into the blend, the impact strength of the blends was significantly increased. Therefore, it was concluded that physical recycling of the RPRF is possible after the hydrothermal treatment.