The Influence of EVA and PE-g-AM Compatibilizers on the Processability, Mechanical and Structural Properties of Recycled PET / HDPE Mix

Protecting the environment by reducing PET waste has become a global priority. Recycling is considered one of the simplest and most environmentally friendly ways to reduce PET waste. However, during recycling, PET undergoes thermal / hydrolytic degradation, which leads to reduced molecular weights and low physical, mechanical, chemical, etc. properties. Thus, in order to prevent the degradation processes and to improve the mechanical and processing properties, various blends based on PETr / HDPE (60: 40 mass ratio) will be processed on a Brabender mixer in the presence / absence of the compatibilizers, EVA and PE-g-AM. The diagrams of torque versus time, recorded during processing demonstrate that PETr suffers degradation processes, which leads to a decrease in torque due to reduced viscosity /molecular weight and reduced physical-mechanical and processing properties. Instead, with the addition of EVA or PE-g-AM, in varying amounts, degradation processes are largely avoided. These observations are also supported by the values obtained from the Izod impact resistance tests, namely the higher the amount of compatibilizer, the higher the shock resistance due to the higher phase adhesion. The hardness of the blends progressively decreases, relative to the PETr control sample value, from 83 to at least 61°Sh D for the compatibilized blends. FTIR microscopy, performed on the obtained samples, shows higher homogeneity between PETr / HDPE if the addition of EVA or PE-g-AM is higher (20%). Melt flow index is improved for compatibilized blends compared to PETr and PETr / HDPE.