Influence of processing and formulation on the properties of PP-PET-blends

The aim of this work was to investigate the effects of the composition and processing on the properties of PP-PET blends with and without compatibilisation. As the processing routes blend production via a co-rotating twin screw extruder as well as single screw extruder were chosen. We found, that it is possible to compatibilize PP-PET blends via the addition of maleic anhydride grafted PP. This effect can be seen from the morphology of the samples as well as from mechanical properties. In twin screw extrusion, the application of vacuum degassing shows additional property improvement due to the condensation of PET. The compatibilizer is also effective in single screw extrusion, but the effect is lower due to the missing degassing options. Nevertheless, the compatibilized blends are stable and the results show, that such mixed plastics, which can also be found in waste streams, can be reused when being properly processed.