ReRecycling of compatibilized blends

Re-recycling of a compatibilized poly(propylene)/ poly(ethylene terephtalate) blend

What is about?

The concept of this research is the (change in) interaction/activity of a functional additive (impact modifier/compatibilizer) after varying processing times/cycles within the framework of mechanical recycling of blends. The main residence time for one compounding step varies between 30 till 90 seconds, depending on the blends’ viscosity, screw settings and configuration. The processing times would be extended to simulate mechanical recycling by using several processing steps wherefore the interaction of the functional additive is compared at different time intervals. Due to these multiple extrusions; thermal-mechanical degradation, thermal degradation, thermal-oxidation degradation and hydrolysis can occur. The heat, shear, oxygen and moisture will alter the properties of the polymer(s) itself and the blends’ during longer processing times.

Objective of the research

The blend would consist of poly(propylene) (PP) used as matrix and a smaller amount (> 30 wt%) of poly(ethylene terephtalate) (PET) as 'contaminant'. Furthermore, an impact modifier/compatibilizer would be added to the blend. This would be a styrene-(ethylene-co-butylene)-styrene (SEBS) and may be additionally grafted with an extra functional group. The impact modifier/compatibilizer would enhance the impact resistance and improve polymer interphase adhesion. At first the mix is prepared in a twin screw extruder for optimal blending and followed with variable extrusion times. The changes in the blend during different extrusion times are amongst others measured by the changes in: viscosity, melt behaviour, morphology and mechanical properties. In time, the extrusion steps will not only be change by different processing times, but will also include different temperatures and torque rates which will be compared to one another.

Type of funding and duration

Ghent University Research Fund, 2017-2021