The upcycling of recycled mixed polyolefines with PET through in-situ microfibrillar preparation

Post-industrial and post-consumer plastic waste streams can be re-used as secondary material sources for polymer processing by extrusion or injection moulding. One of the major commercially available waste streams contains the so called mixed polyolefines (MPO). These MPO consist of a mixture of different grades of polyethylene (PE) and polypropylene (PP). An important practical hurdle for the direct implementation of this waste stream is the immiscibility of PP and PE in the melt, which leads to segregation within the final structure and adversely affects the reproducibility and mechanical properties of the manufactured parts. Melt mixing this primary waste stream with a more rigid polyethylene tereftalate (PET) and subsequently transforming it into a microfibrillar composite could mitigate these drawbacks. Within the current research, a commercially available MPO waste stream together with virgin PET was used as a precursor for the microfibrillar preparation. The mechanical (tensile and impact) properties, physicochemical properties (DSC and TGA) and morphology (SEM) of the composites were characterized at different stages of the microfibrillar preparation