The influence of the sample preparation steps on the properties of pre-treated polyolefin waste – Problems & Solutions

Description

For the conversion of plastic waste into high quality recyclates, the characterization and quality control of incoming materials is essential. Therefore, a proper sample preparation is required to generate datasets with a high precision. Based on the acquired data, it is possible to optimize process steps and processing parameters while meeting target quality characterisitcs of specific products. Milling and compounding of the incoming materials can, potentially, be used to improve the homogenization of plastic waste. Hence, the representativeness of the generated data will be increased. This study, comprehensively, investigates the influence of sample preparation by comparing the impact of milling and compounding on the properties of different polyolefin (PO) waste streams.Samples of five different pre-treated PO feedstocks, two polypropylene (PP) dominated and three color-sorted high-density polyethylene (PE-HD) dominated mixtures, were milled and compounded. Additionally, further processing technologies (e.g., milling technologies, injection molding, pressing) were conducted on one PP and one PE-HD grades to find the best practice sample preparation. Melt flow rate (MFR), plate-plate rheology test, differential thermal analysis (DTA), and mechanical tests were performed to determine the impact of processing on melt properties, material resistance to oxidation, and mechanical performance. For both POs, the detected properties were affected by the various sample preparation steps. However, the impact of milling was less evident in the rheology of the materials than that of compounding. Nevertheless, both processes can be used to map out the property profile of a waste stream. While milling can help determine the actual material property profile of the flakes, compounding can provide an approximate prediction of the property profile of granules after processing with a recycling machine.

Period	02 Sept 2021
Event title	Polymer Meeting 14
Event type	Conference
Location	AustriaShow on map