Sampling Apparatus for the Process Monitoring of Contaminants in Polyolefin Recycling

This article presents fundamental work on online assessment of contaminants in recycled plastic processing. Post-consumer recycled plastic can contain various contaminants that prevent closed-loop recycling, which holds especially true for high quality packaging materials like polyolefins. A current German research cluster aims at increasing the recycling quota of these plastic types by gathering comprehensive data and using intelligent methods to optimize the overall recycling process. Due to the heterogenous quality of post-consumer recycling materials, fast online measurement methods are necessary to discriminate smallest possible portions during material processing. This study presents a method to access the recompounding of recycled plastic. A sampling system has been developed and tested to extract samples from the vacuum degassing of the compounding process. Laboratory analyses using GC-MS/O have demonstrated that this system can sample (odorous) volatile compounds from the extrusion process showing potential for the detection of relevant target components. This could give insights into the general composition of the gas phase and therefore enables further work towards an online measurement system and targeted monitoring of contaminants.