Post-Consumer Resin - Understanding the quality-performance linkage for packaging

Lead Research Organisation: University of Liverpool
Department Name: Chemistry

Abstract

Home and personal care products are often contained in bottles made of high-density polyethylene (HDPE) and about 150,000 tonnes of this packaging are produced annually. The resulting post-consumer plastic is then collected, sorted and mechanically recycled. This mechanical recycling process involves grinding, washing and then extruding to give pellets known as post-consumer resin (PCR). Less than 69,000 tonnes of HDPE PCR are produced annually, which means that more than half of the plastic packaging is going to landfill rather than being recycled. PCR can be incorporated into HDPE packaging to replace virgin plastic which saves on waste and is also more efficient in terms of carbon emissions. However, one of the major issues with using PCR in packaging is that it is a variable material. It may contain different grades of plastic, it can be contaminated with other materials and the recycling process itself can lead to degradation of the plastic. This means that incorporation of PCR into bottles tends to result in reduction in performance of the packaging. The variability in PCR makes it harder for companies to use PCR in packaging, it increases the cost of using PCR and ultimately places an economic penalty on the increased use of PCR. There is currently insufficient scientific understanding of the changes that occur to HDPE during recycling which means that it is challenging to address issues with the inconsistency of PCR. This means there is an urgent need to understand the quality-performance linkage for PCR in packaging.

This ambitious project brings together an interdisciplinary team from the University of Liverpool and University of Manchester to improve the mechanical recycling of HDPE. We will enable rapid delivery towards the goals of the Plastic Pact for this important waste stream, and reduce plastic waste and increase recycling by 2025, by making use of existing plastics and infrastructure. We will generate a detailed understanding of the chemistry and property relationship of PCR. This new knowledge will allow PCRs to be produced with improved performance in packaging and also to prevent degradation in recycling. Simultaneously, we will understand how this disruption within the supply and demand for PCR will impact supply chain. This understanding will allow interventions to be selected that deliver the greatest economic, social and environmental benefits. This research will therefore facilitate improving the quality of PCR in packaging, increasing the value of PCR which will then drive greater investment in plastics recycling.

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