Post-Consumer Resin - Understanding the quality-performance linkage for packaging
Lead Research Organisation:
UNIVERSITY OF MANCHESTER
Department Name: Materials
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.
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.
Publications
McLauchlin A
(2023)
Improving the performance of post-consumer resin feedstocks for rigid packaging applications: A pilot-scale assessment
in Resources, Conservation and Recycling
Smith P
(2024)
A data-driven analysis of HDPE post-consumer recyclate for sustainable bottle packaging
in Resources, Conservation and Recycling
Wang Y
(2024)
Antioxidant-Containing Polymeric Additives for Improved Mechanical Recycling of PET
in Macromolecules
Related Projects
| Project Reference | Relationship | Related To | Start | End | Award Value |
|---|---|---|---|---|---|
| NE/V010778/1 | 01/11/2020 | 29/04/2023 | £751,327 | ||
| NE/V010778/2 | Transfer | NE/V010778/1 | 31/05/2023 | 29/06/2024 | £149,853 |
| Description | This project focused on improving the understanding of post-consumer recycled (PCR) high-density polyethylene (HDPE) used in plastic packaging, particularly bottles. HDPE is a widely used plastic, but recycling it effectively is challenging due to contamination, degradation, and variation in quality. These issues have made it difficult for companies to use more recycled material in their products. Through our research, we conducted the largest-ever study on HDPE PCR, analysing 28 different commercial samples and measuring over 25 unique properties for each one. This resulted in more than 3,300 data points, giving us an unprecedented insight into the chemistry and structure of recycled plastic. Key Discoveries and Achievements: New Methods to Quickly Assess Recycled Plastic Quality: We identified three fast and low-cost testing techniques (FTIR, TGA, and mechanical testing) that can determine the quality of recycled plastic without requiring extensive and expensive laboratory work. Understanding the Impact of Contamination: We pinpointed how different levels of polypropylene (PP) contamination affect the mechanical properties of recycled HDPE, helping manufacturers predict how a given recycled material will perform in packaging. Industry Adoption: Based on our findings, IPL Brightgreen, a major recycler, has invested in a new sorting and washing line to improve the quality of recycled HDPE. Real-World Impact: Companies like Unilever are using our research to improve how they assess and qualify recycled plastic for use in their products, helping them increase the proportion of recycled materials in packaging. |
| Exploitation Route | The insights and tools developed through this project can be applied in multiple ways across industry, policy, and academia to drive greater use of recycled plastics and improve sustainability. 1. Industry Adoption for Improved Recycling Practices Plastic recyclers and manufacturers can use our findings to improve sorting and processing techniques, ensuring more consistent and higher-quality recycled plastics. Companies like Unilever and IPL Brightgreen have already begun applying our data-driven approaches to better assess and qualify PCR materials for packaging, leading to increased use of recycled content. New quality control methods, such as our recommended testing trio (FTIR, TGA, and mechanical testing), allow businesses to rapidly assess PCR quality without expensive and time-consuming lab work. 2. Academic and Research Expansion Our study sets a new benchmark for research into recycled plastics, providing a large dataset that can be used by other researchers studying mechanical recycling. The methods we developed for characterising PCR materials can be applied to other types of recycled plastics beyond HDPE, extending the impact of this work. New research collaborations, such as the EPSRC proposal on circular lab plastics, build on this project's foundations to explore sustainable alternatives in other sectors. 3. Commercial and Supply Chain Innovations Tool and Model Development: Our data-driven models for predicting PCR performance can be developed into software tools or mobile apps to assist companies in evaluating new recycled materials. Investment in Recycling Infrastructure: Our findings have already influenced IPL Brightgreen's decision to invest in a new sorting and washing line, and similar companies may follow suit. New Business Models: The ability to predict the performance of recycled plastics more accurately can help businesses confidently substitute virgin plastic with high-quality PCR, creating new market opportunities for recyclers. 4. Educating and Upskilling the Workforce Training for industry professionals: The methods and tools developed in this project can be used to train engineers, chemists, and materials scientists in better PCR assessment. Supporting student development: Our research has already led to PhD and undergraduate projects, and these opportunities will continue to grow, ensuring a future workforce equipped to tackle sustainability challenges in plastics. By making our research widely accessible, from publications to direct engagement with industry and policymakers, we are ensuring that the benefits of this work extend far beyond this initial project. The ultimate goal is to increase the use of recycled plastics, reduce reliance on virgin materials, and accelerate the transition to a circular economy in plastic packaging. |
| Sectors | Agriculture Food and Drink Construction Environment Manufacturing including Industrial Biotechology |
| Description | The research findings from this project have already been applied in multiple ways in industry, helping to drive improvements in the quality and usability of post-consumer recycled (PCR) plastics. IPL Brightgreen, a major plastic recycler, used our insights on PCR quality variability to invest in a new sorting and washing line, improving the consistency of their recycled HDPE. Unilever has incorporated our data-driven approach to PCR quality assessment, helping them increase the amount of recycled plastic used in their packaging. They are using our principal component analysis (PCA) techniques to compare different PCR resins and assess their suitability for packaging. A risk assessment tool, developed from our research, is being used in industry to compare key PCR property values and predict performance. |
| First Year Of Impact | 2022 |
| Sector | Agriculture, Food and Drink,Chemicals,Construction |
| Impact Types | Economic |
| Description | Collaboration with Unilever |
| Organisation | Unilever |
| Department | Unilever UK R&D Centre Port Sunlight |
| Country | United Kingdom |
| Sector | Private |
| PI Contribution | Our research feeds into Unilever's decision making for the use of recycled plastics in packaging. |
| Collaborator Contribution | Unilever have provided samples for us to analyse, they have shared the key performance requirements for recycled plastics in packaging. They have committed to doing bottle tests on plastic samples that we select. |
| Impact | There are no outputs at this stage. This is a multi-disciplinary collaboration that covers chemistry, materials science and supply chain management. |
| Start Year | 2021 |
| Description | Predictive Quality Metrics for Recycled PET in High-Performance Healthcare Packaging |
| Organisation | Reckitt Benckiser |
| Country | United Kingdom |
| Sector | Private |
| PI Contribution | This collaboration extends the Smart Sustainable Plastic Packaging (SSPP) framework originally developed for HDPE recyclates to recycled PET systems for healthcare packaging applications. Building directly on methodologies established under the NERC Post-Consumer Resin programme , the University of Manchester team transferred and adapted our structured characterisation and data analysis pipeline from polyolefins to PET. Our contribution centred on comprehensive physicochemical characterisation of rPET pellets, including thermal behaviour, rheology, molecular weight distribution and spectroscopic analysis, coupled with multivariate statistical modelling. Rather than relying on intrinsic viscosity as a single quality descriptor, we implemented a multi-parameter structure-property framework to identify the key material signatures that govern downstream bottle performance. Using data-driven approaches, we established predictive relationships linking pellet-level characterisation to bottle mechanical performance and processing behaviour under healthcare-relevant conditions. The work also involved interpretation of degradation signatures, contamination effects and variability across supply streams. A researcher previously embedded within the HDPE SSPP programme was seconded through an IAA CONDI placement to ensure methodological continuity and accelerate translation of established analytical workflows to PET. |
| Collaborator Contribution | The industrial partner, a leading fast-moving consumer goods company, provided commercially relevant rPET feedstocks spanning multiple supply chains and quality grades. They supplied detailed industrial processing information, bottle performance testing data and internal specification thresholds, enabling direct calibration of academic measurements against real-world manufacturing constraints. The partner defined market-specific requirements for healthcare packaging applications, including mechanical integrity, processing robustness and regulatory compliance considerations. They conducted bottle-scale performance testing and shared results to validate predictive models developed at Manchester. The collaboration was directly supported by financial contribution through an Impact Acceleration Account award, including co-funding associated with the CONDI placement. Regular technical exchange ensured alignment with industrial sustainability targets, particularly increasing recycled content while maintaining product performance and safety standards. |
| Impact | Outputs and outcomes arising from the collaboration Transfer and validation of analytical framework from HDPE to PET The structured characterisation and multivariate modelling framework originally developed within the SSPP programme for HDPE recyclates has been successfully transferred and adapted to recycled PET systems. This demonstrates cross-polymer applicability of the SSPP methodology and strengthens its strategic value beyond a single material class. Development of predictive structure-property models for rPET A multi-descriptor analytical dataset has been generated for commercially relevant rPET feedstocks. Using multivariate statistical analysis, relationships have been established between pellet-level characterisation (thermal behaviour, rheology, molecular weight distribution and spectroscopic signatures) and bottle-scale mechanical performance in healthcare packaging applications. This moves beyond intrinsic viscosity as a sole quality metric and provides an evidence-based framework for quality assessment. Industrial validation using bottle-scale testing Academic models have been calibrated and stress-tested against industrial bottle performance data supplied by the partner. This has enabled validation of predictive descriptors under real processing conditions and healthcare-specific performance requirements. Strengthened industrial-academic knowledge exchange The project has enabled sustained technical exchange between the University of Manchester and a leading fast-moving consumer goods company. This includes integration of findings into packaging innovation pipelines and direct alignment with recycled content and sustainability targets. Capacity building through researcher secondment An Impact Acceleration Account supported CONDI placement enabled a researcher previously embedded in the HDPE SSPP programme to apply established workflows to PET systems. This accelerated translation, strengthened methodological continuity and enhanced industrially relevant skills development. Foundation for further funding and cross-polymer circularity research The collaboration provides a platform for future joint proposals focused on predictive quality metrics, cross-polymer recyclate modelling and healthcare packaging circularity. It extends SSPP capability from polyolefins into polyester systems. Yes - this collaboration is explicitly multi-disciplinary. Disciplines involved: • Polymer materials science - thermal, rheological and molecular characterisation of recycled PET. • Analytical chemistry - spectroscopic and molecular weight analysis to quantify degradation and contamination signatures. • Data science and applied statistics - multivariate modelling and descriptor identification to establish predictive structure-property relationships. • Chemical and process engineering - translation of pellet properties to bottle processing behaviour and performance testing. • Sustainable packaging and circular economy - alignment with recycled content targets, healthcare packaging requirements and regulatory constraints. |
| Start Year | 2024 |