About the Project

Recycled plastics are essential to reducing the environmental impact of packaging, but their wider use is limited by variability in composition, processing history, performance, and contamination. This PhD project will investigate how recycled high-density polyethylene (rHDPE) can be used more reliably in lightweight bottle packaging, with a particular focus on applications where mechanical performance, chemical resistance and long-term durability are critical.

The project will be carried out at The University of Manchester in collaboration with a leading fast-moving consumer goods company. It will combine polymer characterisation, materials testing, controlled recycling studies and data-driven analysis to understand which material properties determine whether rHDPE is suitable for demanding bottle applications.

About the project

High-density polyethylene (HDPE) is widely used in rigid bottle packaging because it is lightweight, tough and chemically resistant. Increasing the use of post-consumer recyclate in these applications is an important route to reducing the use of virgin fossil-derived plastic. However, recycled HDPE grades can vary substantially because of differences in the grade composition, contamination and degradation during mechanical recycling, which alters polymer architecture. As a result, it becomes difficult to predict whether a given recycled grade will perform reliably in lightweight bottles.

This PhD will build on existing research at The University of Manchester on the data-driven analysis of HDPE post-consumer recyclates. The project will move beyond simple classification of recycled materials and will ask whether measurable descriptors of rHDPE can be used to predict performance across processing history, repeated recycling and bottle-relevant failure conditions.

The project is expected to involve a combination of experimental polymer science and data analysis with the view to building a model to explain how changes to the polymer architecture influence the processing and application performance. Experimental work may include polymer processing, repeated mechanical recycling, FTIR spectroscopy, thermal analysis, rheology, colour analysis, tensile testing, strain-hardening measurements and environmental stress cracking-related testing. Data analysis will be used to identify relationships between polymer structure, contamination, processing history and performance. Finally, this body of knowledge will be used to build a model to explain the relationships between the polymer structure, processing and performance.

The precise direction of the project will be shaped by the student’s interests, the emerging results and discussions with the industrial partner. The overall goal is to develop a scientifically robust framework for predicting the performance of recycled HDPE in high-recycled-content bottle packaging.

Training and research environment

The student will join a research group working across sustainable polymers, plastic recycling, polymer characterisation and data-driven materials analysis. The project will provide training in polymer processing, mechanical testing, thermal analysis, rheology, spectroscopy, experimental design and multivariate data analysis.

The student will also gain experience of collaborative research with an industrial partner. This will include regular project meetings and opportunities to understand how materials decisions are made in a commercial packaging context. The project is therefore well suited to an applicant who wants to develop strong fundamental materials science skills while working on a problem with clear environmental and industrial relevance.

Eligibility

Applicants should have, or expect to achieve, at least a 2.1 honours degree or a master’s (or international equivalent) in a relevant science or engineering related discipline