Investigation into the release of microplastics and metallic ions into the environment during the long-term degradation of pre-painted metals

Introduction:
The European Commission, as part of their Green Deal, are investigating the generation (intentional or not) of microplastics and chemical species from products during their service life. The European Coil Coating Association (ECCA) is sponsoring an investigation into the formation of microplastics from the organic coating and the release ("run-off") of chemical species during the long-term degradation of prepainted metals. Given the durability of prepainted metals (>40 years), it is important to establish the extent (if any) of microplastic and other particulate formation from the coated product over this period. Whilst there is no current regulation related to these issues, it is conceivable that future legislation may require abatement measures to prevent release of both microplastics and metallic ions.

Objective and scope of the study:
The primary objective of the work is to identify the main mechanisms for microplastic and other particulate formation during the degradation of the prepainted metal product through:
1. The use of advanced analytical techniques such as UV, ATR FTIR, SEM and particle sizing to determine the mechanism and rates of major coating degradation e.g. mechanical, UV and to understand the nature of the organic and inorganic particulates released through erosion.
2. Understanding how representative climatic conditions affect the rates of erosion and changes in coating characteristics using through depth profiling and surface analysis techniques.
3. Detailed investigation of the run-off material released from the coated samples.
4. Correlation of accelerated testing results with naturally weathered material with particular focus on the types and quantity of environmental release.
5. Quantification of the total yearly releases from outdoor prepainted metal exposure, over the whole of the EU.
The experimental design will include an appropriate number and combination of the following systems:
(a) Polyester, polyurethane, PVDF and plastisol coated metal.
(b) Zinc-coated steel and aluminium substrates.
(c) "Model" organic coatings which will rapidly degrade and release chemical components e.g. polyamide beads.

The proposed scope of work could also be extended, where appropriate, to include such topics as:
(i) Determining the fate of the released species in the environment e.g. locations for bioaccumulation.
(ii) Further degradation mechanisms once released into the environment.
(iii) Impact of the released species on the environment e.g. evidence for biotoxicity.

Predicted Outcomes:
The project will provide an understanding for the potential release of organic material and metallic ions into the environment. This may enable ECCA members to formulate improved organic coatings with reduced environmental impact which will maintain the competitive position of the products in the European market.

The CDT will produce 50 graduates with doctoral level knowledge and research skills focussed on the development and manufacture of functional industrial coatings. Key impact areas are:

Knowledge
- The development of new products and processes to address real scientific challenges existing in industry and to transfer this knowledge into partnering companies. The CDT will enable rapid knowledge transfer between academia and industry due to the co-created projects and co-supervision.
- The creation of knowledge sharing network for partner companies created by the environment of the CDT.
- On average 2-3 publications per RE. Publications in high impact factor journals. The scientific scope of the CDT comprises a mixture of interdisciplinary areas and as such a breadth of knowledge can be generated through the CDT. Examples would include Photovoltaic coatings - Journal of Materials Chemistry A (IF 8.867) and Anti-corrosion Coatings - Corrosion Science (IF 5.245), Progress in Organic Coatings (IF 2.903)
- REs will disseminate knowledge at leading conferences e.g. Materials Research Society (MRS), Meetings of the Electrochemical Society, and through trade associations and Institutes representing the coatings sector.
- A bespoke training package on the formulation, function, use, degradation and end of life that will embed the latest research and will be available to industry partners for employees to attend as CPD and for other PGRs demonstrating added value from the CDT environment.

Wealth Creation
- Value added products and processes created through the CDT will generate benefits for Industrial partners and supply chains helping to build a productive nation.
- Employment of graduates into industry will transfer their knowledge and skills into businesses enabling innovation within these companies.
- Swansea University will support potential spin out companies where appropriate through its dedicated EU funded commercialisation project, Agor IP.

Environment and society
- Functionalised surfaces can potentially improve human health through anti-microbial surfaces for health care infrastructure and treatment of water using photocatalytic coatings.
- Functionalised energy generation coatings will contribute towards national strategies regarding clean and secure energy.
- Responsible research and innovation is an overarching theme of the CDT with materials sustainability, ethics, energy and end of life considered throughout the development of new coatings and processes. Thus, REs will be trained to approach all future problems with this mind set.
- Outreach is a critical element of the training programme (for example, a module delivered by the Ri on public engagement) and our REs will have skills that enable the dissemination of their knowledge to wide audiences thus generating interest in science and engineering and the benefits that investments can bring.

People
- Highly employable doctoral gradates with a holistic knowledge of functional coatings manufacture who can make an immediate impact in industry or academia.
- The REs will have transferable skills that are pertinent across multiple sectors.
- The CDT will develop ethically aware engineers with sustainability embed throughout their training
- The promotion of equality, diversity and inclusivity within our cohorts through CDT and University wide initiatives.
- The development of alumni networks to grow new opportunities for our CDT and provide REs with mentors.