Controlled metal-catalysed polymerisation of SO2-derived sources to high performance and recyclable materials

Project Information

PolySO2

Grant agreement ID: 101018516

DOI

10.3030/101018516

Project closed

EC signature date 25 February 2021

Start date 1 May 2021

End date 30 April 2023

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 224 933,76

EU contribution

€ 224 933,76

Coordinated by

THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF OXFORD
United Kingdom

Periodic Reporting for period 1 - PolySO2 (Controlled metal-catalysed polymerisation of SO2-derived sources to high performance and recyclable materials)

Reporting period: 2021-05-01 to 2023-04-30

Summary of the context and overall objectives of the project

The plastic industry is facing numerous challenges to adapt to more sustainable practices, including the phase-out of fossil fuel resources, the minimization of all burdens to the environment and the potential toxicity to humans, and the increase in the amount of recycled (recirculated) plastics material after use. However, new technologies and fundamental discoveries are required to overcome these global barriers. PolySO2 was designed to tackle some of these issues in an unconventional way, that is, by targeting the polymerization of underutilized feedstocks, some from waste gases or with potential to be manufactured from renewable resources. In addition, our goal was to obtain polymeric materials that could address the end-of-life of plastic products once they had become waste by providing chemical routes for their degradation.
At the core of these goals was the exploitation of metal complexes developed in the group of Professor Charlotte Williams at the University of Oxford, who has pioneered in the conversion of CO2 and epoxides for the production of polycarbonates. Dr. Vidal developed and utilized earth-abundant metal complexes, including zinc(II), magnesium(II), potassium(I), and aluminium(III), to explore new directions that could provide access to unprecedented materials designed for high performance and recyclability. Indeed, the work carried out during this project unveiled novel functional polyesters from the ring-opening copolymerization of functional anhydrides with epoxides, whose chemical and physical attributed could find interesting applications in biomedicine for drug delivery, imaging, or sensing. He has also open the path for their implementation as high performance elastomers with improved end-of-life options thanks to their reprocessability. Finally, Dr. Vidal also demonstrated the potential to depolymerize these materials under hydrolytic conditions, proving that new polyester materials can perform as well as traditional commodity polymers but avoiding the pervasiveness of their wastes.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

In summary, dr. Vidal accomplished the following results:
1) Production of new polyesters that achieve the following key characteristics: (1) precise placement of chemical functionalities (e.g. boronic esters, boronic acids, borates, and fluorescent organoboranes); (2) unusually high glass transition temperatures (up to 220 °C) while preserving high thermal stability (~300 °C); and (3) controlled architectures, enabling the formation of multiblock copolymers with amphiphilic characteristics.
2) Exploitation of state-of-the-art catalyzed polymerization methods that use the lowest energy inputs and lowest catalysts loadings with the highest polymer performance possible. For instance, SO2/CHO ROCOP was effective at room temperature and 1 bar of pressure in less than 24 hours. Other catalytic processes have been explored at temperatures between 60-80 °C, many times using the least amount of solvents (or neat) to minimize the use of additional reagents.
3) Increase the knowledge of controlled metal-catalyzed polymerization of epoxides/anhydrides by conducting mechanistic and kinetic studies as exemplified in the ROCOP of PA/CHO
4) Successful implementation of potential pathways for managing the end-of-life of the new materials, particularly by depolymerization and degradation of water-soluble ionic polymers back to small molecules.
5) Investigation of rheological and mechanical properties of new polycarbonate thermoplastics and polyester thermoplastic elastomers. Some of these materials have unprecedented record in the literature (particularly well-defined high molecular weight polycarbonates), and will provide with fundamental knowledge for future developments.
6) Publication of three papers, two of them as first and corresponding author (*): (a) Vidal, F*.; Williams, C.K. Chem, 2021, 7, 11, 2857-2859; (b) Poon, C. K.; Gregory, G. L.; Sulley, G. S.; Vidal, F.; Williams, C.K. Adv. Mater., 2023, 2302825 DOI: 10.1002/adma.202302825; (c) Vidal, F.*; Smith, S.; Williams, C.K. J. Am. Chem. Soc., 2023, 145, 25, 13888-13900 DOI: 10.1021/jacs.3c03261. In addition, he has three more publications in preparation phase, one of them is currently under revision for the journal Nature.
7) Dissemination of results by conference attendance in France, and Spain (GEP-SLAP 2022, European Young Chemists Meeting 2022, and Bordeaux Polymer Conference 2022)

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The progress of this project has resulted in the following socio-economic impacts and implications:
1) Dr. Vidal has trained two masters students full-time (Mr. Sevven Smith, and Ms. Erica Barnes) during the two years of the action, whose project’s resulted in two master thesis dissertations. For his supervising and managing work in the Williams group, he received the “Recognition Award” of the Department of Chemistry at the University of Oxford.
2) Dr. Vidal became a key member of the “Future of Plastics” Programme at the Oxford Martin School, a multidisciplinary project between chemists, international law scholars, and environmental economists, to design a new sustainable plastics economy for the future. The work carried out in this project will result in a perspective article in the journal Nature, which is expected to have an enormous coverage in the context of the new 2024/25 Plastics Treaty to be negotiated by the United Nations Environmental Programme.
3) Dr. Vidal volunteered and collaborated with the Society of Spanish Researchers in the United Kingdom (CERU/SRUK). This work resulted in the organization and hosting of the symposium “Sustainable Plastics of the Future”, a public forum where audience in Oxford engaged with academics studying the plastic problem. For this event, he secured a “Researched Development Grant” of the Royal Society of Chemistry. He also co-organized and hosted one research seminar under the “Organometallic and Main Group Seminar Series” at the department of chemistry (University of Oxford).

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