Coordination Chemistry Inspired Advances in Controlled Radical Polymerisation

Polymers are ubiquitous materials that have touched every aspect of our lives. These inexpensive, varied macromolecules are particularly impressive due to the diversity of physical properties and applications accessible. Innovations ranging from commodity materials to smart coatings to nano medicine are built from the foundation of polymer chemistry. This is especially important in the UK, where the polymer industry contributes >2% of UK GDP.

The tools that polymer scientists and engineers use are also growing. In particular, control over both polymer macrostructure and microstructure has seen an explosion in research activity, particularly in the field of Controlled Radical Polymerisation (CRP) which offers scientists the chance to reproducibly control the synthesis of individual macromolecules. This is achieved through several strategies, but arguably none are as robust as atom transfer radical polymerisation (ATRP). This process has transformed the polymer industry and accessed polymer morphologies and structures with tunable properties, self-assembly, applications and structures. Challenges remain, however, in examining systems beyond copper catalysts. In particular, non-toxic initiators that de-colour readily and are easily tuned are an important target, especially in producing plastics and coatings for packaging and biomedical applications.

Building from our expertise in iron-based systems for CRP, we propose to investigate Fe and Ti based catalysts. Our strategy is unique in that it is inspired by an understanding of coordination chemistry. Through this research programme we will develop new catalysts, with innovation in ligand design and catalyst development; develop new protocols to quickly screen and assess catalyst performance; develop a novel strategy to introduce secondary tuning into the coordination sphere to shape complex reactivity; significantly expand the monomer scope of Fe-mediated CRP; develop new applications at the interface between ethylene/functional monomer polymerisations and vinyl acetate branching.

Through these activities we will establish our iron and titanium systems as the preferred technologies for CRP processes, developing a system that is both environmentally and financially sustainable. Expanding from basic commodity polymers to specialty applications and polymers will diversify the UK product base whilst increasing sales. We will strengthen the UK expertise in CRP to new green ATRP catalysts, promoting innovation whilst minimising environmental impact.

Who will benefit from this research?
(1) The global polymer industry, particularly in the UK
(2) Government, public and industrial bodies targeting carbon dioxide reductions
(3) Residents of the UK, the EU and abroad
(4) The polymer academic community

How will they benefit from this research?
(1) The UK polymer industry employs nearly 290,000 people and has annual sales worth over 2% of UK GDP. These materials are predominantly derived from petroleum resources, with a particular focus on the preparation of high volume commodity polymers with narrow profit margins. With the fluctionality in oil prices providing instability in polymer markets, diversification is essential for continued economic growth in the polymer sector. This research proposal will provide increased value from existing supply chains whilst also opening up new product sectors within the specialty polymer industry. The polymer industry is a supplier to a vast range of other industries in the UK and abroad. Applications in the packaging, transportation, medical, electrical and manufacturing sectors expand the impact of this research significantly. Our catalyst development work has the opportunity to directly impact this industry: We have shown strength in catalyst commercialisation - our first generation iron systems will be sold by Aldrich and several companies are testing our catalysts in pilot facilities through GreenCentre Canada. We believe our second generation catalysts offer an improved approach, producing alternatives that are both inherently flexible, easy to tune, and broad in scope.
(2) While there are clear economic factors as drivers for sustainable change, the environmental impact of polymers on our community needs to be addressed by passionate policy-makers, environmental groups and chemical organisations. A key message to policy makers, especially with the growing strength of the UK's petroleum industry, is that environmental progress and sustainability does not need to depend solely on renewable plresources, but rather the efficient use of all available resources. Policy-makers can focus on sustainability and efficiency as target goals. A key metric in the growing concern over sustainability is carbon dioxide emissions. Our system design will minimise purification solvents: white polymers are accessed by simply acidifying the solutions which can then be semi-batch processed or precipitated. In our previous work we have reduced solvent use by 90% over a traditional copper catalyst, drastically reducing waste, lowering carbon dioxide emissions and improving sustainability. By proving the utility of these complexes on a UK scale it is expected that IP may be out-licensed to the larger EU polymer community and to global partners to further increase the impact of the research.
(3) Residents of the UK, EU and abroad will benefit three-fold from the development of this research proposal: (i) Less waste, less toxicity and improved sustainability for the production of specialty plastics will lead to safer products and reduced incinerator waste and thus lower carbon dioxide emissions. (ii) The jobs in the polymer, petroleum and manufacturing sectors that drive our economy will be more secure, and in fact will likely expand through commercialisation of these complexes and the products we can prepare. (iii) New products, new plastics and new materials with improved properties and new-to-the-world applications will be developed, providing advances in our livelihoods.
(4) The research within the polymer academic community will also have a far-reaching effect. The staff trained within this
programme will be able to transfer their skills and expertise across the UK, increasing productivity, disruptive thought and
translational knowledge in numerous sectors. We also hope that our strategy for CCI-CRP is inspirational, encouraging other academic breakthroughs in the UK and beyond.