Benign Metal Initiators for the Production of Biopolymers and their subsequent depolymerisation

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This project will combine expertise in the Jones group in the preparation of Lewis acidic metal complexes and exploitthis in the production of new biopolymers. Recently several initiator have been shown to be significantly more activethan other systems and are able to work at industrially relevant conditions. The project will be split into severalstrands:1. Ligand modification and varying metal centre (Chemistry Bath/Cardiff). This will involve the expansion of the familyof ligands (varying sterics, electronics) and complexing these to a range of metal centres.2. Homo and co-polymerisation the complexes will be screened for the homo-polymerisation of cyclic esters (eglactide, caprolactone, butryolactone) and co-polymerisation of epoxide/CO2 and epoxide/anhydrides underindustrially relevant conditions (high temperature and solvent free). This is extremely challenging, however, we havedeveloped catalysts that show promise. The most promising homo-polymerisation catalysts will be taken forward forco-polymerisations. This, presumably, will lead to either block copolymers or alternating copolymers depending onthe reactivity ratios. The precise conditions required for effecting highly alternating copolymers is an area that ispoorly understood, and will therefore be an interesting avenue to explore.3. In line with the "cyclic economy concept" we will investigate catalytic depolymerisation of commercially relevantbiopolymers. Initially we will focus our investigation on polyesters {polylactide -PLA}. Disposal of plastics into landfillcauses loss of materials' value and also contributes to environmental problems. It is imperative that technology isdeveloped that can recycle polymers to recover the monomer (or useful chemical starting materials). This potentiallycan be achieved by catalytic depolymerisation