Grant: Discovery Grants Program - Individual

This research program will make new chemicals (catalysts) that will convert small molecules sourced from biomass and renewable feedstocks into degradable polymers-the materials used to make plastics. Polymers are molecules that are made of repeating units of smaller molecules (called monomers). They can be made from one type of monomer (a homopolymer) or from different monomers (a copolymer). The nature and arrangement of comonomers is important, as is the number of monomers in a polymer and how much the number of monomers varies from molecule to molecule of polymer (the dispersity). These variables affect the physical properties of a polymer (its hardness, rigidity, melting point, flexibility at different temperatures, and density). Plastics are formed from choosing a polymer or mixture of polymers with the desired properties to give a material that suits a required purpose, and the range of properties is very diverse. Because of this diversity, plastics are among the most useful and versatile materials used today. The global demand for plastics will only continue to rise. The recycling or reuse of plastics is crucial to prevent the release of plastics into the environment; however, typically fewer than 20% of plastics are recycled, with almost half still being sent to landfills and about 25% are incinerated. Reduction and re-use must be promoted, but our need for and reliance upon single use plastics has been highlighted by the COVID-19 pandemic. Sanitary food packaging, healthcare items and personal protective equipment (PPE), medical consumables (syringes, catheters, gowns, and other medical waste) cannot be reused or reduced without harm to medical staff, patients, and the public. Single use plastics will continue to be required, and these challenges require solutions from many approaches to waste management. One approach is the development of degradable polymers, e.g. through composting or chemical recycling. Compostable polymers such as PLA (polylactide), which is sourced from lactide obtained from corn, are becoming common replacements for petroleum-sourced plastics in single use products such as food containers, however, their mechanical properties, such as a low melting point, limit their use. New polymers are needed that possess the degradable properties of PLA but with higher performance. Using other, ideally bio-derived starting materials will create a wider palette of materials with more tunable physical properties. For this to work, catalysts are needed. Catalysts speed up reactions, but also control the process for selectivity (control of what is formed), degree of polymerization (how many molecules of a feedstock are used to form the polymer), and dispersity (how narrowly or broadly the degree of polymerization is controlled). This research program will make new catalysts for monomers obtained from biomass, and the polymers formed will be degradable either biologically or chemically to make them easier to reuse and recycle.