Plastics from Sugars: The preparation, processing and properties of compostable polymers from lignocellulosic biomass.

The 'plastic age' dominates to such an extent that it would be difficult to imagine life without them. Their manufacture is a growth industry with worldwide production exceeding 150 million tons per year. The most commonly used feedstocks are fossil fuels, with around 7% of worldwide oil and gas being consumed in plastics manufacture. Such resources, although technically renewable, are estimated to be depleted in the next hundred years. Aside from the problems with petrochemicals sustainability and supply, they are becoming increasingly costly. The disposal of waste plastics is also of concern as the majority go into landfill (where they are bulky and pervasive); the recycling of commodity plastics has also recently suffered an economic collapse. There is a clear need for home-compostable plastics which derive from renewable (but inexpensive) resources for commodity applications (packaging). Such materials are also of great interest for medical applications, provided they degrade to metabolites. The proposal focuses on the polymerisation of carbohydrates, derived from lignocellulosic biomass, to give highly functionalized and rapidly degradable plastics. Lignocellulosic biomass derives primarily from non-food crops such as fast growing trees (e.g. poplar or willow) or from grasses (e.g. switch grass). This proposal will use lignocellulosic biomass (i.e. it will not rely on crops such as corn or sugar beet) as the feedstock for plastics production. This is important because it will not deprive poorer communities of essential food crops. Specifically, the feedstocks will be D-glucose, a carbohydrate derived from both cellulose and hemicelluloses, which in turn constitute 55-85% of the plant mass. Such carbohydrates are highly attractive feedstocks for chemicals production as they are abundant, inexpensive and highly functionalised. They are also cost competitive with common petrochemicals and solvents. The plastics prepared in the proposal are 100% degradable and compostable, ultimately they are broken down in soil or in the body to give naturally occurring by-products. The new materials are targeted for use in a variety of applications, including being used in compostable packaging, in particular they will facilitate the disposal and home-composting profile of currently commercial degradable plastics. Furthermore, the degradation of the new materials will be exploited for specialized medical applications. Specifically, we will study the use of the polymers as scaffolds in tissue rengeration; the key advantage of the new materials are the unusual physical properties they display and the ability to fully degrade them in the body. The proposal will involve overcoming key technical barriers to the widespread production and use of the new materials. The new technologies to be developed include developing the preparation, properties, degradation profile and end uses/applications of the materials. The proposal involves collaborations between four academic groups across various discplines (Chemistry, Materials, BioEngineering and Biology at Imperial College London and in Chemistry at Nottingham University) and with two companies (Uhde Inventa Fischer and Bioceramic therapeutics).