Bright IDEAS Award: High strength starch based plastics

The research idea is to develop a range of bioplastics derived from 'grey' starch, a waste product generated by the food industry. Previous EPSRC funded research has identified a range of natural, biodegradeble and inexpensive additives which can produce novel blown foams when added to starch. The materials have truly unique properties which are enabled due to the use of salts as the binding agents. Preliminary studies have shown that alternatives additives and processing techniques can generate hard transparent plastics which have hitherto been impossible to achieve with starch. The so-called 'salt modified starch' could offer the first opportunity for bioplastics to potentially compete with oil-based plastics both on cost and mechanical properties while at the same time winning out on sustainability and environmental impact criteria.The aim of this project is to undertake further research to develop and formulate the conditions required to make rigid, transparent starch-based plastics. The project will also attempt to make the first monophase starch composites with cellulose acetate rendering the materials water stable. We wish to evaluate the mechanical and physical properties of these bioplastics and to produce test samples for evaluation in a variety of applications. Unlike conventional oil-based plastics the starch based materials are fully compostable. As part of the research project we wish to evaluate the time frame and conditions of decomposition these new materials.

The aim of this proposal is to develop novel carbohydrate based materials by mimicking the role of complex aqueous fluids in natural products. A non-volatile, but biodegradable, ionic modifier will be used as a plasticizer which can break up some of the intra-grain interactions while also acting as a binding agent and increasing inter-grain bonding. The modifiers are an economically viable and ecologically suitable method of achieving this. The versatility of these systems means that the same approach can be used to affect the rigidity, hydophobicity and biodegradability. The reason for focussing on starch and cellulose is that they are frequently obtained as waste products from the food and paper manufacturing industries. Processing potatoes produces approximately 1/8th of the product mass as starch waste. The use of starch to make compostable plastics would serve the dual role of using a waste material while circumventing the use of the valuable oil feedstock. It would take between1.5 to 2 million tonnes of potatoes p.a. to yield sufficient starch to replace all EPS and PVC used in packaging in the UK. The project offers a major impact is solving many of the issues associated with oil based plastics and the waste associated with their disposal. Technologically they have the potential to radically change the way in which starch based polymers are made, used and disposed of. Societally they promise to reduced dependancy on oil and capability to produce the raw materials and manufacture bioplastics in the UK would have a major impact on society. It would also reduce the carbonfootprint of the plastics industry. Environmentally they have the potential to save a large amount of oil and reduce our needs for landfill. Packaging accounted for 35% of the UK's consumption of 4.7 million tonnes of plastic products and 56% of the total for plastic waste. More than 80% of all this plastic is used once and then thrown into landfill sites, while only 7% of plastic is recycled. There is no fully compostable plastic or blown foam currently available that competes mechanically or economically. This method is capable of meeting that need and as such would significantly reduce the energy usage, waste production and CO2 footprint within the UK. Economically the ability to produce bioplastics in the UK would help to stimulate the manufacturing sector. Partnering with international companies and licencing the technology internationally would generate inward investment and income to the UK. Bioplastics occupy only a small part of the materials market at the moment due to their poor mechanical properties and their high cost of production. The proposed approach is creative because the manufacturing methodology is not conventional and the materials thus produced is rigid but ductile. The starch will be compression moulded allowing it to be used for structural plastics which is not conventional. Blending hydrophillic and hydrophobic polymers to form a unique monophasic material and this approach will be permitted due to the ionic species used to act as the binding agents allowing one phase to melt and blend more easily with the other.