Sustainable polymers

Over 90% of bulk polymers with a production volume of greater than 150 million tonnes per annum are sourced from crude oil. Within the UK, the polymers industry directly employs 286,000 people and has annual sales of £18.1 billion which accounts for 2.1% of UK GDP. It produces around 2.5 million tonnes of polymer every year and is achieving an annual growth of 2.5%. The UK is in the top 5 polymer producers in the EU and its exports are worth £4.6 billion to the UK economy.

These polymers are ubiquitous in everyday life and have many applications including: medical, transport, electrical, construction and packaging; the latter accounting for over a third of all polymers produced. This dependence on petrochemicals for polymer production has environmental and economic risks and will, ultimately, become unsustainable as supplies of crude oil become exhausted. Therefore, there are good reasons to develop new processes for polymer production using renewable resources and for the UK, such resources must not compete with food production. Carbon dioxide is a particularly promising renewable resource, especially the use of waste carbon dioxide from sources such as power stations, chemical plants, cement and metal works.

The overall aim of this project is to develop the chemistry and engineering required to transform waste biomass and carbon dioxide into commodity polymers (2011 global production 280 million metric tonnes), specifically: polyalkanes, polyethers, polyesters, polycarbonates and polyurethanes. The key reaction pathway is from biomass to alkenes (polymerizable to polyalkanes) to epoxides which can be polymerized to polyethers or copolymerized to produce polyesters or polycarbonates. These can be further reacted to produce polyurethanes suitable for applications in furniture, insulation and adhesives. For this to be sustainable, the alkene and other reactants must also be sustainably sourced and we will investigate the use of terpenes, sugar derivatives and unsaturated acid derivatives obtained from agricultural and forestry waste. For example, during the 2011-2012 growing season, the EU processed 1.9 million metric tonnes of citrus producing approximately 950,000 metric tonnes of waste. After removal of water this left 190,000 metric tonnes of residue from which about 14,000 metric tonnes of limonene could be isolated for use as a polymer feedstock. In addition to carrying out the required chemical research, the engineering necessary to scale up the syntheses to pilot plant and production scale will be carried out.

The chemical and mechanical processes associated with isolating materials from biomass and converting them into polymers will inevitably require energy and other chemicals, the production of which will generate carbon dioxide. Therefore, lifecycle analysis will be used to determine all of the carbon dioxide emissions associated with polymer production from both petrochemical and biomass sources. Comparison of the data will provide a quantitative understanding of how much better the sustainable route is than the petrochemical route and will illustrate which aspects of the synthesis are responsible for most of the carbon dioxide emissions. This, combined with energy usage and cost data will allow the project team to concentrate their efforts on minimising these emissions through for example the use of microwave heating rather than conventional heating and the use of alternative solvents such as supercritical carbon dioxide.

In summary, polymers are ubiquitous in everyday life and the polymer industry is a major UK employer. Their scale of production and range of applications means that they are a high priority target to switch from fossil to sustainable sourcing. Successful completion of this project will protect UK jobs, protect the UK supply of these essential materials and provide income through license agreements with overseas manufacturers.

Major beneficiaries of this research will be the UK polymers industry which directly employs 286,000 people and has sales of £18.1 billion pa (2.1% of UK GDP). Over 80% of commercially produced chemicals are polymers and their production consumes 8% of the oil/gas extracted each year. Polymer manufacturers will benefit from the availability of technology which produces polymers from non-petrochemical feedstocks, thus opening new supply chains and sustainable revenue streams as petrochemical resources become increasingly scarce. One of the waste feedstocks is CO2, so the project will turn CO2 from a waste product into a valuable resource to enhance the wealth generating capacity of UK industry. To facilitate the transfer of the technology to these industrial sectors, the project has an Industrial Advisory Board whose members are drawn from polymer related industries (Lotte, Econic, Plaxica, Bayer). The IAB members were involved in defining the scope of this proposal and will also ensure that the research undertaken during the project is that which is most suited for commercialisation.

The polymers industry supplies a vast range of other industries including those in medical, transport, electrical, construction and packaging sectors. Thus, many other UK companies rely on the polymer industry. This proposal will therefore protect the jobs and wealth creation associated with these industries. Ultimately, these goods are used by UK consumers, so the entire UK population will benefit from sustainably sourced polymer containing products by having their quality of life and standard of living preserved. The UK government has legally binding commitments to reduce the UK's CO2 emissions. Whilst utilization of CO2 in chemicals production can only consume a very small percentage of the UK's CO2 emissions, this can be a very profitable thing to do. For example, the polyether needed to prepare current polyurethanes is prepared from propylene oxide which at commercial rates costs $2,000 per tonne. By replacing the polyether with a polycarbonate, up to 40% of the propylene oxide can be replaced by CO2, resulting in a cost saving of ca $800 per tonne. The revenue raised by utilizing a small percentage of the CO2 in this way can then be used to partially offset the costs associated with carbon capture and storage for the remaining CO2. In addition, the current production of polymers from petrochemicals produces large amounts of waste CO2 and this project aims to reduce these emissions by at least 50%.

Another impact of this proposal will be on supply security by moving from internationally acquired oil to native waste (both CO2 and biomass). CO2 and biomass waste will be available for the foreseeable future, but global production of crude oil is expected to peak within the next 40 years. The UK government's very recent decision (17 July 2013) to phase out subsidies for biomass burning over the next ten years also makes this a very timely proposal as much more waste biomass will now be available and its conversion into high value chemicals will become a more attractive option. There will also be impacts on the environment and safety due to reductions in the amount of oil having to be transported across oceans etc.

There will be a significant impact on the future careers of the six PDRAs recruited to carry out this project as they will be ideally placed to continue work in this highly multidisciplinary area. The project will also have an impact on the academic careers of the PI/CIs by leaving them ideally placed to carry out similar work targeted at other commercial products and/or using other sustainable resources in the future. Finally, there is an impact to EPSRC itself which is under pressure from the UK government to fund research which is of commercial value to the UK. This project falls firmly in that area and the applicants will work with EPSRC to highlight this through articles on the EPSRC web site and in EPSRC newsletters.