Carbon dioxide (CO2) emissions, the end product of burning fossil fuels or biomass, are largely responsible for the greenhouse effect and thus for climate change. A reduction in CO2 emissions is therefore at the very top of the international political agenda. Trials are running in parallel to explore underground sequestration of CO2 from power stations, thereby removing it from the atmosphere.
It would at first sight seem paradoxical to wish to use energy-poor, inert CO2 molecules. Considerable research and development efforts in recent years have led to new and innovative CO2-recycling technologies and a vision of a CO2 economy. CO2 recycling has quickly become a hot topic for the future for every large company in the chemicals and plastics sector. Wirtschaftswoche reports that even Novel prizewinners George Olah and Joseph Stiglitz have recognized the gas as a future fuel and raw material of the chemical industry.
In the last three years, the US Department of Energy and the German Ministry for Research (BMBF) have each provided some €100 million for research into new uses for CO2. These investments are already bearing fruit. Evonik, BASF and Bayer Material Science are working hard on CO2 polymers. Siemens and BASF demonstrated the first applications in household appliances such as fridge compartments and vacuum cleaner casings at the ACHEMA fair in Frankfurt in June 2012. The automobile and aircraft industries are working on fuels that depend on neither from oil nor biomass, but are instead derived from solar and wind power – and CO2. These are also early days for a new chemical sector: recycling – the cascade use of CO2 as a raw material for the chemical industry. Now new chemical and electrochemical reactions must be discovered and further technologies developed (e.g. the efficient separation and purification of CO2 from the emission flow) to turn the climate killer into a renewable resource.
Alessandra Quadrelli from Lyons University sees CO2 as one of the most important raw materials for the chemical industry in the future. According to her calculations, innovative chemical uses of CO2 could achieve up to 10% of the global reduction in greenhouse gases that is required.
CO2 polymers – new options for the plastic industry
The main new CO2 polymer is polypropylene carbonate (PPC), which was first developed 40 years ago by Inoue, but is only now coming into its own. PPC is 43% CO2 by mass, biodegradable, shows high temperature stability, high elasticity and transparency, and a memory effect. These characteristics open up a wide range of applications for PPC, including countless uses as packing film and foams, dispersions and softeners for brittle plastics. The North American companies Novomer and Empower Materials, the Norwegian firm Norner and SK Innovation from South Korea are some of those working to develop and produce PPC.
Carbon Dioxide as Feedstock for Polymers and Fuels – a challenge for sustainable chemistry