Routes towards CO2-based materials for building, textiles and packaging

The urgently needed phasing out of fossil resources requires that we should critically assess for which applications (virgin) carbon-based materials are essential and in which cases it is possible to dematerialise. Nevertheless, it is anticipated that a large fraction of the functionalities that are currently supplied by carbon-based materials will remain essential in the decades to come. Therefore, a transition to new high performance materials and products made from non-fossil renewable feedstock needs to be realized. In the past decade, various studies have pointed out that this transition can be realised by the utilisation of three particular alternative sources, exclusively. These are biomass, recycled materials and carbon dioxide (CO2). Out of these three pathways, the development of processes for the conversion of CO2 into polymers that can be used for plastics is lagging behind. This lag can largely be explained by the technical challenges that still exist for sourcing and subsequent conversion of CO2. As a result, the currently available technologies are not yet cost-effective. Nevertheless, driven by the increasing demand for fossil-free resources and increasing levels of CO2 taxation, a wide range of new chemical and microbial conversion technologies have been developed in the past decade, some of which are currently being investigated at an industrial level. This study identifies and assesses the most relevant sources and conversion routes for CO2-based materials from a technical perspective. A specific focus is placed on the conversion of CO2 into polymers that can be used in packaging, building and textile applications. The present study identifies specific CO2-to-product pathways and the five parameters that determine the technical, economic and ecologic feasibility of these routes, those being: • The CO2 content of the polymer, i.e., the fraction of carbon that originates from CO2 • The energy required for the conversion process(es) • The technical feasibility and yield of the conversion process which is reflected in the technology readiness level (TRL) number • The oxidation state of the carbon within the target polymer • The lifetime of a product that determines the potential of CO2 capture and storage. Based on the performed assessment, the electrochemical conversion of CO2 can be considered one of the most promising routes. Furthermore, all ‘CO2-to-product’ routes score low on the energy required. Currently, most CO2 conversion processes have a low TRL, which is not surprising given the relative new research area. Although multiple polymers (polyethylene, polypropylene and polyglycolic acid) score excellent on the CO2 content in the polymer, only applications in building and construction have a high CO2 capture potential due to their long lifespan. Fast moving consumer goods, like clothing and food packaging, have a short lifespan, and although these materials are partially recycled, there are inherent recycling losses. Overall, these products are considered to be a less effective carbon sink and as such, using CO2 as feedstock will have a lower impact for these applications. Finally, it is concluded that the economic potential of each of the identified CO2 conversion methods heavily relies on whether the technology can mature quickly and significantly, and on the extent to which they can be coupled to excess renewable energy streams in the future. Additionally, a heavy driver in the economics of these solutions will depend on the taxation of the carbon offset that is mitigated by a specific route and whether the potential for long term carbon capture will be taken into account for such taxation.