The activity aims to develop polyurethane formulations for coating and potting applications with reduced human toxicity by elimination of toxic isocyanate chemistry. This shall at the same time allow further performance enhancement compared to established materials (e.g. environmental stability, permeability, thermal resistance).

Increasing numbers of regulations in Europe (e.g. RoHS, REACH) are implemented targeting sustainable development, environmental impact and protection of human health leading directly to obsolescence of qualified materials, processes and technologies, as manufacturers are forced to change materials compositions, alter manufacturing processes or take the decision to remove materials from the European market. The REACH roadmap for identification of future substances of very high concern (SVHC) indicates to target a wider range of isocyanates. These are pre-cursor substances for the manufacturing of polyurethanes, which are 2-component materials where the end-user may be exposed to the hazardous isocyanate component. This class of materials is widely used for space (coatings, potting, conformal coatings) and launcher (liners, insulation foam) applications. In anticipation of materials obsolescence in the coming years, the utilisation of green polyurethane chemistry should be pursued. Also, there is an ongoing effort in Europe to find suitable substitutes for petrochemicals as raw/precursor material for composites and foams. Recycled polyurethane, a sustainable source, has the potential to offer an environmentally-friendly alternative and examples of research are the activities in the EU RECYPOL programme. Composites and foams are used extensively also in the space industry, even if it can be argued that the volumes are smaller than in other sectors of industry. Nevertheless, ESA is in the process of promoting the use of sustainable technology and considers that a timely approach to replacement of hazardous substances will avoid a crash action on obsolescence. The activity includes the following tasks: - Definition of performance requirements for polyurethanes used on spacecrafts and launch vehicles and formulation of three requirement sets targeting applications as conformal coating, thermal control coating, and foam insulation via spray-foaming. - Revision of state of the art for green and sustainable polyurethane chemistry, including the utilisation of non-toxic isocyanates as well as recycling from industrial production and possibly post-consumer waste. - Trade-off between potential for tailoring of polyurethane material and processing properties and system-level requirements. - Small scale formulation of green polyurethanes for the three target applications, screening testing, and performance optimisation. - Performance demonstration on small demonstrator concepts for the three target applications.