Abstract

Fibre reinforced polymers are important materials used in aviation due to their excellent specific properties enabling the reduction of fuel consumption. For example, carbon fibre reinforced epoxy resins are used in fuselage and wing structures. Glass fibre reinforced phenolic resins are mainly used for the interior panels due to their low weight and favourable fire properties. All these composite materials used in aviation have one thing in common: they are man-made. Renewable materials like bio-fibres and bio-resins are under investigation for a long time for composites but they did not made it into modern aircraft in high amounts yet. The project ECO-COMPASS under Horizon 2020 aims to bundle the knowledge of 17 partners from China and Europe to develop ecological improved composites for the use in aircraft interior and secondary structures [1]. Bio-based reinforcements, epoxy resin and sandwich cores are developed and improved for their application in aviation. Furthermore the use of recycled carbon fibres to increase the mechanical strength and multifunctional aspects of bio-composites are evaluated. In order to withstand the special stresses in aviation environment, protection technologies to mitigate the risks of fire, lightning and moisture uptake are under investigation. An adapted modelling and simulation will enable the optimization of the composite design. Electrical conductive composites for electromagnetic interference shielding and lightning strike protection are under investigation in ECOCOMPASS as well. The cooperation includes the exchange of knowledge and materials in order to optimize the development of ecological friendly composites.

Abstract

Low flammable foam-like materials based on renewable bio-based polymers and sodium montmorillonite clay (MMT) were created using water as a solvent and following a simple freeze-drying process. Composites were formed by adding layers of the previously created gel precursors to a Polyvinyl alcohol / MMT based aerogel. A multi-step and a one-pot processes were followed to make the multi-layered aerogels, and the resultant properties of the different processing systems were compared. Similar adhesion between layers was observed in both processes although the multi-step required a longer manufacturing time.

With the aim of improving the mechanical properties, chemical crosslinking of the Polyvinyl alcohol base was induced prior to lyophilization by immersing the material in a sodium borate solution. It was found that the mechanical response under compression was enhanced in regards to the non-crosslinked systems. A highly retardant composite material was fabricated by superposing an alginate/MMT at the external layer as the most promising system for fire protection