From Science & Research
From Science & Research Bioplastics IN SPACE Combining high strength with low weight, corrosionresistant, and shapable into almost any form, composite materials are a key ingredient of modern life: employed everywhere from aviation to civil engineering, sports equipment to dentistry – and also a vital element of space missions. But they have some less desirable aspects: made from petroleum products, they are non-renewable in nature and also non-recyclable. So the European Space Agency (ESA – Paris, France) is working with Côte D’Azur University (Nice, France) on a new breed of space-quality composites made from wholly sustainable sources. Testing biobased expoxy “And when we say biomass we don’t mean growing new crops especially for this purpose, but rather reusing existing biobased material cheaply and efficiently – namely used vegetable oil, timber waste, and oceanic algae”. The idea came out of a discussion with Alice Mija of the Nice Institute of Chemistry (ICN) at Côte D’Azur University in France. “It’s a very ambitious and challenging project – to produce 100 % biobased thermoset resins for space – which draws on a lot of different chemical, engineering, and industrial expertise”, she comments. Europe’s Vega launcher is largely made from composite materials As their name suggests, composites are made from two or more separate materials, combined together to obtain an optimal combination of physical characteristics. ‘Thermoset’ composites are among the most robust examples. They are made from resins which are blended with fibres or fillers for added strength – the same approach as adding steel piles to concrete to make reinforced concrete – which are then ‘cured’ through heating, pressure or chemical reactions to solidify them. Exploring alternatives “The problem with the classical thermoset resins we use to make spacequality composites is that they are petroleum-based, so by definition they come from a non-renewable resource”, explains ESA materials engineer Ugo Lafont. “So we had the idea of exploring alternatives – could we use biomass as a new source of molecules for these resins, harnessing the same kind of chemical processes? “Obviously the desire for greater sustainability by avoiding the use of petroleum products is one important driver of this work. In addition one of the key chemicals used for thermoset production, bisphenol-A, is in the process of being restricted by the European Union’s Registration, Evaluation, Authorisation, and Restriction of Chemicals, REACH, because of its hormone-altering and mutagenic properties. It has already been banned for food packaging products, and further restrictions will come in future”. Composites development 38 bioplastics MAGAZINE [05/22] Vol. 17
Magnetic for Plastics www.plasticker.com • International Trade in Raw Materials, Machinery & Products Free of Charge. • Daily News from the Industrial Sector and the Plastics Markets. • Current Market Prices for Plastics. • Buyer’s Guide for Plastics & Additives, Machinery & Equipment, Subcontractors and Services. • Job Market for Specialists and Executive Staff in the Plastics Industry. Up-to-date • Fast • Professional The cooperation takes the form of a part-sponsored PhD and now post-Doctorate research, supported through ESA’s Open Space Innovation Platform, sourcing promising new ideas for research from academia, industry and the general public. Extreme challenges of space Post-Doc researcher Roxana Dinu adds: “We’ve focused on space because if we can design materials to resist all the peculiar factors of the orbital environment – such as extremes of temperature and radiation as well as sustained hard vacuum encouraging unwanted ‘outgassing’ of fumes – then they should also be suitable for a very wide range of applications on Earth too, such as the aerospace, maritime and construction sectors”. So far numerous 100 % biobased monomers have been synthesized by Mija’s group at laboratory scale, then their formulations into usable resins were studied and optimized. The space-qualification tests are currently ongoing by using the project’s specialist facilities at ESA’s ESTEC technical Centre in the Netherlands (Noordwijk) as well as Ugo adds: “An important aspect of the project is that we want to adapt existing industrial processes for producing these new thermosets, we don’t want to have to reinvent the wheel”. The project is also looking into the idea of harnessing natural materials for the other composite ingredients, Carbon-fibre composite sample using bio-based epoxy ESTEC, ESA’s technical heart Thales Alenia Space in Cannes, a near neighbour of ICN – Côte D’Azur University. Scaling up – and going all natural The next step in this three-year project will be to manufacture the composites at larger, demonstrator scale, then talk to companies about industrial production. resulting in 100 % biobased composites. “Conventional carbon fibres are not recyclable, so we are looking into the use of natural alternatives, such as plant fibres such as flax or hemp, for certain uses”. The 3 Rs: reuse, recycle, repair The great drawback of today’s thermoset composites is that they cannot be melted, reformed or dissolved, so are not recyclable. Disposing of them can prove challenging, potentially involving grinding them down to powder – while from 2025 the disposal of composite wind turbine blades in European landfills will be banned. The project is looking into the potential of composites able to achieve the ‘3 Rs’ – reuse, recycle and repair. Mija says: “100 % biobased composites are not inherently recyclable either – it comes down to the chemical formulation used to make them, but we are actively exploring reuse possibilities. We have used a nontoxic and easy-to-prepare solution, to recover vegetable fibres and recycle the 100 % biobased resin, which was then used for the production of a second generation of composites. The industry is eager for recycling solutions, so the potential here is enormous”. AT https://www.esa.int/ bioplastics MAGAZINE [05/22] Vol. 17 39
