Industrial Production Processes forNanoreinforced Composite Structures

Project results

This project has received funding from the European Union'sSeventh Framework Programme for research, technologicaldevelopment and demonstration under the Grant agreementno 608746.

What is the purpose of this project?

The main objective of the INCOM project is to develop techno­economically viable solutions and production methods formanufacturing of lightweight structures based on advancedsustainable materials for use in vehicles, aeronauticalapplications and sporting goods. Special attention isdedicated to upscaling of production processes, pilot scaletrials and industrial implementation.

Can you explain this in other words?Lightweight and resistant composite sandwich structures aredeveloped and manufactured for different applications. Thesestructures are reinforced with nanofibrillated cellulose (NFC), anano­scale material derived from cellulose found in biomassand bio­waste.

Glossary

Sandwich composites materials: a sandwich structure is a fabricatedmaterial that consists of two thin, stiff facing sheets joined to either side ofa low density core material or structure. They have high mass specificstiffness and strength. Sandwich materials also offer a number of otherpotential benefits including possibilities for functional integration, spacesaving and modular construction (source: Best Practice Guide forSandwich Structures in Marine Applications www.transport­research.info)

Nanomaterials: materials with at least one external dimension in the sizerange from approximately 1­100 nanometers (source: web.stanford.edu).

Nanofibrillated cellulose (NFC): nano­scale cellulose composed by longand semi­flexible fibrils obtained by top­down disintegration of wood orother plant materials (source: Lee et al. 2014, Comp.Sci.Technol, 105 15­27).

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Executive Summary

During the INCOM project lightweight, sustainable and durablecomposite sandwich structures reinforced with nanofibrillatedcellulose (NFC), were developed for different applications.The main modules of the project were:

nanofibrillar cellulose fibre (NFC) production andmodification processcomposites processing and sandwich structuremanufacturingmechanical testing and verification in counterbalance withmodelling and LCA.

For manufacturing, modification and processing ofnanofibrillated cellulose two approaches were used:

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nanofibrillation of cellulose in a pre­polymer medium. Resinsand sol­gel coatings reinforced with NFC or functionalisedNFC were used in cores and skins of structural sandwichcomposites, to enhance mechanical propertiesdevelopment of nanofibrillation mainly in aqueous mediaand optimisation of the nanofibrillation of bioresidues (e.g.carrot bioresidues)

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For sandwich structures, three types of cores were developedto meet different technical requirements: expanded NFCreinforced bio­based PU foam core, bio­based thermoplasticfoam core and thermoplastic honeycomb core.Pilot implementation of both NFC production routes as well asupscaling evaluation was performed with industrial partners.This project proved that sandwich composite materials canreplace monolithic structures in many applications. This allowssaving by reduction of input materials, weight of the structureand consequently also environmental impact.Demonstrators for automotive components, airplane cabinparts and sporting goods were produced during the project.

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Diehl’s stowage unit of the Airbus A350, called “doghouse”,demonstrated the use of cost effective, thermoplastic flameretardant PC honeycomb core.The stowage unit consists of flat panels, highly stressed parts(crash loads) and quite high level of complexity. Highly stressedareas (front panel and slide) were reinforced with embeddednanocellulose paper.Composite structures with PC core and NFC paper weresuccessfully manufactured and no complications occurred inthe subsequent process steps: milling, grinding, filling, varnishingand final assembly.Improvement options were suggested and ecodesignfeedback was given to the consortium partners.The environmental contribution of the INCOM materials NFC(0,3%) and EconCore Thermhex (1,7%) to the environmentalburden of the stowage unit prototype was assessed to berelatively small, the composite structures were successfullymanufactured and the materials seem to give a positive effectto the structure and weight reduction of the prototype. Theseare important aspects in the context of sustainable lightweightstructures applied in aeronautical applications.

Aircraft stowage unit

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Automotive front bulkhead

The front bulkhead of Axon Automotive Far Platform Chassiswas also selected as a demonstrator. The primary purpose ofthe front bulkhead is to isolate the passenger cabin from theharshness of the engine bay. It protects against fumes,prevents the progression of fire into the cabin and providessome level of structural rigidity in a crash.The comparison of the two prototypes developed, thesandwich bulkhead against the monolitic bulkhead, has shownsignificant improvements, both in terms of environmentalimpact and costs. The application of the honeycomb core inthe sandwich bulkhead results in weight savings and thusavoids use of other materials present in the monolithicbulkhead. The mechanical results in conjunction with the LifeCycle Assessment results show that the INCOM materialsprovide a competitive solution to increase resin properties, withnegligible effect on the manufacturing cost of the resin.

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Skiing pole

Producing sporting goods demonstrators enabled to studyseveral material combinations and to validate high volumeproduction. Properties of NFC resin were found to be veryinteresting in terms of gaining enhanced technical features forsporting goods. A process called filament winding was used toproduce the sporting goods demonstrator, which appears tobe an extremely promising method to be used when utilizingthe features of NFC resins.The eco­efficiency performance is similar for the baselineproduct and the INCOM sporting goods due to comparableenvironmental impacts and life­cycle costs. This also meansthat for the same costs and environmental burden, additionalfunctionality can be created for the sporting goods byapplying the NFC materials of the INCOM project. The LifeCycle Assessment performed on the demonstrator indicated asimprovement options the reduction of the use of carbon fibersand the increase of the amount of INCOM materials applied inthe prototype.

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Conclusions

The objective of the INCOM project was to developlightweight structures based on advanced sustainablematerials for use in packaging, vehicles, sporting goods andaeronautical applications. Major consideration was given toproduction methods with high commercialization potentialand upscaling of production processes.

An ecodesign approach was used and evaluation wasperformed by means of Life Cycle Assessment and Life CycleCosting methodologies right from the early stages. This ensureda path of reduced environmental impact for these newindustrial processes for cellulose reinforced nanocomposites.This project proved that sandwich composite materials canreplace monolithic structures in many applications. This allowssaving by reduction of input materials, weight of the structureand consequently also environmental impact.

The work done opens a completely new exploitation possibilityfor strong environmentally friendly composites andreplacement of traditional state­of­the­art solutions leading tolighter high performance composite structures.

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