[HISTORY??]

50 YEARS FROM NOW: CHALLENGES AND OPPORTUNITIES

1. The ultimate carbon fibre: Better properties?and?lower cost?

Can we reduce the cost and improve the sustainability of carbon fibre production? Alternatives to PAN precursor, such as bio-based polymers, have the potential to reduce environmental impact, while polyolefins offer a lower cost alternative. More energy efficient processes are required.

Can we produce a fibre with both high modulus?and?high failure strain??Recent studies on simulated carbon fibres have shown that a failure strain of 8% (or a tensile strength of 19,000 MPa!) would be possible, while experiments on very thin carbon fibres (3 μm) demonstrated tensile strengths of 15,000 MPa. To achieve these values further reduction of fibre defects is required.

2. Thermoplastics head for a breakthrough? … but thermosets fight back

What is needed for thermoplastic composites to realise their full potential? For automotive mass production the main bottleneck might be the investment cost for composite processing equipment, while improved thermoplastics may be needed to address higher temperature and durability requirements in aerospace. In-situ polymerising thermoplastics could combine the processing advantages of thermosets with the toughness and better recyclability of thermoplastics.

Thermosets are also making progress. Much shorter, tuneable processing speeds are now possible, in combination with longer shelf lives. Innovations in epoxies, polyesters, vinyl esters and polyurethanes are expected to improve their thermo-mechanical properties as well as their processing characteristics.?

3. The nano story: A dream, or a future reality?

The application of carbon nanotubes (CNTs) and graphene in composites is currently limited to the improvement of some non-mechanical properties. To improve mechanical properties, the concept of “hierarchical reinforcements” (reinforcements of different length scales, like CNTs and carbon fibres) must be advanced and powerful multiscale models will be needed to simulate the potential beneficial effects on composite properties.

4. Hybrids: Combining the best of both worlds

Fibre-fibre hybrids – combining fibres with different mechanical properties – have the potential to create composites with unique properties, but can scientific innovations be successfully transferred into real materials and products??

Several types of macro-scale hybrids are receiving industry attention. Metal-composite hybrids can serve as local and lightweight reinforcements for metallic structures, while overmoulding of composite parts with stiffening ribs or connection elements is already realising a breakthrough.?

5. Bio-based and bio-inspired composites

Bio-based fibres started their move into the world of composites two decades ago, but issues of moisture sensitivity and cost still need to be addressed. Real breakthroughs are needed to make thermoset epoxy and polyester matrices truly bio-based. On the contrary, thermoplastics could profit from the strong societal push towards ‘zero impact’ plastics in consumer goods.

Composites of all kinds offer great possibilities to mimic the best of nature, but how will scientists transfer their inventions into reality??

6. Smart materials and intelligent structures: Composites can do both

Smart materials and intelligent structures are gradually transitioning from lab and prototype to the real world, but how can this process be accelerated and expanded to many more applications??

Multi-functional composites show great promise. Composites can integrate sensors, actuators and even batteries inside their structure and this simple fact has recently led to interesting innovations, but more are needed to fully realise potential applications in, for example, electric and autonomous vehicles.?

7. Mass production: The real breakthrough of “fast” composites needs to happen now

Materials and process innovations have prepared the path towards the mass production of both thermoset and thermoplastic composite applications. Cost reduction is the driving force: material and manufacturing cost, cost of ownership, and environmental cost. More cost-efficient materials and automated, robotised production methods are under development, and there is much more to come.?

8. 3D printing:??A panacea or only for niche markets?

The challenge is to intelligently combine the strength and stiffness of fibre reinforced composites, which is heavily orientation dependent, with the essence of the 3D printing process itself, namely to follow a path which creates a given shape in the fastest way. Such a path is not necessarily the best one, from a mechanical performance point of view.?

9. Multiscale modelling: Bridging the gap with metals and plastics

Composites lack the integrated material-process-product simulation chain established for metallic and plastic products. Progress has been made in product and process simulation and material properties prediction, but much work is still needed to dramatically reduce the development cost of new composite applications.

10. An improved life cycle assessment (LCA): Recycling, reuse and repair?

Important technological progress has been realised in recycling of carbon and glass fibre composites. Economic viability will require challenges in logistics and upscaling of the processes to be answered and markets for recyclate to be developed.

Maintenance and repair have been addressed extensively in aerospace, but can these solutions also be applied in sectors like automotive and marine? Faster, less costly NDT methods are needed.?

For the full story read our celebration of?50 Years of Composites?>?https://jeckiosk.milibris.com/reader/216bd317-d7cf-4fea-a1aa-9590ef040e01?origin=/50-years-of-composites/50-years-of-composites/n1-2020??