Reinventing the Tyre: using new materials to prevent pollution – Amelia Doran

Tyres are generating tiny microplastics which can be blown to remote, ice-covered areas across the globe and enter the ocean. These particles are increasing the melting speed of these areas of the ice, contributing to rising sea levels and ocean pollution. CarbonX, based in the Netherlands, thinks the solution lies in using their novel carbon material to improve tyre wear and particle emission without sacrificing performance.

The macro microplastic problem

Microplastics are a major polluter: almost invisible plastic particles shed in a range of processes, which are wreaking havoc on the environment. While some sources are well known, like exfoliating beads or clothing production and laundering, other major contributors are less well-known, like the tyre.

Over its lifetime, the average tyre will lose around 4 kg of microplastics, leading to a global annual total of 6.1 million tonnes, according to Andreas Stohl, a researcher at the Norwegian Institute for Air Research.

Tyre microplastics are already a major source of ocean pollutants, with an IUCN study suggesting tyre microplastics represent 53% of microplastic pollution in the Mediterranean. However, these microplastics are also involved in a more nuanced pollution issue: these particles are small enough to be carried by the wind, leading to over 80,000 tonnes reaching ice-covered areas, Stohl’s research group has found.

These microplastics, which are dark in colour due to the use of carbon black in tyres, are much more effective in their absorption of heat than their light-coloured counterparts, meaning their presence in snow or ice-covered regions accelerates the melting of polar ice caps, and contribute to the global rise in sea levels.

A tyred formula

These microplastics are created by the friction between the tyre and road surface, which the driver feels as grip. Grip is just one of the three major properties of a tyre, in addition to rolling resistance, linked to fuel efficiency, and abrasion resistance, also seen as the milage of the tyre, with lower abrasion resistance increasing microplastic pollution. These forces are all connected, and as such, attempting to improve one leads to the reduction of another. Silica was originally added to tyres to improve rolling resistance and grip but worsens the abrasion resistance of the tyre. In response to this, carbon black was added to reinforce tyres, but this reduced some of silica’s grip improvement and made processing more difficult.

The EU will bring in new regulations in May 2021, which mean tyres must be labelled according to their properties, including their abrasion resistance, and will be required to meet wear standards, so a solution is needed. And fast.

‘Xtraordinary’ improvements

CarbonX is a novel carbon compound, with a structure formed from a 3D mesh of equally spaced and interconnecting carbon filaments forming a regular hexagonal repeat. It has excellent reinforcement properties, which lend well to its inclusion in tyres as has been demonstrated in tests.

CarbonX is a compound made from a 3D mesh of interconnected carbon filaments as seen in the above electron micrograph (Image courtesy of CarbonX.nl)

In their laboratory tests, the addition of CarbonX to winter tyres improves abrasion resistance by 12%, while grip measures were increased and fuel efficiency maintained. This is combined with the possibility of a renewable production method, easier processability and reduction of CO2 emissions.

If the global tyre market increased abrasion resistance by just 10%, this would represent a reduction of 610 million tonnes of microplastics being released into the oceans and ice-covered areas. For a market worth over $155.3 billion in 2018, and forecast to increase, the value of this reduction should be obvious, both in environmental terms and customer satisfaction.

CarbonX is allowing an increase in abrasion resistance without decreasing the grip, pushing forward a consumer-, and producer-friendly alternative to the common tyre. Without a remarkable change in vehicle handling, CarbonX has the potential to make a truly remarkable change on the arctic landscape.

References

CarbonX, 2021. Create a better world: Smart and sustainable carbon solutions. [Online] Available at: www.carbonx.nl [Accessed 15 January 2021].

Carrington, D., 2020. Car tyres are major source of ocean microplastics – study. [Online] Available at: https://www.theguardian.com/environment/2020/jul/14/car-tyres-are-major-source-of-ocean-microplastics-study [Accessed 15 January 2021].

European Tyre & Rubber Manufacturers Association, n.d. Addressing tyre and road wear particles. [Online] Available at: tyreandroadwear.com [Accessed 15 January 2021].

Evangeliou, N. et al., 2020. Atmospheric transport is a major pathway of microplastics to remote regions. Nature Communications, Volume 11, p. 3381.

Kann, D., 2020. Microplastics from your tires are likely reaching the most remote places on Earth, study finds. [Online] Available at: https://edition.cnn.com/2020/07/14/world/microplastic-pollution-arctic-air-transport-climate-change-scn/index.html [Accessed 15 January 2021].

Root, T., 2019. Tires: The plastic polluter you never thought about. [Online] Available at: https://www.nationalgeographic.com/environment/2019/09/tires-unseen-plastic-polluter/ [Accessed 15 January 2021].

SIXDEGREES, 2020. Over 200,000 tonnes of plastic leaking into the Mediterranean each year. [Online] Available at: https://www.sixdegreesnews.org/archives/29460/over-200000-tonnes-of-plastic-leaking-into-the-mediterranean-each-year [Accessed 21 January 2021].