Global demand for rubber is soaring, led primarily by the growth in tyre consumption as the developing world increasingly takes to the road. However, since up to 30 per cent of automobile tyres consist of ‘carbon black’ – a petroleum-based reinforcing filler – the knock-on effects of this boom come with environmental consequences.

Furthermore, the worldwide supply of carbon black is proving relatively unsustainable. Katrina Cornish, an Ohio Research Scholar and Endowed Chair in Biomaterials at Ohio State University, explains:

‘At the moment there’s no global surplus of carbon black, and the demand is going up every year in parallel with the demand for rubber, which is why we’re going to have a shortfall in the near future, which is going to be pretty devastating if we don’t have any alternatives in place.’

Dried and ground tomato skins (top) and eggshells (bottom) are shown after coarse, medium, and fine processing before being added to rubber (Image: Kenneth Chamberlain/Ohio State University)

Could so-called ‘sustainable rubber’ produced using industrial food waste be a solution? Cornish and fellow researchers at Ohio State have developed the technology by taking advantage of the vast quantities of tomato peel and eggshells which are otherwise thrown away each year in the production of various canned or otherwise processed food products. In America alone, up to 50 billion eggs are cracked in commercial food operations annually, while the majority of the 13 million tonnes of tomatoes eaten in the country each year are peeled and discarded in similar circumstances.

The processed rubber has proven to be just as tough and reliable as brand new rubber, and scaling up usage of this alternative to the existing carbon black filler could one day have a significant impact on meeting the global demand for tyres. Says Cornish:

‘I do think that there’s the potential here for a real win-win situation. Everybody can make money. It’s environmentally-friendly. Tomato peel is also light-weight, so you could actually reduce [tyre] weight, which is a good thing as well. We may find that we can pursue many applications that were not possible before with natural rubber.’