How green can cars eventually be made? Well, in addition to solar power and hemp-based interiors, automobiles might one day sport tyres made from trees.
Wood science researchers at Oregon State University (OSU) say there’s potential to use microcrystalline cellulose — something that can be made from almost any type of plant fibre — to replace some of the silica used as a reinforcing filler in rubber tyres.
Not only would such tyres be greener than today’s versions, but they could be better at resisting heat buildup and would require less energy — hence, cost — to produce.
“We were surprised at how favourable the results were for the use of this material,” said Kaichang Li, an associate professor of wood science and engineering in the OSU College of Forestry, who conducted this research with graduate student Wen Bai. “This could lead to a new generation of automotive tire technology, one of the first fundamental changes to come around in a long time.”
Cellulose fiber has been used for some time as reinforcement in some types of rubber and automotive products — such as belts, hoses and insulation — but never in tyres, where the preferred fillers are carbon black and silica. Carbon black, however, is made from increasingly expensive oil, and the processing of silica is energy-intensive. Both products are very dense and reduce the fuel efficiency of automobiles.
An inexpensive, easily available, light and renewable alternative could be microcrystalline cellulose, a micrometre-sized type of crystalline cellulose with an extremely well-organised structure. It is produced in a low-cost process of acid hydrolysis using nature’s most abundant and sustainable natural polymer — cellulose — that makes up about 40 to 50 per cent of wood.