One of the plot points in Ayn Rand’s Atlas Shrugged is the invention of an alloy far stronger, durable and lighter than steel called “Rearden metal”, named after Hank Rearden, the fictional industrialist who invents it in the novel.
One of the plot points in Ayn Rand’s Atlas Shrugged is the invention of an alloy far stronger, durable and lighter than steel called “Rearden metal”, named after Hank Rearden, the fictional industrialist who invents it in the novel. Rearden metal becomes something of a byword for a revolution in manufacturing in the course of the novel. Atlas Shrugged came out in 1957, and it spoke of a material that was to steel what steel was to iron. Six decades hence, steel still remains supreme. But the hunt for a substitute has, depending on end-use, variously thrown up plastic, aluminium, titanium, carbon fibre and whatnot. An unlikely candidate is a wood, or more specifically, nanocrystalline cellulose (NCC)—nanofibres made of wood pulp. Wood, you would think, is lighter yes, but what about strength? Researchers at Kyoto University and auto-parts suppliers to Japanese car-makers like Toyota are betting their top yen on cellulose nanofibers to substitute steel, and even the popular carbon-fibre, in the decades to come. They say, as per a Reuters report, that it is one-fifth weight of steel and can be upto five times stronger.
Making NCC starts with the purification of wood. Substances such as lignin, a phenolic polymer that lends wood its rigidity, and hemicellulose, amorphous, randomly arranged heteroplymers that have little strength, are removed. The remainder is pulped and hydrolysed in acid to remove any remaining impurities. After the acid treatment, it is concentrated into a thick paste that can be used to laminate surfaces or is processed into nanofibril strands. The latter are hard, dense and hardy, but can be moulded into different shapes.
NCC has been widely used in the past—by Pioneer Electronics, the Japanese company, to make flexible electronic items, by IBM to make computer parts and by the US army to make lightweight body armour and ballistic glass, among others. The Kyoto University researchers, Denso Corp. (Toyota’s largest supplier) and DaikyoNishikawa Corp are melding NCC with plastic to make a material that can some day be used to make entire cars. At the moment, though, the research is focussed on developing a car by 2020 that has cellulose-nanofibre parts.
The focus on lightweight cars stems from the push for electric cars worldwide. Given these will need to have heavier than conventional batteries, the car weight goes up significantly. A lighter car is double-blessing—it balances out the weight of the batteries while a lighter car itself will need fewer such batteries to be powered. But, the wunder material cellulose nanofibre is turning out to be, it still is not cost competitive against carbon-fibre. Scientists, though, are optimistic. Plant waste—branches and even twigs—could one day be used to make cellulose nanofribres and probably even waste paper. That may bring costs down.