Singapore – Researchers at the National University of Singapore (NUS) have developed a way of converting rubber from scrap tires into super-light aerogels with potential applications in a wide range of industrial and consumer products.
The rubber-based aerogels are “extremely light, highly absorbent, very durable and… very efficient at trapping heat and sound, NUS announced in an 18 March release.
Every year, about 1 billion scrap tires are generated worldwide, with 40% recycled into products, 49% incinerated to generate energy and at least 11% sent to landfills, notes project leader associate professor Duong Hai-Minh.
“By converting waste rubber tires into high-value aerogels, we could enhance the monetary incentive for recycling rubber and in turn, cut down rubber waste,” said the research head at NUS department of mechanical engineering.
In the patent-pending technology, recycled car tire fibres are first blended into finer fibres prior to soaking in water and a “very small amount” of chemical crosslinkers.
The mixture is then dispersed to form a uniform suspension gel, which is freeze-dried at minus 50 degrees Celsius for up to 12 hours to produce rubber aerogels.
“The entire production process takes between 12 to 13 hours to complete and it only cost less than S$10 to produce a sheet of rubber aerogel that is 1 sqm in size and 1cm thick,” said assoc prof Duong. “The process can also be easily scaled up for mass production.”
Potential applications for the rubber aerogels include “extremely light” rigid foams. absorbents for removal of spilled oil and sound absorption products.
The rubber aerogels are also said to be 27% more effective than the commercial foam sound insulating materials, while a 2.5cm-thick piece has a ‘heat transfer limit’ equivalent to 25 standard glass window panes.
More particularly, NUS foresees uses as insulation materials for subsea systems, oil refineries and industrial buildings, and also in homes, refrigerators, as well as personal items such as jackets and shoe insoles.