About 1 billion rubber tires—which are highly durable and non-biodegradable—are generated worldwide every year. Only 40% get recycled into low-value-added products, 49% are incinerated to generate energy, and at least 11% end up in landfills.
While many go into landfills, landfill sites are running out of space. There is also a risk of the consequential leachate causing environmental pollution. Further, burning rubber produces toxic substances that pose health and safety concerns.
To make real use of all those tires going to the landfill, researchers from the National University of Singapore are using waste rubber tires to create super-light aerogels. These aerogels are highly absorbent, extremely durable, and efficient at trapping heat and sound. That makes them the perfect insulation material, whether for industrial buildings or for personal items such as jackets and shoe insoles. They’re also a high-value product, unlike other recycled rubber products.
To create the rubber aerogels, researchers first blended recycled car tire fibers into finer fibers and then soaked them in water and very small amounts of chemical cross-linkers. Next, they dispersed a mixture of rubber fibers and eco-friendly solvents using a stirrer for 20 minutes. The team then freeze-dried the uniform suspension gel at minus 50 degrees Celsius (120 degrees Fahrenheit) for up to 12 hours to produce rubber aerogels. The researchers say the whole process is “simple, cost-effective, and eco-friendly.”