VOICE OVER: Rubber is useful stuff.
And if you take some rubber, and reinforce it with rigid particles, you can make it stiffer - which can be even more useful.
Things like tyres and belts and shock absorbers all need stiff rubber that can resist deformation.
This material property is known as a high elastic modulus - while stretchier rubber would have a low modulus.
It’s easy to increase the elastic modulus by adding rigid particles, but what’s harder is stopping stiff rubber cracking under repeated stress.
The ability of a material to resist cracks under cyclical stress is known as its fatigue threshold. And the fatigue threshold of rubber has stayed the same for decades.
But now a team of researchers have created a new type of rubber with a fatigue threshold 10 times higher than before.
Traditional reinforced rubbers, or Particle Reinforced Elastomers as they are known, are made up of networks of rigid particles and crosslinked polymers.
The crosslinks effectively weld the polymer strands together This makes the rubber stiffer, but also more brittle.
The new rubber is a little different. It’s still made of polymers and reinforced with added rigid particles, but the polymers are much longer with fewer crosslinks. Instead, these long strands are entangled with one another - like a bowl of spaghetti, with the remaining crosslinks locking this structure in place and stopping the polymers coming apart.
