World’s Toughest Material Created by Tying Slip Knots into Weak, Commercial Thread

Nicola Pugno, at the University of Trento in Italy, has succeeded in making by far the toughest material in the world — by taking a conventional piece of fiber… and tying it in a slip knot.

The toughness of a material is measured by how much energy it can absorb before breaking. Strength, on the other hand, is a measure of how much force a material can support: Glass is strong, but not tough; Rubber is tough, but not strong. Toughness is usually measured as the number of joules (think newtons rather than heat) that a gram or cubic meter of a material can withstand before breaking. Kevlar, for example, can withstand 80 joules per gram before snapping, while spider silk can withstand 170 joules per gram. On the upper end of the scale, in a realm that is mostly theoretical for now, carbon nanotubes and graphene are close to 1,000 joules per gram.

In Pugno’s research paper, he is reporting that he has boosted a standard, commercial Endumax polymer fiber from a toughness of 44 joules per gram up to 1,070 joules per gram — by far the toughest material in the world – just by tying the fiber into a slip knot. As the loop of Endumax slips against the bight, massive, mind-boggling amounts of energy are dissipated through friction. Once the loop has been pulled all the way through — once there’s no more friction to be had — the fiber breaks. The paper suggests that Pugno has tried a wide variety of knots, with the basic overhand knot (with a few added coils) being very effective. Basically, the more friction provided by the knot — the more coils, the longer the loop — the better.

Moving forward, Pugno is attempting to patent his method for creating super-tough materials. While the slip-knot approach is certainly very exciting, it isn’t immediately clear how easy it would be to introduce it into an existing manufacturing process. It’s easy enough to tie a knot in a single thread — but a Kevlar vest is made of millions of fibers. A robot or other automated machine could probably tie the knots — but what kind of knot density, and thus added manufacturing cost, are we talking about?

I implore you to put the question of commercial viability aside for just a moment, though, and bear this in mind: Pugno theorizes that knotted graphene thread could obtain a toughness of 100,000 joules per gram — about 1,250 times tougher than Kevlar. Imagine the bullet-proof vests you could fashion! Heck, they’d be rocket-proof.

www.extremetech.com...
nextbigfuture.com...

Amazing how such a small thing might increase the toughness of a material so much. I wonder if this slipknot technique can actually be used in the mass production materials which require toughness.

The bullet proof vest.....while the strength and toughness of the material is important, it would still flex. And if it flexes, some of the energy will pass through into the person.

Unless you can dissipate that energy before it makes human contact, it is no less deadly.

Originally posted by bigfatfurrytexan
The bullet proof vest.....while the strength and toughness of the material is important, it would still flex. And if it flexes, some of the energy will pass through into the person.

Unless you can dissipate that energy before it makes human contact, it is no less deadly.

Ribs being broken isn't uncommon.

Originally posted by Covertblack

Originally posted by bigfatfurrytexan
The bullet proof vest.....while the strength and toughness of the material is important, it would still flex. And if it flexes, some of the energy will pass through into the person.

Unless you can dissipate that energy before it makes human contact, it is no less deadly.

Ribs being broken isn't uncommon.

I can vouch for that from direct experience ;-)

Cheers - Dave

reply to post by Covertblack


Right.

But the article made the cheeky statement that it would be "rocketproof".

Sure...the material will survive. Wrapped around pieces of human hamburger meat.

Originally posted by bigfatfurrytexan
reply to post by Covertblack

 

Right.

But the article made the cheeky statement that it would be "rocketproof".

Sure...the material will survive. Wrapped around pieces of human hamburger meat.

I remember getting a vest with a group of people. Someone asked, "what if you're shot with a 12 gauge?", to which the instructor said you will wish you had died faster.

I just wonder how useful this could really be considering it's a knot...in a string....basically

The material isn't increased in toughness, the configuration of the material has used its flexibility to spread the force over a larger area (which isn't a bad thing of course) and used that configuration so that it will give more so, in the short term, it can 'technically' absorb more force.

And each time it has to absorb, the total amount it could support next time is severely weakened because the knot isn't going to open back up once the force has been removed.

I sure has hell wouldn't want to wear a BP vest made of that. Sure it won't break, but it won't keep the bullet from going through me either...it will just go through with it. Maybe they could use it to beef up existing vests as a cushioned layer on one side, but the amount of force going through would be negligibly reduced.

I feel we will have to wait for more tests.
This tech is hard to consider when Newtonian fluid and ceramic vests are still slowly being perfected.