- Today we're gonna explore
how we got from this,
to this.
Let's cut open a (beep) tire.
(upbeat music)
Polymer.
Pop.
This cars down to the atom.
Science
Ha ha ha.
Rubber has been around forever.
We know that Mayans were using the sap from
the rubber trees over 4,000 years ago.
Raw rubber, or latex occurs naturally.
Harvesting natural rubber is difficult
for a lot of reasons.
Enter: synthetics.
So in 1931, American company DuPont successfully
industrialized synthetic rubber.
They did this by taking petroleum derived monomers
like this ethylene, and bonding it to other molecules
to form long chains like this: poly-ethylene.
The monomer becomes a polymer.
That's what that means.
You're probably wondering:
hey, are my tires real rubber, or synthetic rubber?
Your car's tires are probably mostly synthetic,
but if you drive a bus, plane or a tractor,
there's probably more natural rubber in your tires.
So, how did we get from a white blob
to a solid, black tire?
Vulcanization.
Vulcanization makes rubber tough,
and we have Charles Goodyear to thank for that.
He accidentally dropped latex and sulfur together
on his stove top.
And guess what?
Tougher rubber.
Goodyear died broke, though.
He invented a process perfect for making tires
one hundred years before cars.
Goodyear tires?
That's not his company.
That's just an omage.
Nicoli Tesla did not found Tesla.
With heat as a catalyst, the sulfur molecules
act like bridges between polymers binding them.
What's a catalyst?
Well it's like when you're at your ex-wife's wedding.
Everybody's just millin' about.
Well, there's a punch bowl there.
Drop a little homemade LSD in that,
you got yourself a party.
Party.
Paarrty.
Paarrrttyyy.
They found that adding some metals
to the vulcanizing process helped things along,
and one that was particularly good was zinc.
It made the rubber tough, but it also made the rubber white.
Like this.
That's why the Michelin Man looks like
he's made out of marshmallows.
- Only our standards are high.
- Carbon black,
a waste product of the petroleum industry,
was added to make the tires last longer,
but it changed the color of the tire to black.
The process was a little bit more expensive,
so they only used it on the part of the tire
that hit the road: the tread.
Black tread, and white walls.
Whitewalls!
So how much harder is carbon-black rubber
than regular, white rubber?
We're gonna find out.
(power tool whirs)
(clatters)
Round two.
(power tool whirs)
(laughs)
Rubber!
Oh, it smells so bad.
Okay, this lit right up.
This smells horrible.
I think I'm gonna throw up.
And now, for the carbon black tire.
(power tool whirs)
Holy (beep)
Guys, it's not melting!
It's smokin', but it's not meltin'.
Thanks, carbon.
Okay, look at this.
So this is the non-carbon black rubber
that they just used to use on tires.
You can see how it's a goopy mess.
Look, it's comin' off on my fingers.
'Cause it got so hot that it actually melted the rubber.
That's what we were talkin' about.
You can see here on the road,
it's this sticky little mass.
This tire, with the carbon, it's nice and solid still.
Yeah, it heated up.
Yeah, it spit off these pieces.
This is still whole tire.
It didn't melt.
That's the beauty.
Nowadays, tires contain all kinds of stuff.
(yells over chainsaw engine) What kind of stuff?
Let's find out.
(chainsaw revs)
Woooooo, rubber!
Boy, that was fun.
And easy.
What we've got here is a radial tire.
And we got the first one of these bad boys in 1949.
So, what is in this?
Here, we got this nice, hard carbonized rubber
we've been talkin' about.
And then up in here, we got nylon, we got vinyl.
In here, you're gonna see we got a lotta steel threads.
And then a thicker caliber thread down here.
That's what's gonna seal to your wheel.
This is some heavy-duty (beep).
And, if this was a self-sealing tire,
you'd have a bunch of goop in here
that would seal up a hole if ya ran over a nail,
or I don't know, a porcupine.
'Cause those are sharp.
Rubber has gone from being a flimsy, fragile novelty,
to a modern automotive necessity.
I mean, picture a car without rubber:
no belts, no hoses, no tires.
You're goin' nowhere.
And all that fancy fiber and plastics,
we wouldn't have any of that without polymer research
inspired by rubber.
Well I hope you enjoyed gettin' into
the nitty-gritty properties behind,
what I think, is the most overlooked,
and overworked part of your car with us today.
Please like, comment, share, and subscribe.
I can't wait to do more of this science with you guys.
Hi mom.