This NBC Learn video explains charts the history of nylon, the first synthetic fiber developed for mass production, and explains polymers, polymerization, amide links and polyamides. Includes demonstration of the Nylon Rope Trick: making nylon fiber in a lab beaker. (Beta-sheet protein courtesy Markus Buehler, MIT)
Fabricating Fabric - Profile of Nylon
BETH NISSEN, reporting:
Take a quick look at what you’re wearing. If any of your clothes are made of cotton, you’re wearing one of the most ancient fabrics known: in Ancient India, cotton was spun into fibers, woven into cloth. Flax was used in Ancient Egypt. Silk in Ancient China. Wool in Ancient Rome. All natural fibers from cotton bolls, silkworm cocoons, sheep fleece. Fibers still used to make cloth or fabric, textiles, all these centuries later.
It being in the nature of chemists to try to duplicate nature, many tried, over those centuries, to invent artificial, or synthetic fibers…fibers that could be mass-produced at low cost in a lab. No worry about crops and herds affected by weather and disease; no need for labor-intensive harvesting, shearing, gathering.
But it wasn’t until the late 1930s that someone finally succeeded: this man, Wallace Carothers, a chemist in the Wilmington, Delaware research lab of the DuPont company. What he and his team did, we’ll tell you how in a minute, was create not only the first synthetic fiber, but a revolutionary material: nylon. Strong, yet elastic. Like silk, only better.
In fact, nylon became a huge commercial success in 1940 precisely because of its superiority over silk in making women’s stockings. Nylon stockings didn’t ‘run’ or tear as easily as silk ones – or cost as much. American women bought 60 million pairs of nylons before the U.S. entered World War II, when all nylon production went to the war effort.
New material was strategically important. During the war, nylon was made into uniforms, tents, airplane tires, and with silk supplies from Japan cut off military parachutes, almost 4 million of them. As for nylon stockings – until the war’s end, they were famously rare. Women faked the look of stockings by drawing seams down the backs of their bare legs.
Time to draw your attention back to how nylon was invented – which we’ll explain using paperclips and spider webs. Wallace Carothers was fascinated by polymers, which he correctly guessed were just ordinary molecules, only longer. Here is the way generations of chemistry students have learned about polymers. Take a paper clip. One paper clip represents one molecule or part, called a mer. Since the Latin word for “one” is “mono,” that’s a monomer. The Latin word for “many” is “poly” so if you link several paper clip “monomers” together, you get a polymer… actually, a polymer chain: single units linked together into a long chain.
There are many polymers in nature, most notably, in terms of this story, spider silk…what makes up spider webs. In fact, spider silk is the strongest natural polymer known stronger than steel of the same thickness. To make synthetic silk, Carothers and his team had to mimic the way the molecules – the polymers – in natural silk were linked and structured.
They used raw materials from nature: water and air and, from the mineral kingdom, coal and later, other carbon-based petroleum by-products – yes, nylon comes from crude oil.
Carothers and his team made some early but flawed synthetic fibers: they melted when ironed; dissolved when dry-cleaned. Then in the spring of 1934, Carothers suggested a different combination of molecules. You can actually see a pretty good version of what happened in that lab in 1934 by watching what’s called the Nylon Rope Trick – this one done for us in the chemistry labs at Iowa State University.
IOWA STATE STUDENT: We make nylon polymers out of these two chemicals here. One is hexamethylenediamine; the other is sebacoyl chloride.
NISSEN: The names of the chemicals aren’t as important in this story as how these two react when one less dense is poured on top of the other. Right where the two layers meet each other – right there, at what’s called the interface – is where it happens: a chemical reaction that creates this…a material that can be pulled out in long, strong stretchy strings…that have a silky texture and shine.
IOWA STATE STUDENT: This is it. Nylon.
NISSEN: What’s happened is called polymerization: different monomers in each solution – like individual paperclips in two different colors – have linked, in an alternating pattern, to form polymers…like long paperclip chains. All the different types of nylon – let’s use as our example the most common kind, called Nylon 6,6 are made from two kinds of monomers: diamines, let’s let the green paperclips represent these, and dicarboxylic acids the blue paperclips.
On the molecular scale, both have similar basic structures: backbones of six carbon atoms, which is why this type of nylon is called Nylon 6,6.
We won’t go into all the details here – but you can see: their ends are quite different.
When these different ‘ends’ come together, they react…form what’s called an amide link. Just so you know, because of all those amide links, synthetic polymers are called polyamides – many amides. As the monomers link, small molecules of water are pushed out, or condensed (which is why this process is called condensation polymerization.
So now we have synthetic polymer chains that mimic the molecular structure of the natural polymers: this is a depiction of spider silk. Carothers and his team at DuPont were also able to get the synthetic polymer chains to arrange themselves in the same ‘parallel’ pattern as the natural ones – and link the chains together in the same way with hydrogen bonds, just so you know.
Synthetic polymer chains made in carefully-controlled conditions…make
perfectly uniform fine strands that can be woven into fabric that is lightweight but strong, difficult to tear or puncture. all properties that have made nylon the most-used synthetic fiber in the U.S., after polyester, a descendant of nylon, along with all polymer plastics.
So that’s the story of a true American success, exported around the planet and off it: the Stars and Stripes planted on the surface of the moon in 1969? An American flag made of nylon.
Imagine your body floating weightlessly through space. Up in space, a slight push and pull would allow you to easily change speed and direction.
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