Tuesday, August 3, 2010

Nylon

Way back when I took first year chemistry I found the labs to be great fun. In one lab we made our own nylon. Now, actually wearing nylons is something I despise, one step down the slippery slope to high-heels (I'm 5'10”, I don't need to be taller) and caking my face with excessive make-up, not to mention an exponential requirement for more hairspray. It's probably obvious I'm not a girly-girl, nor ever plan on becoming one (if you are a girly-girl, go ahead and be girly, I'm not judging, it's just not my thing). But, making nylon intrigues me as I'm always interested in how things are made.

The invention of Nylon is credited to Wallace Carothers in 1935 at the DuPont Experimental Station. In 1930, Carothers with the folks at DuPont had their first success with what would be eventually called neoprene – the first synthetic rubber. Carothers and his team went on to tackle the creation what would become nylon. Unfortunately, Carothers tended to bouts of depression and alcoholism, and his actual contribution to the development of nylon probably wasn't significant. Instead his coworkers did the work and credited him. In 1937, Carothers committed suicide.

Nylon was the first synthetic fiber, in a 22 September 1938 New York Times article nylon was touted to be 'stronger than steel, fine as a spider's web, more elastic than any of the common natural fibers'. Once it was announced nylon could be knitted in to stockings that were better than silk people got excited. Ironically, the first commercial application turned out to be a nylon-bristled toothbrush. Nylon stockings were said to be indestructible (I've worn nylons enough times to know that isn't true). Today nylon fibers are the second most used synthetic fiber and can be found in all sorts of things like: fabrics, carpets, musical instrument strings and ropes. The down side to nylon is that in a fire it breaks down into nasty stuff like hazardous smoke and toxic fumes. Most nylon ends slowly decaying in landfill as recycling for it isn't widely implemented.

According to Wikipedia to make nylon, molecules with an acid group on each end are reacted with molecules containing an amine group on each end. They react and form long polymer chains – and that's is what nylon is, just a trade name for a synthetic polymers.

On to how we made nylon fiber in my first year lab. I poured one liquid very carefully over a the back of a metal spoon into a glass jug so it sat on top of another liquid without excess mixing. I had forgotten what the chemicals were, but a quick internet search gave me hexanedioxyl dichloride and diaminohexane. After a minute or so a layer formed between the two chemicals. With some tongs, I pulled out the interface, which had changed to nylon. As I pulled the two liquids would form new nylon when ever they came in contact with each other and I ended up with a long string of nylon. So, from the boundary between two liquids came a length of nylon thread.

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