Chemistry: Demo: Synthesis of Nylon

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In this demonstration we are going to make nylon. What we have here are two solutions, one solution is a water solution of 1/6 hexamethylene diamene. This is the molecule that contains amines at the very end of six carbons, one on each carbon.
This is a solution of adipoyl chloride. Adipoyl chloride is a compound that contains two very reactive functionalities called acid chlorides, and they are also at the very end of the molecule. The adipoyl chloride solution is in hexanes. Hexanes is a hydrocarbon and it is lighter than water. What I am going to do, is I am going to pour that hexane solution of adipoyl chloride on top of the water solution and we are going to get two layers, but at the interface of the two layers, what is going to happen is, that the molecules are going to react to form a condensation polymer, and a condensation reaction to form a polymer. The polymer is actually a copolymer, because it consists of two different molecules. The hexane diamene and the adipoyl chloride.
Now the way the reaction works is that because it is copolymer, the end of the hexane diamene molecule reacts with one end of the adipoyl chloride molecule, and then the other end of the adipoyl chloride molecule reacts with another hexane diamene molecule and then the other end of that molecule reacts with the adipoyl chloride and that keeps happening on and on again, until we get this to be a polymer structure. And the key to doing this is the pouring of the two solutions very carefully so that I don't disturb the layers too much, because, like I said, the only place that the reaction can occur, is where the two reactive molecules can actually meet and that is at the interface between the two layers.
Okay, so I am going to pour these now and then I am going to pull out the polymer that is formed in the middle and I am going to roll it around. So now, at the interface you can see, is a molecule of nylon. Now you can tell, this is not exactly the same kind of nylon you get that you make your stockings from. The stocking nylons are made from a similar kind of compound, but they are not exactly made of this composition, and they are made in a much more careful, much more controlled way.
But, you can see that the only place the reaction is occurring is at the interface, and the trick to doing this right is to get it to go right up the middle, if possible. There we go. So as it rolls, you get nylon and the nylon is formed right at the interface between the two layers.
Now of course the thickness of the nylon and all these other properties that you can control are going to be controlled in a complicated process and, in fact, this has been engineered very carefully by the folks that make nylon to optimize this for the right thickness and the right properties that they are looking for in their materials. And over here we are just kind of doing this on the fly. And never the less it illustrates the principle of the synthesis of a copolymer.
And there you have it. I could pull this and dry it and it would be a nice strong string of nylon.
Organic Chemistry
Organic Polymers
CIA Demonstration: The Synthesis of Nylon Page [1 of 1]