Cassandra Krack

Nylon Rope

Concept: Polymer, Density, and Polarity.

A polymer is a chain of molecules. In this experiment, adipoylchloride and hexamethylenediamine react together to form a polymer chain.

Materials:

* 25 mL hexamethylenediamine in water

* 25 mL adipoylchloride in hexane

* 100 mL beaker

* wire hook

* gloves

Directions:

Be sure to follow steps 1 and 2 in the correct order.

1. Pour 25 mL of hexamethylenediamine in a 100 mL beaker.

2. Tilt the beaker slightly, and pour 25 ml of adipoylchloride down the side of the beaker very slowly, allowing it to form a layer on top of the hexamethylenediamine.

3. Slowly dip the wire hook in the beaker, and you should be able to pull out a string of nylon from the interface where the two chemicals meet.

4. Do not let the two chemicals mix until after the experiment, because if mixed the chemicals will form a ball instead of a chain.

5. When you are finished pulling the rope, at that time you may mix everything together to form a ball of nylon.

Introduction:

You normally have to go to a pond or a lake to go fishing for something, but not today!!! I am going to go fishing right here in your classroom. Let's see what I'll come up with!

Explanation:

The two chemicals do not mix because they are of different polarities and densities. The rule of "likes dissolve likes" does not take place. The two solutions have unlike properties. Adipoylchloride dissolved in hexane is less dense than hexamethylenediamine dissolved in water, and that is why the adipoylchloride solution does not sink to the bottom of the beaker, but rests on top of the other chemical.

The nylon rope that formed in the solution at the interface between the two solutions is called a polymer chain. The polymer chain is formed when a molecule in the hexamethylenediamine = B, connects with another molecule in the adipoylchloride = A. The first chemical (B) is an amine and the second (A) is an acid. The chain is made of alternating molecules of acid, amine, acid, amine... This may be represented by A-B-A-B-A-B.......

Graphic with Nylon Polymer Reaction

Safety: DO NOT let these chemicals touch skin. BE CAREFUL of fumes.

Waste Disposal: Throw the nylon solid in the garbage can. Give the left over liquids to instructor for proper waste disposal which may include neutralization with sodium carbonate and then flushed down the drain.

Source: Shakhashiri, Bassam, Chemical Demonstrations, Vol. 1, U. Wisconsin Press, 1983, p. 213