How is polymer nylon made?

Question

How is polymer nylon made?

Answer 1

It depends upon which nylon you mean.   There are many.

The two most common types are nylon 6   and nylon 6.6

Nylon 6 is a homopolymer of caprolactam which is a ring compound of chemical composition   CH2CH2CH2CH2CH2CONH

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Under appropriate conditions,  it ring opens and transamidates so the carbonyl on one caprolactam linkage bonds to the amine on another.   This continues to give a high polymer.   The excess caprolactam is then removed in a vacuum extrusion and the water present is controlled to give the molecular weight desired.    Water reacts reversibly with nylon 6 to break the polymer chain and give carboxyl and amine groups.

The molecular structure of nylon 6 is

(CH2CH2CH2CH2CH2CH2CONH)n

Nylon 6.6. is a copolymer of hexamethylenediamine and adipic acid.

NH2CH2CH2CH2CH2CH2CH2NH2  and  

HOOCCH2CH2CH2CH2COOH

The molecular structure of nylon 6,6 is

(OC(CH2)4CONH(CH2)6NH)n

These materials are blended and water removed in a solid state reaction to give amide bonds.    Again,  the water is then controlled to give the molecular weight desired.