Editing Nylon (section)

== Chemistry ==
{{external media | width = 210px | float = right | headerimage= | video1 = [https://www.youtube.com/watch?v=y479OXBzCBQ "Making Nylon"], Bob Burk, CHEM 1000, Carleton University, Ottawa, Canada | video2 = [https://www.youtube.com/watch?v=HTh_5CWMSoQ "Making Nylon 6,6"] | video3= [https://www.youtube.com/watch?v=4GxeSO7DyaE "Nylon production"], [[Royal Society of Chemistry]] |video4= [https://www.youtube.com/watch?v=Qos7E7dDMyo "Nylon and Rayon Manufacture 1949"], Encyclopedia Britannica Films }}

In common usage, the prefix "PA" ([[polyamide]]) or the name "Nylon" are used interchangeably and are equivalent in meaning.

The nomenclature used for nylon polymers was devised during the synthesis of the first simple aliphatic nylons and uses numbers to describe the number of carbons in each monomer unit, including the carbon(s) of the carboxylic acid(s).<ref>{{cite book |last=Cowie |first=J. M. G. |title=Polymers: Chemistry and Physics of Modern Materials |edition=2nd |publisher=Blackie |date=1991 |pages=[https://archive.org/details/polymerschemistr0000cowi/page/16 16–17] |isbn=0-216-92980-6 |url=https://archive.org/details/polymerschemistr0000cowi/page/16 }}</ref><ref>{{cite book |last=Rudin |first=Alfred |title=Elements of Polymer Science and Engineering |publisher=Academic Press |date=1982 |pages=[https://archive.org/details/elementsofpolyme0000rudi/page/32 32–33] |isbn=0-12-601680-1 |url=https://archive.org/details/elementsofpolyme0000rudi/page/32 }}</ref> Subsequent use of cyclic and aromatic monomers required the use of letters or sets of letters. One number after "PA" or "Nylon" indicates a [[homopolymer]] which is ''monadic'' or based on one amino acid (minus H<sub>2</sub>O) as monomer:
: PA 6 or Nylon 6: [NH−(CH<sub>2</sub>)<sub>5</sub>−CO]<sub>''n''</sub> made from ε-caprolactam.

Two numbers or sets of letters indicate a ''dyadic'' homopolymer formed from two monomers: one diamine and one dicarboxylic acid. The first number indicates the number of carbons in the diamine. The two numbers should be separated by a comma for clarity, but the comma is often omitted.
: PA or Nylon 6,10 (or 610): [NH−(CH<sub>2</sub>)<sub>6</sub>−NH−CO−(CH<sub>2</sub>)<sub>8</sub>−CO]<sub>''n''</sub> made from [[hexamethylenediamine]] and [[sebacic acid]];

For copolymers the comonomers or pairs of comonomers are separated by slashes:
: PA 6/66: [NH−(CH<sub>2</sub>)<sub>6</sub>−NH−CO−(CH<sub>2</sub>)<sub>4</sub>−CO]<sub>''n''</sub>−[NH−(CH<sub>2</sub>)<sub>5</sub>−CO]<sub>''m''</sub> made from caprolactam, hexamethylenediamine and adipic acid;
: PA 66/610: [NH−(CH<sub>2</sub>)<sub>6</sub>−NH−CO−(CH<sub>2</sub>)<sub>4</sub>−CO]<sub>''n''</sub>−[NH−(CH<sub>2</sub>)<sub>6</sub>−NH−CO−(CH<sub>2</sub>)<sub>8</sub>−CO]<sub>''m''</sub> made from hexamethylenediamine, adipic acid and sebacic acid.

The term [[polyphthalamide]] (abbreviated to PPA) is used when 60% or more moles of the carboxylic acid portion of the repeating unit in the polymer chain is composed of a combination of [[terephthalic acid]] (TPA) and [[isophthalic acid]] (IPA).