[28a1a]

Can anyone show me the chemical structure (or where to find it) of this nylon 12 copolymer?

1,3-Benzenedicarboxylic acid, polymer with azacyclotridecan-2-one and 4,4’-methylenebis(2-methylcyclohexanamine)

CAS 79331-75-2

Another description I found through google searching is:
Nylon 12 copolymers with cycloaliphatic and aromatic comonomers
Poly(azacyclotridecan-2-one-co-4,4'-methylenebis(2-methylcyclohexanamine-co-1,3-benzenedicarboxylic acid))

Thanks appreciate it!

[fledarmus]

Do you know the structures of 1,3-benzenedicarboxylic acid, azacyclotridecan-2-one and 4,4'-methylenebis(2-methylcyclohexanamine)?

Nylons are polyamides - they are long chains formed by links between carboxylic acids on one molecule and amines on another molecule. In your case, you have one molecule with two carboxylic acids on it, and one with two amines. So your polymer will be alternating between the two, with amide bonds holding them together. The azacyclotridecan-2-one is a large ring amide (twelve carbons and a nitrogen in one ring). My guess is that a small amount is added to the polymerization, so every once in a while in your alternating chain of benzene rings from the carboxylic acid and cyclohexane rings from your amine, you will get a twelve carbon alkane chain where a molecule of the azacyclotridecan-2-one has opened up to give an acid on one end and an amine on the other.

I wish I could figure out how to get images on here...

[jaspevacek]

What the Fledarmus is describing is the preparation of "m,n" nylons, such as nylon 6, 6 or nylon 4, 10 or... as opposed to nylon 6 or nylon 12 or... The former are commonly made by copolymerizing diacids and diamines; the latter are commonly made by ring-opening polymerization of a lactam. In all cases, the numbers refer to the number of carbons in the monomers. You can clearly see that nylon 6 is different than nylon 6,6, and the same goes for nylon 12 vs. nylon 12, 12.

Given your particulars, the aza... is the main component of nylon 12.  The other materials are bifunctional and probably serve to crosslink the nylon. They are not components of normal linear nylons.