Question

What are the monomeric repeating units of Nylon-$6$ and Nylon-$6,6$?

Answer 1

The monomeric repeating unit of Nylon-$6$ polymer is $NH(C{H}_2{)}_{5}CO$ which is derived from caprolactam.

The monomeric repeat unit of Nylon-$6,6$ polymer is $\left[NH\right(C{H}_2{)}_{6}NH-CO\left(C{H}_2{)}_{4}CO\right]$ which is derived from the two monomers, hexamethylene diamine, $N{H}_2(C{H}_2{)}_{6}N{H}_2$ and adipic acid, $HO-C\left(O\right)(C{H}_2{)}_{4}COOH$ as shown in the figure.