Hydrogen bonding between polyamide chains plays an important role in determining the properties of a nylon such as nylon 6,6. Draw the structural formulas for two adjacent chains of nylon 6,6, and show where hydrogen-bonding interactions could occur between them.

See figure 1

Explanation:

In the structure of nylon 6,6 we have amide groups. In this functional group, We have a nitrogen bond to hydrogen, so in this bond, we will have a dipole, due to the electronegativity difference. Nitrogen has more electronegativity than hydrogen, therefore a positive dipole would be generated in the hydrogen atom. Additionally, in the carbonyl group (C=O) due to the oxygen, we will have also a dipole, in this case, a negative dipole because the oxygen atom has more electronegativity (compare with carbon).

When we put two strings of nylon 6,6 the positive dipole will interact with the negative dipole and vice-versa and we will obtain the "hydrogen bonds".

See figure 1

I hope it helps!