What do '6, 6' indicate in the nylon-6, 6 ?

Explanation

### Step-by-Step Solution:

1. **Identify the Components of Nylon 6,6**:
Nylon 6,6 is a type of polyamide, which is made from two specific monomers: adipic acid and hexamethylenediamine.

2. **Understand the Monomer Structures**:
- **Adipic Acid**: The chemical formula for adipic acid is \( C_6H_{10}O_4 \). It contains 6 carbon atoms in its structure.
- **Hexamethylenediamine**: The chemical formula for hexamethylenediamine is \( C_6H_{16}N_2 \). This compound also contains 6 carbon atoms.
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