Which one of the following structures represents nylon-6,6 polymer?

Options

A.
B.
C.
D.

Answer

To determine which structure represents nylon-6,6, we need to understand the components that make up this polymer and how they combine. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Monomers
Nylon-6,6 is formed from two specific monomers:
- **Hexamethylenediamine**: This molecule has the structure NH2-(CH2)6-NH2, meaning it contains two amine groups (NH2) and a six-carbon chain.
- **Adipic Acid**: This molecule has the structure HOOC-(CH2)4-COOH, meaning it contains two carboxylic acid groups (COOH) and a four-carbon chain.

### Step 2: Understand the Polymerization Process
Nylon-6,6 is a condensation polymer, which means that during the polymerization process, water (H2O) is eliminated. The reaction involves the amine groups of hexamethylenediamine reacting with the carboxylic acid groups of adipic acid.

### Step 3: Write the General Structure of Nylon-6,6
The general repeating unit of nylon-6,6 can be represented as follows:
- The structure will include the amine and carboxylic acid groups, along with the carbon chains.
- The repeating unit will look like this:
- HN-(CH2)6-NH-CO-(CH2)4-CO

### Step 4: Analyze the Given Options
Now, we need to evaluate the provided structures (options A, B, C, D) to see which one matches the structure of nylon-6,6:
- **Option A**: Incorrect structure.
- **Option B**: Incorrect structure.
- **Option C**: Incorrect structure.
- **Option D**: This option should have the correct arrangement of the repeating units of nylon-6,6.

### Step 5: Confirm the Correct Structure
To confirm that option D is correct:
- Check for the presence of the amine and carboxylic acid groups.
- Ensure that the carbon chain lengths match those of hexamethylenediamine (6 carbons) and adipic acid (4 carbons).
- Verify that the structure reflects the condensation reaction (removal of water).

### Conclusion
The correct structure that represents nylon-6,6 is given in **Option D**.

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