Which of the following polymers, need atleast one diene monomer for their preparation ?

Options

A. dacron
B. Novolac
C. Neoprene
D. Teflon

Answer

To determine which of the given polymers requires at least one diene monomer for their preparation, we will analyze each option based on the presence of diene monomers (monomers with two double bonds).

### Step-by-Step Solution:

1. **Understanding Diene Monomers**:
- A diene monomer is a compound that contains two double bonds. We need to identify if any of the polymers listed are derived from such monomers.

2. **Analyzing Each Polymer**:
- **Option A: Dacron**
- Dacron is a polymer made from ethylene glycol and terephthalic acid. The structure of these monomers does not contain any double bonds between carbon atoms.
- **Conclusion**: Dacron does not require a diene monomer.

- **Option B: Novolac**
- Novolac is formed from phenol and formaldehyde. Similar to Dacron, there are no carbon-carbon double bonds present in these monomers.
- **Conclusion**: Novolac does not require a diene monomer.

- **Option C: Neoprene**
- Neoprene is a polymer derived from chloroprene, which has the structure CH2=CHCl-CH=CH2. This structure contains two double bonds (one in each of the two carbon units).
- **Conclusion**: Neoprene requires a diene monomer.

- **Option D: Teflon**
- Teflon is made from tetrafluoroethylene, which has the structure CF2=CF2. This monomer contains only one double bond.
- **Conclusion**: Teflon does not require a diene monomer.

3. **Final Answer**:
- After analyzing all the options, the only polymer that requires at least one diene monomer for its preparation is **Neoprene**.

### Final Answer:
**Neoprene (Option C)** is the polymer that needs at least one diene monomer for its preparation.