Which polymer has a 'chiral' monomer (s) ?

Options

A. Nylon 6,6
B. Neoprene
C. PHBV
D. Buna - N

Answer

To determine which polymer has a chiral monomer, we need to analyze the monomers of each given polymer option and identify if any of them contain a chiral center.

### Step-by-Step Solution:

1. **Understanding Chiral Molecules**:
- A chiral molecule is one that has a carbon atom bonded to four different groups. This creates non-superimposable mirror images, known as enantiomers.

2. **Analyzing Nylon 6-6**:
- Nylon 6-6 is synthesized from hexamethylene diamine and adipic acid.
- The structure of hexamethylene diamine is:
\[ H_2N-(CH_2)_6-NH_2 \]
- The structure of adipic acid is:
\[ HOOC-(CH_2)_4-COOH \]
- Neither of these monomers has a carbon atom bonded to four different groups. Therefore, **Nylon 6-6 does not have a chiral monomer**.

3. **Analyzing Neoprene**:
- Neoprene is made from chloroprene, which has the structure:
\[ CH_2=C(CH_2Cl)-CH=CH_2 \]
- In chloroprene, there is no carbon atom bonded to four different groups. Thus, **Neoprene does not have a chiral monomer**.

4. **Analyzing PHVB (Poly(3-hydroxybutyrate-co-3-hydroxyvalerate))**:
- PHVB is formed from 3-hydroxybutanoic acid and 3-hydroxyvaleric acid.
- The structure of 3-hydroxybutanoic acid is:
\[ CH_3-CHOH-CH_2-COOH \]
- The structure of 3-hydroxyvaleric acid is:
\[ CH_3-CH_2-CHOH-CH_2-COOH \]
- In both of these monomers, there are carbon atoms that are bonded to four different groups, making them chiral. Therefore, **PHVB has chiral monomers**.

5. **Analyzing Bunan**:
- Bunan is formed from 1,3-butadiene and acrylonitrile.
- The structure of 1,3-butadiene is:
\[ CH_2=CH-CH=CH_2 \]
- The structure of acrylonitrile is:
\[ CH_2=CH-CN \]
- Neither of these monomers has a chiral center. Thus, **Bunan does not have a chiral monomer**.

### Conclusion:
After analyzing all the options, the polymer that has a chiral monomer is **PHVB**.