Which of the following are not thermosetting polymers?

Options

A. Bakelite
B. Polystyrene
C. PVC
D. Melmac

Answer

To determine which of the following are not thermosetting polymers, we will analyze the options provided: Bakelite, Polystyrene, PVC, and Melmac.

### Step-by-Step Solution:

1. **Understanding Thermosetting Polymers**:
- Thermosetting polymers are materials that, once set into a given shape, cannot be remolded or reheated to change that shape. They undergo extensive cross-linking when heated, which makes them hard and rigid.

2. **Identifying Thermosetting Polymers**:
- Common examples of thermosetting polymers include Bakelite and Melmac. These materials are known for their rigid structure and inability to be reshaped upon reheating.

3. **Analyzing the Options**:
- **Bakelite**: This is a well-known thermosetting polymer. It cannot be reshaped once it has been set.
- **Polystyrene**: This is a thermoplastic polymer. It can be melted and reshaped upon heating.
- **PVC (Polyvinyl Chloride)**: This is also a thermoplastic polymer. Like polystyrene, it softens upon heating and can be reshaped.
- **Melmac**: This is another thermosetting polymer, similar to Bakelite, which cannot be reshaped once set.

4. **Conclusion**:
- From the analysis, Bakelite and Melmac are thermosetting polymers, while Polystyrene and PVC are thermoplastic polymers. Therefore, the options that are not thermosetting polymers are **Polystyrene (Option B)** and **PVC (Option C)**.

### Final Answer:
The polymers that are not thermosetting are **Polystyrene and PVC**.

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