Which is not classified as thermoplastics?

Options

A. Polyethylene
B. Polystyrene
C. Bakelite
D. Neoprene

Answer

To determine which material is not classified as a thermoplastic, we will analyze the options provided: polyethylene, polystyrene, bakelite, and neoprene.

### Step 1: Understand the definitions
- **Thermoplastics** are materials that become soft when heated and harden upon cooling. They can be remolded and reshaped multiple times without undergoing any significant chemical change.
- **Thermosetting plastics**, on the other hand, are materials that, once set into a given shape, cannot be remolded or reshaped upon heating. They undergo a chemical change during the curing process.

### Step 2: Analyze each option
1. **Polyethylene**: This is a common thermoplastic used in various applications, such as plastic bags and bottles. It can be melted and reshaped.

2. **Polystyrene**: This is also a thermoplastic used in products like disposable cutlery and insulation. It can be melted and reshaped.

3. **Bakelite**: This is a thermosetting plastic made from phenol and formaldehyde. Once it is set, it cannot be remolded or reshaped.

4. **Neoprene**: This is a synthetic rubber that is classified as a thermoplastic elastomer. It can be processed like a thermoplastic but retains some elastic properties.

### Step 3: Conclusion
Based on the definitions and analysis:
- The material that is **not classified as a thermoplastic** is **Bakelite** (option C), as it is a thermosetting plastic.

### Final Answer
The correct option is **C. Bakelite**.

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