Which of the following processes can be used to prepare polystyrene?

Options

A. Anionic
B. Cationic
C. Free radicals
D. Zigler-Natta

Answer

To determine which processes can be used to prepare polystyrene, we need to analyze the different polymerization methods mentioned in the question. Polystyrene is a type of addition polymer, and it can be synthesized through various polymerization techniques. Let's break down each option:

### Step-by-Step Solution:

1. **Anionic Polymerization**:
- Anionic polymerization involves the initiation of the polymerization process by a negatively charged species (an anion). This method can be used to create polystyrene because it allows for the addition of styrene monomers to a growing polymer chain through the reaction of the anion with the monomer.
- **Conclusion**: Anionic polymerization can be used to prepare polystyrene.

2. **Cationic Polymerization**:
- Cationic polymerization is initiated by a positively charged species (a cation). In this process, a strong acid can be used to generate a carbocation from an alkene, which then reacts with styrene monomers to form polystyrene.
- **Conclusion**: Cationic polymerization can also be used to prepare polystyrene.

3. **Free Radical Polymerization**:
- Free radical polymerization is one of the simplest and most common methods for synthesizing addition polymers. In this method, a free radical initiator is used to start the polymerization process, allowing styrene monomers to add to the growing chain.
- **Conclusion**: Free radical polymerization is a valid method for preparing polystyrene.

4. **Ziegler-Natta Polymerization**:
- Ziegler-Natta polymerization utilizes catalysts to produce polymers with specific stereochemistry. While it is primarily used for the polymerization of alkenes, it can also be adapted for styrene, leading to high-density and high-strength polystyrene.
- **Conclusion**: Ziegler-Natta polymerization can be used to prepare polystyrene.

### Final Conclusion:
All four processes—anionic polymerization, cationic polymerization, free radical polymerization, and Ziegler-Natta polymerization—can be used to prepare polystyrene.