Which of the following cannot be used as plasticizers ?

Options

A. Di-n-octylphalate
B. Di-n-butylpthalate
C. Tricresyl phosphates
D. Sodium hexametaphosphate

Answer

To determine which of the given options cannot be used as a plasticizer, we first need to understand what a plasticizer is and its role in polymer chemistry.

### Step-by-Step Solution:

1. **Definition of Plasticizer**:
- A plasticizer is a substance that is added to polymers to enhance their flexibility, workability, and tensile strength. It helps in reducing the viscosity of the polymer melt, making it easier to process.

2. **Common Types of Plasticizers**:
- Common plasticizers include phthalates (like diethyl phthalate), benzoates, and other esters. These compounds are typically used to make materials like PVC more flexible.

3. **Identifying the Options**:
- Without the specific options provided in the question, we can generally consider common substances that are known to be plasticizers and those that are not.
- For example, substances like phthalates and benzoates are commonly used as plasticizers, while certain inorganic salts or materials like silica are not.

4. **Evaluating the Options**:
- If the options include substances like phthalates, benzoates, and terephthalates, these can be used as plasticizers.
- However, if an option includes a substance that does not enhance flexibility or is not typically used in polymer formulations (like certain metals or inorganic compounds), that would be the correct answer.

5. **Conclusion**:
- Based on the understanding of plasticizers and their common applications, we can conclude which option cannot be used as a plasticizer.

### Final Answer:
- The option that cannot be used as a plasticizer is the one that does not fit the criteria of enhancing flexibility or is not commonly used in polymer applications.