Which of the following is not a characteristics of thermosetting polymers-

Options

A. Linear or slightly branched long chain polymers
B. Heavivly branched and cross - linked polymers
C. Become infusible on moulding .
D. Cannot be remoulded or resused on heating

Answer

To determine which of the following is not a characteristic of thermosetting polymers, we need to first understand what thermosetting polymers are and their properties.

### Step-by-Step Solution:

1. **Definition of Thermosetting Polymers**:
- Thermosetting polymers are a class of polymers that, once cured or set, cannot be remolded or reheated to change their shape. They are typically formed from low molecular mass monomers that undergo a chemical reaction to create a rigid, cross-linked structure.

2. **Characteristics of Thermosetting Polymers**:
- **Cross-linked Structure**: Thermosetting polymers have a heavily branched or cross-linked molecular structure, which contributes to their rigidity.
- **Permanently Rigid**: Once set, these polymers remain rigid and do not soften upon heating.
- **Infusible**: They cannot be melted or reshaped by heating, which means they are infusible.
- **Cannot be Remolded**: After the initial setting, they cannot be remolded or reshaped, even with heat.

3. **Analyzing the Options**:
- **Option 1**: Linear or slightly branched long chain polymer - This is characteristic of thermoplastic polymers, not thermosetting polymers.
- **Option 2**: Heavily branched or cross-linked polymer - This is a characteristic of thermosetting polymers.
- **Option 3**: Become infusible or molding - This is also a characteristic of thermosetting polymers.
- **Option 4**: Cannot be remolded upon heating - This is a characteristic of thermosetting polymers.

4. **Conclusion**:
- The option that does not describe a characteristic of thermosetting polymers is **Option 1: Linear or slightly branched long chain polymer**. This is characteristic of thermoplastic polymers.

### Final Answer:
**Option 1: Linear or slightly branched long chain polymer** is not a characteristic of thermosetting polymers.

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