Question

Glass transition temperature (\(T_g\)) in polymers marks:

• A. Melting point
• B. Onset of cross-linking
• C. Transition from brittle to rubbery state
• D. Start of crystallization

Hint:

The glass transition temperature marks the point at which a polymer changes from a brittle glassy state to a more flexible rubbery state. This is crucial in determining the material's processing and use temperature.

Answer 1

The Correct Option is C

The glass transition temperature (\( T_g \)) is the temperature range in which a polymer transitions from a brittle, glassy state to a more flexible, rubbery state. This is not a true phase transition like the melting point but rather a transition in the polymer's physical properties. Below \( T_g \), the polymer is rigid and brittle; above \( T_g \), it becomes more flexible and rubber-like.
- The melting point refers to the phase change from solid to liquid, which is a different process from the glass transition.
- The onset of cross-linking refers to the beginning of polymer chain linking, which is not directly related to \( T_g \).
- Transition from brittle to rubbery state is the correct description of the glass transition temperature, as explained above.
- The start of crystallization occurs at a different temperature and refers to the formation of a crystalline structure in polymers.
Thus, the correct answer is Transition from brittle to rubbery state.