Question

The temperature of orientation is ______ the flow temperature and _____ the glass transition temperature.

(a) above, above

(b) above, below

(c) below, below

(d) below, above

This question was addressed to me by my college professor while I was bunking the class.

This question is from Orientation of Thermoplastic Films topic in portion Thermoplastic Polymers Properties & Processing of Food Packaging Technology

Answer 1

Correct answer is (d) below, above

Best explanation: The temperature of orientation is below the flow temperature and above the glass transition temperature. When the temperature of the film is above glass transition temperature and below flow temperature, the molecules readily glide past one another when the material is stressed. This is the optimal temperature for stretching the thermoplastic film. As a result of this stretching, the direction of the molecules changes toward that in which the material is stressed, and the molecules are extended like springs. The lower temperature enables the setting the configuration of molecules in the strained position.