Question

material Science

3. using the concept of the relation between glass transition temperature and structure, explain why polyethylene is ductile at room temperature whereas polystyrene is brittle at room temperature.

Answer 1

factor affecting glass transition temperature

-chemical structure

which is responsible of bond strenth , polystyrene have higher bond strenth.

-free volume

-molecular weight

for higher molecular weight polymer have higher glass transition temperature. so generally polystyrene have higher molecular weight.

-degree of freedom of internal rotation

if polymer have low glass transition temperature, it is ductile at room temerature.

if polymer have high glass transition temperature, it is brittle at room temperature.