Can Molecular Structure Affect Impact Strength in Polymers?

[rexol]

This is not a specific question. it's just common sense. all temp values in celsius.

The impact values of polymers are definitely astonishing when i think at the molecular level

it is said that increasing the molecular weight of the chains increase the impact strength.
consider same polydispersity index (Mw / Mn).

now consider a cross section where u are applying the impact.

won't there be less number of chain ends to absorb the impact? so, impact strength should decrease right?

also, how does Polycarbonate have such a high impact strength at 0. it's glass transition is 140 !

 

[jbsteele]

Yes, increasing the molecular weight of the chains can increase the impact strength. However, it is important to consider the molecular structure of the polymer when assessing the impact strength. The number of chain ends available to absorb the impact can make a difference, as you suggested. Polycarbonate has a high impact strength due to its molecular structure. Its glass transition temperature of 140°C is an indication that it may have crystalline properties which make it more resistant to impacts.