Lecture 2: Rheology

Question 1

Polymers are viscoelastic

Answer 1

Elastic part: energy is stored-complete recovery after deformation
Viscous part: Energy is dissipated-permanent deformation

Question 2

The mechanical properties of polymers are very temperature sensitive!

Answer 2

Be careful

Question 3

Short time tests

Answer 3

Tensile tests, flexural tests, impact strength,

- How the material respond to a sudden deformation

Question 4

Long time tests

Answer 4

Creep, stress relaxation, fatigue

- How the material perform when subjected to a deformation for a long time

Question 5

Rheology

Answer 5

The science of flow

• Or the fluid response of a material to an impose stress
• Important when processing the polymer (mechanical properties important for the final product)