What are the mechanisms of fracture in ductile polymers? a) Propagation of cracks and fracture toughness. b) Flow by shear bands and cracking. c) T...

What are the mechanisms of fracture in ductile polymers?
a) Propagation of cracks and fracture toughness.
b) Flow by shear bands and cracking.
c) Tensile strength and elastic modulus.
d) Creep and stress relaxation.
I- The process of fracture in ductile polymers occurs in several stages, including the flow of polymer molecules, cold stretching of molecules, and the final stage of fracture.
II- The process of deformation by shear bands is responsible for large deformations in toughened polymers.
III- The process of cavitation involves cracking, cavity formation, and fracture, characterized by the local loss of intramolecular cohesion and significant decrease in density at that point.
IV- The process of crack propagation and fracture toughness is characterized by the ability of a material to resist the propagation of a crack once it has been initiated.
a) I and IV are correct.
b) II and III are correct.
c) I, II, and III are correct.
d) III and IV are correct.