Deformation of Polymers

Many semicrystalline polymers have the spherulitic structure and deform in the following steps :

•   elongation of amorphous tie chains                           

•  tilting of lamellar chain folds towards the tensile direction

•  separation of crystalline block segments

• orientation of segments and tie chains in the tensile direction

The macroscopic deformation involves an upper and lower yield point and necking. Unlike the case of metals, the neck gets stronger since the deformation aligns the chains so increasing the tensile stress leads to the growth of the neck.