The Deformability of Polymers: The Role of Disordered Mesomorphic Crystals and Stress‐Induced Phase Transformations

Crystals in polymers: The γ form of isotactic polypropylene shows an unexpected better ductility than the mesophase because of the occurrence of a stress-induced transition from the γ form to the mesophase. This provides a mechanism of conversion of mechanical energy into latent heat of fusion that induces local melting of the crystals followed by recrystallization at high deformation in the mesophase (see picture).