Mechanodestruction of isotactic poly(propylene) subjected to plastic flow under high pressure

The molecular mass distribution (MMD) of isotactic PP subjected to shear de formation under a pressure of 1 GPa in the Bridgman anvils was investigated . The M-w and M-n values decrease with increasing shear angle. Three region s with different extent of the mechanodestruction and type of plastic flow can be distinguished. In the central and middle regions, the polymer is def ormed in azimuthal direction the M-w and M-n values change in phase dependi ng on the deformation only, and the MMD width remains constant. In the peri pheral region, the plastic flow is biaxial and the pressure is smaller than that in the central region. At large shear angles, M-n does not change and , therefore, the MMD is narrowing. The kinetics and mechanisms of mechanode struction in PP subjected to plastic flow under high pressure are discussed . Kinetic equations, describing the change of M-n depending on deformation, are proposed.