Molecular properties and behavior of polyolefin solutions modified under conditions of solid-phase extrusion

Variations in the molecular characteristics of polyolefins modified under the conditions of solid-state extrusion were studied by gel-permeation chromatography. It was shown that the molecular mass of PP modified by polar comonomers increases by several times. However, the molecular mass of PE decreases under the same conditions of mechanochemical modification. This difference may be explained by either different mechanisms of solid-state modification of PP and PE or formation of macromolecular associates in the solutions of modified polyolefins, as confirmed by the study of their rheological behavior.