Exploring the Compositional Heterogeneity of Vis‐Broken Impact Poly(propylene) Copolymers by Advanced Fractionation Methods

Abstract

Vis‐breaking or rheology control is an important technical process to improve the processability of impact poly(propylene) copolymers (IPCs). In the vis‐breaking process the molar mass and its dispersity are reduced and the crystallinity changes and polar carbonyl functionalities are introduced due to the reaction of the polymer with peroxide. Although the fundamental principles of vis‐breaking are well understood, not much research has been devoted to the investigation of the molecular changes brought about by the vis‐breaking process. In the present study, the effect of vis‐breaking on the molecular parameters of IPCs is elucidated using advanced fractionation methods. After the analysis of the bulk sample properties, the samples are fractionated using preparative temperature rising elution fractionation and the fractions are analyzed by Fourier transform infrared spectroscopy, differential scanning calorimetry, crystallization analysis fractionation, and high temperature high performance liquid chromatography techniques. For the first time, an effective multidimensional analytical approach is established to study compositional heterogeneities in vis‐broken IPC materials.