• Spoelstra, A. B.
• Peters, Gwm Gerrit
• Gahleitner, M.
• Govaert, Leon E.
• Van, M. Drongelen

Abstract

Polypropylene-based impact copolymers are a complex composition of matrix material, a dispersed phase and many optional modifiers. The final heterophasic morphology of such systems is influenced significantly by the processing step, adding an additional level of complexity to understanding the structure-property relation. This topic has hardly been studied so far. The effect of thermal history and shear flow on the solidification process of three different compositions of a polypropylene-based impact copolymer, i.e., one base material and two compounds with either high density polyethylene or ethylene-co-octene added, is investigated. Samples are examined using differential scanning calorimetry, extended dilatometry, transmissions electron microscopy, and finally, tensile testing. With flow, the materials show pronounced flow-enhanced crystallization of the matrix material and deformed filler content. Compared to the base polymer, the stress–strain response of the compounded samples shows a lower yield stress and more pronounced influence of shear, reflected in the increasing strain hardening modulus.

Topics

• density
• impedance spectroscopy
• morphology
• compound
• phase
• differential scanning calorimetry
• electron microscopy
• copolymer
• crystallization
• dilatometry