SoR logo The Society of Rheology 81st Annual Meeting
October 18-22, 2009 - Madison, Wisconsin
View Paper Info and Abstract


Emulsions, Blends and Multiphase Systems

Rheological properties of metallocene-catalyzed ethylene copolymers and morphology control of their blends with polypropylene

October 20, 2009 (Tuesday) 5:40

Track 3 / Meeting Rooms OP

(Click on name to view author profile)

  1. Maani, Amirhossein (École Polytechnique, CREPEC - Chemical Eng.)
  2. Heuzey, Marie-Claude (École Polytechnique, CREPEC - Chemical Eng.)
  3. Carreau, Pierre J. (Ecole Polytechnique, CREPEC, Chem. Eng. Dept.)

(in printed abstract book)
Amirhossein Maani, Marie-Claude Heuzey, and Pierre J. Carreau
CREPEC - Chemical Eng., École Polytechnique, Montreal, QC, Canada

Carreau, Pierre J.

With the development of metallocene catalysts technology, a new generation of ethylene a-olefin copolymers with fairly controlled co-monomer compositions and also narrow distributions of molecular weight have been commercially produced. These copolymers are widely used as the toughening compound in thermoplastic olefin (TPO) blends and the rheological behavior of these copolymers as well as morphological aspects of the TPOs based on these elastomers have gained a great interest. In this study, rheological properties of a series of ethylene-octene copolymers (with co-monomer compositions ranging between 0 and 38 wt%) and morphology evolution of their blends with polypropylene have been investigated. Thermo-rheological measurements showed that the copolymers of low level of octene content are slightly long-chain branched, though extensional measurement (using a SER geometry) showed that this level of branching does not result in a pronounced difference in the melt strength of these elastomers. However, using a Palierne emulsion model, it was found that the increase in the octene content improves the interfacial miscibility between the polypropylene and the copolymers, and this can result in a finer droplet-matrix morphology. Transient morphology obtained at high shear rate showed that even when the Capillary number is large, flow-induced coalescence plays a major role in the morphology evolution of these blends. A series of random copolymers was used as surface modifiers to prevent the coalescence and control the morphology. These formulations were compared to a blend which was compatibilized with a di-block copolymer synthesized in a grafting reaction, and the impact of the compatibilizers on the transient rheological/morphological properties in shear and elongational flow was also investigated.