Rheological properties of two polypropylenes with different molecular structure

Two polypropylenes with different molecular structure were investigated in shear and elongational flow. One resin is an ethylene–propylene copolymer with linear molecules and the other is a long-chain branched propylene homopolymer. The elongational flow behavior was investigated in stressing and cr...

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Bibliographic Details
Published in:Journal of rheology (New York : 1978) 1999-03, Vol.43 (2), p.359-374
Main Authors: Kurzbeck, S., Oster, F., Münstedt, H., Nguyen, T. Q., Gensler, R.
Format: Article
Language:English
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Summary:Two polypropylenes with different molecular structure were investigated in shear and elongational flow. One resin is an ethylene–propylene copolymer with linear molecules and the other is a long-chain branched propylene homopolymer. The elongational flow behavior was investigated in stressing and creep experiments. For the linear material no strain hardening can be observed whereas the strain-hardening behavior of the long-chain branched material is more pronounced than it was found for any other polyolefin up to now. The branched resin also exhibits high recoverable strains. The strain-hardening behavior is analyzed with respect to its strain and strain rate dependence. The results are discussed with regard to the molecular structure. The coexistence of a long-chain branched structure and a high molecular weight component is assumed to be the reason for the outstanding elongational flow behavior of the branched polypropylene.
ISSN:0148-6055
1520-8516
DOI:10.1122/1.551040