Shear and elongational rheology of polyethylenes with different molecular characteristics. I. Shear rheology |
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| Authors: | X. Wei J. R. Collier S. Petrovan |
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| Affiliation: | 1. Unilever, 40 Merritt Blvd., Trumbull, Connecticut 06611;2. Chemical and Biomedical Engineering, FAMU/FSU, Tallahassee, Florida 32320;3. Chemical Engineering Department, The University of Tennessee, Knoxville, Tennessee 37996‐2200 |
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| Abstract: | Four metallocene polyethylenes (PE), one conventional low density polyethylene (LDPE), and one conventional linear low density polyethylene (LLDPE) were characterized in terms of their complex viscosity, storage and loss moduli, and phase angle at different temperatures. The effects of molecular weight, breadth of molecular weight distribution, and long‐chain branching (LCB) on the shear rheological properties of PEs are studied. For the sparsely long‐chain branched metallocene PEs, LCB increases the zero‐shear viscosity. The onsets of shear thinning are shifted to lower shear rates. There is also a plateau in the phase angle, δ, for these materials. Master curves for the complex viscosity and dynamic moduli were generated for all PE samples. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 |
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| Keywords: | polyethylene molecular characteristics shear rheology long‐chain branching master curve |
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