From Reactor to Rheology in LDPE Modeling
- Department of Applied Mathematics, University of Leeds, Leeds, LS2 9JT (United Kingdom)
- Department of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT (United Kingdom)
- Performance Materials, Materials Science Center, DSM Research, Geleen 6160 MD (Netherlands)
- Polyethylene Product Research, Dow Benelux B.V., Terneuzen 4530 AA (Netherlands)
- Polymer Physics and Characterization, Basell Polyolefines, Frankfurt, Hessen 65926 (Germany)
In recent years the association between molecular structure and linear rheology has been established and well-understood through the tube concept and its extensions for well-characterized materials (e.g. McLeish, Adv. Phys. 2002). However, for industrial branched polymeric material at processing conditions this piece of information is missing. A large number of phenomenological models have been developed to describe the nonlinear response of polymers. But none of these models takes into account the underlying molecular structure, leading to a fitting procedure with arbitrary fitting parameters. The goal of applied molecular rheology is a predictive scheme that runs in its entirety from the molecular structure from the reactor to the non-linear rheology of the resin. In our approach, we use a model for the industrial reactor to explicitly generate the molecular structure ensemble of LDPE's, (Tobita, J. Polym. Sci. B 2001), which are consistent with the analytical information. We calculate the linear rheology of the LDPE ensemble with the use of a tube model for branched polymers (Das et al., J. Rheol. 2006). We then, separate the contribution of the stress decay to a large number of pompom modes (McLeish et al., J. Rheol. 1998 and Inkson et al., J. Rheol. 1999) with the stretch time and the priority variables corresponding to the actual ensemble of molecules involved. This multimode pompom model allows us to predict the nonlinear properties without any fitting parameter. We present and analyze our results in comparison with experimental data on industrial materials.
- OSTI ID:
- 21149138
- Journal Information:
- AIP Conference Proceedings, Vol. 1027, Issue 1; Conference: 15. international congress on rheology: Society of Rheology 80. annual meeting, Monterey, CA (United States), 3-8 Aug 2008; Other Information: DOI: 10.1063/1.2964715; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Influence of macromolecular architecture on necking in polymer extrusion film casting process
Linear two-pool models are insufficient to infer soil organic matter decomposition temperature sensitivity from incubations