Levich Institute Seminar Announcement, 03/08/2011
Tuesday, 03/08/2011
2:00 PM
Steinman Hall, Room #312
(Chemical Engineering Conference Room)

Dr. Joontaek Park
City College of CUNY
Levich Institute

"Stochastic Simulation of Entangled Polymeric Liquids in Fast Flows: Microstructure Modification by the Configuration-Dependent Friction Factor "


ABSTRACT


We have modified the full-chain stochastic tube model developed by Xu et al. [J. Rheology (2006) 50:477-494] to simulate entangled melts and solutions of linear monodisperse polymers at high shear rates. The previous model, which has only one adjustable parameter equivalent to the Rouse time, successfully described shear and normal stress data at low to moderate rates, but its results deviated systematically from experimental data at high rates. The previous model has been modified to reduce the deviation in the steady and transient material functions at high rates: The algorithm for re-entanglement was revised and the microstructure change of the tube at non-equilibrium was accounted for by the incorporation of the configuration-dependent friction factors. The simulation results from the modified model showed that the deviation from the experimental data was greatly reduced. We also applied the configuration-dependent friction factor to the models developed by Mead et al. [Macromolecules (1998) 31: 7895-7914] as well as Graham et al. [J. Rheology (2003) 47:1171-1200]. The results showed that the modification also improved both models at high shear rates, which suggests the idea there is a structural change in the tube far from equilibrium such that the relaxation process at high deformation rates where the microstructure is far from equilibrium is enhanced.

BRIEF ACADEMIC/EMPLOYMENT HISTORY

  • October, 2009 Research Associate, Levich Institute, City College of CUNY
  • May, 2009 Ph.D. in Chemical Engineering, University of Florida
  • 1998-2004 Research Engineer in SK Engineering & Construction
  • Feb. 1998 M.S. in Chemical Engineering, Korea Adnaced Institute of Science & Technology
  • Feb. 1996 B.S. in Chemical Technology, Seoul National University