WLF

1. WLF Multi-Scale Simulation of Polymer Processing Kathryn Garnavish, David Kazmer, William Rousseau, & Yingrui Shang University of Massachusetts Lowell Conventional (Continuum) Approach: Research Goal: Develop and validate a multi-scale polymer processing simulation for concurrent engineering design and manufacturing process development Continuum Models Consititutive Models ◦Mass ◦Viscosity ◦Compressibility ◦Viscoelasticity ◦Relaxation ◦Momentum ◦Heat Research Tasks:  Develop & validate continuum polymer processing simulation with non-Newtonian, non-isothermal, compressible flow, and thermoviscoelasticity Literature review of atomistic modeling of boundary conditions  Specification of performance measures and end-use requirements Implement atomistic heat transfer boundary conditions (2005/06)  Implement atomistic wall slip boundary conditions (2005/06) Implement molecular dynamic simulation for rheological development (2006/07) Validate against molding and extrusion processes (2006/07) Improve & define future work (2007/08)  Optical Media ◦Birefringence Publications: • Kathryn Elise Garnavish, An Investigation into Hesitation Defects from Oscillating Flows, Univ. of Mass. Lowell, Dept. Plastics Engineering, 2005. • William Rousseau, Effect of Shear Stress and Velocity Profile Development on Flow Bore Wall Slip, Univ. of Mass. Lowell, Dept. Plastics Engineering, 2005. • Bingfeng Fan and David Kazmer, Low Temperature Modeling of the Time-Temperature Shift Factor for Polycarbonate, Submitted to Advances in Polymer Technology. Nano-Scale Investigation: Atomistic Modeling of Heat Transfer Atomistic Modeling of Wall Slip Atomistic Modeling of Rheology  ◦Boltzmann Transport Equation ◦Modified Bose-Einstein distributionto estimate Q=f(stress, compatibility,…) ◦Wall slip condition characterized on meso-scale ◦On atomistic level, compare molecularstrain to wall adhesive forces ◦Incorporation of MD simulationfor rheological development References:    B. Fan, D. O. Kazmer, W.C. Bushko, R. P. Thierault, A. J. Poslinski, Birefringence Prediction of Optical Media, Polymer Engineering & Science, v. 44, n. 4, April, 2004, p. 814-824. A.N. Smith and P. M. Norris, Microscale Heat Transfer, Chapter 18 of Heat Transfer Handbook, eds. A. Bejan and A. D., Kraus, John Wiley & Sons, 2003. K. S. Narayan* and A. A. Alagiriswamy, R. J. Spry, DC Transport Studies of poly(benzimida-zobenzophenanthroline) a ladder-type polymer, Physical Review B, v. 59, n. 15, p. 10054-8, 1999. Fritch, L.W., ABS Cavity Flow – Surface Orientation and Appearance Phenomena Related to the Melt Front, SPE Technical Papers, Vol. 21, 1979, pp. 15-20.  J. S. Bergström and M. C. Boyce, Deformation of Elastomeric Networks: Relation between Molecular Level Deformation and Classical Statistical Mechanics Models of Rubber Elasticity, Macromoleclues, Vol. 32, pp. 3795-3808, 2001. S. H. Anastasiadis and S. G. Hatzikiriakos, The Work of Adhesion of Polymer/Wall Interfaces and the Onset of Wall Slip, J. Rheol., v. 42, n. 4, p. 795-812, 1998. M. Doi, Challenges in polymer physics, Pure Appl. Chem., Vol. 75, No. 10, pp. 1395–1402, 2003.  <  Structural change of the microphase of ABA tri block polymers under elongation. ACKNOWLEDGEMENT: This research has been sponsored by the National Science Foundation under DMI-0425826.