(217ao) Non-Isothermal Analysis of Extrusion Film Casting Process Using Molecular Constitutive Equations

Extrusion film casting (EFC) is a commercially important process that is used to produce several thousand tons of polymer films and coatings. In a recent work we demonstrated the influence of polymer chain architecture on the extent of necking in an isothermal film casting operation (Pol et al. 2013). In the present research we have explored experimentally and theoretically the effects of long chain branching on the extent of necking during non-isothermal film casting conditions. Polyethylenes of linear and long-chain branched architectures were used for experimental studies. The EFC process was analyzed using the one-dimensional flow model of Silagy and coworkers (Silagy et al. 1996) in which the energy equation was introduced to model non-isothermal effects, and two multi-mode constitutive equations namely the ‘eXtended Pom-Pom’equation (XPP, for long chain branched polymer melts) and the ‘Rolie-Poly’ equation (RP-S, for linear polymer melts) were incorporated to account for the effects of polymer chain architecture. We show that the model does a better job of capturing the qualitative features of the experimental data thereby elucidating the role of chain architecture and non-isothermal conditions on the extent of necking. Further, the work is underway to explore the role played by the chain architecture in determining EFC process stability using the tools of linear and nonlinear stability analysis.

Pol, H. V et al., 2013. Necking in extrusion film casting : The role of macromolecular architecture. Journal of Rheology, 57(2), pp.559–583.

Silagy, D., Demay, Y. & Agassant, J.-F., 1996. Study of Stability of the Film Casting Process. Polymer Engineering and Science, 36(21), pp.2614–2625.