02034nas a2200181   4500008004100000022001400041245007900055210006900134260011000203300001200313490000700325520132300332100002701655700002601682700001801708700002101726856010501747       2013                        eng d  a0148-605500aNecking in extrusion film casting: the role of macromolecular architecture0 aNecking in extrusion film casting the role of macromolecular arc  aSTE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USAbJOURNAL RHEOLOGY AMER INST PHYSICScMAR  a559-5830 v573 a<p>Extrusion film casting (EFC) is used on an industrial scale to produce several thousand tons of polymer films and coatings. While significant research has been carried out on necking of films of viscoelastic melts in EFC, the influence of macromolecular chain architecture on the necking behavior is not yet fully understood. In the present research, we have explored experimentally and theoretically the effects of long chain branching and molecular weight distribution on the extent of necking during EFC. Polyethylenes of essentially linear architecture but having narrow and broad molecular weight distributions, and polyethylenes having long chain branching were used for experimental studies. The EFC process was analyzed using the one-dimensional flow model of Silagy et al. [Polym. Eng. Sci. 36(21), 2614-2625 (1996)] in which multimode molecular constitutive equations namely the ``extended pom-pom'' equation (for long chain branched polymer melts) and the ``Rolie-Poly (Rouse linear entangled polymers)'' equation (for linear polymer melts) were incorporated. We show that the model qualitatively captures the salient features of the experimental data thereby elucidating the role of chain architecture on the extent of necking. (C) 2013 The Society of Rheology. [http://dx.doi.org/10.1122/1.4788911]</p>1 aPol, Harshawardhan, V.1 aThete, Sumeet, Suresh1 aDoshi, Pankaj1 aLele, Ashish, K.  uhttps://library.ncl.res.in/content/necking-extrusion-film-casting-role-macromolecular-architecture-002230nas a2200289   4500008004100000022001400041245010000055210006900155260005700224300001100281490000700292520129500299653001301594653001401607653000901621653001101630653001201641653001801653653001701671100002301688700001801711700002201729700002601751700001801777700002101795856012401816       2014                        eng d  a0035-451100aNonisothermal analysis of extrusion film casting process using molecular constitutive equations0 aNonisothermal analysis of extrusion film casting process using m  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcJAN  a85-1010 v533 a<p>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., J Rheol 57:559-583, 2013). In the present research, we have explored experimentally and theoretically the effects of long-chain branching on the extent of necking during nonisothermal film casting conditions. Polyethylenes of linear and long-chain branched architectures were used for experimental studies. The EFC process was analyzed using the 1-D flow model of Silagy et al. (Polym Eng Sci 36:2614-2625, 1996) in which the energy equation was introduced to model nonisothermal effects, and two multimode constitutive equations, namely the ``extended pom-pom'' (XPP, for long-chain branched polymer melts) equation and the ``Rolie-Poly stretch version'' (RP-S, for linear polymer melts) equation, 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 nonisothermal conditions on the extent of necking.</p>10aBranched10aExtrusion10aFilm10aLinear10aNecking10aNonisothermal10aPolyethylene1 aPol, Harshawardhan1 aBanik, Sourya1 aAzad, Lal, Busher1 aThete, Sumeet, Suresh1 aDoshi, Pankaj1 aLele, Ashish, K.  uhttps://library.ncl.res.in/content/nonisothermal-analysis-extrusion-film-casting-process-using-molecular-constitutive-001322nas a2200181   4500008004100000022001400041245006400055210006200119260007900181300001100260490000700271520067500278100002600953700002500979700002301004700001801027856009501045       2015                        eng d  a1539-375500aSelf-similar rupture of thin free films of power-law fluids0 aSelfsimilar rupture of thin free films of powerlaw fluids  aONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USAbAMER PHYSICAL SOCcAUG  a0230140 v923 a<p>The rupture of a thin free film of a power-law fluid under the competing influences of destabilizing van der Waals pressure and stabilizing surface tension pressure is analyzed. In such a fluid, viscosity decreases with the deformation rate raised to the n - 1 power where 0 &lt; n &lt;= 1 (n = 1 for a Newtonian fluid). When 6/7 &lt; n &lt;= 1, film rupture occurs under a balance between van der Waals pressure, inertial stress, and viscous stress. When n &lt; 6/7, however, the dominant balance changes: Viscous stress becomes negligible and the film ruptures under the competition between van der Waals pressure, inertial stress, and surface tension pressure.</p>1 aThete, Sumeet, Suresh1 aAnthony, Christopher1 aBasaran, Osman, A.1 aDoshi, Pankaj  uhttps://library.ncl.res.in/content/self-similar-rupture-thin-free-films-power-law-fluids-1