02229nas a2200289 4500008004100000022001400041245010000055210006900155260005700224300001100281490000700292520129500299653001301594653001401607653000901621653001101630653001201641653001801653653001701671100002301688700001801711700002201729700002601751700001801777700002101795856012301816 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

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.

10aBranched10aExtrusion10aFilm10aLinear10aNecking10aNonisothermal10aPolyethylene1 aPol, Harshawardhan1 aBanik, Sourya1 aAzad, Lal, Busher1 aThete, Sumeet, Suresh1 aDoshi, Pankaj1 aLele, Ashish, K. uhttp://library.ncl.res.in/content/nonisothermal-analysis-extrusion-film-casting-process-using-molecular-constitutive-002608nas a2200337 4500008004100000022001400041245017500055210006900230260000800299300002100307490000700328520146600335653001901801653003301820653001401853653000901867653003001876653001301906653001901919653001701938653001301955653001401968100002201982700002102004700002002025700002902045700002502074700002302099700001802122856013002140 2021 eng d a8756-087900aControlling draw resonance during extrusion film casting of nanoclay filled linear low-density polyethylene: an experimental study and numerical linear stability analysis0 aControlling draw resonance during extrusion film casting of nano cJUL a87560879209784430 v373 a

Commercially important extrusion film casting (EFC) processes for manufacturing plastic films or sheets are hampered by several instabilities that severely limits their productivity. In this research we focussed on one important instability: the draw resonance that occurs during the EFC process mainly under extensional flow conditions. Draw resonance is the sustained periodic oscillations in the film dimensions, notably film width and thickness, when the process operates beyond a critical draw ratio (CDR). In this research our goal was to reduce this draw resonance instability by incorporating well dispersed nanoclay fillers in a base polymeric resin (such as a linear low density polyethylene - LLDPE) to determine how these nanocomposite (NC) formulations can prevent or reduce the draw resonance defect. EFC experiments were conducted on the base resin and on the NC formulations under non-isothermal conditions to determine the onset of the draw resonance experimentally. Conventional linear stability analysis was performed to determine the onset of the draw resonance defect numerically. Numerical predictions for the onset of draw resonance were in qualitative agreement with our experimental data. Our results showed that incorporating appropriate nanoclay concentrations in a base polymeric resin indeed enhanced the EFC process stability for those polymer formulations and thus can have important economic implications for processors.

10aDraw resonance10aextensional strain hardening10aExtrusion10aFilm10ahydrodynamic interactions10aNanoclay10aNanocomposites10aPolyethylene10aRheology10astability1 aRokade, Dhammaraj1 aChougale, Sanket1 aPatil, Prashant1 aBhattacharjee, Tanushree1 aGawande, Dnyaneshwar1 aPol, Harshawardhan1 aDhadwal, Renu uhttp://library.ncl.res.in/content/controlling-draw-resonance-during-extrusion-film-casting-nanoclay-filled-linear-low-density02389nas a2200253 4500008004100000022001400041245018700055210007000242260000800312300000900320490000600329520149200335653001901827653001401846653000901860653001901869653001201888653002501900100001801925700002101943700002301964700001801987856013002005 2022 eng d a2542-504800aFlow visualization by Matlab® based image analysis of high-speed polymer melt extrusion film casting process for determining necking defect and quantifying surface velocity profiles0 aFlow visualization by Matlab® based image analysis of highspeed  cJAN a1-110 v53 aThe primary objective of this research paper is to detect and quantify the necking defect and surface velocity profiles in high-speed polymer melt extrusion film casting (EFC) process using Matlab® based image processing techniques. Extrusion film casting is an industrially important manufacturing process and is used on an industrial scale to produce thousands of kilograms of polymer films/sheets and coated products. In this research, the necking defect in an EFC process has been studied experimentally and the effects of macromolecular architecture such as long chain branching (LCB) on the extent of necking have been determined using image processing methodology. The methodology is based on the analysis of a sequence of image frames taken with the help of a commercial CCD camera over a specific target area of the EFC process. The image sequence is then analyzed using Matlab® based image processing toolbox wherein a customized algorithm is written and executed to determine the edges of the extruded molten polymeric film to quantify the necking defect. Alongwith the necking defect, particle tracking velocimetry (PTV) technique is also used in conjunction with the Matlab® software to determine the centerline and transverse velocity profiles in the extruded molten film. It is concluded from this study that image processing techniques provide valuable insights into quantifying both the necking defect and the associated velocity profiles in the molten extruded film.10aEdge detection10aExtrusion10aFilm10aimage analysis10aNecking10aVelocity measurement1 aVagga, Aarati1 aAherrao, Swapnil1 aPol, Harshawardhan1 aBorkar, Vivek uhttp://library.ncl.res.in/content/flow-visualization-matlab%C2%AE-based-image-analysis-high-speed-polymer-melt-extrusion-film02654nas a2200289 4500008004100000022001400041245013800055210006900193260000800262300001200270490000700282520171900289653001902008653001402027653000902041653001702050653002402067653002002091653001202111653001002123653002102133100002202154700002002176700002302196700002302219856012202242 2023 eng d a8756-087900aRheology and processing study on controlling material and process defects in polymer melt extrusion film casting using polymer blends0 aRheology and processing study on controlling material and proces cAPR a211-2400 v393 a

The primary objective of this research paper is to control the material and process defects in polymer melt extrusion film casting (EFC) process for linear chain architecture polyethylene (PE) resins through polymer blending methodology. Extrusion film casting is a well-known industrially important manufacturing process that is used to manufacture thousands of tons of polymer/plastic films/sheets and coated products. In this research, the necking defect in an EFC process has been studied experimentally for a linear low density polyethylene (LLDPE) resin and attempts have been made to control its necking by blending in a long chain branched (LCB) low density polyethylene (LDPE) resin. The blending methodology is based on the understanding that a LDPE resin displays enhanced resistance to necking as compared to the LLDPE resin. It is found that added LDPE resin enhances necking resistance for the primary LLDPE resin. Further, as the LDPE concentration increases in the blend formulation, the necking is further reduced as compared to pure LLDPE. Analogous to past studies on EFC of linear and long chain branched architecture containing PEs, it is observed that as the LDPE is increased in the blend formulations, the formulations displayed enhanced melt elasticity and extensional strain hardening in rheological studies. It is concluded from this study that polyethylene resins having linear chain architecture can be made amenable to enhanced resistance to necking using appropriate amount of a long chain branched resins. Finally, process defects such as the draw resonance onset could be shifted to higher draw ratios as the LDPE level is increased in the LLDPE-LDPE blend formulation.

10aDraw resonance10aExtrusion10aFilm10alinear chain10along-chain branched10amelt elasticity10aNecking10aonset10astrain hardening1 aRokade, Dhammaraj1 aPatil, Prashant1 aNandimath, Sheetal1 aPol, Harshawardhan uhttp://library.ncl.res.in/content/rheology-and-processing-study-controlling-material-and-process-defects-polymer-melt