@article { ISI:000329101700009,
	title = {Nonisothermal analysis of extrusion film casting process using molecular constitutive equations},
	journal = {Rheologica Acta},
	volume = {53},
	number = {1},
	year = {2014},
	month = {JAN},
	pages = {85-101},
	publisher = {SPRINGER},
	address = {233 SPRING ST, NEW YORK, NY 10013 USA},
	abstract = {<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 {\textquoteleft}{\textquoteleft}extended pom-pom{\textquoteright}{\textquoteright} (XPP, for long-chain branched polymer melts) equation and the {\textquoteleft}{\textquoteleft}Rolie-Poly stretch version{\textquoteright}{\textquoteright} (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>},
	keywords = {Branched, Extrusion, Film, Linear, Necking, Nonisothermal, Polyethylene},
	issn = {0035-4511},
	doi = {10.1007/s00397-013-0739-x},
	author = {Pol, Harshawardhan and Banik, Sourya and Azad, Lal Busher and Thete, Sumeet Suresh and Doshi, Pankaj and Lele, Ashish K.}
}
@article {44538,
	title = {Non-isothermal analysis of extrusion film casting using multi-mode Phan-Thien Tanner constitutive equation and comparison with experiments},
	journal = {Rheologica Acta},
	volume = {57},
	year = {2018},
	month = {JUL},
	pages = {493-503},
	abstract = {<p>Extrusion film casting (EFC) is an industrially important process which produces thousands of tons of polymer films, sheets, and coating used for various industrial as well as household applications. In this paper, we focus on an instability which occurs during certain polymer processing operations operating under predominantly elongational flow, such as extrusion film casting and fiber spinning. This instability, called the draw resonance, occurs in the form of sustained periodic fluctuations in the film dimensions. It appears when the process goes beyond the critical line speed of the EFC process. In this work, a conventional linear stability analysis is carried out for nonisothermal EFC process to determine the onset of the draw resonance. The polymer rheology is modeled by the Phan-Thien Tanner (PTT) multi-mode constitutive equation. For the implementation, a conventional shooting method approach is used. Extrusion film casting experiments were also carried out using a conventional linear low-density polyethylene (LLDPE) by varying process parameters such as draw ratio and aspect ratio, to observe the effect on the stability of the process. Linear stability analysis results under non-isothermal conditions are compared and validated with existing results from literature and with our own experimental data. This work displays the effect of multiple relaxation modes as well as the temperature influence on the stability of EFC process. Finally, results also indicate that the temperature highly affects the stability of the EFC process and cannot be ignored from modeling of EFC process.</p>},
	keywords = {Deborah number, Draw resonance, Film extrusion, Multi-mode, Nonisothermal, stability},
	issn = {0035-4511},
	doi = {10.1007/s00397-018-1095-7},
	author = {Chougale, Sanket and Rokade, Dhammaraj and Bhattacharjee, Tanushree and Pol, Harshawardhan and Dhadwal, Renu}
}
