02308nas a2200193 4500008004100000245007900041210006900120260000800189300001200197490000700209520165900216100002201875700001801897700002001915700002201935700002701957700001901984856011102003 2017 eng d00aControlling necking in extrusion film casting using polymer nanocomposites0 aControlling necking in extrusion film casting using polymer nano cFEB a213-2330 v563 aThe research described was concerned with the effect of layered-silicate-based organically modified nanoclay fillers on controlling the extent of necking in a polymer melt extrusion film casting (EFC) process. We show that a linear polythylene resin (such as a linear low-density polyethylene-LLDPE) filled with a very low percentage of well-dispersed (or intercalated) nanoclay displays an enhanced resistance to the necking phenomenon. In general, melt-compounded nanoclay-filled LLDPE resin formulations displayed a higher final film width (less necking), thus a lower final film thickness (greater draw down for the same draw ratio), and cooled down faster when compared to the base LLDPE resin. Incorporation of nanoclay filler in the mainly linear chain LLDPE resin led to significant modification of the melt rheological properties that, in turn, affected the melt processability of these formulations. Primarily, the intercalated nanoclay-filled LLDPE formulations displayed the presence of strain-hardening in unaxial extensional rheology. Additionally, the presence of well-dispersed nanoclay in the LLDPE resin led to a display of prominent extrudate swell indicating the presence of melt elasticity in such formulations. The presence of melt elasticity, as shown by shear rheology and strain-hardening, observed by uniaxial extensional rheology, contributed to the LLDPE nanoclay formulations displaying an enhanced resistance to necking for these films. It can be concluded that linear chain polymers susceptible to necking in an EFC process can be made more resistant to such necking by using nanoclay fillers at very low levels of loading.1 aRokade, Dhammaraj1 aAzad, Lal, B.1 aPoddar, Suparna1 aMishra, Satyendra1 aPol, Harshawardhan, V.1 aShukla, Rishab uhttps://library.ncl.res.in/content/controlling-necking-extrusion-film-casting-using-polymer-nanocomposites02520nas a2200265 4500008004100000022001400041245014300055210006900198260000800267300001200275490000700287520162200294653001901916653001901935653001901954653001501973653001801988653001402006100002102020700002202041700002902063700002302092700001802115856012102133 2018 eng d a0035-451100aNon-isothermal analysis of extrusion film casting using multi-mode Phan-Thien Tanner constitutive equation and comparison with experiments0 aNonisothermal analysis of extrusion film casting using multimode cJUL a493-5030 v573 a

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.

10aDeborah number10aDraw resonance10aFilm extrusion10aMulti-mode10aNonisothermal10astability1 aChougale, Sanket1 aRokade, Dhammaraj1 aBhattacharjee, Tanushree1 aPol, Harshawardhan1 aDhadwal, Renu uhttps://library.ncl.res.in/content/non-isothermal-analysis-extrusion-film-casting-using-multi-mode-phan-thien-tanner00704nas a2200133 4500008004100000245010200041210006900143260004000212520012200252100002200374700002100396700002300417856013000440 2018 eng d00a Strategies to reduce necking and drawdown defects in polymer melt extrusion film casting process0 aStrategies to reduce necking and drawdown defects in polymer mel aBoston, MAbAMER CHEMICAL SOC.cAUG3 a256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond1 aRokade, Dhammaraj1 aChougale, Sanket1 aPol, Harshawardhan uhttps://library.ncl.res.in/content/strategies-reduce-necking-and-drawdown-defects-polymer-melt-extrusion-film-casting-process02609nas a2200337 4500008004100000022001400041245017500055210006900230260000800299300002100307490000700328520146600335653001901801653003301820653001401853653000901867653003001876653001301906653001901919653001701938653001301955653001401968100002201982700002102004700002002025700002902045700002502074700002302099700001802122856013102140 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 uhttps://library.ncl.res.in/content/controlling-draw-resonance-during-extrusion-film-casting-nanoclay-filled-linear-low-density02263nas a2200217 4500008004100000022001400041245011800055210006900173260000800242300001400250490000700264520147700271100002701748700002401775700002701799700001901826700002201845700002301867700002401890856013101914 2023 eng d a1759-995400aPalladium-catalyzed polar solvent empowered synthesis of hyper-branched ethylene oligomers and their applications0 aPalladiumcatalyzed polar solvent empowered synthesis of hyperbra cJUL a3239-32510 v143 a

In this contribution, we report the synthesis of two naphthoxy imine ligands, 2-(((2,6-dibenzhydryl-4-methoxyphenyl)imino)methyl)naphthalen-1-ol (L1) and 2-(((2,6-diisopropylphenyl)imino)methyl)naphthalen-1-ol (L2), with different steric and electronic features. L1 and L2 were treated with [(TMEDA)PdMe2] to obtain the corresponding neutral palladium(ii) complexes Cat.1 and Cat.2 in excellent yields. The identity of Cat.1 and Cat.2 was unambiguously ascertained using a combination of spectroscopic and analytical methods, including single-crystal X-ray diffraction. When exposed to 5 bar ethylene pressure, Cat.1 produced hyperbranched ethylene oligomers. The microstructure analysis of ethylene oligomers confirmed the existence of methyl, ethyl, propyl, and sec-butyl branches, with a molecular weight (M-n) of 500-1400 g mol(-1), a PDI of 1.46-2.10, and 67-106 branches per 1000 carbon atoms. The use of a polar solvent, tetrahydrofuran, led to a remarkable 3-fold increase in oligomerization activity without compromising the branching and molecular weight. The resultant hyperbranched ethylene oligomers were selectively monofunctionalized using industrially practiced hydroformylation, ozonolysis, and epoxidation, almost quantitatively. The hydroxy functionalized ethylene oligomer (F4) (5 wt%) was melt-compounded with LLDPE and Nylon-6 to produce a tough yet flexible blend with a higher strain-to-failure as compared to an uncompatibilized blend.

1 aBirajdar, Rajkumar, S.1 aGonnade, Rajesh, G.1 aPol, Harshawardhan, V.1 aPrabhu, Basava1 aRokade, Dhammaraj1 aNandimath, Sheetal1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/palladium-catalyzed-polar-solvent-empowered-synthesis-hyper-branched-ethylene-oligomers-and02655nas a2200289 4500008004100000022001400041245013800055210006900193260000800262300001200270490000700282520171900289653001902008653001402027653000902041653001702050653002402067653002002091653001202111653001002123653002102133100002202154700002002176700002302196700002302219856012302242 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 uhttps://library.ncl.res.in/content/rheology-and-processing-study-controlling-material-and-process-defects-polymer-melt