Extrusion film casting of long chain branched polypropylene

Chikhalikar, Kalyani; Banik, Sourya; Azad, Lal Busher; Jadhav, Kishor; Mahajan, Sunil; Ahmad, Zubair Sultan; Kulkarni, Surendra U.; Gupta, Surendra K.; Doshi, Pankaj; Pol, Harshawardhan; Lele, Ashish

doi:10.1002/pen.24039

Cited by 30 publications

(25 citation statements)

References 43 publications

(70 reference statements)

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“…There has also been done a considerable amount of work on EFC under the non-isothermal conditions by Lamberti et al [18][19][20], Lamberti and Titomanlio [21][22][23][24], and Titomanlio [25]. Recently, Pol et al [26,27] and Chikhalikar et al [28] have published a series of articles investigating the influence of the polymer molecular structure on the necking development. For this purpose they utilized the 1D membrane model, originally proposed by Silagy et al [14], the multimode eXtended Pom-Pom constitutive equation and the multimode Rolie-Poly stretch constitutive equation,…”

Section: Introductionmentioning

confidence: 99%

Multifunctional surfaces produced by femtosecond laser pulses

Vorobyev

Chen

2015

Journal of Applied Physics

379

179

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In this work, viscoelastic, isothermal extrusion film casting modeling utilizing 1D membrane model and modified Leonov model was performed in order to understand the role of viscoelastic stress state at the die exit on the polymer melt film stretching in the post die area. Experimental data for LDPE and theoretical predictions based on the eXtended Pom-Pom (XPP) model taken from the open literature were used for the validation purposes. It was found that predicting capabilities of 1D membrane model utilizing XPP and modified Leonov model are comparable for the given processing conditions and material. Consequent theoretical parametric study revealed that increase in the viscoelastic stress state at the die exit, characterized as the ratio of second and first normal stress differences, -N 2 /N 1 , leads to increase in neck-in phenomenon. This suggests that specific attention should be paid to optimization of the extrusion die design in order to stabilize polymer melt film stretching in the post die area. respectively, for the long chain branched (LDPE, PP) and the linear (HDPE, PP) polymers. Even if many useful findings and conclusions regarding to neck-in phenomenon can be found in the open literature [29][30][31][32][33], the effect of polymer melt flow history, generated inside the extrusion die, on the neck-in phenomenon occurring in post die area still remains unclear. In order to extend the knowledge in this field, the 1D membrane model proposed by Silagy et al. [14] together with viscoelastic modified Leonov model [34] was utilized in this work for the EFC modeling. MODELING Modified Leonov ModelThis constitutive equation is based on heuristic thermodynamic arguments resulting from the theory of rubber elasticity [35][36][37]. Mathematically it is relating the stress and elastic strain stored in the material as:

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Section: Introductionmentioning

confidence: 99%

Multifunctional surfaces produced by femtosecond laser pulses

Vorobyev

Chen

2015

Journal of Applied Physics

379

179

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“…The introduction of long chain branching structure into polymer is proved to be an efficient way to enhance its matrix strength, [17][18][19][20] which could benet the scCO 2 foaming of polymer. [20][21][22] It was found that the long-chain branching structure decreased the degree of coalescence in polymers, and the higher cell density was observed in branched polymers due to its enhanced melt strength.…”

Section: Introductionmentioning

confidence: 99%

Introduction of a long-chain branching structure by ultraviolet-induced reactive extrusion to improve cell morphology and processing properties of polylactide foam

Liao

et al. 2017

RSC Adv.

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“…Over the past few years, different basic concepts have been studied in the literature to achieve high melt strength PP (PP-HMS) using different methods [5][6][7][8][9]. According to Chikalikar et al [10], it is possible to increase the melt strength of PP in different ways:…”

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confidence: 99%

Influence of Different Types of Peroxides on the Long-Chain Branching of PP via Reactive Extrusion

et al. 2020

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Long-chain branching (LCB) is known as a suitable method to increase the melt strength behavior of linear polypropylene (PP), which is a fundamental weakness of this material. This enables the modification of various properties of PP, which can then be used—in the case of PP recyclates—as a practical “upcycling” method. In this study, the effect of five different peroxides and their effectiveness in building LCB as well as the obtained mechanical properties were studied. A single screw extruder at different temperatures (180 and 240 °C) was used, and long-chain branched polypropylene (PP-LCB) was prepared via reactive extrusion by directly mixing the peroxides. The peroxides used were dimyristyl peroxydicarbonate (PODIC C126), tert-butylperoxy isopropylcarbonate (BIC), tert-Butylperoxy 2-ethylhexyl carbonate (BEC), tert-amylperoxy 2-ethylhexylcarbonate (AEC), and dilauroyl peroxide (LP), all with a concentration of 20 mmol/kg. The influence of the temperature on the competitive prevalent reactions of degradation and branching was documented via melt mass-flow rate (MFR), rheology measurements, and gel permeation chromatography (GPC). However, via extensional rheology, strain hardening could be observed in all cases and the mechanical properties could be maintained or even improved. Particularly, PODIC C126 and LP signaled a promising possibility for LCB in this study.

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Extrusion film casting of long chain branched polypropylene

Cited by 30 publications

References 43 publications

Multifunctional surfaces produced by femtosecond laser pulses

Multifunctional surfaces produced by femtosecond laser pulses

Introduction of a long-chain branching structure by ultraviolet-induced reactive extrusion to improve cell morphology and processing properties of polylactide foam

Influence of Different Types of Peroxides on the Long-Chain Branching of PP via Reactive Extrusion

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