Flow property at capillary extrusion for ethylene–tetrafluoroethylene copolymer

Kotera, Seigo; Yamaguchi, Masayuki

doi:10.1016/j.jfluchem.2015.05.002

Cited by 8 publications

(4 citation statements)

References 20 publications

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“…[ 19,20 ] Polymer processing aids such as fluoropolymer and boron nitride pile up on the wall surface of the die. This leads to stable slippage, like super extrusion, [ 21 ] which reduces the actual shear stress to below the critical onset value for shark‐skin failure. [ 22 ]…”

Section: Introductionmentioning

confidence: 99%

Viscosity decrease by interfacial slippage between immiscible polymers

Moonprasith

Nasri

Saari

et al. 2021

Polymer Engineering & Sci

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The rheological behavior under pressure‐driven shear flow was studied using binary blends with a sea‐island structure. The addition of a low‐viscosity dispersion having a high interfacial tension with the continuous phase greatly reduces the shear viscosity, for example, the addition of atactic polystyrene (PS) with a low viscosity to isotactic polypropylene (PP) and the addition of PP with a low viscosity to PS. The interfacial slippage occurs because of the poor adhesive strength with the enlarged interfacial area and is responsible for the viscosity decrease. When the dispersion has a similar viscosity to the continuous phase, the viscosity decrease is barely detected. This is because the deformation of dispersed droplets is restricted, which creates a small interfacial area. The interfacial tension between the continuous and dispersed phases plays a crucial role on the shear viscosity. In the case of PP, the addition of linear low‐density polyethylene with a relatively low interfacial tension to PP has almost no impact on the shear viscosity. This is despite the polyethylene having a low viscosity.

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Section: Introductionmentioning

confidence: 99%

Viscosity decrease by interfacial slippage between immiscible polymers

Moonprasith

Nasri

Saari

et al. 2021

Polymer Engineering & Sci

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“…Although fluoropolymers have been extensively employed as insulation materials in spaceships and aircrafts, fluoropolymer, which is used for aerospace applications, is frequently decomposed on account of its rather low radiation resistance performance derived from fluoride precipitation after cosmic ray radiation [ 3 , 4 ]. Hence, there has been a substantial drop-off in mechanical properties, chemical resistance, electrical properties, thermal stability, surface properties, and other characteristics of perfluoropolymers where the body is exposed to rays [ 5 , 6 ] and the extent of degradation depends upon the radiation dose, dose rate, and energy of the incident radiation [ 7 , 8 , 9 , 10 , 11 , 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Radiation-Induced Cross-Linking on Thermal Aging Properties of Ethylene-Tetrafluoroethylene for Aircraft Cable Materials

Zhang

Chen

et al. 2021

Materials

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The effects of electron beam irradiation on ethylene-tetrafluoroethylene copolymer (ETFE) were studied. Samples were irradiated in air at room temperature by a universal electron beam accelerator for various doses. The effect of irradiation on samples and the cross-linked ETFE after aging were investigated with respect to thermal characteristics, crystallinity, mechanical properties, and volume resistivity using thermo-gravimetric analysis (TGA), differential scanning calorimeter (DSC), universal mechanical tester, and high resistance meter. TGA showed that thermal stability of irradiated ETFE is considerably lower than that of unirradiated ETFE. DSC indicates that crystallinity is altered greatly by cross-link. The analysis of mechanical properties, fracture surface morphology, visco-elastic properties and volume resistivity certify radiation-induced cross-linking is vital to aging properties.

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“…Dubrocq‐Baritaud et al reported that the addition of copolymers consisting of vinylidene fluoride and hexafluoropropylene to linear low‐density polyethylene (LLDPE) postponed surface defects, reduced the pressure at the die, and delayed the onset of sharkskin failure by inducing slippage at the die wall. Kotera et al studied the capillary extrusion properties of an ethylene–tetrafluoroethylene copolymer (ETFE) and found that it exhibited a range of flow instability phenomena. Interestingly, a quasi‐stable flow region was detected over a wide range of shear rates between the sharkskin and gross melt fracture regions, which was caused by steady slippage.…”

Section: Introductionmentioning

confidence: 99%

Impact of Mixing Method on Rheological Instability for Binary Mixture of Linear Low‐Density Polyethylene

et al. 2016

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The impact of different mixing methods on flow instability in capillary extrusion was examined using binary mixtures of linear low-density polyethylene with different molecular weights. The polymers were blended using a single-screw extruder, a twin-screw extruder, and a twin-screw mixer. The onset of flow instability changed depending on the mixing method used, even though their linear viscoelastic properties were almost identical. The mixtures that were subjected to mixing methods with weak mixing capability exhibit sharkskin failure even at low shear stress and low values of the maximum draw ratio without rupture in the molten state. The results suggested that mechanically weak points were present, which led to cohesive failure at the strand surface following abrupt stretching at the die exit (i.e., sharkskin failure). In contrast, the mixture that was subjected to thorough mixing exhibited smooth surface at high shear stress and a large maximum draw ratio.

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Flow property at capillary extrusion for ethylene–tetrafluoroethylene copolymer

Cited by 8 publications

References 20 publications

Viscosity decrease by interfacial slippage between immiscible polymers

Viscosity decrease by interfacial slippage between immiscible polymers

Effect of Radiation-Induced Cross-Linking on Thermal Aging Properties of Ethylene-Tetrafluoroethylene for Aircraft Cable Materials

Impact of Mixing Method on Rheological Instability for Binary Mixture of Linear Low‐Density Polyethylene

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