Rheology of organoclay assisted extrusion of HDPE using Particle Image Velocimetry

Adesina, Ayuba A.; Nasser, M. N.; Teixeira, Paulo Francisco; Hilliou, L.; Covas, J. A.; Hussein, Ibnelwaleed A.

doi:10.1016/j.cherd.2015.05.018

Cited by 7 publications

(4 citation statements)

References 72 publications

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“…This can be explained by the fact that particles align with the flow direction to weaken the particle–particle and polymer–particle interactions at a high shear rate. Therefore, the flow resistance caused by the clusters of fumed silica decreased, leading to low viscosity at a high shear rate [ 23 , 24 ], and this shear-thinning character was more noticeable in the composites with high filler loading. Figure 5 b shows the loss factor (tan δ) of neat epoxy and the composites measured at 1 rad/s.…”

Section: Resultsmentioning

confidence: 99%

Super-Toughened Fumed-Silica-Reinforced Thiol-Epoxy Composites Containing Epoxide-Terminated Polydimethylsiloxanes

Bok

Lim

Kwak

et al. 2021

IJMS

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In response to the demand for high-performance materials, epoxy thermosetting and its composites are widely used in various industries. However, their poor toughness, resulting from the high crosslinking density of the epoxy network, must be improved to expand their application to the manufacturing of flexible products. In this study, ductile epoxy thermosetting was produced using thiol compounds with functionalities of 2 and 3 as curing agents. The mechanical properties of the epoxy were further enhanced by incorporating fumed silica into it. To increase the filler dispersion, epoxide-terminated polydimethylsiloxane was synthesized and used as a composite component. Thanks to the polysiloxane–silica interaction, the nanosilica was uniformly dispersed in the epoxy composites, and their mechanical properties improved with increasing fumed silica content up to 5 phr (parts per hundred parts of epoxy resin). The toughness and impact strength of the composite containing 5 phr nanosilica were 517 (±13) MJ/m3 and 69.8 (±1.3) KJ/m2, respectively.

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Section: Resultsmentioning

confidence: 99%

Super-Toughened Fumed-Silica-Reinforced Thiol-Epoxy Composites Containing Epoxide-Terminated Polydimethylsiloxanes

Bok

Lim

Kwak

et al. 2021

IJMS

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“…b) and LLDPE + FPPA (Fig. b) in region III, exhibit non‐zero velocity values at the wall, according to the presence of slip (see for example ).…”

Section: Resultsmentioning

confidence: 96%

“…Strong slip conditions during the extrusion of polymer melts may be achieved by using low‐surface energy coatings in extrusion dies , as well as with some dies made up of high‐surface energy materials, like brass or other copper alloys . Also, slip flow of polyolefins has been reported when using solid‐based processing additives like boron nitride and organoclays . In particular, the extrusion of LLDPE under strong slip conditions produces outstanding macroscopic phenomena as elimination of sharkskin, monotonic flow curves (no stick‐slip), significant decrease of the extrusion pressure and tribocharging or electrification of the melt due to dynamic friction at the die wall .…”

Section: Introductionmentioning

confidence: 99%

Measurements of slip velocity and frictional heating in the capillary extrusion of linear‐low‐density polyethylene with a fluoropolymer processing aid

Zamora-López

Perez‐González

Marín-Santibáñez

et al. 2016

Polymer Engineering & Sci

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The slip velocity and frictional or slip heating of linear‐low density polyethylene with a fluoropolymer processing aid in capillary flow were measured by rheo‐particle image velocimetry and thermal imaging. The pure polymer did not show slip before the stick‐slip regime but exhibited strong slip when blended with the processing additive. However, for shear stresses beyond the stick‐slip regime, the pure polymer and the blend exhibited the same flow behavior with slip. The slip velocity increased with the shear stress at two different rates before and after the stick‐slip and the contribution of slip to the total flow rate exhibited a minimum. Significant rises in temperature were measured under slip and no slip conditions, being these much higher than the values predicted by the adiabatic flow assumption. Clear difference was made between viscous and frictional heating before the stick‐slip regime, even though they could not be distinguished from one another at higher stresses. Overall, in the presence of slip, frictional and viscous heating act synergistically producing higher temperature rises in the melt. Finally, in contrast to predictions by numerical simulations of viscous heating, measured velocity profiles did not evidence the heating effects in the shear stress range analyzed in this work. POLYM. ENG. SCI., 56:837–845, 2016. © 2016 Society of Plastics Engineers

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“…As far as the decrease of η app with clay content is concerned, three tentative explanations can be put forward. First, a lubrication effect of the clay caused by the migration of particles towards the walls of the slit can contribute to a reduced apparent viscosity [28]. However, a statistical analysis of SEM images taken at different locations within extrudates cross sections (see examples of such images in Figure 9 for the PNC formulated with 2.5 wt% clay) does not seem to indicate such particle migration.…”

Section: Resultsmentioning

confidence: 99%

Multi-parameter in-process monitoring of clay dispersion during melt compounding with PLA

Teixeira¹,

Sutera²,

Scaffaro³

et al. 2019

Express Polym. Lett.

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The time evolution of organoclay particle size and volume fraction, as well as the shear viscosity, are measured in-line for a series of Poly(lactic acid)/organoclay composites, using a rheo-optical die coupled to a prototype modular corotating twin screw extruder. The small angle light scattering patterns and light attenuation recorded during transient experiments indicate that clay dispersion develops through melt intercalation between the clay galleries, thereby expanding the aggregates size, and eventually leads to aggregates break-up, i.e., exfoliation. The simultaneous recording of shear viscosity also indicates that smaller viscosities promote a faster melt intercalation and exfoliation but hinder the extent of clay dispersion. The methodology used in the present study validates the well accepted mechanism for clay dispersion and can be applied straight away for the monitoring of PNC manufacturing during practical production.

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Rheology of organoclay assisted extrusion of HDPE using Particle Image Velocimetry

Cited by 7 publications

References 72 publications

Super-Toughened Fumed-Silica-Reinforced Thiol-Epoxy Composites Containing Epoxide-Terminated Polydimethylsiloxanes

Super-Toughened Fumed-Silica-Reinforced Thiol-Epoxy Composites Containing Epoxide-Terminated Polydimethylsiloxanes

Measurements of slip velocity and frictional heating in the capillary extrusion of linear‐low‐density polyethylene with a fluoropolymer processing aid

Multi-parameter in-process monitoring of clay dispersion during melt compounding with PLA

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