Effects of dispersion and deformation histories on rheology of semidilute and concentrated suspensions of multiwalled carbon nanotubes

Küçük, İlknur; Gevgilili, Halil; Kalyon, Dilhan M.

doi:10.1122/1.4819745

Cited by 17 publications

(13 citation statements)

References 42 publications

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Section: Resultsmentioning

confidence: 99%

“…The effect of nanofillers dispersion on the viscoelastic properties of composites has been systematically investigated in the past . One important conclusion from these works is that adequate dispersion of nanotubes could significantly change the linear viscoelasticity even at very low filler contents . Although the relatively good dispersion of CNTs in PA6 has much improved its viscoelastic properties, the effect could be more significant with finer dispersion of nanotubes, as in the case of solution‐based preparation techniques.…”

Section: Resultsmentioning

confidence: 99%

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Effect of dispersion and selective localization of carbon nanotubes on rheology and electrical conductivity of polyamide 6 (PA6), Polypropylene (PP), and PA6/PP nanocomposites

Moud

Javadi

Nazockdast

et al. 2014

J Polym Sci B Polym Phys

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Nanocomposites were prepared by adding 1-3 vol % multiwalled carbon nanotubes (MWCNTs) to polyamide 6 (PA6), polypropylene (PP), and their co-continuous blends of 60/40 and 50/50 volume compositions. Because of the good interaction and interfacial adhesion to the PA6, nanotubes were disentangled and distributed evenly through nanocomposites containing PA6. In contrast, lack of active interactions between the matrix and the CNTs resulted in poor tube dispersion in PP. These observations were then verified by studying the rheology and electrical conductivity of their respective nanocomposites. Absence of percolated CNT clusters and possible wrapping of the tubes by PA6 resulted in low electrical conductivity of PA6/CNT nanocomposites. On the other hand, despite the weak dispersion of the tubes, electrical conductiv-ities of PP/CNT nanocomposites were much higher than all other counterparts. This could be the result of good threedimensional distribution of the agglomerated bundles and secondary aggregation of tubes in PP. Adding CNTs to blends of PA6/PP (60/40 and 50/50) resulted in almost full localization of carbon nanotubes in PA6, leading to their higher effective concentration. At the same CNT loadings, the blend nanocomposites had three to seven orders of magnitude higher electrical conductivity than pure PA6.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Effect of dispersion and selective localization of carbon nanotubes on rheology and electrical conductivity of polyamide 6 (PA6), Polypropylene (PP), and PA6/PP nanocomposites

Moud

Javadi

Nazockdast

et al. 2014

J Polym Sci B Polym Phys

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“…[1] Such network formation can also affect the processability and viscoelastic material functions of the nanocomposite. [3,[19][20][21][22] A wide range of percolation thresholds have been reported for both electrical and rheological properties of polymer/CNT nanocomposites. [1,4] In addition, numerous studies have shown that rheological and electrical percolation thresholds strongly depend on the type of polymer, CNT aspect ratio, degree of breakdown of CNT agglomerates, and the degree of alignment and spatial distribution of the embedded CNTs.…”

Section: Introductionmentioning

confidence: 99%

Impact of ultrasonication on carbon nanotube demixing and damage in polymer nanocomposites

Ganapathi

Lee

Kalyon

et al. 2020

J of Applied Polymer Sci

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While ultrasonication is universally employed for dispersion and distribution of carbon nanotubes (CNTs) in a solvent or polymer solution, the current work focuses on the underlying mechanisms of CNT demixing and CNT damage that can occur during processing. Here, multi‐walled CNTs were dispersed in a polycaprolactone polymer matrix using an established solution processing technique. Electrical, rheological, and mechanical characterization results suggest that once nanocomposite property enhancements reach an optimal level, further sonication leads to a decrease in the corresponding properties due to a combination of CNT damage and demixing mechanisms. Evidence of CNT damage from transmission electron microscopy, poor CNT distribution from optical image analysis and shear‐induced crystallization results, and reagglomeration observed from ultraviolet–visible results, taken together, suggest that mechanisms of demixing and damage of the CNTs coexist for excessive sonication times.

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“…The thermo-mechanical history that the suspension is exposed to during processing dictates the homogeneity of the spatial distribution of the particles and consequently the resulting rheological and wall slip behavior [1][2][3][4][5][6]. Ultimate properties including electrical properties [4,7,8], fire retardance [9], crosslink density and swelling [10], energetic properties [11] and the development of crystalline morphologies following shearing [12] are dependent on the dynamics of the mixing processes.…”

Section: Introductionmentioning

confidence: 99%

Shear viscosity and wall slip behavior of dense suspensions of polydisperse particles

Lee

Kalyon

2018

Journal of Rheology

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Shear viscosity and wall slip of dense suspensions of a silicone polymer incorporated with polydisperse particles were investigated. Three types of particles with low aspect ratios were used to achieve a relatively high maximum packing fraction,  m =0.86.Such a high  m allowed the preparation of suspensions with a wide range of solid volume fractions, , i.e., 0.62  0.82. The wall slip velocities of the suspensions in steady torsional and capillary flows were characterized and determined to be fully consistent with the mechanism of apparent slip layer formation at the wall. Upon wall slip corrections it was found that at shear stresses which are significantly above the yield stress the relative shear viscosity of the suspensions obeys well the Krieger-Dougherty relationship that links the relative shear viscosity behavior of dense suspensions solely to / m . However, at lower shear stresses that are in the vicinity of the yield stresses the relative shear viscosity becomes functions of both / m and the shear stress. It is clearly demonstrated that without wall slip analysis the accurate characterization of the relative shear viscosity of dense suspensions is not possible. 3 I.

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Effects of dispersion and deformation histories on rheology of semidilute and concentrated suspensions of multiwalled carbon nanotubes

Cited by 17 publications

References 42 publications

Effect of dispersion and selective localization of carbon nanotubes on rheology and electrical conductivity of polyamide 6 (PA6), Polypropylene (PP), and PA6/PP nanocomposites

Effect of dispersion and selective localization of carbon nanotubes on rheology and electrical conductivity of polyamide 6 (PA6), Polypropylene (PP), and PA6/PP nanocomposites

Impact of ultrasonication on carbon nanotube demixing and damage in polymer nanocomposites

Shear viscosity and wall slip behavior of dense suspensions of polydisperse particles

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