Block‐Copolymer‐Assisted Solubilization of Carbon Nanotubes and Exfoliation Monitoring Through Viscosity

Cotiuga, IM Irina; Picchioni, Francesco; Agarwal, US Uday; Wouters, D Daan; Loos, Joachim; Lemstra, PJ Piet

doi:10.1002/marc.200600163

Cited by 52 publications

(48 citation statements)

References 30 publications

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“…[2][3][4] It has been shown that carbon nanotubes can be dispersed in aqueous media or organic solvents via noncovalent adsorption of low molecular weight surfactants 5 and polymers [6][7][8] (such as diblock copolymers and amphiphilic polymers). The covalent functionalization with organic molecules is mostly achieved by exploiting the reactivity of carbon nanotube-bound carboxylic acids via amidation or esterification reactions.…”

Section: Introductionmentioning

confidence: 99%

Cross-Linking of Multiwalled Carbon Nanotubes with Polymeric Amines

et al. 2008

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Functionalization of carbon nanotubes is considered as an essential step to enable their manipulation and application in potential end-use products. In this paper we introduce a new approach to functionalize multiwalled carbon nanotubes (MWNTs) by applying an amidation-type grafting reaction with amino-functionalized alternating polyketones. The functionalized MWNTs were characterized by using thermogravimetric analysis (TGA), X-ray photoemission spectroscopy (XPS), element analysis, Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Around 40 wt % polyamines based on the total weight of the MWNTs can be covalently attached to the surface of the MWNTs. It is found that polyamines act as crosslinking agents to interconnect or cross-link the MWNTs within and between bundles, as demonstrated by SEM and TEM analysis. After cross-linking, the functionalized MWNTs are insoluble in any solvent. The cross-linked MWNTs can be melt-blended into polyethylene, and the resulting composites show comparable mechanical properties to those obtained by simple blending of "un-cross-linked" nanotubes with polyethylene.

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Section: Introductionmentioning

confidence: 99%

Cross-Linking of Multiwalled Carbon Nanotubes with Polymeric Amines

et al. 2008

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“…In a recent study 12 , the authors have showed that the addition of acetone decreases, in up to 50%, the viscosity of the epoxy resin, what is expected considering that the solvating effect of the solvent weakens inter-chain interactions 10 . Furthermore, Cotiuga et al 14 found that increasing the duration of ultrasonic irradiation of the CNTs dispersions, an initial increase in solution viscosity was obtained, suggesting this to be an indication of the progress of the SWCNTs exfoliation. For long sonication periods, however, the viscosity started decreasing, which was interpreted as a 50 nm consequence of breakage/damage (with a possible decrease in average length) of the SWCNTs.…”

Section: Sample Characterizationmentioning

confidence: 99%

Effect of carbon nanotubes addition on the mechanical and thermal properties of epoxy matrices

et al. 2008

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In this work, nanocomposites were prepared by adding a small amount of single walled carbon nanotubes (SWCNTs) to an epoxy resin aiming to study the resulting mechanical, viscoelastic and thermal properties of the nanocomposites. To optimize the processing of the nanocomposites and to favor a homogeneous dispersion of the SWCNTs on the matrix, acetone was used to reduce resin viscosity, increasing diffusion of the SWCNTs in the solution. The epoxy/SWCNTs/acetone systems were also sonicated in order to minimize entanglement of the SWCNTs. The systems were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetry, differential scanning calorimetry and dynamic mechanical analysis. The results indicated that the addition of small amounts of SWCNTs to epoxy leads to slight structural changes in the epoxy matrix which, together with the presence of SWCNTs, may reflect on its mechanical and viscoelastic properties

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“…A second family of interesting materials with potential for third componentassisted carbon nanotube dispersion are block copolymers. [23][24][25] In general, the block copolymer is designed in such a way that one block of the polymer will form a close interaction with the carbon nanotube walls, while the other block(s) will provide the solubility to the exfoliated nanotubes by forming a steric barrier or repulsion interaction between polymer-wrapped nanotubes.[26] So far, a wide range of charged and neutral block copolymers such as poly(ethylene oxide) (PEO) with poly(propylene oxide) (PPO) (PEO-PPO-PEO), [15] polystyrene (PS) with poly(t-butylacrylate) (PBA) [15] or poly(vinyl pyridine) (PVP) [23] have been reported for carbon nanotube dispersion. However, among all the block copolymers being studied, they do not contain conjugated polymers as part of the block copolymer structure.…”

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Dispersion of Pristine Carbon Nanotubes Using Conjugated Block Copolymers

et al. 2008

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Despite many of the intriguing and excellent electrical, mechanical and optical properties of carbon nanotubes (CNTs), [1,2] extensive applications of these nanomaterials are still limited. One of the main challenges in carbon nanotube research field is the dispersion and stabilization of CNTs in different solvent media and polymer matrices. The as-synthesized CNTs are often bundled together due to strong van der Waals interactions between the nanotubes. There have been three most widely used methods to disperse CNTs into solvents and polymer matrices: [3] physical blending, [4][5][6] chemical functionalization, [7][8][9][10][11] and dispersants-assisted dispersion. [12][13][14][15][16] Each of these methods has its own advantages and disadvantages. For physical blending using mechanical forces such as sonication, although simple and cost effective, the dispersion quality is often the poorest. The so-dispersed nanotubes will quickly precipitate out again when sonication stops. For chemical modification and functionalization, CNTs are treated with strong oxidizing reagents to form functional groups such as carboxylic acids on the nanotube walls. CNTs can be made water or organic solvent soluble, depending on the modification degree and further molecular moieties attached to the nanotubes. Although most effective as a dispersion method, such treatment inevitably disrupts the long range p conjugation of the nanotube, often leads to decreased electrical conductivity, diminished mechanical strength, and other undesired properties. In the dispersants-assisted dispersion, a third component chemical is mixed with CNTs in solutions. Through sonication, the CNTs are mechanically de-bundled and then stabilized by a dispersant chemical through noncovalent interactions, therefore, avoiding the destruction of the chemical structures, electronic and mechanical properties of the carbon nanotubes. Recently, there are two types of materials that have attracted significant amount of attention as dispersants to assist carbon nanotube dispersion. One of these materials is the conjugated polymers, such as poly(m-phenylene vinylene), [17,18] poly(3-alkylthiophene), [19,20] and poly(arylene ethynylene). [21,22] These polymers stabilize carbon nanotubes by forming strong p-p stack interactions with carbon nanotube walls. However, the thus-formed dispersions have limited solubility and stability because the conjugated polymers themselves face solubility and miscibility issues due to the strong inter-chain p-p interactions. A second family of interesting materials with potential for third componentassisted carbon nanotube dispersion are block copolymers. [23][24][25] In general, the block copolymer is designed in such a way that one block of the polymer will form a close interaction with the carbon nanotube walls, while the other block(s) will provide the solubility to the exfoliated nanotubes by forming a steric barrier or repulsion interaction between polymer-wrapped nanotubes.[26] So far, a wide range of charged and neutral block copoly...

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Block‐Copolymer‐Assisted Solubilization of Carbon Nanotubes and Exfoliation Monitoring Through Viscosity

Cited by 52 publications

References 30 publications

Cross-Linking of Multiwalled Carbon Nanotubes with Polymeric Amines

Cross-Linking of Multiwalled Carbon Nanotubes with Polymeric Amines

Effect of carbon nanotubes addition on the mechanical and thermal properties of epoxy matrices

Dispersion of Pristine Carbon Nanotubes Using Conjugated Block Copolymers

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