Ultrahigh Strength and Stiffness in Cross‐Linked Hierarchical Carbon Nanotube Bundles

Filleter, Tobin; Bernal, Rodrigo A.; Li, S.; Espinosa, Horacio D.

doi:10.1002/adma.201100547

Cited by 221 publications

(127 citation statements)

References 32 publications

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“…Realization of these properties in applications has been impeded by micro structure-processing challenges. Specifically, in their pristine form CNT display strong van der Waals interactions, which cause them to aggregate into entangled bundles that prevent the formation of uniform, optimal materials [3]. To circumvent these problems, numerous covalent [4][5][6][7] and non-convalent [8][9][10] methods have been developed to aid in CNT dispersion.…”

Section: Introductionmentioning

confidence: 99%

Epoxy functionalized multi-walled carbon nanotubes for improved adhesives

Sydlik

Lee

Walish

et al. 2013

Carbon

108

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Three different types of epoxy-functionalized multi-walled carbon nanotubes (EpCNTs) were prepared by multiple covalent functionalization methods. The EpCNTs were characterized by thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), and Raman spectroscopy to confirm covalent functionalization. The effect of the different chemistries on the adhesive properties was compared to a neat commercial epoxy (Hexion formulation 4007) using functionalized and unfunctionalized multi-walled carbon nanotubes (MWCNT) at 0.5, 1, 2, 3, 5, and 10 weight %. It was found that a EpCNT at 1 weight % increased the lap shear strength, tested using the American Society for Testing and Materials standard test D1002, by 36 % over the unfilled epoxy formulation and by 27 % over a 1 weight % unmodified MWCNT control sample. SEM images revealed a fracture surface morphology change with the incorporation of EpCNT and a deflection of the crack fronts at the site of embedded CNTs, as the mechanism accounting for increased adhesive strength. Rheological studies showed non-linear viscosity and DSC cure studies showed an alteration of cure kinetics with increased CNT concentration, and these effects were more pronounced for EpCNT. AbstractThree different types of epoxy-functionalized multi-walled carbon nanotubes (EpCNTs) were prepared by multiple covalent functionalization methods. The EpCNTs were characterized by thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), and Raman spectroscopy to confirm covalent functionalization. The effect of the different chemistries on the adhesive properties was compared to a neat commercial epoxy (Hexion formulation 4007) using functionalized and unfunctionalized multiwalled carbon nanotubes (MWCNT) at 0.5, 1, 2, 3, 5, and 10 weight %. It was found that a EpCNT at 1 weight % increased the lap shear strength, tested using the American Society for Testing and Materials standard test D1002, by 36 % over the unfilled epoxy formulation and by 27 % over a 1 weight % * Corresponding author. Tel/Fax: 1-617-253-4423. E-mail address: tswager@mit.edu (T. M. Swager) *Manuscript Click here to view linked References 2 unmodified MWCNT control sample. SEM images revealed a fracture surface morphology change with the incorporation of EpCNT and a deflection of the crack fronts at the site of embedded CNTs, as the mechanism accounting for increased adhesive strength. Rheological studies showed non-linear viscosity and DSC cure studies showed an alteration of cure kinetics with increased CNT concentration, and these effects were more pronounced for EpCNT.

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Section: Introductionmentioning

confidence: 99%

Epoxy functionalized multi-walled carbon nanotubes for improved adhesives

Sydlik

Lee

Walish

et al. 2013

Carbon

108

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“…62 In practice, however, MWNTs also tend to suffer additional strength reductions due to shear interactions between the various cylinders that comprise the MWNTs. 27 As might be intuitively expected, the strength of CNTs is primarily found in tensile stress; due to their extremely large lengths relative to their radii or diameters, they buckle relatively easily under compressive loads. 28 Measurements with an atomic force microscope have also shown CNTs to have limited strength perpendicular to their longitudinal axes (i.e.…”

Section: Carbon Nanotube (Cnt) 'Fibers'mentioning

confidence: 97%

Three-Dimensional Constitutive Relations of Aligned Carbon Nanotube Polymer Nanocomposites

Handlin

2013

54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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Variable and high volume fraction aligned carbon nanotube (CNT) polymer nanocomposites (A-PNCs) are fabricated by biaxial mechanical densification of the CNTs, followed by polymer infiltration via capillarity-assisted wetting using an aerospace-grade epoxy. These APNCs are mechanically tested in order to determine the full elastic constitutive relations of the material as a function of volume fraction. Prior to this work, only bulk compression or nanomechanical tests have been attempted due to the small size of the samples. Elastic stiffness results derived from optical strain mapping via digital image correlation are in agreement both with prior experimental nanoindentation measurements and finite element calculations that include the effects of waviness of the reinforcing CNT 'fibers'. Results from longitudinal, transverse, and shear directed testing are shown for 0 to ~20% volume fraction aligned CNT reinforcement. Imaging via scanning electron microscopy and micro-computed tomography is used to establish morphology for structure-property relations. These are the first full elastic constitutive relations for non-isotropic aligned-CNT PNCs. Such relations are needed for modeling and understanding hierarchical nanoengineered composite architectures. Recommended future work includes more comprehensive shear sample testing and concerted modeling efforts to relate this experimental work to computational/theoretical studies of the nanocomposite properties as a function of morphology. AcknowledgementsI have received a great deal of help from many individuals without whom it would not have been possible to complete this thesis.First and foremost, my advisor Professor Brian Wardle has been a fantastic mentor from day one at MIT. He is always available to answer my numerous questions and many times throughout my project offered a new avenue to explore when I felt like I had run into a wall with one approach or another. From familiarizing me with the literature and teaching me the methodology and mindset of a successful researcher and scientist, this project could not have been completed without his guidance.My colleagues in necstlab have been enormously helpful throughout my experiences. Sunny Wicks was always happy to share her enormous expertise in all aspects of the research process, whether dealing with curing epoxy, growing and densifying CNT forests, or more mundane matters like which classes to take or which of the bewildering array of forms at MIT actually need to be filled out. Ethan Parsons provided incalculable help in the aspects of digital image correlation and testing, and taught me a great deal about the mindset of a good scientist. He introduced me to the DIC literature and taught me to use Vic-2D as software that performs digital image correlation rather than a program where I press some buttons and hope that a black box process gives me a logical answer. He also helped to show me the importance of attention to detail-making sure that cameras are parallel to the ground, not 5 degrees from para...

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“…CARBON NANO TUBES AND NANO FIBERS Carbon Nanotubes/Nano fibers were used as the Nano reinforcement in cement based materials.CNTs/CNFs will gives the greater strength in terms of modulus of elasticity (TPA) and the tensile strength (GPA) and it has distinctive chemical and electronic properties [69][70][71].CNTs/CNFs Nano materials can strengthen the mechanical properties of the cement based materials [72,73].CNFs,SWCNTs and MWCNTs are highly structured graphene ring based on high aspect ratio (1000 or more) [74] and it is having a high surface areas. CNTs/CNFs were broadly studied in the polymeric composites [75][76][77].In the present days carbon Nanotubes and carbon fibers were the most extensively used research materials.…”

Section: Synthesis Of Carbon Nano Tubesmentioning

confidence: 99%

Usage of Carbon nanotubes and nano fibers in cement and concrete: A review

A¹,

Shanmugasundaram²

2017

IJET

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Abstract-Carbon Nanotubes (CNTs) are basic carbon consisting of curved graphene layer which consists of a single layer of atoms in a combined hexagonal structure. After plenty of years several characterization of the carbon Nanotubes has become very popular in various applications in civil engineering. Carbon Nanotubes shows good results in terms of mechanical properties of cement mortar when added to it. Literature has showed that carbon Nanotubes can be used in the manufacture of the concrete and the cement pastes. This paper represents the summary of the various research works on the usage of the carbon nanotubes in cement paste, mortars and concrete.

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Ultrahigh Strength and Stiffness in Cross‐Linked Hierarchical Carbon Nanotube Bundles

Cited by 221 publications

References 32 publications

Epoxy functionalized multi-walled carbon nanotubes for improved adhesives

Epoxy functionalized multi-walled carbon nanotubes for improved adhesives

Three-Dimensional Constitutive Relations of Aligned Carbon Nanotube Polymer Nanocomposites

Usage of Carbon nanotubes and nano fibers in cement and concrete: A review

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