Morphology and thermal characterization of nanographene platelets

Koo, Joseph H.; Lao, S.; Lee, J.; Chen, D. Z.; Lam, C.; Wang, Yong; Londa, M.; Pilato, Louis A.

doi:10.1007/s10853-011-5272-7

Cited by 12 publications

(9 citation statements)

References 5 publications

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“…According to Koo et al 34 , during the nanoparticles dispersion into polymeric matrices nano-structures are formed. The two most common detection techniques to nano-structures identification are X-ray diffraction and electron microscopy.…”

Section: Methodsmentioning

confidence: 99%

Nano-engineered composites: interlayer carbon nanotubes effect

et al. 2013

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The concept of carbon nanotube interlayer was successfully introduced to carbon fiber/epoxy composites. This new hybrid laminated composites was characterized by Raman spectroscopy, X-ray diffraction, scanning electron microscopy and tensile tests. An increase on peak stress close to 85% was witnessed when CNTs interlayer with 206.30 mg was placed to carbon fiber/epoxy laminates. The failure mechanisms are associated to CNTs distribution between and around carbon fibers. These CNTs are also responsible for crack bridging formation and the increase on peak stress. Initial stiffness is strongly affected by the CNT interlayer, however, changes on stiffness is associated to changes on nano/micro-structure due to damage. Three different behaviors can be described, i.e. for interlayers with ≈ 60 mg of CNT the failure mode is based on cracks between and around carbon fibers, while for interlayers with CNT contents between 136 mg and 185 mg cracks were spotted on fibers and inside the CNT/matrix mix. Finally, the third failure mechanism is based on carbon fiber breakage, as a strong interface between CNT/matrix mix and carbon fibers is observed.

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Section: Methodsmentioning

confidence: 99%

Nano-engineered composites: interlayer carbon nanotubes effect

et al. 2013

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“…Before we initiated our polymer nanocomposites (PNC) research, we examined the morphology, thermal stability, and kinetics parameters of each MWNT [19]. They were (i) Iljin Nanotech Co., Ltd.'s CM95, (ii) Arkema's Graphistrength® C100, and (iii) Bayer Material Science's Baytubes® C150P multiwall carbon nanotubes.…”

Section: Nanoparticlesmentioning

confidence: 99%

“…This instrument is equipped with micro and ultra-micro balances providing ultra-microgram resolution (~1.0µg) over the whole measurement range (from ambient to 1600°C). The standard heating rates of 5°C/min, 10°C/min, and 20°C/min were used, so that kinetics calculation for activation energy can be performed using isoconversion technique in the future [19].…”

Section: Thermal Stability Testingmentioning

confidence: 99%

Processing and Characterization of Cyanate Ester-MWNT Nanocomposites

Lao

Moon

Koo

et al. 2013

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

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, who shared the many research projects over the past years and assisted in many ways the making of this project. Lastly and most importantly, the author would like to thank his family for the continual support. Partial financial support from Air Force Office of Scientific Research (AFOSR) and KAI, LLC is greatly appreciated. vi Tomorrow's lightweight, high-performance composite systems will be made of structures built with materials that have unprecedented intrinsic properties for performing a wide range of functions, such as EMI shielding, thermal management, flame resistance, lightning strike protection, acoustic damping, and health-monitoring. Current structures require parasitic components, e.g., metal strips, copper wire meshes, strain gauges, and heat sinks to provide these functions. By eliminating parasitic components, future high-performance multifunctional systems can achieve the intended objectives, while maintaining optimum weight, reliability, cost, and fuel efficiency. With the continuing growth of polymer composites in industries, such as aerospace, automotive, and wind energy, research and development on lightweight, high-performance composites that possess extraordinary properties for future multifunctional systems has generated considerable interest and excitement. Recent advances in nanomaterial synthesis and functionalization have shown that tailored property combinations are possible with reduced parasitic content to achieve multifunctionality. Cyanate ester (CE), a class of high-performance thermosetting resins (high T g , >250°C), has received considerable attention due to its good mechanical properties, vii thermal stability, flammability properties, ease of process, and volatile-free curing process. Multiwall carbon nanotubes were selected due to their unique combination of excellent mechanical, electrical, and thermal properties. The principal objective of this work is to determine the extent to which several different processing techniques will affect the MWNT dispersion and corresponding nanocomposite properties, such as thermal, flammability, mechanical, and electrical properties. A processing-structure-property relationship, as well as performance of this class of carbon-based CE nanocomposite, will be established. Therefore, a major scientific contribution of this study will be the development and characterization of a novel, multifunctional CE nanocomposite. Different mixing instruments, such as high shear mixer, ultrasonicator, planetary centrifugal mixer, etc. were used to disperse the nanotubes in the cyanate ester resin matrix. Microstructural morphology characterizations by SEM, STEM, and TEM show that various degrees of dispersions of MWNTs were obtained by the different mixing techniques. An attempt to quantify the MWNT dispersion was made. Electrical resistivity of samples processed by both stand mixer and three-roll mill passes the ESD requirement; however, the MWNT percolation thresholds by the two techniques are different. Thermal analysis shows that the addition of th...

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“…It is an extension of our ongoing PNCs research program to study these NPGs as new type of nanomaterials [8][9][10][11][12] to enhance PNC properties. This paper describes eleven NGPs that are available to our research group from different sources.…”

Section: Introductionmentioning

confidence: 99%

Methodology for Assessment of Morphological and Thermal Characteristics of Nanographene Platelets

Koo

Pinero

Hao

et al. 2013

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

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This paper describes the methodology used to characterize the as-received nanographene platelets (NGPs) from several nanomaterial manufacturers. The microstructures of these NGPs were first examined using scanning electron microscopy at several different magnifications. The thermal stability of these NGPs was evaluated using thermogravimetric analysis with at least three different heating rates, such as 5, 10, 20, and 40 o C/min in argon or nitrogen atmosphere. The residual mass and rate of mass loss of these NGPs was compared. The kinetics parameters, such as the activation energy and pre-exponential factor of these NGPs were then calculated using the isoconversion technique. Eleven NGPs were characterized using the above methods. The similarities and differences of these NPGs were compared. Based on these facile techniques, one can rank the morphological and thermal characteristics of these NGPs. The methodology serves as a unique screening technique to select the appropriate NPG that can be chosen for whatever specific application is desired. NomenclatureA = Pre-exponential factor A avg = Average pre-exponential factor A s = Maximum mass loss attainable Cpm = o C/min E = Activation energy E avg = Average activation energy E peak = Peak activation energy 1 Sr. 2 k = Kinetic constant n = Order of reaction R = Universal gas constant T = Temperature t = Time w = Instantaneous weight X s = Solid conversion β = Heating rate Subscripts avg = Average f = Final o = Initial peak = Peak

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Morphology and thermal characterization of nanographene platelets

Cited by 12 publications

References 5 publications

Nano-engineered composites: interlayer carbon nanotubes effect

Nano-engineered composites: interlayer carbon nanotubes effect

Processing and Characterization of Cyanate Ester-MWNT Nanocomposites

Methodology for Assessment of Morphological and Thermal Characteristics of Nanographene Platelets

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