Browsing by Author "Peng, Haiqing"

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    Chemistry of single wall carbon nanotube derivatives
    (2004) Peng, Haiqing; Margrave, John L.
    Single wall carbon nanotubes (SWNTs) are novel materials with unique chemical and physical properties: they are the strongest fiber ever made; they have outstanding thermal conductivity and unique one dimensional electrical conductivity; their weight is light and their individual size is only 0.4 to several nm in diameter. A wide range of applications of SWNTs were proposed including high performance polymer composites, field emitter for flat panel display, energy storage, molecular electronics and biomedical applications, etc. Functionalization of SWNTs has been an important pathway to utilize SWNTs for many of these applications. This thesis studies the fluorination of SWNTs, electrochemical properties of fluorinated SWNTs as a cathode material in lithium batteries and oxidative properties and thermal stabilities of fluorinated SWNTs in a binary metal compound matrix. This thesis also studies functionalization of SWNTs through a free radical addition process, in which radicals were from the thermal decomposition of organic diacyl peroxides including lauryl peroxide, benzoyl peroxide, succinic acid peroxide and glutaric peroxide. Functionalized SWNTs prepared from this method have improved solubility in various common organic solvents. They are characterized with a variety of techniques including Raman, FTIR, TGA/MS, TEM and solid state 13C NMR. A parallel study on C60 fullerene is also included. The succinic acid peroxide is of particular interest for functionalization because it can attach ethylenecarboxyl groups (--CH2CH 2COOH) to the sidewall of SWNTs. The sidewall acid groups, after reacting with thionyl chloride and diamines, are converted to terminal amine groups, which can form covalent bonds with epoxy polymers to prepare SWNT reinforced epoxy polymer composites. Mechanical tests show that the tensile strength, elongation and storage modulus of epoxy are greatly improved (25∼30%) with 1 weight percent of SWNTs addition.
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    Fabrication of carbon nanotube reinforced epoxy polymer composites using functionalized carbon nanotubes
    (2009-10-13) Khabashesku, Valery N.; Zhu, Jiang; Peng, Haiqing; Barrera, Enrique V.; Margrave, John L.; Margrave, Mary Lou; Rice University; United States Patent and Trademark Office
    The present invention is directed to methods of integrating carbon nanotubes into epoxy polymer composites via chemical functionalization of carbon nanotubes, and to the carbon nanotube-epoxy polymer composites produced by such methods. Integration is enhanced through improved dispersion and/or covalent bonding with the epoxy matrix during the curing process. In general, such methods involve the attachment of chemical moieties (i.e., functional groups) to the sidewall and/or end-cap of carbon nanotubes such that the chemical moieties react with either the epoxy precursor(s) or the curing agent(s) (or both) during the curing process. Additionally, in some embodiments, these or additional chemical moieties can function to facilitate dispersion of the carbon nanotubes by decreasing the van der Waals attractive forces between the nanotubes.
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    Fiber-reinforced polymer composites containing functionalized carbon nanotubes
    (2012-05-29) Zhu, Jiang; Khabashesku, Valery N.; Peng, Haiqing; Barrera, Enrique V.; Margrave, John L.; Margrave, Mary Lou; Rice University; United States Patent and Trademark Office
    The present invention is directed to methods of integrating carbon nanotubes into epoxy polymer composites via chemical functionalization of carbon nanotubes, and to the carbon nanotube-epoxy polymer composites produced by such methods. Integration is enhanced through improved dispersion and/or covalent bonding with the epoxy matrix during the curing process. In general, such methods involve the attachment of chemical moieties (i.e., functional groups) to the sidewall and/or end-cap of carbon nanotubes such that the chemical moieties react with either the epoxy precursor(s) or the curing agent(s) (or both) during the curing process. Additionally, in some embodiments, these or additional chemical moieties can function to facilitate dispersion of the carbon nanotubes by decreasing the van der Waals attractive forces between the nanotubes.
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    Flow dielectrophoretic separation of single wall carbon nanotubes
    (2012-01-17) Schmidt, Howard K.; Peng, Haiqing; Mendes, Manuel Joao; Pasquali, Matteo; Rice University; United States Patent and Trademark Office
    According to some embodiments, a method for separating a first fraction of a single wall carbon nanotubes and a second fraction of single wall carbon nanotubes includes, but is not limited to: flowing a solution comprising the nanotubes into a dielectrophoresis chamber; applying a DC voltage, in combination with an AC voltage, to the dielectrophoresis chamber; and collecting a first eluent from the dielectrophoresis chamber, wherein the first eluent comprises the first fraction and is depleted of the second fraction, wherein the first and second fractions differ by at least one of conductivity, diameter, length, and combinations thereof.
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    Method for functionalizating carbon naontubes utilizing peroxides
    (2011-07-12) Khabashesku, Valery N.; Peng, Haiqing; Margrave, John L.; Margrave, Mary Lou; Billups, Edward W.; Ying, Yunming; Rice University; United States Patent and Trademark Office
    A method for functionalizing the wall of single-wall or multi-wall carbon nanotubes involves the use of acyl peroxides to generate carbon-centered free radicals. The method allows for the chemical attachment of a variety of functional groups to the wall or end cap of carbon nanotubes through covalent carbon bonds without destroying the wall or endcap structure of the nanotube. Carbon-centered radicals generated from acyl peroxides can have terminal functional groups that provide sites for further reaction with other compounds. Organic groups with terminal carboxylic acid functionality can be converted to an acyl chloride and further reacted with an amine to form an amide or with a diamine to form an amide with terminal amine. The reactive functional groups attached to the nanotubes provide improved solvent dispersibility and provide reaction sites for monomers for incorporation in polymer structures. The nanotubes can also be functionalized by generating free radicals from organic sulfoxides.
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    Method for functionalizing carbon nanotubes utilizing peroxides
    (2006-10-24) Khabashesku, Valery N.; Peng, Haiqing; Margrave, Mary Lou; Billups, Edward W.; Ying, Yunming; Rice University; United States Patent and Trademark Office
    A method for functionalizing the wall of single-wall or multi-wall carbon nanotubes involves the use of acyl peroxides to generate carbon-centered free radicals. The method allows for the chemical attachment of a variety of functional groups to the wall or end cap of carbon nanotubes through covalent carbon bonds without destroying the wall or endcap structure of the nanotube. Carbon-centered radicals generated from acyl peroxides can have terminal functional groups that provide sites for further reaction with other compounds. Organic groups with terminal carboxylic acid functionality can be converted to an acyl chloride and further reacted with an amine to form an amide or with a diamine to form an amide with terminal amine. The reactive functional groups attached to the nanotubes provide improved solvent dispersibility and provide reaction sites for monomers for incorporation in polymer structures. The nanotubes can also be functionalized by generating free radicals from organic sulfoxides.
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    Method for functionalizing carbon nanotubes utilizing peroxides
    (2010-06-22) Khabashesku, Valery N.; Peng, Haiqing; Margrave, John L.; Margrave, Mary Lou; Billups, Edward W.; Ying, Yunming; Rice University; United States Patent and Trademark Office
    A method for functionalizing the wall of single-wall or multi-wall carbon nanotubes involves the use of acyl peroxides to generate carbon-centered free radicals. The method allows for the chemical attachment of a variety of functional groups to the wall or end cap of carbon nanotubes through covalent carbon bonds without destroying the wall or endcap structure of the nanotube. Carbon-centered radicals generated from acyl peroxides can have terminal functional groups that provide sites for further reaction with other compounds. Organic groups with terminal carboxylic acid functionality can be converted to an acyl chloride and further reacted with an amine to form an amide or with a diamine to form an amide with terminal amine. The reactive functional groups attached to the nanotubes provide improved solvent dispersibility and provide reaction sites for monomers for incorporation in polymer structures. The nanotubes can also be functionalized by generating free radicals from organic sulfoxides.
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    Methods for solubilizing and separating large fullerenes
    (2013-11-26) Rai, Pradeep K.; Parra-Vasquez, Nicholas A. G.; Peng, Haiqing; Hauge, Robert H.; Pasquali, Matteo; Rice University; United States Patent and Trademark Office
    We have discovered that size dependent solubility of large fullerenes in strong acids is dependent on acid strength. This provides a scalable method for separating large fullerenes by size. According to some embodiments, a method for processing a fullerene starting material comprises large fullerenes comprises mixing the starting material with a first concentrated sulfuric acid solution so as to obtain a first dispersion comprising a first portion of the large fullerenes solubilized in the first concentrated sulfuric acid solution.
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    Multi-step purification of single-wall carbon nanotubes
    (2010-03-02) Hauge, Robert H.; Xu, Ya-Qiong; Peng, Haiqing; Smalley, Richard E.; Marek, Irene Morin; Rice University; United States Patent and Trademark Office
    The present invention relates to processes for the purification of single-wall carbon nanotubes (SWNTs). Known methods of single-wall carbon nanotube production result in a single-wall carbon nanotube product that contains single-wall carbon nanotubes in addition to impurities including residual metal catalyst particles and amounts of small amorphous carbon sheets that surround the catalyst particles and appear on the side of the single-wall carbon nanotubes. The present purification processes remove the extraneous carbon as well as metal-containing residual catalyst particles.
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    Nanotube-amino acids and methods for preparing same
    (2012-01-10) Khabashesku, Valery N.; Peng, Haiqing; Margrave, John L.; Margrave, Mary Lou; Rice University; United States Patent and Trademark Office
    The present invention is directed toward compositions comprising carbon nanotubes (CNTs) that are sidewall-functionalized with amino acid groups, and to amino acid compositions comprising carbon nanotubes. The present invention is also directed to simple and relatively inexpensive methods for the preparation of such compositions. Such compositions are expected to greatly extend the bio-medical applications of CNTs.