Browsing by Author "Bustero, I."
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Item Carbon nanotubes for biological devices(2006-05) García, A.; Bustero, I.; Muñoz, R.; Goikotxea, L.; Obieta, I.; PRINTEX; Biomateriales; Tecnalia Research & InnovationThe unique properties of carbon nanotubes open attractive possibilities in many applications areas, for instance as biological devices. Multi Wall Carbon Nanotubes (MWNT) have been synthesized by Chemical Vapour Deposition (CVD) and the influence of certain process variables in the final product yield have been studied. In addition, purification treatment applied at synthesized carbon nanotubes, has been developed. Biocompatibility tests have demonstrated that purified carbon nanotubes are non-cytotoxic. Finally, a functionalization process is developed to help in carbon nanotubes-biomolecule interaction.Item The effect of the addition of carbon nanotubes in the hydrothermal synthesis and in the thermal phase stability of nanozirconia(2010-04) Garmendia, N.; Arteche, A.; García, A.; Bustero, I.; Obieta, I.; Mercado; PRINTEX; Tecnalia Research & InnovationThe yttria partially stabilized zirconia is a very attractive material for orthopaedic applications. It exhibits excellent biocompatibility, high fracture toughness, high strength and low wear rates. But case studies show that delayed failure can occur in vivo due to crack propagation. Carbon nanotubes could avoid the slow crack propagation and enhance the toughness of the ceramic material used for prostheses fabrication. In this work, X-ray diffraction has been used to study the influence of the addition of MWCNT on the hydrothermal synthesis of tetragonal zirconia nanoparticles and on the phase stability of the CNT-nanozirconia nanocomposite with the temperature. First, the influence of the processing variables on the hydrothermal synthesis has been studied. The theoretical mathematical models that relate the percentage of tetragonal zirconia nanocrystals and the relative crystallinity with the processing variables in the range of analyzed values have been obtained. The values that give the maximum percentage and crystallinity of tetragonal phase in the studied range have been established. No significant differences were observed in the crystalline phases obtained when adding MWCNT during the synthesis. Nanozirconia partially coated MWCNT synthesized under the optimized parameters were added to commercially available nanozirconia particles and their influence in the phase stability of the zirconia with the temperature was studied by XRD. It was concluded that the addition of the carbon nanotubes delays both the monoclinic phase decomposition and the grain growth.Item Graphene and its application in polymer composites(European Conference on Composite Materials, ECCM, 2014) Flórez, S.; Chapartegui, M.; Bustero, I.; Gaztelumendi, I.; Mendizábal, M.; Iraola, B.; Atxaga, G.; Jurado, M.; POLIMEROS; PRINTEX; EXTREMAT; Tecnalia Research & InnovationThis paper looks at the development of graphene/polymer nanocomposites to be used as adhesives for Thermal Interface Materials (TIMs) and lightweight high performance CFRP composite laminates with conductive properties. The addition of graphene, even at a very low concentration level (usually less than 5%), into a polymeric matrix can significantly improve its thermal conductivity. The achievement of a good dispersion of graphene and the interfacial bonding of graphene and the polymer matrix is a key aspect. Different qualities of graphene material have been characterised and tested to obtain good dispersion in the polymer matrixes tested. High improvements in the thermal conductivity for both applications under study have been achieved.Item Nanozirconia partially coated MWNT: Nanostructural characerization and cytotoxicity and lixivation study(2008) Garmendia, N.; Bilbao, L.; Muñoz, R.; Goikoetxea, L.; García, A.; Bustero, I.; Olalde, B.; Garagorri, N.; Obieta, I.; PRINTEX; Biomateriales; Tecnalia Research & InnovationCarbon nanotubes could avoid the crack propagation and enhance the toughness of the ceramic material used for prostheses applications. So nanozirconia partially coated carbon nanotubes have been obtained via hydrothermal synthesis of zirconia nanoparticles in presence of multiwall carbon nanotubes. The as covered nanotubes should have a better wettability in the ceramic matrix and improve the dispersion of the CNTs in the nanocomposite, which results in a new ceramic biomaterial with a longer lifetime and better reliability. The obtained product has been structurally characterized by several techniques such as FTIR, XRD, SEM, AFM, EELS, XPS and TGA. The citotoxicity of the sintered product was studied by the change in the pH and ICP-AES in in-vitro biocompatibility tests.Item New sensitive layers for surface acoustic wave gas sensors based on polymer and carbon nanotube composites(2012-12) Sayago, I.; Fernández, M. J.; Fontecha, J. L.; Horrillo, M. C.; Vera, C.; Obieta, I.; Bustero, I.; Biomateriales; Tecnalia Research & Innovation; PRINTEXSurface acoustic wave (SAW) gas sensors based on polymers and carbon nanotube composites as sensitive layers were investigated for the detection of low concentrations of volatile organic compounds as octane and toluene. Several nanocomposites based on polyepichlorohydrin (PECH) and polyetherurethane (PEUT) with different percentage of multiwalled carbon nanotubes (MWCNT) were tested to study the effect of MWCNTs in the response of sensors. The sensors exhibited at room temperature high response to volatile gases (toluene and octane) but did not detect other gases tested as H2, NH3, NO2 and CO.Item New sensitive layers for surface acoustic wave gas sensors based on polymer and carbon nanotube composites(2011) Sayago, I.; Fernández, M. J.; Fontecha, J. L.; Horrillo, M. C.; Vera, C.; Obieta, I.; Bustero, I.; Biomateriales; Tecnalia Research & Innovation; PRINTEXSurface acoustic wave (SAW) gas sensors based on carbon nanotube polymer composites as sensitive layers were investigated for the detection of low concentrations of volatile organic compounds as octane and toluene. Several nanocomposites based on polyepichlorohydrin (PECH) and polyetherurethane (PEUT) with different percentage of multiwalled carbon nanotubes (MWCNT) were tested to study the effect of MWCNTs in the response of sensors.Item Surface acoustic wave gas sensors based on polyisobutylene and carbon nanotube composites(2011-08-10) Sayago, I.; Fernández, M. J.; Fontecha, J. L.; Horrillo, M. C.; Vera, C.; Obieta, I.; Bustero, I.; Biomateriales; Tecnalia Research & Innovation; PRINTEXSurface acoustic wave (SAW) gas sensors based on polyisobutylene (PIB) and composites (PIB and carbon nanotubes) as sensitive layers were investigated for the detection of octane and toluene (volatile organic compounds) and other atmospheric pollutants (H2, CO, NO2 and NH3) at room temperature. In order to study the effect of nanotubes in the response of SAW sensors, several composites based on PIB with different percentages of multiwalled carbon nanotubes (MWNTs) were tested and compared to the response obtained from PIB SAW sensors. Sensors exhibit high responses and selectivity to volatile organic compounds (VOCs) with fast response and recovery times as well as good repeatability and reproducibility. Experimental results show as small percentages of nanotubes improve the response to octane.Item Synthesis of dendrimer-carbon nanotube conjugates(2008-06) García, A.; Herrero, M. A.; Frein, S.; Deschenaux, R.; Muñoz, R.; Bustero, I.; Toma, F.; Prato, M.; PRINTEXWe describe the coupling between Carbon Nanotubes (CNTs) and a second-generation cyanophenyl-based dendrimer. The goal of our work is the synthesis of highly functionalized CNTs without provoking damage to the conjugated π-system. One approach is the attachment of dendrimers with a high density of functional groups to the CNTs. These groups serve as anchor points for further reactions. With this aim, we have carried out a primary modification on CNTs by the use of 1,3 dipolar cycloaddition reaction. We have employed Single Wall Carbon Nanotubes (SWNTs) as well as Multi Wall Carbon Nanotubes (MWNTs) obtaining 238 μmol and 511 μmol of pyrrolidine groups per gram, respectively. The amount of amino groups introduced in the system was measured by the Kaiser test as well as thermogravimetric analyses. As a second step, dendrimer incorporation was performed by carbodiimide chemistry. Thermogravimetric Analysis, Raman Spectroscopy and Atomic Force Microscopy characterization techniques are reported for the characterization of the final CNT-dendrimer conjugate. The results show that the dendrimer has been attached covalently to the previously generated amine groups. Morphologically, the attached dendrimer with an estimated theoretical molecular length of 6.4 um, generates a wrapping of 8 nm thick around the CNTs walls.Item Toxicogenomics study of nanomaterials on the model organism zebrafish(2007) Rojo, I.; Uriarte, M.; Obieta, I.; Bustero, I.; Egizabal, A.; Pardo, M. A.; De Martínez Ilárduya, O.; Tecnalia Research & Innovation; PRINTEX; BiomaterialesWe have adapted an "in vitro" toxicity test using zebrafish embryos for a toxicogenomics approach. Our goal is to develop a rapid toxicity assay for nanoparticles to be used in food and other applications. We incubated fertilized fish eggs for 48 h in the presence of a solution of purified MWCNT (1 ppb to 10 ppm) or with nanosilver solutions (1 ppb to 5 ppm). We could not detect effects on development or timing. We have used quantitative RT-PCR to analyze the expression patterns of Cyp1A1, Ahr2, Cpt1, iNOS, Ncf1, NudT1, c/EBP-a and MafT. These genes are involved in detoxification patterns, in the protection against oxidative stress or code for regulatory factors involved in the immune response. At these concentrations, nanosilver had clear effects on the expression of most of the genes in a dose dependant manner. Induction was maximum in the case of regulatory factors. On the contrary, changes in gene expression induced by MWCNTs were much lower, suggesting a reduced toxicity at the tested concentrations.Item XRD study of the effect of the processing variables on the synthesis of nanozirconia in the presence of MWCNT(2009-02) Garmendia, N.; Arteche, A.; García, A.; Bustero, I.; Obieta, I.; Mercado; PRINTEX; Tecnalia Research & InnovationSeveral challenges must be solved to obtain an effective introduction of carbon nanotubes in a ceramic matrix. Dispersion, good load transfer, and wettability are the major issues to be overcome to obtain good final properties of a zirconia nanocomposite. We have developed a process to coat multi-wall carbon nanotubes with nanozirconia to deal with these challenges. The process is based on the hydrothermal synthesis of tetragonal zirconia nanoparticles in the presence of multi-wall carbon nanotubes (MWCNT). In this work, X-ray diffraction has been used to study the influence of the processing variables in order to optimize this process. The theoretical mathematical models that relate the percentage of tetragonal zirconia and their crystallinity in relation to the processing variables have been extracted.Item Zirconia coating of carbon nanotubes by a hydrothermal method(2008-11) Garmendia, N.; Bilbao, L.; Muñoz, R.; Imbuluzqueta, G.; García, A.; Bustero, I.; Calvo-Barrio, L.; Arbiol, J.; Obieta, I.; PRINTEX; SISTEMAS FOTOVOLTAICOS; Tecnalia Research & InnovationCarbon nanotubes have unique mechanical properties that open attractive possibilities in many fields, such as the biomedical one. Currently, zirconia ceramics are widely used as femoral heads, but case studies show that delayed failure can occur in vivo due to crack propagation. Nanotubes could avoid the slow crack propagation and enhance the toughness of the ceramic material used for prostheses fabrication. In this work, single-wall carbon nanotubes and multi-wall carbon nanotubes have been partially coated with nanozirconia via hydrothermal synthesis and characterized by several techniques: X-ray diffraction, infrared spectroscopy, scanning electron microscope, transmission electron microscope, electron energy loss spectra, X-ray photoelectronic spectroscopy and atomic force microscopy. By means of these techniques, the existence of bonds between zirconium and the carbon nanotube has been proved. The as covered nanotubes should offer a better wettability in the ceramic matrix and improve the dispersion of the carbon nanotubes, to obtain the desired new ceramic biomaterial with a longer lifetime and better reliability.