Browsing by Keyword "Nanocomposites"
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Item The effect of nanosilica (SiO2) and nanoalumina (Al2O3) reinforced polyester nanocomposites on aerosol nanoparticle emissions into the environment during automated drilling(2017-05) Starost, Kristof; Frijns, Evelien; Van Laer, Jo; Faisal, Nadimul; Egizabal, Ainhoa; Elizetxea, Cristina; Nelissen, Inge; Blázquez, María; Njuguna, James; Biomateriales; POLIMEROSThe aim of this study is to investigate the effect nanosilica and nanoalumina has on nanoparticle release from industrial nanocomposites due to drilling for hazard reduction whilst simultaneously obtaining the necessary mechanical performance. This study is therefore specifically designed such that all background noise is eliminated in the measurements range of 0.01 particles/cm3 and ±10% at 106 particles/cm3. The impact nano-sized SiO2 and Al2O3 reinforced polyester has on nanoparticle aerosols generated due to drilling is investigated. Real-time measurement was conducted within a specially designed controlled test chamber using a condensation particle counter (CPC) and a scanning mobility particle sizer spectrometer (SMPS). The results show that the polyester nanocomposite samples displayed statistically significant differences and an increase in nanoparticle number concentration by up to 228% compared to virgin polyester. It is shown that the nanofillers adhered to the polyester matrix showing a higher concentration of larger particles released (between 20 – 100 nm). The increase in nanoparticle reinforcement weight concentration and resulting nanoparticle release vary considerably between the nanosilica and nanoalumina samples due to the nanofillers presence. This study indicates a future opportunity to safer by design strategy that reduces number of particles released concentration and sizes without compromising desired mechanical properties for engineered polymers and composites.Item Free-standing graphene films embedded in epoxy resin with enhanced thermal properties(2020-03) Bustero, Izaskun; Gaztelumendi, Idoia; Obieta, Isabel; Mendizabal, María Asun; Zurutuza, Amaia; Ortega, Amaya; Alonso, Beatriz; PRINTEX; POLIMEROS; Tecnalia Research & InnovationThe poor thermal conductivity of polymer composites has long been a deterrent to their increased use in high-end aerospace or defence applications. This study describes a new approach for the incorporation of graphene in an epoxy resin, through the addition of graphene as free-standing film in the polymeric matrix. The electrical and thermal conductivity of composites embedding two different free-standing graphene films was compared to composites with embedded carbon nanotube buckypapers (CNT-BP). Considerably higher thermal conductivity values than those achieved with conventional dispersing methods of graphene or CNTs in epoxy resins were obtained. The characterisation was complemented with a study of the structure at the microscale by cross-sectional scanning electron microscopy (SEM) images and a thermogravimetric analysis (TGA). The films are preconditioned in order to incorporate them into the composites, and the complete manufacturing process proposed allows the production and processing of these materials in large batches. The high thermal conductivity obtained for the composites opens the way for their use in demanding thermal management applications, such as electronic enclosures or platforms facing critical temperature loads.Item Furan resin as a replacement of phenolics: In fluence of the clay addition on its thermal degradation and fire behaviour(2014-10-01) Rivero, Guadalupe; Villanueva, Sara; Manfredi, Liliana B.; ECOEFICIENCIA DE PRODUCTOS DE CONSTRUCCIÓNNanocomposites based on a furan resin and different types of clays were obtained. Their thermal and fire behaviours were compared with traditional phenolic resins, which are known by their excellent flame resistance. Three types of montmorillonite clays were in situ added to the thermosetting matrix. A cone calorimeter and a smoke chamber were used to evaluate the performance of the materials against fire and their smokes generation. Global parameters were calculated for comparison purposes. Fires derived from the furan resin combustion grow faster than the phenolic ones, but they are extinguished more rapidly. This effect is enhanced by the incorporation of inorganic nanofillers. The only addition of any clay causes shorter fires but slightly speeds up the degradation process. A homogeneous nanofiller dispersion was found to be crucial to achieve good fire behaviour. Nevertheless, formaterials with similar dispersion, the crosslinking degree of the polymer matrix appears as a secondary factor that determines slighter differences in the performance. Nanocomposites with organomodified clays showed a quite similar fire performance, though the composite containing the clay (Southern Clay Products, Inc., Louisville, Ky, USA) Cloisite® 30B showed the best performance taking into account both the fire risk and the smoke evolution and obscuration.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 Influence of carbon chemical bonding on the tribological behavior of sputtered nanocomposite TiBC/a-C coatings(2010-07-30) Abad, M. D.; Sánchez-López, J. C.; Brizuela, M.; García-Luis, A.; Shtansky, D. V.; INGENIERÍA DE SUPERFICIES; TECNOLOGÍAS DE HIDRÓGENOThe tribological performance of nanocomposite coatings containing Ti-B-C phases and amorphous carbon (a-C) are studied. The coatings are deposited by a sputtering process from a sintered TiB2:TiC target and graphite, using pulsed direct current and radio frequency sources. By varying the sputtering power ratio, the amorphous carbon content of the coatings can be tuned, as observed by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The crystalline component consists of very disordered crystals with a mixture of TiB2/TiC or TiBxCy phases. A slight increase in crystalline order is detected with the incorporation of carbon in the coatings that is attributed to the formation of a ternary TiB xCy phase. An estimation of the carbon present in the form of carbide (TiBxCy or TiC) and amorphous (a-C) is performed using fitting analysis of the C 1s XPS peak. The film hardness (22 to 31 GPa) correlates with the fraction of the TiBxCy phase that exists in the coatings. The tribological properties were measured by a pin-on-disk tribometer in ambient conditions, using 6 mm tungsten carbide balls at 1 N. The friction coefficients and the wear rates show similar behavior, exhibiting an optimum when the fraction of C atoms in the amorphous phase is near 50%. This composition enables significant improvement of the friction coefficients and wear rates (μ ∼ 0.1; k < 1 × 10 -6 mm3/Nm), while maintaining a good value of hardness (24.6 GPa). Establishing the correlation between the lubricant properties and the fraction of a-C is very useful for purposes of tailoring the protective character of these nanocomposite coatings to engineering applications.Item Morphology and mechanical properties of poly(ethylene brassylate)/cellulose nanocrystal composites(2019-10-01) Butron, Amaia; Llorente, Olatz; Fernandez, Jorge; Meaurio, Emilio; Sarasua, Jose Ramon; BIOECONOMÍA Y CO2Poly(ethylene brassylate), a novel inexpensive biodegradable polyester, has been reinforced with cellulose nanocrystals (CNCs) with the aim of improving its thermal stability and mechanical properties. The composites have been characterized through calorimetry, tensile tests, thermogravimetry and electron microscopy. The addition of small amounts of CNCs improves both the stiffness and the ductility of the composites, suggesting the existence of some compatibilizing effect. Adding large CNC amounts increases the Young modulus (e.g., 150% for 50 wt% CNCs), but now the material shows brittle behavior. Degradation of the CNCs starts at lower temperature suggesting mutual reactivity. The SEM analysis of the composites with ductile behavior reveals the formation of a percolating network crossing through the interconnected domains that conform a PEB-rich continuous phase. Processing consisting on reinforcement dispersion by sonication followed by melt processing results in composites in which the improvement of mechanical properties does not involve any trade-off.Item Novel Antibacterial and Toughened Carbon-Fibre/Epoxy Composites by the Incorporation of TiO2 Nanoparticles Modified Electrospun Nanofibre Veils(2019-09-01) Monteserín, Cristina; Blanco, Miren; Murillo, Nieves; Pérez-Márquez, Ana; Maudes, Jon; Gayoso, Jorge; Laza, Jose Manuel; Hernáez, Estíbaliz; Aranzabe, Estíbaliz; Vilas, Jose Luis; Tecnalia Research & Innovation; PRINTEX; Caracterización y Validación. MecánicosThe inclusion of electrospun nanofiber veils was revealed as an effective method for enhancing the mechanical properties of fiber-reinforced epoxy resin composites. These veils will eventually allow the incorporation of nanomaterials not only for mechanical reinforcement but also in multifunctional applications. Therefore, this paper investigates the effect of electrospun nanofibrous veils made of polyamide 6 modified with TiO2 nanoparticles on the mechanical properties of a carbon-fiber/epoxy composite. The nanofibers were included in the carbon-fiber/epoxy composite as a single structure. The effect of positioning these veils in different composite positions was investigated. Compared to the reference, the use of unmodified and TiO2 modified veils increased the flexural stress at failure and the fracture toughness of composites. When TiO2 modified veils were incorporated, new antibacterial properties were achieved due to the photocatalytic properties of the veils, widening the application area of these composites.Item Polyfire project- an example of an industrial research project promoting safe industrial production of fire-resistant nanocomposites(2011) Vaquero-Moralejo, Celina; López de Ipiña, J.M.; Galarza, N.; Hargreaves, B.; Weager, B.; Breen, C.; Tecnalia Research & InnovationNew developments based on nanotechnology have to guarantee safe products and processes to be accepted by society. The Polyfire project will develop and scale-up techniques for processing halogen-free, fire-retardant nanocomposite materials and coatings based on unsaturated polyester resins and organoclays. The project includes a work package that will assess the Health and Environmental impacts derived from the manipulation of nanoparticles. This work package includes the following tasks: (1) Identification of Health and Environment Impacts derived from the processes, (2) Experimentation to study specific Nanoparticle Emissions, (3) Development of a Risk Management Methodology for the process, and (4) A Comparison of the Health and Environmental Impact of New and Existing Materials. To date, potential exposure scenarios to nanomaterials have been identified through the development of a Preliminary Hazard Analysis (PHA) of the new production processes. In the next step, these scenarios will be studied and simulated to evaluate potential emissions of nanomaterials. Polyfire is a collaborative European project, funded by the European Commission 7th Framework Programme (Grant Agreement No 229220). It features 11 partners from 5 countries (5 SMEs, 3 research institutes, 2 large companies, 1 association) and runs for three years (1st September 2009 – 31st August 2012). This project is an example of an industrial research development which aims to introduce to the market new products promoting the safe use of nanomaterials.Item Polyfire project-an example of an industrial research project promoting safe industrial production of fire-resistant nanocomposites(2011) Vaquero, C.; De Ipĩa, J. López; Galarza, N.; Hargreaves, B.; Weager, B.; Breen, C.; PRINTEX; SMART_MONNew developments based on nanotechnology have to guarantee safe products and processes to be accepted by society. The Polyfire project will develop and scale-up techniques for processing halogen-free, fire-retardant nanocomposite materials and coatings based on unsaturated polyester resins and organoclays. The project includes a work package that will assess the Health and Environmental impacts derived from the manipulation of nanoparticles. This work package includes the following tasks: (1) Identification of Health and Environment Impacts derived from the processes, (2) Experimentation to study specific Nanoparticle Emissions, (3) Development of a Risk Management Methodology for the process, and (4) A Comparison of the Health and Environmental Impact of New and Existing Materials. To date, potential exposure scenarios to nanomaterials have been identified through the development of a Preliminary Hazard Analysis (PHA) of the new production processes. In the next step, these scenarios will be studied and simulated to evaluate potential emissions of nanomaterials. Polyfire is a collaborative European project, funded by the European Commission 7th Framework Programme (Grant Agreement No 229220). It features 11 partners from 5 countries (5 SMEs, 3 research institutes, 2 large companies, 1 association) and runs for three years (1st September 2009 - 31st August 2012). This project is an example of an industrial research development which aims to introduce to the market new products promoting the safe use of nanomaterials.Item Slip casting of nanozirconia/MWCNT composites using a heterocoagulation process(2009-07) Garmendia, Nere; Santacruz, Isabel; Moreno, Rodrigo; Obieta, Isabel; Tecnalia Research & InnovationThe addition of carbon nanotubes (CNTs) is expected to increase the fracture toughness of ceramic matrix composites, but an uniform dispersion of the nanotubes in the matrix is essential. This is a complex issue in aqueous medium because of the nanotubes hydrophobicity. In this work, the stability and rheological behaviour of nanozirconia concentrated suspensions, from 20 to 33 vol% solids, with and without multiwall carbon nanotubes (MWCNTs) was optimised in order to obtain homogeneous green samples by slip casting. The manufacture of nanozirconia/MWCNTs composites was performed using a heterocoagulation process in which the CNTs were homogeneously coated by the ceramic particles through strong electrostatic attractive forces between the two phases and further consolidation by a slip casting route. After sintering, the effect of the MWCNT on the hardness and fracture toughness of the nanostructured zirconia samples was evaluated.Item Zirconia-multiwall carbon nanotubes dense nano-composites with an unusual balance between crack and ageing resistance(2011-06) Garmendia, N.; Grandjean, S.; Chevalier, J.; Diaz, L. A.; Torrecillas, R.; Obieta, I.; Tecnalia Research & InnovationYttria stabilized zirconia (Y-TZP) ceramics are used in a wide variety of applications, such as orthopaedic and dental implants. Y-TZP offers indeed a unique combination of biocompatibility and mechanical properties (high crack resistance for a ceramic). However, the major drawback of Y-TZP is their lack of stability: zirconia is prone to ageing, especially under humid atmosphere. Increasing the ageing resistance of Y-TZP led so far to a decrease of toughness and crack resistance. Here we show that the addition of a small volume fraction of multiwall carbon nanotubes (MWCNT) in a polycrystalline nano-structured Y-TZP sintered under specific conditions (Spark Plasma Sintering) leads to a material exhibiting a balance between ageing and crack resistance never reached before.