Zamudio, Spain
Zamudio, Spain

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Ruiz J.,Gaiker Technology Center | Ruiz J.,University of the Basque Country | Gonzalo B.,Gaiker Technology Center | Dios J.R.,Gaiker Technology Center | And 3 more authors.
Advances in Polymer Technology | Year: 2013

Polyaniline (PANI) is one of the most widely used conductive polymers because of its ease of synthesis in addition to its good electrical properties. However, the difficulty in its processability limits its potential applications. In this work, conductive emeraldine salt (i.e., one of the different oxidation states of PANI) was synthesized by oxidative chemical polymerization. Different techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and dynamical mechanical thermal analysis were used to characterize the synthesized PANI. The processability of PANI has been improved by processing it, both by compression and extrusion methods, with different thermoplastic matrices such as polycaprolactone and polybutylene terephthalate. The obtained compounds have not only better processability but also improved thermal and mechanical properties. However, their conductivity decreases with respect to PANI, to a greater extent, for the compounds synthesized by the extrusion method. © 2012 Wiley Periodicals, Inc.


Garcia-Huete N.,Basque Center for Materials | Laza J.M.,University of the Basque Country | Cuevas J.M.,Gaiker Technology Center | Vilas J.L.,Basque Center for Materials | And 2 more authors.
Radiation Physics and Chemistry | Year: 2014

A gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical, chemical and mechanical properties. Gamma irradiation originates free radicals able to induce chain scission or recombination of radicals, which induces annihilation, branching or crosslinking processes. The aim of this work is to research the structural, thermal and mechanical changes induced on a commercial polycyclooctene (PCO) when it is irradiated with a gamma source of 60Co at different doses (25-200kGy). After gamma irradiation, gel content was determined by Soxhlet extraction in cyclohexane. Furthermore, thermal properties were evaluated before and after Soxhlet extraction by means of Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC), as well as mechanical properties were measured by Dynamic Mechanical Thermal Analysis (DMTA). The results showed the variations of the properties depending on the irradiation dose. Finally, a first approach to evaluate qualitatively the shape memory behaviour of all irradiated PCO samples was performed by a visually monitoring shape recovery process. © 2014 Elsevier Ltd.


Cuevas J.M.,Gaiker Technology Center | Rubio R.,Gaiker Technology Center | Laza J.M.,University of the Basque Country | Vilas J.L.,University of the Basque Country | And 2 more authors.
Smart Materials and Structures | Year: 2012

The mechanical response of a series of semicrystalline shape memory polymers was considerably enhanced by incorporating short glass fibres without modifying the thermo-responsive actuation based on balanced crystallinity and elasticity. The effect of different fractions of inorganic reinforcement on thermo-mechanical properties was evaluated using different instrument techniques such as differential scanning calorimetry (DSC), thermogravimetry (TGA), dynamic mechanical thermal analysis (DMTA) and three-point flexural tests. Moreover, we studied the inorganic reinforcement influence on the shape memory actuation capabilities by thermo-mechanical bending cycle experiments. As demonstrated, the manufactured polymer composites showed excellent shape memory capacities, similar to neat active polymer matrices, but with outstanding improvements in static and recovering mechanical performance. © 2012 IOP Publishing Ltd.


Cuevas J.M.,Gaiker Technology Center | Laza J.M.,University of the Basque Country | Rubio R.,Gaiker Technology Center | German L.,Gaiker Technology Center | And 2 more authors.
Smart Materials and Structures | Year: 2011

A series of thermo-responsive shape memory polymers were developed from commercially available polyalkenamer by balancing competitive crystallinity and elasticity via a monofunctional peroxide based crosslinking process. The main thermomechanical and shape memory properties of covalently crosslinked samples were characterized using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamical-mechanical-thermal analysis (DMTA), flexural mode stress-strain tests and thermomechanical bending experiments. The obtained semi-crystalline polymer networks were characterized by shape memory activation temperatures from - 10 to 60 °C and shape recovery ratios from 95 to 100% by adjusting the melting temperatures and elasticity through a controlled density of covalent knots along the polymeric network from an accurate peroxide fraction. © 2011 IOP Publishing Ltd.


Cuevas J.M.,Gaiker Technology Center | Rubio R.,Gaiker Technology Center | German L.,Gaiker Technology Center | Laza J.M.,University of the Basque Country | And 3 more authors.
Soft Matter | Year: 2012

Triple-shape memory polymers are developed by blending and crosslinking two semicrystalline polymers (poly(cyclooctene), PCO, and polyethylene, PE) towards creating two pronounced segregated crystalline domains within a covalently crosslinked network. The key thermo-mechanical properties of a series of a polyalkenamer and a polyolefin based polymer blends are characterised using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). Furthermore, the versatile multi-shape memory functionality is demonstrated, and main shape memory response is evaluated by performing consecutive thermo-mechanical bending experiments based on a two-step programming process and subsequent progressive thermal recovery. The proposed approach, thanks to the excellent achieved shape memory properties, as well as the possibility of tailoring the thermo-mechanical response, is presented as a versatile method to increase the potential applications of these thermo-active materials by designing optimal compositions. © 2012 The Royal Society of Chemistry.


Garcia-Huete N.,Basque Center for Materials | Laza J.M.,University of the Basque Country | Cuevas J.M.,Gaiker Technology Center | Gonzalo B.,Gaiker Technology Center | And 2 more authors.
Journal of Polymer Research | Year: 2014

Self-repair properties based on shape-memory features of covalently crosslinked semi-crystal line polyalkenamers were demonstrated by thermal-activated recovery of performed surface marks (indented holes and scratches). Shape memory polymers were prepared by mixing a commercial polycyclooctene (PCO) with different percentages of peroxide, and then these mixtures were processed by compression moulding to obtain crosslinked sheets. With the aid of a hardness test pencil, holes and scratches in the surface of the materials were realized with different known forces (5, 10 and 15 N). The disappearance of surface defects was evaluated using both optical and contact surface profilometry, as well as optical microscopy under heating processes. This technique allowed evaluating shape recovery ratios of edgewise holes in PCO samples. In parallel, the analysis of maximum depth of indentations with temperature for edgewise samples by optical microscopy allows evaluating shape recovery. As a complementary tool for analysing thermal shaperecovery and surface resistance to indentation, thermal properties and hardness were investigated by DSC and Shore durometer test, respectively. © Springer Science+Business Media Dordrecht 2014.


Lucero M.L.,Faes Farma S.A. | Gonzalo A.,Faes Farma S.A. | Mumford R.,Charles River Laboratories | Betanzos M.,Gaiker Technology Center | Alejandro A.,Gaiker Technology Center
Drug and Chemical Toxicology | Year: 2012

Knowledge of the biotransformation of oral H1 antihistamines is clinically important because it can define their pharmacokinetic profile through possible effects on absorption (i.e., first-pass metabolism) and elimination. Further, clinically significant interactions with inhibitors of cytochrome P450 (CYP) have previously been reported for drugs of this therapeutic group, such as terfenadine and astemizole, indicating the possibility of drug-drug interactions involving agents that share the same metabolic pathway. The aim of this article was to review the preclinical testing of a new antihistamine (i.e., bilastine) in terms of its biotransformation in various animal species, including humans, and to evaluate its potential for possible drug-drug interactions involving the CYP system. A wide array of preclinical experiments were reviewed, all of which demonstrated that bilastine undergoes minimal metabolism in all species tested to date, including humans. Further, bilastine did not interact significantly, either as an inhibitor or inducer, with the CYP enzyme system, suggesting a low propensity for involvement in drug-drug interactions. These characteristics demonstrate the potential for bilastine to be a good choice for allergic patients receiving treatment for other concomitant diseases, including those with renal or hepatic dysfunction. © 2012 Informa Healthcare USA, Inc.


Arnandis-Chover T.,Polytechnic University of Valencia | Morais S.,Polytechnic University of Valencia | Tortajada-Genaro L.A.,Polytechnic University of Valencia | Puchades R.,Polytechnic University of Valencia | And 3 more authors.
Talanta | Year: 2012

A DNA oligonucleotide array for duplex pathogen detection on a DVD platform is developed. The assay involves hybridization of PCR products and optical detection using compact disc technology. Different DNA array constructions for attachment of synthetic oligonucleotides on to DVD surface are evaluated, finding that streptavidin-biotin coupling method yielded the highest sensitivity in combination with enzymatic signal amplification. Issues of importance for the DNA array construction such immobilized probes design, PCR product labeling strategy and composition of the hybridization buffer were addressed. The methodology was proved scoring single nucleotide polymorphisms with high selectivity. The assay capability was also demonstrated by the identification of two pathogenic microorganisms in powder milk samples. In fifty minutes, the DVD-array system identifies Salmonella spp. and Cronobacter spp. (previously named Enterobacter sakazakii) precise and simultaneously with a sensitivity of 100 and 102 cfu/mL, respectively, in infant milk. Results were in good agreement with those obtained by quantitative real-time PCR. © 2012 Elsevier B.V. All rights reserved.


Urkiaga A.,Gaiker Technology Center | Iturbe D.,Gaiker Technology Center | Etxebarria J.,Gaiker Technology Center
Desalination and Water Treatment | Year: 2015

Polysulfone ultrafiltration membranes have been widely applied, especially for water and wastewater treatment. Polysulfone as membrane material presents several advantages, such as good mechanical properties, high thermal and chemical resistance, processing easiness, and wide availability in the market. However, the hydrophobic nature of the polysulfone membrane leads to a low water flux and increases the proneness to organic fouling. In order to overcome this problem, the effect of different additives and polymer concentration on the performance and morphology of polysulfone flat sheet membranes, prepared by phase inversion process, were investigated in this work. Several experimental sets were performed. The effect of polyvinylpyrrolidone to increase the pore density and membrane permeability was confirmed. Moreover, the effect of lithium chloride to reduce the amount of macrovoids in the membrane and to increase the viscosity of the casting solution was also confirmed. The fabricated membranes were characterized by atomic force microscopy, scanning electron microscopy, and infrared spectroscopy (ATR-IR). Furthermore, water permeability, retention tests to evaluate the molecular weight cut-off, and the real thickness of the prepared membranes as well as viscosity of the casting solutions were measured. © 2015 Balaban Desalination Publications. All rights reserved.


Urkiaga A.,Gaiker Technology Center | Iturbe D.,Gaiker Technology Center | Etxebarria J.,Gaiker Technology Center | Agirre E.,Gaiker Technology Center
Desalination and Water Treatment | Year: 2015

Membrane fouling is still the greatest handicap to overcome in membrane bioreactor (MBR) technology. In this study, a multi-factorial experimental design was carried out in order to optimize the MBR process, studying the effect of major variables involved in the fouling phenomenon as well as the interaction between them. To that end, a submerged membrane bioreactor was operated at three different levels of: sludge retention time (SRT) [25 and 60 d], mixed liquor suspended solids (MLSS) [6 and 14 g/L], and ratio between soluble and particulate chemical oxygen demand (sCOD/pCOD) [1 and 4] in the wastewater. The concentration of extracellular polymeric substances (EPS), as one of the most relevant factor responsible for membrane fouling, and the permeate flux were measured. After an exhaustive statistical analysis, it was confirmed that there is a relationship between the concentration of EPS and membrane fouling. It also appears that the ratio sCOD/pCOD in the composition of the wastewater plays a very important role in the fouling which becomes less pronounced as the soluble fraction increases. Moreover, high fouling potential was observed at high SRT values. Finally, it was proved that the membrane fouling was slightly less pronounced at higher MLSS concentration. © 2015 Balaban Desalination Publications. All rights reserved.

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