Soluble polythiophenes as anticorrosive additives for marine epoxy paints

This study compares the resistance against corrosion of a marine epoxy primer modified with Zn-3(PO4)(2) (10 wt%) or a small concentration (0.3 wt%) of conducting polymer (CP) as inorganic or organic anticorrosive pigment, respectively. More specifically, the behavior of three different CPs has been evaluated: polyaniline (PAni) emeraldine base, poly(3-thiophen-3-yl-acrylic acid methyl ester) and poly(2-thiophen-3-yl-malonic acid dimethyl ester), the latter two being soluble polythiophene (PTh) derivatives bearing carboxylate side groups. In a first stage, the structural, thermal, and mechanical properties of all the modified epoxy coatings were characterized using infrared spectroscopy, thermogravimetric analyses and stress-strain assays, respectively. After this, accelerated corrosion assays have evidenced that the degree of protection imparted by a small concentration of PAni is higher than that obtained using 10wt% of Zn-3(PO4)(2). Indeed, PAni has been found to be more effective as anticorrosive additive than the two PTh derivatives. This fact has been attributed to the electroactivity of the former, which is higher than that of the latter. Thus, the ability to store charge has been proposed to be also responsible of protection against corrosion imparted by organic additives, based on CPs.Peer ReviewedPostprint (author’s final draft

Puzzle-Pro: aplicación de la técnica en clases de problemas

En el presente trabajo se muestran las experiencias de aplicación de una técnica de aprendizaje cooperativo en una asignatura de quinto curso de la titulación de Ingeniería Química. La asignatura se llama “Diseño de Equipos e Instalaciones” y se imparte en la Escuela Técnica Superior de Ingenieros Industriales de Barcelona. En la asignatura de “Diseño de Equipos e Instalaciones” se ha aplicado una variante de la técnica del puzzle (rompecabezas) de Elliot Aronson (1978), denominada puzzle para problemas o puzzle-pro. Esta técnica fue desarrollado por Joan Domingo y Maria Pilar Almajano y ya ha sido aplicada en otras asignaturas como son la de “Enlace y Estructura” y “Química II”, dos asignaturas de primer curso de Ingeniería Química e Ingeniería Industrial, respectivamente. El PUZZLE-PRO es una técnica que se puede emplear en cualquier asignatura, es una técnica muy motivadora para profesores y alumnos y las claves de éxito están garantidas. La metodología, los consejos para emplear la técnica y los resultados obtenidos se muestran en la comunicación completa.Postprint (published version

Preparation, surface characterization ans anticorrosive behavior of polynailine and poly(3,4-ethylenedioxythiophene) deposited on aluminum alloy AA2024-T3

Peer ReviewedPostprint (author's final draft

Electrical and chapacitive response of hydrogel solid-like electrolytes for supercapacitors

Flexible hydrogels are attracting significant interest as solid-like electrolytes for energy storage devices, especially for supercapacitors, because of their lightweight and anti-deformation features. Here, we present a comparative study of four ionic conductive hydrogels derived from biopolymers and doped with 0.1 M NaCl. More specifically, such hydrogels are constituted by κ-carrageenan (κC), carboxymethyl cellulose (CMC), poly-γ-glutamic acid (PGGA) or a phenylalanine-containing polyesteramide (PEA). After examining the morphology and the swelling ratio of the four hydrogels, which varies between 483% and 2356%, their electrical and capacitive behaviors were examined using electrochemical impedance spectroscopy. Measurements were conducted on devices where a hydrogel film was sandwiched between two identical poly(3,4-ethylenedioxythiophene) electrodes. The bulk conductivity of the prepared doped hydrogels is 76, 48, 36 and 34 mS/cm for PEA, PGGA, κC and CMC, respectively. Overall, the polyesteramide hydrogel exhibits the most adequate properties (i.e., low electrical resistance and high capacitance) to be used as semi-solid electrolyte for supercapacitors, which has been attributed to its distinctive structure based on the homogeneous and abundant distribution of both micro- and nanopores. Indeed, the morphology of the polyestermide hydrogel reduces the hydrogel resistance, enhances the transport of ions, and results in a better interfacial contact between the electrodes and solid electrolyte. The correlation between the supercapacitor performance and the hydrogel porous morphology is presented as an important design feature for the next generation of light and flexible energy storage devices for wearable electronics.Postprint (published version

Structural polymorphism in poly(3-ethyl-3-phenyl-2-azetidinone)

The structural characterization of chiral nylon-3 derivative, poly (3-ethyl-3-phenyl-2- azetidinone) (PEPA) has been carried out using FTIR, thermal analysis, X-ray diffraction and electron microscopy. X-ray diffraction of power and fiber samples were analyzed together with electron diffraction patterns of single crystals obtained from isothermal crystallization in solution. Two different crystalline forms were found in accordance with DSC traces, FTIR spectra and X-ray diffraction diagrams. Electron microscopy corroborates the morphological and crystallographic differences between both crystalline forms. Molecular modeling was applied to characterize the two crystalline forms, which were related to different conformation and consequent space symmetry into the crystal unit cellPeer ReviewedPostprint (published version

Structural polymorphism in poly(3-ethyl-3-phenyl-2-azetidinone)

The structural characterization of chiral nylon-3 derivative, poly (3-ethyl-3-phenyl-2- azetidinone) (PEPA) has been carried out using FTIR, thermal analysis, X-ray diffraction and electron microscopy. X-ray diffraction of power and fiber samples were analyzed together with electron diffraction patterns of single crystals obtained from isothermal crystallization in solution. Two different crystalline forms were found in accordance with DSC traces, FTIR spectra and X-ray diffraction diagrams. Electron microscopy corroborates the morphological and crystallographic differences between both crystalline forms. Molecular modeling was applied to characterize the two crystalline forms, which were related to different conformation and consequent space symmetry into the crystal unit cellPeer Reviewe

Corrosion experiments in metals and alloys. Comparison between field and laboratory tests: a research work in high school degree

The aim of this work is to show the experimental results corresponding to comparative corrosion studies carried out with five commercially pure different metals (iron, lead, zinc, aluminum, and copper) together with the alloy stainless steel 316. Field tests were performed in two different environments. The first, urban environment was represented by a zone corresponding to metropolitan area of Barcelona (Spain). The second environment, a marine environment, was selected on the coast line of the same metropolitan area. The time corresponding to field tests was a half year and the subsequent results were compared with laboratory accelerated tests from robotized equipment, chosen to simulate urban and marine environments, by using aqueous sodium hydrogen sulphite and sodium chloride solutions, respectively. Equivalent time between both field and accelerated tests has been obtained. The results allow a good correlation between both types of exposures and make it possibleto study morphological and quantitative aspects of corrosion process, as well as the influence of different variables that influence the corrosion resistance of each metal and alloy. The main feature of this work is the collaboration between high school students and university faculty , to illustrate, by active participation, the concept of “research work”, in the second year of high school, just before beginning their higher education studies.Postprint (published version

Corrosion experiments in metals and alloys. Comparison between field and laboratory tests: a research work in high school degree

The aim of this work is to show the experimental results corresponding to comparative corrosion studies carried out with five commercially pure different metals (iron, lead, zinc, aluminum, and copper) together with the alloy stainless steel 316. Field tests were performed in two different environments. The first, urban environment was represented by a zone corresponding to metropolitan area of Barcelona (Spain). The second environment, a marine environment, was selected on the coast line of the same metropolitan area. The time corresponding to field tests was a half year and the subsequent results were compared with laboratory accelerated tests from robotized equipment, chosen to simulate urban and marine environments, by using aqueous sodium hydrogen sulphite and sodium chloride solutions, respectively. Equivalent time between both field and accelerated tests has been obtained. The results allow a good correlation between both types of exposures and make it possibleto study morphological and quantitative aspects of corrosion process, as well as the influence of different variables that influence the corrosion resistance of each metal and alloy. The main feature of this work is the collaboration between high school students and university faculty , to illustrate, by active participation, the concept of “research work”, in the second year of high school, just before beginning their higher education studies

Diseño de equipos e instalaciones

El libro está dirigido a técnicos de las industrias de la producción y del mantenimiento de instalaciones, a estudiantes de ingeniería y de ciencias de los materiales, y en general, a todos aquellos profesionales preocupados para combatir el deterioro prematuro que ocasiona la corrosión y vitar la pérdida económica que presenta. En el capítulo 1 se dan unas reflexiones sobre la forma en que hay que diseñar instalaciones sujetas a ambientes agresivos. En los capítulos 2, 3, 4 y 5 se estudian los efectos de la corrosión sobre diferentes materiales (aceros inoxidables, aluminio, níquel, titanio, materiales refractarios, plásticos) y las formas de prevenirla así como los criterios para escoger el más adecuado para cada ambiente. En el capítulo 6 aborda el diseño de aparatos, en especial los aparatos a presión y las uniones (soldaduras, adhesivos, juntas, bridas). En el capítulo 7 se exponen, de forma resumida, los diferentes métodos de inspección de materiales, resaltando los métodos no destructivos. Por último, dada la función docente de la obra, se incluyen unas preguntas de síntesis, unos problemas y prácticas

Diseño de equipos e instalaciones

El libro está dirigido a técnicos de las industrias de la producción y del mantenimiento de instalaciones, a estudiantes de ingeniería y de ciencias de los materiales, y en general, a todos aquellos profesionales preocupados para combatir el deterioro prematuro que ocasiona la corrosión y vitar la pérdida económica que presenta. En el capítulo 1 se dan unas reflexiones sobre la forma en que hay que diseñar instalaciones sujetas a ambientes agresivos. En los capítulos 2, 3, 4 y 5 se estudian los efectos de la corrosión sobre diferentes materiales (aceros inoxidables, aluminio, níquel, titanio, materiales refractarios, plásticos) y las formas de prevenirla así como los criterios para escoger el más adecuado para cada ambiente. En el capítulo 6 aborda el diseño de aparatos, en especial los aparatos a presión y las uniones (soldaduras, adhesivos, juntas, bridas). En el capítulo 7 se exponen, de forma resumida, los diferentes métodos de inspección de materiales, resaltando los métodos no destructivos. Por último, dada la función docente de la obra, se incluyen unas preguntas de síntesis, unos problemas y prácticas