Daniel Garcia-Garcia

The effect of maleinized linseed oil (MLO) on mechanical performance of poly(lactic acid)-thermoplastic starch (PLA-TPS) blends

In this work, poly(lactic acid), PLA and thermoplastic starch, TPS blends (with a fixed content of 30wt.% TPS) were prepared by melt extrusion process to increase the low ductile properties of PLA. The TPS used contains an aliphatic/aromatic biodegradable polyester (AAPE) that provides good resistance to aging and moisture. This blend provides slightly improved ductile properties with an increase in elongation at break of 21.5% but phase separation is observed due to the lack of strong interactions between the two polymers. Small amounts of maleinized linseed oil (MLO) can positively contribute to improve the ductile properties of these blends by a combined plasticizing-compatibilizing effect. The elongation at break increases over 160% with the only addition of 6phr MLO. One of the evidence of the plasticizing-compatibilizing effect provided by MLO is the change in the glass transition temperature (Tg) with a decrease of about 10°C. Field emission scanning electron microscopy (FESEM) of PLA-TPS blends with varying amounts of maleinized linseed oil also suggests an increase in compatibility.

Corrosion Resistance and Galvanic Coupling of UNS N08031 Base Metal, Heat-Affected Zone, and Weld Metal in Phosphoric Acid at Different Temperatures

Abstract Open-circuit potential tests and potentiodynamic anodic polarization curves have been carried out to obtain information about the electrochemical behavior of a highly alloyed austenitic stainless steel (UNS N08031) used as base metal (BM), heat-affected zone (HAZ) region, and weld metal (WM). The weld was performed using the gas tungsten arc welding technique (GTAW) with a nickel-based alloy (UNS N06059) as filler metal. The galvanic corrosion generated by the electrical contact between the base metal, the HAZ, and the weld metal was estimated from the polarization diagrams according to the mixed potential theory. The objective of the present work was to study the effect of the solution temperature on the corrosion resistance of the studied materials. These materials were tested in 5.5 M phosphoric acid (H3PO4) solution at 25°C, 40°C, 60°C, and 80°C. Results demonstrated that materials passivated spontaneously in the studied solution and their corrosion resistance decreased with temperature.

Manufacturing and Characterization of Composite Fibreboards with Posidonia oceanica Wastes with an Environmentally-Friendly Binder from Epoxy Resin

Highly environmentally-friendly fibreboards were manufactured by hot-press moulding using Posidonia ocaeanica wastes and a partially biobased epoxy resin as binder. Fibreboards with a constant fibre content of 70 wt % were successfully manufactured by thermo-compression. The effects of a conventional alkali treatment were compared to the synergistic effects that additional silanization with two silanes (amino and glycidyl) can exert on the mechanical and thermo-mechanical properties of fibreboards. The results revealed a remarkable improvement of the mechanical properties with the combination of the alkali treatment followed by the silanization. Scanning electron microscopy also revealed increased resin-fibre interactions due to the synergistic effect of both amino- and glycidyl-silanes. These fibreboards represent a formaldehyde-free solution and can positively contribute to sustainable development as the lignocellulosic component is a waste and the binder resin is partially biobased.

Incorporación de la aplicación Kahoot! para la evaluación de las prácticas de la asignatura de “Ciencia de Materiales”

Resumen Durante la realizacion de las practicas de laboratorio de la asignatura de “Ciencia de Materiales” en el Grado de Ingenieria Quimica se ha incorporado el uso de la aplicacion multiplataforma Kahoot! para su evaluacion. Con la incorporacion de esta aplicacion se consigue incrementar la atencion del alumno de forma efectiva y dinamica durante el desarrollo de las mismas. Ademas la aplicacion permite tanto la participacion individual como el debate entre los propios alumnos de manera dinamica y entretenida, mejorando la colaboracion y la atencion del alumno en el transcurso de las practicas. Con la implementacion de la aplicacion multiplataforma Kahoot! se fomenta la atencion y participacion del alumnado en las clases practicas de una forma muy efectiva. Palabras clave: gamificacion, metodologia, aplicaciones, Kahoot!, juego, competicion, formacion, evaluacion, dispositivo movil.