La fecha del entremés de Los habladores.

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Avellaneda no es Passamonte

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Comedia del viaje del Hombre.

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Bis(sulfonil)etilenos cíclicos como aceptores efectivos en reacciones asimétricas de Michael

[EUS] El trabajo de fin de grado aquí presentado se ha realizado en el departamento de Química Orgánica I de la Facultad de Química de San Sebastián bajo la supervisión del Dr. Aitor Landa Álvarez. En este trabajo se estudia el alcance de las reacciones asimétricas de Michael entre las N1-acil-1H-imidazol-4(5H)-onas y las diferentes vinil bis(sulfonas) promovidas por catalizadores orgánicos bifuncionales. Hemos observado que las vinil bis(sulfonas) abiertas β-sustituidas no son eficaces para llevar a cabo las adiciones. Por el contrario, los bis(sulfonil)etilenos cíclicos han resultado ser unos excelentes aceptores de Michael, proporcionando los correspondientes aductos con excelentes rendimientos y diastereo- y enantioselectividades[ENG] The end of degree work presented here has been carried out in the Department of Organic Chemistry I of the Faculty of Chemistry of San Sebastian under the supervision of Dr. Aitor Landa Álvarez. This work describes some Michael additions between N1-acyl-imidazole-4(5H)- ones and different vinyl bis(sulfones) promoted by a bifunctional organic catalyst. We have observed that open β-substituted vinyl bis(sulfones) are not effective Michael acceptors in that kind of reactions, in contrast to bis(sulfonyl)ethylenes, which have proved to be so effective, providing excellent yields as well as diastereo- enantioselectivitie

Remembranza de don Joaquín de Entrambasaguas en su centenario

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Flexible Biocomposites with Enhanced Interfacial Compatibility Based on Keratin Fibers and Sulfur-Containing Poly(urea-urethane)s

Feathers are made of keratin, a fibrous protein with high content of disulfide-crosslinks and hydrogen-bonds. Feathers have been mainly used as reinforcing fiber in the preparation of biocomposites with a wide variety of polymers, also poly(urea-urethane)s. Surface compatibility between the keratin fiber and the matrix is crucial for having homogenous, high quality composites with superior mechanical properties. Poly(urea-urethane) type polymers are convenient for this purpose due to the presence of polar functionalities capable of forming hydrogen-bonds with keratin. Here, we demonstrate that the interfacial compatibility can be further enhanced by incorporating sulfur moieties in the polymer backbone that lead to new fiber-matrix interactions. We comparatively studied two analogous thermoplastic poly(urea-urethane) elastomers prepared starting from the same isocyanate-functionalized polyurethane prepolymer and two aromatic diamine chain extenders, bis(4-aminophenyl) disulfide (TPUU-SS) and the sulfur-free counterpart bis(4-aminophenyl) methane (TPUU). Then, biocomposites with high feather loadings (40, 50, 60 and 75 wt %) were prepared in a torque rheometer and hot-compressed into flexible sheets. Mechanical characterization showed that TPUU-SS based materials underwent higher improvement in mechanical properties than biocomposites made of the reference TPUU (up to 7.5-fold higher tensile strength compared to neat polymer versus 2.3-fold). Field Emission Scanning Electron Microscope (FESEM) images also provided evidence that fibers were completely embedded in the TPUU-SS matrix. Additionally, density, thermal stability, and water absorption of the biocomposites were thoroughly characterized.This work was supported by KaRMA2020 project. This project has received funding from the European Union’s Horizon 2020 Research and Innovation program under Grant Agreement n 723268

Fully Biodegradable Biocomposites with High Chicken Feather Content

The aim of this work was to develop new biodegradable polymeric materials with high loadings of chicken feather (CF). In this study, the effect of CF concentration and the type of biodegradable matrix on the physical, mechanical and thermal properties of the biocomposites was investigated. The selected biopolymers were polylactic acid (PLA), polybutyrate adipate terephthalate (PBAT) and a PLA/thermoplastic copolyester blend. The studied biocomposites were manufactured with a torque rheometer having a CF content of 50 and 60 wt %. Due to the low tensile strength of CFs, the resulting materials were penalized in terms of mechanical properties. However, high-loading CF biocomposites resulted in lightweight and thermal-insulating materials when compared with neat bioplastics. Additionally, the adhesion between CFs and the PLA matrix was also investigated and a significant improvement of the wettability of the feathers was obtained with the alkali treatment of the CFs and the addition of a plasticizer like polyethylene glycol (PEG). Considering all the properties, these 100% fully biodegradable biocomposites could be adequate for panel components, flooring or building materials as an alternative to wood–plastic composites, contributing to the valorisation of chicken feather waste as a renewable material.This work was supported by KaRMA2020 project. This project has received funding from the European Union’s Horizon 2020 Research and Innovation program under Grant Agreement n° 723268