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El objeto de la invención es una composición que contiene como principio activo ácido monocloroacético (MCA), en disolución con etanol (50% en volumen), preparado según un procedimiento que se describe, empleado para el tratamiento químico sistemático de la verruga plantar (papilomavirus humano plantar), sin cirugía, produciendo su cauterización química., Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (España), B1 Patente sin examen previo

This paper examines the polymerization of acrylonitrile to poly(acrylonitrile)(PAN), and its cyclization, in bulk form and using N,N-dimethylformamide (DMF) as solvent in which both monomer and polymer are soluble. Thermal analysis of the resultant products after polymerization has been performed by DSC and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). Scanning electron microscopy has been used to study the morphology of the resultant products and after thermal treatments. The DSC thermal curve of PAN-DMF sample is quite different from the PAN bulk sample, showing a single sharp exothermic peak associated with nitrile group polymerization (cyclization) of PAN at lower temperature (240°C) than that of bulk PAN sample (314°C). Cyclization of PAN was confirmed by IR spectroscopy. It was found that the amide molecules are difficult to eliminate completely in the product obtained after the polymerization reaction, even after prolonged heating at 110°C, and remain occluded. The formation of a complex by dipolar bonding is also possible and it is discussed. It is concluded that the amount of heat evolved as well as the temperature interval over which it is released are influenced by the chemical processing of PAN when using DMF as solvent of both monomer and polymer. Pyrolysis of these PAN samples revealed the release of occluded molecules of DMF, and several compounds containing nitrogen produced from the thermal degradation processes. All these results are interesting to know the chemical processing of carbon fibres and activated carbon fibres from PAN modified precursors.

The polymerization of acrylonitrile to polyacrylonitrile (PAN) has been studied using several solvents: N,N-dimethylformamide (DMF), hexane, toluene, water, and in bulk form (no solvent). The addition of DMF is the only case where both monomer and polymer are soluble in the solvent. Thermal analyses of the resultant products after polymerization have been performed by differential scanning calorimetry and pyrolysis–gas chromatography: mass spectrometry. The effect of the solvents employed as media for polymerization is interpreted from the results of the thermal and structural (X-ray diffraction) methods. The polymer samples obtained when using water or toluene as solvents have the greater content of amorphous components compared to the others. The amide molecules are difficult to completely eliminate in the product obtained after the polymerization reaction and even after prolonged heating at 110°C and remain occluded. DMF can be considered to exert a plasticized effect on PAN and is even capable of forming complexes by dipolar bonding. As a result of this interaction, the thermogram is quite different from the other samples studied in the present work, showing a single sharp exothermic peak. This is associated with nitrile group polymerization (cyclization) of PAN. It is deduced that the amount of heat evolved as well as the temperature interval over which it is released are influenced by the chemical processing of PAN, in particular when using DMF as solvent for both monomer and polymer. Pyrolysis of the different PAN samples revealed the release of occluded solvent molecules, mainly when using DMF, and compounds produced from the thermal degradation processes. Different types of cyclized compounds, such as pyridine derivatives and aromatic nitriles were identified. All these compounds could be derived from cyclized PAN structures which are not completely degraded by the thermal treatment of pyrolysis. Alkyldinitriles have also been tentatively identified associated with the final molecular breakdown of cyclized structures with six-member rings by pyrolysis. Valuable complementary information on the structure of the PAN samples (homopolymer) obtained using the different processing approaches involving several solvent media has been provided by pyrolysis. The present results will improve our understanding of the evolution of the structure and properties of carbon and activated carbon fibres which will enable us to establish processing strategies in order to obtain these materials under adequate and reproducible conditions.

Desde su creación en el año 1986, en el Instituto de Ciencia de Materiales de Sevilla se viene desarrollando una línea de investigación denominada “síntesis y preparación de nuevos materiales a partir de silicatos naturales”. Dentro de este campo específico se enmarca la presente Tesis Doctoral, en la que se realiza un estudio sobre la síntesis de materiales cerámicos avanzados mediante la reducción carbotérmica de vermiculita.Se consideranmateriales cerámicos avanzados aquellos compuestos inorgánicos policristalinos, no metálicos, consolidados mediante tratamiento térmico a alta temperatura y que poseen excelentes propiedades mecánicas, eléctricas, magnéticas, ópticas, o bien, excepcional resistencia a altas temperaturas y ambientes corrosivos.Lareduccióncarbotérmica es uno de los métodos de preparación de materiales cerámicos avanzados más utilizados en la industria y consiste en el tratamiento de un compuesto oxidado a alta temperatura, generalmente entre 1300 ºC y 1700 ºC, en una atmósfera controlada y en presencia de un reductor. Existen numerosos ejemplos en la bibliografía en los que se utiliza este métodos, utilizando como materiales primas sílice, alúmina o silicatos.La presente Tesis Doctoral tiene como objetivo el estudio del proceso de la reducción carbotérmica devermiculita, la cual no se había usado con anterioridad en este tipo de reacciones.Teniendo en cuenta la composición de la vermiculita, como se ha mencionado formada por silicio, aluminio, magnesio, hierro, oxígeno e hidrógeno, los productos que cabe esperar se obtengan al final del proceso son:nitruros de silicio, nitruros de aluminio, oxinitruros de silicio y aluminio (sialones) y carburos de silicio. De estos compuestos, así como de la vermiculita y del poliacrilonitrilo, se ha realizado una minuciosa revisión bibliográfica, con anterioridad al desarrollo del trabajo experimental, con el propósito de tener una base a partir de la cual avanzar en las investigaciones objeto de la Tesis.De acuerdo con lo expuesto anteriormente, cabe destacar que las innovaciones que se investigan dentro del objetivo general de la presente Tesis Doctoral son:- Estudio de la evolución térmica de la vermiculita hasta una temperatura de 1400 ºC, para conocer sus transformaciones y servir de referencia para tratamientos posteriores.- Estudio del tratamiento mecánico realizado sobre la vermiculita en molino de anillos, para investigar el efecto de la molienda en el silicato y su influencia en la reactividad.- Preparación del complejo de intercalación de vermiculita con poliacrilonitrilo, para conseguir el máximo grado de interacción ente la red del silicato y la cadena carbonada.- Utilización de la vermiculita en una reacción de reducción carbotérmica en atmósfera controlada, para estudiar la síntesis de los materiales avanzados que puedan obtenerse.