Preparación de nuevos nanocomposites multifuncionales de matriz epoxi basados en el empleo de materiales grafénicos
In this PhD Thesis, multifunctional epoxy matrix nanocomposite materials have been prepared and characterized, based on graphene related materials (GRMs). Four types of GRMs have been characterized by three different graphite exfoliation techniques: Liquid Phase Exfoliation (LPE) aiming to obtain t...
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Universidad de La Rioja (España)
2017
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In this PhD Thesis, multifunctional epoxy matrix nanocomposite materials have been prepared and characterized, based on graphene related materials (GRMs).
Four types of GRMs have been characterized by three different graphite exfoliation techniques: Liquid Phase Exfoliation (LPE) aiming to obtain two types of graphene with different lateral size; ultra-expansion of an intercalated compound, in this case a Stage I of GIC (graphite intercalation compound), producing a very high lateral size graphene; oxidation-exfoliation-reduction process to obtain a highly reduced graphene oxide.
By in situ polymerization, multifunctional nanocomposites have been successfully prepared owning a suitable combination of electrical, thermal and fire resistance properties, due to the incorporation of fire retardant reagents (FRs) and GRMs with synergistic effect. The key points to achieve good results have been the optimization of the dispersion processes at different loads and the composites processing.
Regarding GRMs, their presence in the epoxy resin involved structural and functional changes in the polymer as it could be verified through the characterization of the resulting nanocomposites. The crosslinking processes, thermal behaviour, electrical and thermal conductivity and flame retardancy of materials were defined by the chemical nature of the different types of GRMs studied as well as their interaction with the other loads and with the polymer. Among the graphene materials investigated, a multilayer pseudopristine graphene material obtained by intercalating the graphite was the most efficient to achieve a suitable degree of synergy with the CFRs (encapsulated fire retardant). This synergy makes possible to obtain the desired fire resistance, electrical and thermal conductivity using concentrations of 3%, and even lower in some cases.
Microencapsulations were studied for the flame retardant reagents aiming to partially reduce the water solubility and to improve the compatibility with the epoxy matrix, as it was proved by microstructural studies with SEM-EDX and the flammability test UL94 V; this improvement was obtained without causing problems in epoxy resin reticulation. Furthermore, the effect of CFRs in flame retardant properties of the epoxy resin implies very low auto-extinguishing times and high fire resistance, revealing a very effective interaction between CFRs and the polymer. The optimum levels of FRs for the composites were achieved for the four epoxy resin studied, using formulation of CFRs with concentrations between 10-17% (% in weight). |
| author2 |
Campos García, Pedro José (null) |
| author_facet |
Campos García, Pedro José (null) Garrido Martínez, Elena |
| format |
text (thesis) |
| author |
Garrido Martínez, Elena |
| spellingShingle |
Garrido Martínez, Elena Preparación de nuevos nanocomposites multifuncionales de matriz epoxi basados en el empleo de materiales grafénicos |
| author_sort |
Garrido Martínez, Elena |
| title |
Preparación de nuevos nanocomposites multifuncionales de matriz epoxi basados en el empleo de materiales grafénicos |
| title_short |
Preparación de nuevos nanocomposites multifuncionales de matriz epoxi basados en el empleo de materiales grafénicos |
| title_full |
Preparación de nuevos nanocomposites multifuncionales de matriz epoxi basados en el empleo de materiales grafénicos |
| title_fullStr |
Preparación de nuevos nanocomposites multifuncionales de matriz epoxi basados en el empleo de materiales grafénicos |
| title_full_unstemmed |
Preparación de nuevos nanocomposites multifuncionales de matriz epoxi basados en el empleo de materiales grafénicos |
| title_sort |
preparación de nuevos nanocomposites multifuncionales de matriz epoxi basados en el empleo de materiales grafénicos |
| publisher |
Universidad de La Rioja (España) |
| publishDate |
2017 |
| url |
https://dialnet.unirioja.es/servlet/oaites?codigo=122709 |
| work_keys_str_mv |
AT garridomartinezelena preparaciondenuevosnanocompositesmultifuncionalesdematrizepoxibasadosenelempleodematerialesgrafenicos |
| _version_ |
1718346664318599168 |
| spelling |
oai-TES00000228292018-05-13Preparación de nuevos nanocomposites multifuncionales de matriz epoxi basados en el empleo de materiales grafénicosGarrido Martínez, ElenaIn this PhD Thesis, multifunctional epoxy matrix nanocomposite materials have been prepared and characterized, based on graphene related materials (GRMs). Four types of GRMs have been characterized by three different graphite exfoliation techniques: Liquid Phase Exfoliation (LPE) aiming to obtain two types of graphene with different lateral size; ultra-expansion of an intercalated compound, in this case a Stage I of GIC (graphite intercalation compound), producing a very high lateral size graphene; oxidation-exfoliation-reduction process to obtain a highly reduced graphene oxide. By in situ polymerization, multifunctional nanocomposites have been successfully prepared owning a suitable combination of electrical, thermal and fire resistance properties, due to the incorporation of fire retardant reagents (FRs) and GRMs with synergistic effect. The key points to achieve good results have been the optimization of the dispersion processes at different loads and the composites processing. Regarding GRMs, their presence in the epoxy resin involved structural and functional changes in the polymer as it could be verified through the characterization of the resulting nanocomposites. The crosslinking processes, thermal behaviour, electrical and thermal conductivity and flame retardancy of materials were defined by the chemical nature of the different types of GRMs studied as well as their interaction with the other loads and with the polymer. Among the graphene materials investigated, a multilayer pseudopristine graphene material obtained by intercalating the graphite was the most efficient to achieve a suitable degree of synergy with the CFRs (encapsulated fire retardant). This synergy makes possible to obtain the desired fire resistance, electrical and thermal conductivity using concentrations of 3%, and even lower in some cases. Microencapsulations were studied for the flame retardant reagents aiming to partially reduce the water solubility and to improve the compatibility with the epoxy matrix, as it was proved by microstructural studies with SEM-EDX and the flammability test UL94 V; this improvement was obtained without causing problems in epoxy resin reticulation. Furthermore, the effect of CFRs in flame retardant properties of the epoxy resin implies very low auto-extinguishing times and high fire resistance, revealing a very effective interaction between CFRs and the polymer. The optimum levels of FRs for the composites were achieved for the four epoxy resin studied, using formulation of CFRs with concentrations between 10-17% (% in weight).En esta Tesis Doctoral se han preparado y caracterizado materiales compuestos nanoestructurados multifuncionales de matriz epoxi, basados en materiales derivados del grafeno (GRMs). Mediante el empleo de la polimerización in situ se han preparado con éxito nanocomposites multifuncionales empleando materiales grafénicos y resina epoxi como matriz, que presentan una combinación de propiedades eléctricas, térmicas y de resistencia al fuego, para lo que se han combinado con materiales retardantes de llama encapsulados (CFRs), debido a que los materiales grafénicos por si solos no han presentado retardancia a la llama. Los GRMs utilizados fueron preparados mediante tres técnicas diferentes de exfoliación del grafito y su presencia en la resina epoxi ha supuesto una serie de cambios estructurales y funcionales en el polímero, como pudo comprobarse a través de la caracterización de los nanocomposites resultantes. La naturaleza química de los distintos tipos de GRMs estudiados así como su interacción con el resto de cargas presentes y con el propio polímero han definido los procesos de reticulación, el comportamiento térmico, la conductividad eléctrica y térmica y la retardancia a la llama de los materiales multifuncionales obtenidos. Para los reactivos retardantes de llama se han desarrollado microencapsulaciones que han resultado eficaces para la reducción parcial de su solubilidad así como para lograr una buena compatibilidad con la matiz epoxi, como así lo demuestran los estudios microestructurales por SEM-EDX y los ensayos de inflamabilidad UL94 V con unos tiempos de auto-extinción muy bajos. Los nanocomposites obtenidos presentan una de los mayores aumentos en la conductividad térmica publicados en la literatura científica y nanocomposites con conductividad eléctrica mayor de 1 S/m, con bajo contenido en carga. También se han conseguido composites multifuncionales en los que el material que mejor comportamiento ha presentado es un multilayer de grafeno pseudoprístino obtenido mediante intercalación del grafito, presentando elevada conductividad térmica y eléctrica y la máxima clasificación en retardancia la llama, V0. Este tipo de GRM ha mostrado efectos sinérgicos con los CFRs, permitiendo aumentar la conductividad térmica hasta un 30% frente a la obtenida por el GRM/epoxi, lo que supone un aumento del 480% frente a la conductividad térmica que presenta el epoxi.Universidad de La Rioja (España)Campos García, Pedro José (null)Gómez Cordón, Julio (null)2017text (thesis)application/pdfhttps://dialnet.unirioja.es/servlet/oaites?codigo=122709spaLICENCIA DE USO: Los documentos a texto completo incluidos en Dialnet son de acceso libre y propiedad de sus autores y/o editores. Por tanto, cualquier acto de reproducción, distribución, comunicación pública y/o transformación total o parcial requiere el consentimiento expreso y escrito de aquéllos. Cualquier enlace al texto completo de estos documentos deberá hacerse a través de la URL oficial de éstos en Dialnet. 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