An underrated variable essential for tailoring the structure of xerogel: the methanol content of commercial formaldehyde solutions
Resorcinol-formaldehyde xerogels are polymers whose porosity can be designed for a specific application by the selection of appropriate physical and chemical synthesis variables. Until recently, the methanol content of commercial formaldehyde solutions has never been considered as a chemical variabl...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/152483 |
| Acceso en línea: | http://hdl.handle.net/10261/152483 |
| Access Level: | acceso abierto |
| Palabra clave: | Xerogel Formaldehyde Methanol Controlled porosity |
| Sumario: | Resorcinol-formaldehyde xerogels are polymers whose porosity can be designed for a specific application by the selection of appropriate physical and chemical synthesis variables. Until recently, the methanol content of commercial formaldehyde solutions has never been considered as a chemical variable that must also be taken into account. However, it has been demonstrated that the proportion of methanol might be even more important than other variables for tailoring the porosity of xerogels. Different reaction mechanisms are proposed to explain this heavy dependence of the final structure of RF xerogels. Organic and carbon xerogels synthesized with low concentrations of methanol showed a higher porosity with much larger pore sizes (up to two orders of magnitude) than when using formaldehyde with high concentrations of methanol. This means that extra caution needs to be shown in choosing these commercial products since formaldehyde solutions differ greatly in methanol content from one supplier to another. |
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