Reinforced silica-carbon nanotube monolithic aerogels synthesised by rapid controlled gelation
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This work introduces a new synthesis procedure for obtaining homogeneous silica hybrid aerogels with carbon nanotube contents up to 2.50 wt.%. The inclusion of nanotubes in the highly porous silica matrix was performed by a two-step sol–gel process, resulting in samples with densities below 80 mg/cm3. The structural analyses (N2 physisorption and SEM) revealed the hierarchical structure of the porous matrix formed by nanoparticles arranged in clusters of 100 and 300 nm in size, specific surface areas around 600 m2/g and porous volumes above 4.0 cm3/g. In addition, a relevant increase on the mechanical performance was found, and an increment of 50% for the compressive strength and 90% for the maximum deformation were measured by uniaxial compression. This reinforcement was possible thanks to the outstanding dispersion of the CNT within the silica matrix and the formation of Si–O–C bridges between nanotubes and silica matrix, as suggested by FTIR. Therefore, the original synthesis procedure introduced in this work allows the fabrication of highly porous hybrid materials loaded with carbon nanotubes homogeneously distributed in the space, which remain available for a variety of technological applications.
KeywordsSilica hybrid aerogel Carbon nanotube Controlled gelation Structure Reinforcement Mechanical properties.
Dr. Miguel Castillo is acknowledged for their wise advises and original ideas. Mr. Alejandro Jurado-Jiménez is acknowledged for his contributions to the starting of this work during his stage at our laboratory. Dr. Alberto Santos and Mr. José Francisco Hidalgo Ramírez are acknowledged for their help in the experimental setup. The technical staff of the characterisation services of the CITIUS (Universidad de Sevilla) is also acknowledged. J.A.D.F. thanks the grant from VI Plan Propio de la Universidad de Sevilla for 'starting researchers', M.V.R.P. thanks the 'Programa de contratación de personal técnico de apoyo a la I+D+I 2017' from the Junta de Andalucía (Spain) and V.M.F thanks the postdoctoral grant from the 'V Plan Propio de la Universidad de Sevilla'. This work has been financed by the support of the Junta de Andalucía (Spain) to the research group TEP-115 (Spain) and by the 'Plan Propio de Investigación (I.5 Ayudas uso SGI)' of the Universidad de Sevilla.
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Conflict of interest
The authors declare that they have no conflict of interest.
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