abstract
Monolithic mechanically reinforced CNTs-silica aerogel composites have been successfully synthesized by two-step sol-gel methodology using methyltrimethoxysilane as the main silica precursor, combined with an eco-friendly ethanol/water mixture as solvent, and dried at ambient pressure. For an effective linkage of the carbon nanotubes with the silica network, the CNTs were submitted to a silanization treatment. With this approach, the chemical binding between the two phases takes place, with the silica particles following the elongated shape of CNTs, which leads to an improvement of the mechanical properties, with Young's modulus up to 201.5 kPa, when compared to the corresponding silica aerogel counterpart without CNTs (104.9 kPa). Moreover, the developed materials show high porosities (up to 95.8%), low densities (as low as 61.3 kg m(-3)), good thermal insulation performance of 31.2-44.1 mW m(-1) K-1 and superhydrophobic character. The significant improvements regarding physical and mechanical properties make these composite aerogels attractive for several applications, ranging from thermal insulators to adsorbents.
keywords
CARBON NANOTUBE; THERMAL-CONDUCTIVITY; MECHANICALLY STRONG; RAMAN-SPECTROSCOPY; FTIR SPECTROSCOPY; NITROGEN SORPTION; METHYLTRIMETHOXYSILANE; ADSORPTION; MICROSTRUCTURE; GRAPHITE
subject category
Chemistry; Science & Technology - Other Topics; Materials Science
authors
Lamy-Mendes, A; Girao, AV; Silva, RF; Duraes, L
our authors
Alyne Cristina Lamy Mendes
PhD Student
Ana Violeta Girão
Junior Researcher
Rui Ramos Ferreira e Silva
Associate Professoracknowledgements
Alyne Lamy-Mendes acknowledges CNPq (Brazil) for the funding of the PhD fellowship project 234184/2014-0/GDE, under the programme Ciencia sem Fronteiras. The authors also would like to thank to CIEPQPF research unit (Coimbra) funded by FEDER funds through the Operational Programme for Competitiveness Factors - COMPETE and National Funds, through FCT - Foundation for Science and Technology, Portugal, under the project POCI-01-0145-FEDER-006910 (FCT Ref. UID/EQU/00102/2013). Ana Violeta Giran is thankful for funding by national funds (OE), through FCT - Fundacao para a Ciancia e a Tecnologia, I.P., Portugal, in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. This work was also developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), funded by national funds through the FCT/MEC (Portugal) and when appropriate co-financed by FEDER (EU) under the PT2020 Partnership Agreement.