resumo
Carbon nanostructures-silica aerogel composites were synthesized and characterized to assess the effect of carbon nanotubes (CNTs) or graphene oxide (GO) on the silica aerogel properties. The sol-gel chemistry was based on methyltrimethoxysilane (MTMS) and 3-aminopropyltrimethoxysilane (APTMS) as silica precursor system, with varying amounts of APTMS (0-20% mol of Si). APTMS significantly impacted the materials' physical properties. The chemistry and microstructure were investigated by FTIR, NMR, TEM, SEM, SAXS and BET. The addition of CNTs induced the growth of the silica matrix around them; thus, an elongated shape was observed in the silica structural units. APTMS and CNTs have a synergistic effect on the mechanical properties, increasing the Young's modulus up to 14 MPa. Small amounts of carbon materials (similar to 1 wt%) in the MTMS-matrix improved its thermal insulation property, particularly for temperatures above 50 degrees C. In terms of electrochemical properties, the carbon nanostructures lead to higher specific capacitances and a reduction in resistance. The characterizations here performed allowed a better understanding of the interactions between the silica and carbon phases. The possibility to obtain materials with tailored properties demonstrates their application potential in several areas, such as thermal insulation and energy storage. (C) 2021 Elsevier Ltd. All rights reserved.
palavras-chave
HIGH-SURFACE-AREA; GRAPHENE-OXIDE; THERMAL-CONDUCTIVITY; POLYMETHYLSILSESQUIOXANE AEROGELS; MECHANICAL-PROPERTIES; NANOTUBE; NANOCOMPOSITES; SPECTROSCOPY; ELECTRODES; XEROGELS
categoria
Chemistry, Physical; Materials Science, Multidisciplinary
autores
Lamy-Mendes, A; Malfait, WJ; Sadeghpour, A; Girao, AV; Silva, RF; Duraes, L
nossos autores
Alyne Cristina Lamy Mendes
Estudante de doutoramento
Ana Violeta Girão
Investigador Júnior
Rui Ramos Ferreira e Silva
Professor associadoagradecimentos
Alyne LamyMendes acknowledges CNPq (Brazil) for the funding of the PhD fellowship project 234184/20140/GDE, under the programme Ciencia sem Fronteiras and the COST Action AERoGELS (CA18125) for the ShortTerm Scientific Mission (STSM) Grant. Ana Violeta Girao is thankful for funding by national funds (OE) , through FCT Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the DecreeLaw 57/2016, of August 29, changed by Law 57/2017, of July 19. This work was developed within the scope of the projects CICECO Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, and CIEPQPF Chemical Process Engineering and Forest Products Research Centre projects POCI-01-0145-FEDER-006910 and UID/EQU/00102/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. We thank Daniel Rentsch for access to the NMR spectrometer, which was funded in part by grant SNF-150638 from the Swiss National Science Foundation. We also thank Dr. Goreti Sales for the sharing of CV and EIS equipment and Dr. Ana Moreira for the support in the electrochemical measurements.