Understanding the silylation reaction of multi-walled carbon nanotubes

• Type: Article in International Scientific Journal
• Date: 2011

Authors

Gaspar, H (Author) Other; Pereira, C (Author) FCUP; Rebelo, SLH (Author) FCUP; Pereira, MFR (Author) FEUP; Figueiredo, JL (Author) FEUP; Freire, C (Author) FCUP

Journal

Title: Carbon

Vol. 49

Pages: 3441-3453

ISSN: 0008-6223

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 55 Citations

Scopus - 55 Citations

Scientific classification

FOS: Engineering and technology > Materials engineering

Other information

Authenticus ID: P-002-NJE

DOI: 10.1016/j.carbon.2011.04.041

Abstract (EN): Functional organosilanes were appended, in aprotic and anhydrous conditions, onto multi-walled carbon nanotubes (MWCNTs) previously submitted to three different oxidative treatments: acid, acid with subsequent thermal treatment at 400 degrees C and 5% O(2)/N(2) treatment at 500 degrees C. The materials were characterised by X-ray photoelectron spectroscopy, elemental analysis, temperature programmed desorption, Fourier transform infrared spectroscopy, thermogravimetry, nitrogen adsorption isotherms at -196 degrees C and scanning electron microscopy. The techniques provided a correlation between the type and oxygen contents present in the oxidised MWCNTs and the silylation reaction efficiency, leading to a comprehensive overview of the reaction mechanism and materials structure/composition. The highest silylation reaction efficiencies were achieved with the aminosilane in all the oxidised materials and with mercaptosilane in the acid oxidised MWCNTs with nearly 4% Si insertion, whereas for the other organosilanes values lower than 2% were observed. The silylation mechanism was found to proceed through reaction of the alkoxy moieties from the organosilane with phenol surface groups from the MWCNTs; in the case of aminosilane for all MWCNTs and mercaptosilane in acid oxidised MWCNTs, it also occurred by reaction with the carbonyl surface groups. Furthermore, for these latter materials a polymerisation side-reaction was proposed as a parallel functionalisation pathway.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13