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Spectroscopic study of polymer composite material based on functionalized carbon nanotubes and characterization of individual carbon nanotubes for composites synthesis
2009 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

In this work high-resolution confocal Raman spectroscopy and spectral imaging technique along with supporting methods (scanning electron microscopy (SEM), focused ion beam (FIB) and atomic force microscopy (AFM)) were used for extensive characterization of different carbon nanotube-based systems. Single-wall (SWCNT) and double-wall carbon nanotubes (DWCNT) which are used for synthesis of novel composite materials were studied in bundled and individ-ual (debundled) state. The protocol which we set up earlier [1] was successfully applied for de-bundling of HipCO-produced single-wall carbon nanotubes and DWCNTs in aqueous solution of sodium dodecylbenzene sulfonate (SDBS). CNT individualization was detected by Raman spectroscopy and verified in (AFM) experiment. Change in resonance Raman conditions due to laser induced heating – change in spectra profile of radial breathing modes and a red-shift of tangential vibrational modes (G-band) - was studied in both bundled and individualized CNT samples. As expected, these effects were far less pro-nounced for the individualized (debundled) CNTs. Laser heating studies on DWCNTs revealed similar changes in the resonance Raman spectra. More importantly, the effect was manifested by both outer and inner shells (tubes). Spectroscopic (Raman) imaging technique was used for extended characterization of composite material comprised of functionalized arc-discharge-produced SWCNTs in a polymethylmetacry-lat (PMMA) matrix. Raman spectroscopy showed that carbon nanotubes are only partially dispersed in the polymer matrix – CNT agglomerates (clusters) of different size and shape were present. Employment of different laser excitation energies (1.96eV and 2.33eV) allowed to probe separately the distribution of metallic and semiconducting CNTs in the composite samples. The results demonstrated better dispersion of the metallic CNTs which have higher degree of functionalization. Laser heating experiments on the CNT-PMMA composites exhibit different behavior of the CNTs in the polymer matrix and in aggregates (clusters). The latter were substantially more sensitive to laser irradiation thus acting as heat absorbers. FIB technique was used for direct study of the composites microstructure by acquisition of SEM crossectional images taken directly in a cluster as well as in a matrix area for direct proof of different local CNT concentrations.

Place, publisher, year, edition, pages
Keyword [en]
Technology, CNT, carbon nanotubes, SWCNT, DWCNT, SWNT, DWNT, composite, PMMA, Raman spectroscopy, AFM, FIB, Laser heating
Keyword [sv]
URN: urn:nbn:se:ltu:diva-55833ISRN: LTU-PB-EX--09/040--SELocal ID: ca546fb4-3196-410a-a6f7-08fcd12b70d4OAI: diva2:1029217
Subject / course
Student thesis, at least 30 credits
Educational program
Materials Engineering, master's level
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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