Surface modification of multi-walled carbon nanotubes by a sol–gel reaction to increase their compatibility with PMMA resin

• Published in: Composites science and technology 2007-05, Vol.67 (6), p.1018-1026
• Main Authors: Wei, Hsiao-Fen, Hsiue, Ging-Ho, Liu, Chin-Yh
• Format: Article
• Language: English
• Subjects: A. Nanostructures; Applied sciences; B. Surface treatments surfaces; Composites; E. Sol–gel methods; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; Technology of polymers
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2006.06.005

The dispersion and the thermal characteristics of surface-modified MWNTs introduced into PMMA resin were investigated. The surface was modified by the chemical syntheses of a series of siloxane-containing compounds using acid-treated MWNTs through a sol–gel reaction. The acid-treatment was performed by ultrasonicating the pristine MWNTs in an HNO 3/H 2SO 4 solution. These new materials were characterized by FTIR, zeta potential measurement and SEM. The sol–gel products were negatively charged and could be easily dispersed in toluene and THF solvent. The surface-modified MWNT/PMMA composites were generated by ultrasonicating and the mechanical stirring of the sol–gel products with the PMMA resin. The dispersion effect was maximized by incorporating octyltriethoxysilane to acid-treated MWNT in the PMMA resin. The thermal stabilities of the MWNT-containing PMMA resins were determined by DSC and TGA. The T g values decreased as the content of the surface-modified MWNT increased, but the T d values were rose drastically from 207.7 to 271.7 °C. The marked improvements in thermal properties were attributed to the well dispersion of MWNTs that were bonded with organosilane chains on the surface.