Asif Rasheed

Graduate Student, Department of Chemistry,

University of Tennessee

Current Research

Carbon nanotubes are well known for their excellent mechanical, electrical and thermal properties. Composites of polymer and carbon nanotube promise enhanced properties, however, nanotubes have to be well dispersed in the polymer matrix in order to achieve the desirable properties in the resulting composite. Dispersing nanotube into a polymer matrix however is a grand challenge due to the strong interaction that exists among nanotubes and as a result nanotubes often remain as aggregates in the host polymer.

Current research in our lab involves enhancing nanotube dispersion in polymer matrix by creating favorable interaction between the two components. The interaction between polymer and nanotube is expected to assist nanotube dispersion. The polymers used in this study are copolymers of styrene and vinylphenol (PSVPh) with varying amount of vinylphenol. These polymers are used to create composites with nanotubes with no chemical modification and after chemically modifying the nanotube by oxidative treatment (both MWNT and SWNT). The variation in polymer structure provides a systematic way to control and optimize the interaction between the polymer and nanotube.

Multi-walled Carbon Nanotubes/Polymer Composites

SEM of fractured surface of PSVPh20+5% oxidized MWNT

• Dynamic mechanical analysis shows improved mechanical properties for oxidized MWNT with PSVPh20 copolymer.
• SEM of fractured surface of the composite bar reveals improved dispersion of oxidized MWNT in PSVPh20

Recent Results on Single-walled Carbon Nanotubes/Polymer Composites

• Optical microscopy reveals aggregates of SWNT on all composite samples however, the aggregate size is significantly smaller for oxidized SWNT in PSVPh matrix, as measured by SIMAGIS research software for image analysis, indicating better dispersability of oxidized SWNT in the copolymer.
• Raman measurements show enhanced dispersion and better interaction of oxidized SWNT in PSVPh20 matrix.

PSVPh20+1% purified SWNT

PSVPh20+1% oxidized SWNT

The project is funded by Center for Nanophase Materials Science (CNMS) of Oak Ridge National Lab and NSF.

Presentations on this Project

• “Optimization of Hydrogen Bonding in Polymer Carbon Nanotube Nanocomposites”, APS (March 2004) Montreal, Canada
• “Polymer-Carbon Nanotube Composites: Enhancing Nanotube Dispersion by Oxidation”, Invited presentation at NanoSummit, hosted by Department of Energy, (June 2004) Washington D.C.
• “Enhanced Properties of Single-Walled Carbon Nanotubes-Poly(Styrene-co-vinylphenol) Nanocomposite by Hydrogen Bonding”, MRS (Nov29-Dec3 2004), Boston MA.
• “Controlling the Dispersion and Properties of Single-Walled Carbon Nanotube-Polymer Nanocomposite”, APS (March 2005) Los Angeles