A process has been developed for growing polymer chains via anionic, cationic, or radical polymerization from the side walls of functionalized carbon nanotubes, which will facilitate greater dispersion in polymer matrices, and will greatly enhance reinforcement ability in polymeric material.
Aryl bromide functionalized carbon nanotubes are dispersed in 5-mL tetrahydrofuran (THF), and a solution of nbutyllithium (5 mL, 2.19 M in hexane) was added at 23 °C, and the solution stirred for 10 min. The stirring was then turned off, and the nanotubes were allowed to settle out of solution. After settling, the excess n-butyllithium solution was removed from the reaction vessel via cannula, and the nanotubes were washed three times with dry THF (10 mL) to remove traces of n-butyllithium.
The flask was then charged with dry THF (10 mL), and the tubes were dispersed in solution with rapid stirring. Styrene (1.7 mL, 15 mmol) was added to the reaction vessel, and the mixture was stirred for 180 min before adding ethanol (1 mL) or a function terminator of choice such as trimethylsilyl chloride. The mixture was then diluted with 100 mL dichloromethane, and filtered through Fisherbrand P8 filter paper to remove any large particulates. The filtrate was concentrated under reduced pressure and precipitated into methanol. The resulting gray powder was then collected by filtration, using Whatman 451 filter paper and dried under vacuum (0.1 mm) to a constant weight (typically 0.100–1.00 g, depending on the precise amount of styrene added). This material can then be blended with other polymers, or can be molded and used by itself as a specialty material.
This work was done by James M. Tour and Jared L. Hudson of Rice University for Johnson Space Center. For further information, contact the JSC Innovation Partnerships Office at (281) 483-3809.
In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to: