| Summary: | 碩士 === 國立清華大學 === 材料科學工程學系 === 97 === In this work, we studied the optimization of the growth parameters for synthesizing high quality fluffy single-walled carbon nanotubes in a vertically hot-walled furnace using the floating catalyst method. Taguchi analytical method was used to set the processing parameters by L18 orthogonal array. The ID/IG ratios of the Raman spectrum was selected as the quality index of the as-synthesized SWCNTs, and the optimum condition of the seven parameters could be determined. Furthermore, the quantitated contribution of the processing parameters could be obtained by performing the analysis of variance (ANOVA). Although almost all the seven parameters affect the growth of SWCNTs, the reaction temperature and the sublimation temperature of ferrocene influence the quality most obviously. The furnace pressure seems to be of minor importance to the quality compared with the other factors. The SWCNT fluff synthesized using the optimized parameters achieved superior quality (the ID/IG ratio was 0.02), which was similar to the predicted results using the Taguchi method.
Moreover, we produced CNT long strand using the optimized parameters. In-situ observation was recorded with a digital camera to find a growth mechanism of the CNT long strand. The CNT long strand was longer than 30 cm with about 0.8 cm in width. FE-SEM and Raman spectrum revealed that it was mainly composed of single-walled CNT bundles with well alignment.
|
|---|
