Abstract
The high purity fluffy SWNT ball was synthesized through the floating catalyst method in a horizontal tube furnace. Ignition and photoacoustic effects of SWNT ball due to flash exposure were investigated. Acoustic wave accompanied with formation of Fe2SiO4 particles was detected. This phenomenon can be further verified as rapid expansion of surrounding air and carbon oxidation. Ferrocene on fluffy SWNT ignited after flashing, which indicates that the surface temperature of carbon nanotubes after flashing exceeds burning temperature of ferrocene. It also found that the appearance of Fe2SiO4 was related to the existence of iron catalyst. Depending on the catalyst amount in SWNTs, the fluffy ball may ignite or oxidize, according to the response of carbon nanocapsules after flash exposure. The acoustic intensity of fluffy SWNT ball is stronger than that of other carbon materials such as MWNT, carbon fiber, carbon powders etc. Based on the results, it is concluded that the structure transformation of fluffy ball is due to the photoacoustic effect. Moreover, this work established a vertical tube furnace to synthesize the SWNTs with large scale production rate, and a production rate high up to 200 mg/10 min can be achieved. This one dimension SWNT rope can be applied to composite and reinforced materials in the future.