Synthesis of Carbon Nanotubes from Polymers by using Chemical Vapor Deposition-Fluidized Bed Reactor
| Autor: | Ming-de Huang, 黃銘德 |
|---|---|
| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 CNTs formed by one layer or the multi-layer graphite are a special hollow structure. It’s made by pure carbon so that it’s in charge of having light weight, high surface area, high thermal conductivity, high strength, and such chemistry, machinery and excellent characteristics of photoelectricity as the electric conductivity is good. Because it has interesting properties, it is extensive studied and nowadays become one of the hottest nano-materials. There are few ways at present to synthesize CNTs by arc discharge, laser ablation and chemical vapor deposition, but unable a large amount of continual production. But the fluidized-bed reactor has possessed the advantage transmitted in high-mass transmission and heat and can operate and produce in a large amount in succession. It is successful to synthesize CNTs by fluidized-bed reactor in literatures. And using polymers to synthesize CNTs has already had a successful instance in literatures. So this research is drafted with the polymers, for instance: The polycarbosilane (PCS) and the polyethylene (PE) regard as the carbon source that the carbon is in charge of growing up and mixing the MgO powder with the Fe2O3 regards as catalyst. Regard the fluidized-bed reactor designed by oneself as the experimental device and find out the optimal parameters for operation such as temperature, weight ratio of catalyst and polymer or flow rate to synthesize CNTs. Properties of CNTs were examined by scanning electron microscope (SEM), transmission electron microscope (TEM), high resolution TEM (HRTEM) and Raman spectrum. It is successful to synthesize CNTs in the fluidized-bed reactor by using the polymer as the carbon source. CNTs were synthesized by using the parameter of PE as the carbon source, Fe2O3/MgO as catalyst, weight ratio of catalyst and polymer is 1:3, upper temperature is 750 ℃, lower temperature is 850 ℃, 10 %H2 + 90 %Ar as the carrying gas, flow rate is 400 cc/min and reaction time is 1 hour. The diameter is 40-60 nm and the length is longer than 1μm. The value of ID/IG of CNTs is 0.88. Although there is a few CNTs, the major production is fiber-like by using the parameter of PCS as the carbon source, Fe2O3/MgO as catalyst, weight ratio of catalyst and polymer is 1:3, upper temperature is 850 ℃, lower temperature is 950 ℃, 10 %H2 + 90 %Ar as the carrying gas, flow rate is 400 cc/min and reaction time is 1 hour. The value of ID/IG of CNTs is 1.19. The graphitized of CNTs prepared by using PE as the carbon source is better than that prepared by using PCS as the carbon source. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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