| 摘要 |
The present invention relates to a method for preparing a carbon nanotube material, comprising the steps of: (a) preparing a modified montmorillonite by an ion exchange reaction comprising the substeps of: i) acidifying an alkylamine with equal mole of a concentrated HCl; ii) mixing the resulting acidified alkylamine with a montmorillonite dispersion in 1:1~2 volume ratio of the acidified alkylamine to the montmorillonite dispersion; and iii) precipitating, filtering and pulverizing to obtain a modified montmorillonite; (b) preparing a catalyst by a hydrogenation reduction method, comprising the substeps of: i) mixing an aqueous solution of nickel nitrate and an alumina-silica hybrid in a weight ratio of 35-45 parts of nickel to 55-65 parts of alumina-silica hydrid, wherein the alumina-silica hydrid contains 10 wt % of alumina and has a particle size of 10-30 mum; ii) drying and calcining the resulting product; and iii) reducing the product with a reducing gas containing hydrogen to produce a nickel-supported catalyst; (c) preparing a polyolefin mixture of a polyolefin, the modified montmorillonite prepared in step a) and the catalyst prepared in step b) in a mixer in the weight ratio of 75~97.5:0~20:0~5 provided that the amounts of the modified montmorillonite and the catalyst are not both 0; and (d) preparing and purifying a nanotube, comprising the substeps of: i) placing the polyolefin mixture obtained in step (c) in a crucible and heating the temperature inside crucible up to 550° C.~650° C., wherein the heating time begins from the burning of the polymer and ends when no flame can be observed and cooling the polyolefin mixture to obtain a mixture of carbon nanotube, nickel catalyst and montmorillonite; ii) adding a hydrofluoric acid with a concentration of 20-50% to the mixture, mixing, and separating to obtain a carbon powder; and iii) adding a mixture of a concentrated sulfuric acid and a concentrated nitric acid, refluxing, and separating to obtain a purified carbon nanotube. The carbon source material used in the present invention was polyolefin or recovered polyolefin whose price was low and whose source was abundant. The manufacturing facilities involved for preparing supported catalyst and modified montmorillonite were simple. The mixer used was that of the conventional fabricating equipment for polymeric materials while the facilities used for synthesizing carbon nanotube material were porcelain crucible and common flame. The method could simultaneously solve the problem of recovery and utilization of waste plastics.
|
